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                          A
                 COMPENDIUM
                       OF THE

             A  N  A  T  O MY

                       OF THB

               HUMAN BODY.
INTENDED PRINCIPALLY FOR THE USE OF STUDENTS.

           " BY ANDREW J^YFE.
IN	TWO VOLUMES.	
	—~«-.::-	
	VOL.	II.
              This Edition is prefixed with
      A Compendious History  of Anatomy^

                     And the
           Ruyschian Art and  Method

Of making Preparations  to exhibit the Structure of the
   Human Body, illujirated with a Reprefcntation of the
      Quicksilver  Tray and its Appendages,
                 k
          JVb'tch are not in the London Ed





PRINTED AND SOLD  BY JAMES
      At the N.W. Corner of Walnut and Dock-ftreets.
ISO J, 
 
A
COMPENDIUM
ANATOMY
HUMAN  BODY.
• <3><
INTENDED PRINCIPALLY FOR THE USE
           OF STUDENTS.
By  ANDREW FYFE
IN TWO VOLUMES
pfiilafcelpfiia:
PRINTED AND SOLD BY JAMES HUMPHREYS,
   At the N. W. Corner of Walnut and Dock-ftreets.
1802. 
 
PART   IV.
■O'
OF THE
VISCERA,
AND
ORGANS  OF THE SENSES.
                    ----«0»>---


         OF  THE  COMMON  INTEGUMENTS. "

                     The Cuticle.

     THE Cuticle, Epidermis, or Skarf-Skin,  is a thin  femitranf-
      parent infenfible Membrane, which covers  the  Skin, and
adheres to it by fmall Vafcular Filaments.
  The Cuticle is readily  feparated  from the Cutis by boiling
water, or by putrefaction, and in  the living body, by the appli-.
cation of bliiiers.
  It is  not every  where of the fame denfity, being even in the
Foetus,  thickeft in  the Palms and  Soles; in which  parts, the
thicknds is afterwards much increafed by peeiTure.
  The External Surface is marked  by  Furroivs, which corref-
pond with thpfe in the Cutis Vera.
  Upon the Surface of the Body  it is perforated by  the termina-
tion cf  the Exhalent VefTels,—which thiow out the Perfpirable
Muter,  and which,  when increafed, is confidered by moftofthe
modern Phyllologilrs, as  forming the  Sweat ;—by the ends of
the Excretory Duc^s, which are found in particular parts of the
Skin ;—by the beginnings of the Abforbents, which  take  in
certain  Subftances applied to the Surface of the Skin ; and—by
the different Hairs. 
4
  The Perforations, or Pores, are moft evident upon the Palms
and Soles,  and upon the Nofe, Ears, and external parts ot  Ge-
neration.
  The Cuticle covers the Skin through its  whole extent,.excep-
ting under  the Nails.
  From the External Surface of the  Body, it  is refleSed in-
njuards, to line the large Paflages; as the Alimentary Canal, the
Trachea, the Urethra, Vagina, &c.
  In thefe  Paflages, however, the Cuticle becomes lefs uniform
in its texture 3 and  in fome of them,  as in  the Stc?/iacb, is either
awanting, or is fo much changed in ftrucluie, as to have the ap-
pearance of being fo.
  From the Surface of the Cuticle,  certain Proccffes are fent
into the Skin, which line the Paflages by which the Cutis is per-
forated.
  Many  opinions have been advanced concerning the  origin of
the Cuticle :—the lateft and moft  probable  is,  that it  is formed
by a condenfction of the Corpus Mucofum, or by the Extremi-
ties  of Excretory  Veflels;—its denfity, however,  is fuch, that
no veflels can be traced in it, either by the Eye or by the aflift-
ance of glafles.
  The Cuticle ferves to proteft the fenfible  parts under it; and
to regulate the proportion of  the  Fluids thrown out or taken in
by the Surface of the Skin ;—particularly to prevent too great a
degree of evaporation.
                   Corpus Mucosum.
  The Corpus Mucofum has been commonly called Rete Mucofum,
from the fuppofuion that it  is  formed of a Mucous Net ivork, and
is htuated under the Cuticle which it connects to  the Cutis
Vera.
  It is compofedol  the terminations of extremely  minute Veflels
psflim, between  the Cutis and Cuticle,  which are  Anroundtd by
al.ucilaginous 01  Vifcid Subftance, properly culled Corpus Mu-
cofum.                                         .
  It is the chief caufe of th3t  variety of colour which character-
ifes the natives of different climates, and different people of the
fame climate,  beinf: white, or rather of a,light-grey femi-trans-
parent colour in  the European, black iifthe Ethiopian, brown in
the Aliatic, &c.
  It  is thicker and Jlronger in the Negro than in the white per-
fon,  and ca*n be readily eparated in the foimer into two Lajers.
   It covers every part, of  the Surface of  the Cutis,  exceptng
below the Nails, where it  is awanting ;  and is  of fuch  a  light
colo. r in the P.ums and Soles of tie Negro, as to have been fup-
pofed by fome authors to be deficient there alfo. 
                              5

  Its origin has not yet been fufficiently afcertained, nor is it fully
determined what particular purpofes it ferves.
  Among other purpofes, however, it  contributes to preferve
the ftru&ure of the tender Veflels,  Dufts, and Papillae,  placed
between  the Cutis and Cuticle ; and  in the Negro,  it is  fup-
pofed to  ferve as a  defence againft the heat ofv$he climate, by
preventing the rays of the Sun from penetrating the Skin.
                      Cutis  Vera.
   The Cutis Vera, or Skin,  properly  fo called, lies immediately
under the Corpus Mucofum, and gives a general covering to the
whole Body.
   It is formed of Fibres intimately interwoven, and runn'ng in
every direction, and is fo  plentifully  fupplied with Nerves  and
Blood-Veffels, that the fmalleft puncture cannot be made in  any
part of it, without occafioning pain and  bringing Blood.
   The Blood-Veffels of the Cutis are fo numerous, as  to  appear
to form almoft the whole of its  Subftance, and are of  fuch a fize
as to be  readily  injected.
   It is ftrong  and  elaftic, and  may be elongated  in every direc-
tion, after which it  recovers its former dimenfions.
   It forms the body of the Skin, and  is that part in Quadrupeds
of which Leather is made.
   The outer part  of it is denfe and  firm, the inner  loofe,  and
gradually degenerating into the common Cellular Subfbnce.!
   It is  thicker and  loofer on  the pouerior than  on the anterior
 part of the Body, and thicker and  firmer in the Palms and Soles
 than in the other parts of the extremities.
   The colour of the Cutis alfo differs -in different parts of the
 body, in proportion  to the quantity of Blood in the extreme Vef-
 fels, and to the thinnefs of the Cuticle.
   At the edge of the Eye-lids,  the red part of the Lips, and mar-
gin of the Anus, the Cutis  becomes  fo  immediately and remarka-
bly thin, as to appear to be loft.
   Upon  the Surface of the  Cutis,  fmall Eminences are obferved,
 called Papilla;, Papilla Nervofa, and Papilla Pyramidales; ike
 term being borrowed from the  Papillae  of the Tongue,  which
 were firft difcovered, and to which the name is  moft applicable.
   They are confidered as forming  the Organ of Touch,  from
 their being extremely fcnhble; and i^m  their being very Vaf-
 cular,  they  are  alfo  regarded a^'furnilhing  a paflage to p .it of
 the Perlpirable Matter.
    The  Papilla are moft  evident in the Palms and Soles, where
 they are placed in double rows upon  the ridges,  which  on  the
 points of the Fingers and Toes, generally run  in a femewhat
 fpiral and parallel direction.         *
    -Vol. II.           A 2 
D
   The Ridges are fuppofed to defend the Papillae, and to increale
the Su, face for Perfpiration.
   In fome places, as in the red part of the Lips, the Papilla? arc
termed Villi, from their refemblance to the pile of Velvet.
   Various kinds of folds are obferved in the Skin ;  fome depend-
ing upon  the  form  of  the Cellular Subftance, as in  the Hips ;
others on  Mufcular  Contraction,  a<;  in the Fore-head ;  and
others on  Articular Motion,  as at the Joints of the extremities,
—particularly thofe of the Fingers and Toes;—and thefe folds
are thinner than the reft of the Skin, to allow eafy motion.
   In an inflamed Skin, as in  the  cafe of Small-pox, a  Reticular
Texture of Veflels is obferved, which can be eatily injected, and
has been confidered by fome as the Corpus Mucofum,  and by
otherg as an additional Cuticle;—but no fuch appearance is to be
met with in the found Skin.
   The Cutis Vera ferves to cover and give form to the Body,  it
unites the  different parts,  and defends  them from injury.   It
forms the External Organs of  Senfation or of Touch,  and gives
pafliige to  the Fluids which are Perfpired or Abforbed.




              APPENDAGES OF THE  SKIN.
                          Nails.
   The Nails were  formerly regarded as  a continuation of the
Papilla; of  the Cutis, but are now more generally confidered as
a continuation of theCu'icle,
   They are removed along with it by  boiling water, or by ma.
ceration.
   Like the Cuticle alfo,  they are infenfible, are  renewable after
having been ieparated, and have no evident Vtffels.
   They differ  from it,  however,  in (tincture, being formed of
Pl.ihs, and thefe of Longitudinal  Fibres, which are clofely com-
pacted.
   They begin  by a fquare root, a  little before the laft Joint of
the Fingers and Toes.
   When  feparated  from  the  Skin, they  are tranfjarent  like
Ho;n, but are .coloured in the living Body by the Vcffeis of the
Cuti.-, to  which they adhere, and from which they derive their
nourifhment.
   They are fixed at their roots to  a femilunar fold of the Cutis,
nnd aie there covered  by a reflection of the Cuticle,  which firmly
adheres to thtm.
   They growTrom the roots, and not from the points.
   The nails ftrengthen and defend the  ends  of the. Fingers and
Toes, and thereby ferve as Buttreffts. 
7
  In the Fingers they increafe the power of apprehenfion, being
ufeful inlaying hold of minute objects.
                          Hairs.
"  The Hairs arife by roots or bulbs, which are fituated in the
Cellular Subfcance under the Skin.
  The Bulbs are of various,fhap$s in. different parts of the Bedy,
and have Blood-Veffels difperfed upon them for their nourifh-
roent.
  Each of the Bulbs has tnvo  Membranes,  or Capfules, contain-
ing an  Oily Fluid between them, which ^ives colour to the Hair,
and for want of which, as in advanced life, or in certain diTeales,
the Hair is fiippofed to change its colour, and become white.   It
may be remarked,  however, that the Hair, after  being cut off,
continues uniformly to preferve its colour.
  The body of the.Hair coniifts of fmaller hairs inclofed in  a
Membrane, and is fomewhat of  the nature  of the Nails.  Like
them alfo, it grows only from .the root.
  The ufe of the Hair is not yet fully known.—It ferves in general
for the ornament, warmth, or protection of the  different parts on
or near which it is placed.

   Sebaceous  Ducts or Follicles,  and Miliary
                         Glands.
  The Sebaceous Follicles derive their name from the Fluid they
contain becoming like Suet, after acquiring a  certain degree of
confiftency^^or being infpiffated by ftagnation.
  They are feated under the  Cutis,  and are  found in greateft
abundance in thole parts which are expofed to the  air, or to  at-
trition ; as in  the Nofe, Ears,  Nipples, Groins,  and external
Parts of Generation.
  The Sebaceous, or Miliary Glands, are fo called  from their
contents, and from their refemblance to  Millet  Seeds,  and  are
feated in the Axilla.
  Other Miliary Glands  are  defcribed  by Authors as  being
placed under the Skin over the whole Surface ot the Body, and
as ferving for the fecretion of Perfpirable Matter ;—but they are
not demonftrable to fuch a genera! extent;. and  the Sweat  is con-
fidered as being derived from another  fouice.
  Thefe Follicles and Glar.us  lecrete a fluid which ferves to lu-
bricate the Skin, and defend it from the inclemency of the weather,
or from the effects of friction.

   Miimbrana Cellularis, or Tela  Cellulosa,  or
         Reticular, or Cellular  Substance
  This  is p;en''rally confidered  as one  of the;  Ir.teguments,
thorn?': common to thefe and to j.he other parts or '.he Bou/. 
8
  It is compofedoia fine web, formed of many Membranes join-
ed irregularly together, and thefe made up of Cells, which com-
municate freely with each other wherever they are found.
  It is very elaftic,  may be drawn out to a confiderable extent,
after which it fuddenly recoils, and may be condenfed or com-
pacted to a great degree.
  It lines the Skin,  covers the Mufcles in general,  and enters in
between their different Fibres;—is an univerfal covering to all
the  other parts,  and even enters into the compofition of almoft
every one of them.
  It is thicker): where the parts are moftexpofed to preflure, as in
the  Hips, Palms, and Soles.
  The different Cells  of which it is compofod, are conftantly
moiftened by an Interftitial  Fluid, and in  many parts  of the
Body are filled with  Fat.
  It has little or no  fenfibility, can be handled freely,  or cut or
punctured without giving pain.
  It ferves to connect parts to each other,—but fo as to prevent
them from growing together;—it covers them, fupplies them  with
(heaths to move in, and contains the Fat.
    Corpus Adiposum,  Adeps,  Pinguedo, or Fat.
  The Fat is lodged in the common Cellular Subftance, but with-
out  communicating with it, and is made up of Maffes compofed of
fmall Veiicles containing the Fat, and thefe are furrounded  by a
net  work of Blood-Veffels, from which the Fat  is fuppofed  to be
fecieted, without the intervention of Glands.
  The Veficles are not found to have  any communication  with
each other, nor  have any Excretory Ducts yet been perceived in
them,—the Fat being fuppofed to tranfude from the Cells.
  It is of different  confifiency in different parts of the Body : In
the  living Body-it is generally fluid,  though in fome parts  it ap-
proaches to  a folid, and is altogether of this nature in the dead
Body.
  In  the Bones it forms the Marrow, whch has been formerly
defcnbed.
  The Fat is chiefly fituated immediately under the  Skin, and
covers almoft the whole Sui face of the Body.   It  is alfo  found
between  the different Mufcles and Fibres of Mufcles,—within
the  Orbits, and  in the Cheeks,—in the Subftance  of  the Mam-
mae, and about the Heart.
  It abounds in the  Abdomen, about the Kidneys, Loins, Omen-
tum, and Mefentery ;—and in the Joints it forms the Subftan-
ces called Glands of the Joints, already mentioned.
  The Fat is aiuanting in the Scrotum, Penis, and  Eye-Lids,
and is found only in fmall quantity  in the Fore-head, or about
the Joints, where, from its bulk, it would have been  inconveni- 
LI
ent.—Tt isaiio awanting in the Subftance of  the Vifcera fituated
m the great Cavities of the Body; as the Brain, Lungs, Liver,
Spleen, Kidneys, &c.
  The Fat ferves to lubricate every part of the Body to  which it
is connected, and facilitates the action of the Mufcles.  It fills
(he Interftices,  fo  as to give form and fmoothnefs, and  guard
againft preflure.   It ferves alfo as  a refervoir of nouriihmtnt.
                Panmculus Carnosus,
               Defcribed by the Ancients as an
                 Additional Covering.
  This  is  a  general Covering found  in the  Quadruped,  and
formed by  a thin Subcutaneous Mufcle, which  ferves to agitate
the Skin.
  It  is found only in certain parts  of the Human  Body; as in
the Fore-head, where  it  is  formed  by the Occipito-Frontalis
Mufcle ;  and in. the Neck, where it is  formed by  the Platyfma
Myoides.
00000000®00000000'
OF  THE  BRAIN.
o
  THE term Brain is applied to the whole of that Mafs which,
with its furrounding Membranes, fills  the Cavity of the Crani-
um ; and is larger in Man, in proportion to the fize of the body,
ti.a;i in any other animal.
  The Membranes of  the  Brain were called Meninges and Ma-
ters by the  Ancients, from an idea that they gave  birth or ori-
gin to all the other Membranes of the Body.
  They comiil of the Dura Mater, Tunica Arachnoidea, and Pia
Mater.
  The Dura Mater,  named  from its being of a firmer tex-
ture than the oiher two Membranes, inclofes the Brain and all
its Appendages, am! lines the different parts of the  Cranium.
  It is  compofed  <if one Membrane,  which, in feveral  parts,
is divifibic  by maceration  into two, or even more layers of Fi-
bres. 
                             10

  The texture of the Dura Mater is very denfe.   It  is the  H
thickeft and ftrongeft Membrane of  the Body, and is compofed
of  Tendinous like Fibres,  which  have  a fhining appearance,
particularly in its inner Surface.   In many parts thefe  Fibres
run in a variety cf directions, and decuffate each other at  differ-
ent angles.
  The Dura  Mater adheres evsry where to  the Surface of the
Cranium, in  the fame manner as the Perioflxum  adheies  to the
Bones in  the other parts of the Body;  but it is more firmly ' con-
nected at the Sutures and  Foramina than  ellcwhere ; and -fo *M
much more firmly in Children than in  Adults,  thar in feparating
it from the Cranium, it is apt to bring along with it fome of the  ]J
Fibres of the Bone to which it is attached.—In  ^ie adult, the fe-
paration of the Bone from the Membrane is lefs difficult, in con-
fcquence of many of the Fibres being obliterated.
  The inner  Surface of the Dura Mater, which  s remarkably
fmooth, is in clofecontad, with the Brain,  but adheres only where
the Veins go into the Sinufes,—and is  lubricated by a Fluid d;f-
charged through its Veflels,  which  guards the Brain  from dan-
ger,  according as  it  may be affected by the  different ftates of
Kcfpiration.
  The Dura Mater ferves as a defence to the  Brain, and fup-
plies the  place of a Periofleum to the infide of  the  Bones of the
Cranium, giving nourifliment to them,—as is evident from the
numerous  drops  of  Blood which  appear after  removing the
Skull-cap.
  From the inner fide of the Dura Mater, Procefj'es are fent off,
which divide  the Brain into certain parts*, and ferve  to keep it
fteady, tviz.
  I. TheFALX, Superior Longitudinal Procefs, or Septum Cere-
bri, which is  formed  by a doubling of the Dura Mater,  and is
fituated between the Hemifpheres of the Brain.
  It begins at the middle of the Sphenoid, and  Crifta Galli of the
Ethmoid Bone, and runs along the upper and middle part of the
Head, adhering firft to the Frontal, then to the joining of the
Parietal,  and afterwards to the middle of the Occipital Bone.
   In its paffage it becomes gradually  broader, extends from the
Cranium  to near the Corpus Callofum, and terminates behind in
the middle of the Tentorium.
   It luns from behind forwards in a ftraight direction, and has
Tome refemblance in fliape to a Sickle or Scythe, from  which cii -
cumftance it has obtained the name of  Falx.
   Between the under ed,,e of the Falx and Bafe of  the  Ci rnium,
there is a  large fpace,  of an  oval form, occupied by that  pan  ot
the Brain which is common to the two Hemifpheres.
   The Falx fupports  the Tentorium,  and prevents the two fides
of the Brain from preding upon each other. 
11
  II. The Tentorium CEREBELLi,or Tranjverfe Septum, o;
Lateral Proceffes of the Dura Mater.
  The Tentorium is continued  laterally from  the Falx, is con-
nected behind to  the  inner Tranfverie Ridges  and Grooves of
the  Occipital  Bone,  and  at the fore  and outer edges,  to the
Ridges and great Angles of the Temporal Bones, and terminates
at the Pofterior Clinoid Procefs of the Sphenoid Bone.
  Between the middle and  inner edges of the  Tentorium  and
pofterior Clinoid Procefs of  the Sphenoid Bone, there is  a large
Notch, or Foramen Ovale,  where the  Brain and Cerebellum are
united, or where the Tuber Annulare is chiefly fituated.
  The Tentorium keeps the Falx tenfe and  forms a floor or vault
over the Cerebellum, which  prevents the Brain from prefling up-
on it.
  III. The Falx Minor,  or Septum Cerebelli, which is placed
between  the Lobes of the  Cerebellum.   It defcends from the
under and back-part of the Falx in the middle of the Tentorium,
adheres to the inferior Longitudinal Spine  of the Os Occipitis,
and terminates infenfibly  at the edge of the Foramen Magnum
of that Bone.
  Befides the Proceffes of  the Dura  Mater  already defcribed,
there are four of inferior confideration, two of which are fituated
at the fides of the Sella Turcica and two at  the edges of the Fora-
mina Lacera.
  Several other Proceffes pafs out at  the different  openings of
the Cranium, to be connected to  the Pericranium, or to accom-
pany the Spinal Marrow and Nerves :—Thefe of the laftdefcrip-
tion (hall be afterwards taken notice of.
  The Arteries of the Dura Mater are derived partly from the
External  Carotids, and partly from the  internal Carotids and
Vertebrals.
  The Veins of  this Membrane are of two kinds.   One fet of
them,  like the Veins  in  other parts of the body accompany the
Arteries ;—the  others  are termed Sinufes  and differ  from Vein.
only in this,  that they are of  a triangular Figure, and inclofed
in a doubling of the Dura Mater, which is fo tenfe over them,
as  to become affected in confequence of  the preffure from fur-
rounding parts.
   In the bottom  of the Sinufes are fmall Tranfverfe chords ter-
med Chorda Wilisii, which may add a little to their ftrength, and
afiift in preventing them from being too much diftended.
   The Sinufes ferve to carry the Blood from the  Brain, and con-
vey it to the Veins of the Neck, for which  purpofe  they are pro-
perly fitted, their covering from the Dura Mater giving them
ftrength, and their frsquent  communications preventing congef-
tion. 
                            1 2

                The Principal Sinuses are,
  I. The Superior Longitudinal Sinus, which begins at
the Crifta Galli of the Ethmoid Bone, runs along the upper
edge of the Falx, becomes gradually larger in its progrefs, and
terminates in the Lateral  Sinufes.
  II. TheToRCULAR Herophili, or fourth Sinus of the  An-
cients ; the term Torcular is applied to it  from the fuppofuion
that the Blood is fqueezed in that S nus  as in a Wine prefs.—
It is chiefly formed  of the Vena Galeni, runs between the  Falx
and Tentorium, and and terminates  with the former Sinus in the
beginning of the Lateral Sinufes.
  III. The  Two Lateral  Sinuses, which are formed by
the Longitudinal and Torcular Sinufes, run  in depreflions of the
Occipital and Temporal  Bones, firft  tranfverfely, then   in  a
winding direction downwards,  and  terminate at the Bafe of the
Cranium, in the beginning of the Internal Jugular Veins.
  Befides the Sinufes mentioned above, feveral others of lefs con-
fideration will be pointed out in the  particular defcription of the
Veins.
  The Nerves of the Dura  Mater are fo very minute, that they
have not  as yet  been diftinctly traced, and it is found to poffefs
very little fenfibility in the found ftate.
  Upon the  fide of the fuperior longitudinal Sinus", and contigu-
ous parts of the Brain, there are numerous fmall Granulations,
of a vjhitifbcolour, called Glandula Pachioni.
  Befides thefe  Granulations,  there are others of the fame name,
of a Flejhy colour, fituated on certain parts of ihe outer Surface of
the Duia Mater, and frequently projecting fo much as to  form
deep pits in the  Skull.
  The nature of thefe Granulations is ftill  unknown.—rBy  fume
they have been fuppofed to belong to the Lymphatic Syfteni.
  The Tunica Arachnoidi;a, named from its  cob-web ap-
pearance, is an  exceedingly  thin,  render, and tranfparcnt Mem-
brane, in which no veflels have been hitherto obicrved.
  It is fpread uniformly  over  the Surface of the Brain, inclo-
fing all its Convolutions,  without inlinuating itfelf between any
of them.
  At the upper  part of the Brain, it adheres fo clofely to the fub-
jacent Coat by fine Cellular Subftance, that  it can fcarcelv  be
feparated from it; but in diffeient parts of the Bafe of the Brain,
particularly  about the Tuber Annulare and Medulla Oblongata,
it , merely  in contact with the  Membrane urul«r  it, and  "may
readily be raifed from it by the afliftance of  the Blow-pine.
   The Tunica  Arachnoidea,  like  the  Cuticle, covers  and de-
fends the parts under it.
   The Pia Mater, named from its tendernefs, is fomewhat of
the nature of the former covering, but is extremely Vafcular. 
115
  It covers the Brain  in general, enters double between  all its
Convolutions, and lines the diff*. rent Cavities called Ventricles.
  It fervrs to co.itmi and  iup o t the Veffls of the  Brain, and
allows the,n to divide  mo fu.'h minute part  , as to prevent the
Blood  from en ering the tender Subftance of this Vifcus with too
great f.nce.
   The A-teries of the Pia  Miter are the fame with thofe  of tire
Bra.n and ire derived from the In.ernal Car.itids and Vertebrals.
  The Veins lifter in no r-fpect from  th A'e of the other  Vifcera,
exceotin * in this, that they do not accom nny the Arteries.
  The Bran is  d vided into  Cerebrum,  Cerebellum, Tuber An-
nulare and Medulla Oblongata.
                        Cerebrum.
  The Cerebrum is fituated in  the upper part of the Cranium,
which it completely filis.
  It is divided  into two halves,  termed Hemifpheres, which are
feparated from each other by  the Falx.
   Each of the tijmifpheres is of  an oval form, or  they  fome-
what refemble an egg cut into t jvo longitudinal halves.   The in-
ner fides are flat, the upper and outer parts convex, and the un-
der Surface irre  ular.
  The under Sjiface is div'ded into tvji Anterior, tvfo Lateral,
and  tzuo Pojlerior Lobes, or Proceffes.
  The Anterior Lobes are fituated  in the fore-part of the Bafe of
the Cranium.
  The Lateral or Middle Lobes, are lodged in the Foffa? formed
by the Temporal and S;iheno;d Bones.
  The Pojlerior Lobes are placed  over  the  Cerebellum, and are
feparated from .t by the Tentorium.
  Bnw.-.j i the Anterior and  Lateral Lobes,  there is a Furrovu
formj.-I by the Anterior Clinoid Procefl'es of the Sphenoid  Bone,
which has been termed Foffa,  or Fiffura Magna SrLvu.
  The.Surface of  the Brain is  divided into many  turnings or
windings,  termed Circumvolutions, which run in various  direc-
tions, and are or different  iizes and lengths on different parts of
the Brain.
  The Circumvolutions are  every where connected  to  the Pia
Miter by an   infinite number  of fmall Veffels,—called  by
Ruvsch, Tomentum Cerebri,— vhich  run into the Subftance of
the Brain ; as may  be readily feen, upon  fcparaiing the Circum-
volutions a liale from each other.  -         •»-.
   Between  the Hem Ibheies a white Subftance is obferved,  cal-
led Corpus Callofum, from  its being a little firmer than the  reft of
the Brain.—It goes acrofs the Brain, under the Falx,  and is
merely a continuation of  Medullary Subftance, running  hori-
   Vou II.          B 
I i
 eontally,  and joining the two fides of  the  Hemifpheres to each
 other.
   In  the middle of the Corpus Callofum there is a longitudinal
 Raphe,  with a Medullary Cord on each fide,  from which  many
 tranfverfe  ftreaks  iffue."Thefe  Cords, like the  Corpus  Cal-
 lofum itfelf,  become gradually broader towards  the pofterior ex-
 tremity.
   An horizontal Section,  a little above the middle height of the
 Brain, or upon a level with the Corpus Callojum, ftiews the di-
 vifion of the Subftance of the Brain into outer or inner, or Cor-
 tical and Medullary parts.
   The outer  Subftance  is termed Cineritious, from its be-ng of
 a greyifh or  ^colour,—though a little tinged with  brown;—
 and Cortical, from its furrounding the inner part of the Brain, as
 the Bark does the Pith of a  Tree
   It is termed by fome Authors Glandular, and by others Secre-
 tory,  from a fuppofition  that a Flu d  w; s fecreted in it.
   The Cine<-itious Subflanee covers the Brain in  general,  and en-
 ters de>-p between  its Convolutions,  is of  a foft confiftence, and
t»mpofed  of numerous fmall Vt.ffls  carrying red Blood ;  but
 it is uniform, and  without any appearance of a  Fibrous  texture.
   The inner  Subftance is termed White or Medullary, and is con-
 fidered as giving origin to the different Nerves.   It has been  by
 fome called Excretory, having been fuppofed to be formed of hol-
 low TuIks continued  fiom  the Vtffels of the  Coi tical  part;—
 but no  Cavit es  have ever been obferved  in  the foft Fibres of
 which it is compofed.
   It is greater in quantity, and fomewhat firmer in texture, than
 the Cinerilious Subftance, and is fo intimately connected  as to
 appear to be a continuation of it.—The foft Fibres or ftreaks of
 the Medullary Matter, run in general in a parallel and tranfverfe
 direction.
   In many parts of the  Cineritious Subftance,  Medullary  Mat-
 ter appears ;  and,  on the cc ntraiy, in diffeient  parts of  the Me-
 dullary  Subftance,  Cineritious Matter is found ; the two being
 frequently blended together in the form of ftreaks.  See Monro
 en Nervous Syjfew.
   The  Centrum Ovale of Vieussens.  This  is the Medullary
 Subftance  of the  Brain,  forming a  kind  of Nucleus,  which is
 feen after removing the  Cineritious Subftance, and all  the Me-
 dullary parts mixed with it, which be between the Cortical  Con-
 volutions.    .*>
   To obtain a proper view  of the Centrum Ovale, the Nucleus
 ought to be cut in  fuch  a manner as to pieferve the Corpus Cal-
 lofum,  and the fame convexity with that of the general convexity
 of the Brain. 
  The Centrum Ovale forms an arch or rooj'ovar the two Lateral
Ventricles ; and the under part of this root, which is fmooth and
uniform, conftitutes the upper part of thefe Ventricles.
  Vieussi':ns Confidered  the Centrum Ovale  as  the great Dif-
penfatory of the Animal Spirits.
  The Ventricles of  the Brain are four in  number, two of
wh cli aie called  Lateral.
  The four Veniiicles have th;ir (ides contiguous to each other,
are chiefly foimed of  Medullary Matter, and are  lined with a
continuation of the Pia Mater, which differs from that covering
the exterior Surface of the  Brain,  in  having  fewer Veflels dif-
pcifed upon it.
  They are  conftantly moiftened by  a  Fluid, which prevents
their oppofite fides from adhering to each other.
  The «/>of tlie  Ventricles, like many other parts cf the Brain,
is (till unknown.
  The Lateral, formerly  called Superior Ventricles,  are fituated
in the Hemifpheres, one in each, and run Horizontally in the fame
direction with the Hemifpheres theml'elves.
   They are of  an irregular form,  lying  under the  Centrum
Ovale, and have each three winding corners, compared to Ram's
Horns, which are therefore called Comua.
   The Anterior Comua are feparated only  by  the  Septum Luci-
dum.
   The Pojlerior Comua,  called alfo Digital Cavities,  are at  a
confiderable diftance from  each  other,  but approach nearer at
their pointed extremities ; while the inferior Cornua, the begin-
ning  of which is  feen, run downwards and forwards, and termi-
nate in the Lateral Lobes of the Brain.
   In each  of the  Pofterior Cornua there is an Elongation, which
terminates in a point, and  is called Ergot by  the  French,  from
its refemblance to the Spur  of a Cock; or, Hippocampus Minor,
from  i's fimilarity to,  and connection with, the fubftance termed
Hippocampus Major.
   In  the fore-part of the bottom of the  Lateral  Ventricles,  are
two large  Eminences, called Corpora Striata,  which  become
gradually narrower, and recede from each  other at their pofterior
extiemities.
   The Struflure of thefe is Cineritious externally, and mixed
with  Medullary Stria? within, fome or which  form large Tranl-
verfe Medullary  Arches,  and others run more  in a ftraight direc-
tion.
   Between the pofterior parts  of the Corpora Striata,  are fituated
the Thalami Nervorum Opticorum, which  have a  roundifh form
and Medullary Surface, and are of a Suiated  appearance within,
bu; the Striae are  lei's diftinct than  in the Corpora Striata.' 
IS
 "Upon the Sui face of thefe Bodie=, there are fmall Eminences or
Tubercles, fome of which aie placed  upon  their iupei ior, and
others upon their inferior extremit ts.
  The inner pans  of the Thalaini are flat and contiguous, aid
above they aie foclofelv connected as to form one continued Sur-
face, called Ccmmiffura Mollis of the Optic Thalami.
  The pofterior parts of the Thalami turn downwards and out-
wards, after which they  aie  elongated, to form  the two  white
Cords, called Traclus Optici.
  In theGioove between the  Corpora Striata and Thalami, there
is a Meduil'iy Band on  each fide, called Centrum Semicirculare
Ccmii-um cj V ieuss e n  s, or Tania Semicircularis oj HALL t r, or
fimply Taenia.
  Over the Thalami  is placed the Choroid Plexus,—named fiom
its  being  compofed  of a  Chorus of  Veflels and Membranes.
It is a fine Vafcular  Web, confifting of  tmall  ramifications  of
Ai tents and Veins, comucted by the Pia Mater, and lpie;>d upon
the Surface of the Thalami. and fome of the adjacent parts.
  The  Choroid Plexus frequently contains  numerous round
Globules, refembling  Hydatids,  which   have  been confidered by
fome Authors  as Lymphatic Glands.
  Under the Raphe of the Corpus Callofum, is placed the Septum
Lucidum, which, when viewed laterally, is obferved to be  bioad
bef< re,  curved at its  edge, and to become gradually narrower to-
wards its pofterior exiiemity.
  It is connected  above to the  Corpus Callofum, below  to the
Fornix, and foims a  dillinct partition between the lateral Ventri-
cles.
  It is formed of two Cineritious and Medullary Laminae, more
or lets feparated from  each other at tluir  fore-part,  by a fmall
Cavity, called Fiffure,  or 1'cffa of Sylvius  or Sinus of the Sep-
tum Lucidum, winch, however, doe. not  communicate with lue
Lateral  Ventricles^ though in lome fubjtcls ir reaches a confider-
able way backwards, and, as well  as  the other Ci. uies of the
Brain, has been found  full of water in  Hydioccpiialous cafes.
  Under the Septum  Lucidum is placed the Subitance which has
been compared in fhape  to a  Vault by  the Ancients,  and  fix in
that htis obtained the name of Fornix.      ■■*'
  The Fcr/tix is merely  a continuation of the Corpus  Callofum,
and forms a fort of hoMow Ceiling, with four Pillars call.d Cru-
ra, or Cornua, from their winding diitction, cf which theic are
two anterior aid£two pofterior.
   The tivo  Anterior Crura  r.re fliort, run  clofe together,  and
become enlarged at their inferior parts.   ,The t-ivo Po/le/ior Cru-
ra  are Ion<?, confidtrably diitant from each other, and ft im Cur-
vatures which corieljiond w.th the courfe of the Iuftnoi Cornua
of the Lateral Vumielcs. 
n
  That part of the Crura Fornicis lying in the Inferior Cornua
of thefe Ventricles, forms thin borders, getting the name of Cor-
pora Fimbriata ;  but, according to the Vic D'Azyr, they are
more  properly termed  Tosnia Hippocampi,  from being  united
with the great Hippocampus.
  The body of the Fornix is narrovj anteriorly, and  becomes
coniiderably  broader behind, where it is incorporated  with  the
Corpus Callofum.
  The under Surface of the pofterior part of the body of the For-
nix, is impreffed  with  numerous  tranfverfe  and oblique Lines,
which have been called iPfalterium, or Lyra, from  fome refem-
blance  they  bear to  the ancient  mufical  inftruments  of thefe
names.
   The body of  the Fornix is joined above to the Septum Luci-
dum;  below it is connected  to the Thalami Optici  by  a Vafcu-
lar Membrane,  called  Tela Choroidea,  which fpreads over the
Thalami,  and unites  the Choroid Plexus of the Lateral Ventri-
 cles.
   The Pedes Hippocampi, Great Hippocampus, or Cor-
 nua Ammonis,—named from a fuppofed refemblance to thefe
parts,—are two Medullary Eminences, which arife from the fides
of the pofterior extremity of the Corpus Callofum, and are fituated
in the inferior Prolongations of the  Lateral Ventricles.
   They run through the whole extent of the  Prolongations,  firft
 behind, then at the outer part of the pofterior Pillars of the
 Fornix, and aie  fo intimately  connected  with them,  that they
 have been conlidered by fome Authors as  forming part of  the
 Pillars thoinl'elves.
   They are  fmall at their origin, from  which they continue to
 increafe to their farther extremity.
   Like the greater pai t of the Ventricle?, they are covered exter-
 nally  with a Medullary Lamina ;—internally  they are  found to
 conlift of  Medullary and Cineritious Lamina,  of a convoluted
 appe.uance.
   At  the inner edge of the Pedis Hippocampi,  there is a plaited,
J'errated, or indented Margin, which, in the generality  of Quad-
 rupeds, is much larger, in proportion to  the  fize of the Brain,
 than  it is in Man.—The refem'lance,  however,  to the  liumnH
 kind,  in the ftructure of  this, particular part  of  the  Brain,  is
 more,  ftriking in the Ape th?n in any other  Quadruped.
   In the  bottom  of the Lateral  Ventricles,  behind the anterior
 Ci ura of  the Fornix,  and  before the meeting of the Choroid
 Plexufes of thefe Ventricles,  below the anterior part of the body
 of the Fornix, and ovcthe fore-part of the third Ventricle, there
 is a  Hole, of  an oval jorm, by which  the  Lateral  Ventricles
 communicate  freely  with each  other.  See  Monro's Obf. on
 Nefv. Syft.  1783, and Treatife otiytbe Brain, 1797.
    Vol. ll:     •     B2 
                            18

  After dividing and turning back the Fornix,  another commu-
nication fiom the above  p;tfiage is found, cailed Foramen Com-
mune Ante ius. Vulva, or Iter ad Infundibulum;  but properly,
Iter ad i iritum Ventriculum, or Paftaje to the  third
Ventricle.
  B.-.ween the Commiffura Mollis of the Optic Thalami, and
Subftance cailad  Final  Gland, there is a fmall pafl'age teimed
Anus, or Foramen Commune Po,ur'ius, which has I ctn fuppofed
by lbme Authors to f> i in a communication between the back part
of the thud Ventric.e and Lateral Ventricks; but it is complete-
ly ftiut  up by the Tehi Choroidea, and alio by the Fornix, which
adheres clo.ely to ih s Membrane.
  The  Third Ventricle is infoim of a deep Fiffurc, placed
between the  inner ends of the Thalami Optici, having the Coni-
miflura Mollis of thefe rhr.laim li uated above,  the Crura C'ere-
bii below, and the bodes of the Thalami on each  fide.
  i he  Infu n DiEUI.UM is  a paffage of  confiderable iizc, of a
Cineritious and Medulla, i  ftructure, which  leads  downwards
and forwards, gradually contracting, and becoming i'olid at its
under end, where ;t  terminates in the Glandula tituitaria and
t!ins, contrary to the opinion of the Anci< ins, pieventing the paf-
f.igeof  nny Pituitous Fluid fiom it to the Nofe.
  The  Glandula PiTuitaria is of  an oval form,  about
the  Ihi' of   field-Bean, lodged in the Sella Turcica, and fur-
rounded by a doubling of the Dura Mater.
  On the oi'tlide it is of a brownifh colour, being formed of Ci-
neritious Matter ; it is  whiter within, wheie  it is m.xed with
Medullaiy Subftan  e.
3Whe  Gl n lula Pituitaiia was formerly  fuppofed to  abforb a
Fluid from me Infundibulum, and  ranfmit it to the Nol'e.  It
has heen  already mentoned,  however, that the  Infundihulum is
impervious;  and the real ufe of this Glafid, as well fls of the
other Tubercles of the Brain, feen;. ftill uriknown.
  At the fore part of the third Ven'.ricle, and  immediately be-
foie  the Ai.ierior Crura of the Fornix, there is a white Medul-
lary Cord, whth runs tranfverfely through the  Corpora Striata,
and has the*iame of Commissura Cerebri Anteriou.
  At the back-part of the child Ventricl  , and under  the root of
the'Pineal Gland,  there  is another Cord  fitnilar to  the former,
but fhorter, cabed Commissura  Cerebri Posterior.  The
Commiffura Ce-ebri afl;lt in uniting the two fides of the Brain to
which they are fijjjtd
  From the under and back-part of the third Ventricle, there is
a.P.ffage which leads to  the  fourth,  under the  name of  Iter
ad  Quartum Ventriculum, Canalis Medius, or Aquaduc-
tks Sylvii. 
19
  After the pofterior part of the Fornix, and the Tela Choroidea
to which  it  adheres,  have been  removed, there appear at the
back part of  the third Ventricle, behind the Thalami,  and over
the Iter a Tertio ad Quartum Ventriculum, the Nates and Tes-
tes, or Tubercula Quadrigemina, and  Pineal  Gland.
  The Nates, or Tubercula Quadrigemina Anteriora, are placed
uppermoft, and are ot a rounder form than the '1 tSTEs, or Tuber-
cula S^iiadrigemina  Poflerioru,—winch lie immedia ely below the
former.— Tne Teftes are broader from one  lide to the other than
from top to bottom, and of a white colour.
  A longitudinal Section fhews the Tubercula to be covered ex-
ternally with  a thin Medullary Lamina, and  to be  Cineritious
w, thin.
  In Man  they are more nearly of an equal fize than in Quad-
rupeds, as  in  the Ox, Sheep, Sec. in which the Nates are large,
round, and of a brown colour, and the Teftes fmall  and long. ~^.
  Over the Nates, and under  the back-part  of the Fornix, is
placed a fmall body, of a Cineritious  nature, about the  fize of a
Garden-Pea,  and of a Conoid figure, called  Glandula  Pi-
ne alis, from its refemblance in fhape to a Pine, or Fir Cone.
  In confequence of being always prefent, and feldom found in
a difeafed ftate, it has been celebrated by Des Cartes, as be-
ing, according to his fuppofition, the  Seat of the Soul.
  Tue i'ineal Gland is fixed at its root to the Commiffura Cere-
bri  Pofterior, an'd fends out tvjo long Medullary-  Peduncles,  or
Footflalks, to be fixed to the upper and inner lide of the Thaiami
and to  the Anterior Crura of the Fornix.
  Ne..r, or in the Subftance of the Pineal Gland, fmall Calcare-
ous Concretions are fometimes found, called by Soemmering,
Acervulus  Cerebri, from their being generally found collected  in
a heap.
  They*do not appear to be the effects of difcife ; nor  are they
met with till  after the age of Puberty.

                      Cerebellum.
  The Cerebejlum is fituated in the  Inferior Foflae of the  Occi-
pital Bone, under the  Pofterior Lobes of the Brain, and is fepa-
rated from  thefe Lobes by the Tentorium.
  It is fomewhat of a roundifh fSrm, though a  little broader  from
one  lide  to the other than from before  backwards.   It  is  only
about a filth or lixth pait of trie fize of the Cerebrum, and much
limpjer.
  It is divided behind  by the Falx Minor into two L.bes or He-
mifpheres,  but has no reparation above like the Brain.
  Its  Surface is divided into numerous Circumvolutions, which
from arches,  decuflating each otner in m;.ny parts, at fliarp an-
gles.          * 
20
   The Circumvolutions run  chiefly in  a Lateral direction, ami
 are formed of Laminae,  with deep Sulci between  them,  into
 which as  in  the Brain, the Piaf Mater  infinuates itfelf,  which
 may be readily feen by making a puncture into  the Arachnoid
 CMR, and blowing in air till it diftend  the Cellular  Subftance,
 and feparate^the Coats from each other.
   It has  two middle  Eminences,  called Appendices Vermifor-
 mes, from their, refemblance to Earth Worms, one of which  is
 fituated anteriorly and  fuperiorly,  the other inferiorly and pof-
 teriorly.
   Each  of the Lobes of the Cerebellum is again divided into
 Montivuli, or Lobules, which  have  different names according  to
 their relative fituations, connections  with other parts, &c.  They
 vary a little in the different Subjects, but  are beft diftinguifhed
 from the direction of their  Convolutions.
»   The Subftance of  the Cerebellum confifts of. Cineritious and
 Medullary Matter,  as in the Cerebrum ;  but  the  Cineritious
 bears  a greater proportion to the Medullary  in the former than  in
 the  latter.
   When the Cerebellum is cut in a vertical direction,  the Me-
 dullary  part  is then  found  to  bear   a  ftriking  refemblance
 to the branching  of the fh ub called Arbor Vita,  from  which
 circumftance it  has obtained trie name of this fhrub.
   When cut in  flices nearly parallel to the Bale of ihe Brain, the
 Medullary Subftance appears in Laminae, correfponding to thole
 of the Surface of  the Cerebellum ; and when cut to a confidera-
 ble depth,  there is a Centrum Medullare uniting the Lateral Lobes
 as  in the Brain.
   Between the Ceiebellum; the under part  of the Tuber Annu-
 lare, ar.d  upper part of the Medulla Oblongata,  the Fourth Ven-
 tricle is fituated, which extends from the tniintnees called Tefles
 to the pofterior inferior Notch of  the Ceiebtlluin.     4
   A little lower than the Teftes, the Ventricle becomes  wider,
 and forms an angle  * ehind, from which again it contracts, and
 becoming  narrower and pouted below like a writing-pen,  is cal-
 led  Calamus Scriptorius.
   Over the under end of  the Aquaeductus Syivii,  and  upper
 part of the fourth  Ventricle, time is  a  itiin Medullary  Lami-
 na,  cailed Valvula, hut properly Velum Vieussenii.
   At the fides of th'i Velum Vieullcnii there are two Medullary
 iracts, called Proceffus  ad lejtes,  or Colu/u,:uValvula: Vieus-
 semi.
   The under end of the Ventricle is found  to  be flint Uj>  by its
 Choroid  Plexus,  which p-events  any communication octvvieu
 this Cavity and that of the Spine. 
                             ci


          UNDER SURFACE OF  THE BRAIN.

  Near the middle of the Bafe of the Brain,  and between its La-
teral Lobes,  there  are  two fmall,  round,  white bodies, termed
Eminentiae   Mammilares,   or  Corpora Albicantia,  Medullary
without,  Cineritious within,   mittaken  by fome  Authors for
Glands.
  In the Corpora Albicantia,  various Medulkiry Strata termi-
nate,, which come from  different parts of the Brain.
  Immediately before the Corpora Albicantia,  two  large white
Cords are obferved, called  Crura,  or Pedunculi Cerebri,  or Cru-
ra Anteriora Medulla? Oblongata*,  which arile from the Medul-
lary Subftance  of the Br.iin, and gradually approach each other
in their courfe, till they unite with  the Tuber Annulare.
  Their  Sui face is flat, and compofed of diitinct Medullary
Fibres ;  internally they are compofed of a Mixtuie of Lineriti-
ousand Medullary Matter, the former of which being of a darker
colour at one paiticular part than in any other of the Brain, has
been termed  Locus Niger Crurum Cerebri.
   Between the Crura Cerebri and Corpora  Albicantia, there is a
Cinertious  Subftance,  called  Pons Tarini, which joins ihefe
two bodies of  the  oppofite fides together, and  aflifts in forming
the bottom of the third Ventricle.
   From  the  Medullary part of the  Cerebellum,  which forms the
trunk of the  Arbor Vitas two white cords arile, under the name
of Crura Cerebelli,  or Crura  Pofleriora, or Pedunculi Cerebelli,
which unite  with the Crura Cerebri,  to compofe the Tuber An-
nulare, or Pons Varolii,  fo  named  from forming a Ring  or
 Bridge  over the  Ciura.  This  ring  is intimately  incorporated
 w:th,  and formed by thefe Crura.
    fiie Tuber Annulare is fituated over the back part of the body
of the Sphenoid and Cuneiform Procefs of the Occip.tal Bone.
Many tranfverfe ftreaks run on its Surface, and  it is  divided
into two lateral parts by a  longitudinal deprefiion, occafioned by
the fituation of the Vertebral Artery,
   At the  fore and b.ick parts  of the Tuber,  are  the Foramina
Cceca A.iterius et Poflerius, the former placed between  the third,
 and the  latter between the lix.h Pair of Nerves :  Thefe two Fora-
 mina penetrate only a little way at  the edges of the  Tuber, and
 receive a Plexus of Veflels.
   In the Subft:mce of the Tuber, there is much Cortical Matter,
 which is formed into Stria, imining in different directions.
   Continued fV.iin the Tuber,  the.eisa laige Subftance in form
 of an  inverted Cone, which extends to the  Foramen Magnum  of
 the Occipital B. no, under ihe n-nu of Medulla Oblongata.
   Upon ihe  Surface of the Medulla Oblongata, two fmall Emi-
 nences appear, which run Ioi.Jtudinally and contiguous to each
             •
t» 
22
•ther and from their fhape have the name of Corpora  Pyramida-
lia, or Eminentia Pyramidalcs.
  Between ihe Corpora Pyr..midalia, there is a deep Fiflnre, into
which the Pia Miter penetrates, and where   Blood  veflels pafs
into the interior part of the Medulla.
  At theousfide of the former Eninences, are two othen, fome-
what of the form of Olives, fi\ m which they are termed Corpora
Olivaria, or Eminentia Olivares.
  More  externally than  thefe,   are two  other Eminences, lefs
evident* than the former, which have been defcribed by fome Au-
thors by  the name of Corpora Pyramidalia Lateralia.
  The Medulla Oblongata  is divided into twolateial portions,
by  an anterior and  poii.iioi Fiffuie, and the two portions are
formed of Medullaiy Matter without, and a larye  piopcrtion  of
Cineiitious Matter internally,  and joined together by Medullary
Fibres.
  The Brain is the Gra.id and Primary  Organ of  Senfe, with
which the Mind is fuppofed to be moft immediately and intimate-
ly connected, and  from which the Nervous Influence is  found,
by experiment, to be communicated to all the  other parts of the
Body.

                  Origin  of the Nerves.

  The Nerves arife from  the Medullary parts  of the Brain, fome
in fol;d Curds, others in feparate  Threads which afterwards unite
into Cords ; and have their name in numerical  fucceffion, accord-
ing to their fituations, beginning anteriorly.
  The Firfl,  or  Olfactory Pair of Nerves, arife from the back-
part  of the pofterior lobes of the Brain, and run towards the Crifta
Galli of the Ethmoid Bone, over which each  forms a brownifh-
coloured  Bulb, from whence numerous fmall Nerves are fent
off.
  The Second Pair, or  Optic Nerves, are  the  continuations of
the Thalami  Optici.  They are  united immediately before Hie
Infundibulum,  and form an intimate intermixture of  parts, and
again feparate previous  to their palling into the Orbits.
  The Third Pair arife by numerous Threads, wh.ch are foon
collected  into Trunks.
  The Fourth Pair, which are the fmalleft Nerves of the Body,
arife behind the Teftes, and have a long and winding courfe.
  The Fifth Pair,  which are the  largeft  Nerves in  the Brain,
have  each  an anterior fmall, and a pofterior large Fatciculus,
which arifes from the fide of the Tuber Annulare.
  The Sixth  Pair aiife  from  the  beginning of  the Me lulla Ob-
longata, where it joins the Tuber Annulare.   Each of the Nerves
of this Pair has a fmall Thread at its inner part. 
-3
  The SevAitb Pair arife from the beginning of the lateral parts
of the Medullary Oblongata, and  are divided on each fide into a
Portia Mollis, and Portio Dura.
  The Eighth Pair arile by fmall Fafciculi from the Corpora Oli-
varia.
  The Ninth Pair of Nerves alfo arife by fmall  Fafciculi, a lit-
tle below the former, from the Corpora Pyramidalia.
  The Origin of the Nerves  will be defcribed at greater length,
in a  fwbfequeht part  of the Volume.
OOOOOOCO~:>00000000'
OF  THE  EYE.
•Q
  The Eyes,  which conftitute the Organ of Virion, are fituated in
the Cavities of the Orbits, and  are  lurround.d by feveral parts,
fome of which protect  them from injury, and others affift in  the
peifoimance of their various motions.
  The Orbits are formed of two Cones, fituated in the fore-part
of the  Cranium,  with  their  Apices behind, their  Axes in  an
horizontal  fituation, and their Bafes turned obliquely ou'wards.
   Each of the Orb;ts is formed  of different Procefl'es of the fol-
lowing Bones, viz.
  The upper  part  -f  each Oi hit, by the Orb'tar  Plate of  the
Frontal Bone;—the inferior,  by the Oibitar Plates of the fuperi-
or  Maxillary and Malar Bones ;—the  internal,  chiefly by  the
Ortiittr part  of the Os Unguis and Pars Piana of the Ethmoid
Bone;—the external, by the Orbitai Plates of the Sphenoid and
Malar B nes;—thr pofterior, by the Sphenoid and Palate Bones;
—and  the  anterior edsje of  the Orbit,  by the Frontal, fuperior
Maxiliary, and Malar  Bones.
   The Cavities of  the Orbits are lined  with  Productions of the
Dur.i Mater,  which pafs out at the  Foramina Optica and Lacera
and, at the anterior edges of the Orbits, join the  Periofteum of
the Face, where they lupply  the  place  of Ligaments to the Pal-
pebral.
                        Supercilia.
   The Supercilia, or Eye-Brovjs, which are peculiar to the Hu-
man fpecies, are the arches of Hair fituated upon the Supercilia- 
2^
ry Ridges of the Frontal Bone.  T'ie Hairs are placed obliquely,
with their roots towards the Nofe, and the Arches elevated a lit-
tle above the left of the Fore-head, by a confiderable quantity of
Cellular Subftance lying under the Skin.
   They a.e moved in diffeient diiect ons by the acl: m of the
Frontal Corru:ator, and Oibicular.s Palpebiarum Mulcles.
   They are intended pi.rtlv for ornamem, and paitly as  fnr.dcs
over trie  Eves  thereby  pieventing  them from being injured by
t::„antoiis  Mattel,  or  by too great a quantity of light.  They
alfo aflilt in expi Tiling the paflion*  of the Mmd.
                       Palpebrje-
   The Palpebra, or Eye-lids, are chiefly  compofed of a doubling
of ihe Skin, mcl« lint;  pait  of  the Orbicularis Palpebrarum
Mufcle,  and the Cartilages called Tarfi,  and  forming angles at
therou.erand  inner extremities,  termed  Canthi,  or  Corners  of
the Eye.
   The Upper Fje-lid  is the one which moves  principally in clo-
fing or opening ihe Eye, the under moving only when the Eye-lids
are fliut with uncommon foice.
   The n">ticns of the Eye-lids are performed by the action of the
Oib-culans nnd  Lev'tor Palpebrarum Mufcles.
   The Eve-lids  feive an Curtains or Veils, to defend the Eyes
during Ueep : They likewife pi event them from being injured by
extianeoiis  obj its, or  by  too much light.   By  their frequent
motion they increafe the fecreiion of the Tears, apply them pro-
peily to the Surface of the  Eye,  and conduct what remains, after
waflnng the Eye, to the Pin.eta Lacrymaha.
                         Tarsus.
   This is a thin Cartilaginous Arch, fitintel in the cif-t of each
Eye-bd,  that in the upper  one being confiderably broader than
the one  below,  and each broader  at its  middle than towards its
extremities.
   Their edges are fo placed, that  when the Eye-lids  are fliut, a
groove is left next the Eye. by which the Tears are conveyed to-
wards the Nofc—They terminate  at a little dillance from the in-
ner angle of the  Kye.
   They ferve to  keep the Eyelids extended,  allow them to be ac-
curately applied  to each other, and prevent them from being col-
lected into  folds.
   Glandule  Sebaceae, Ciliares,-or  Meiboitianve,—
the laft term obtained from their being dtferibed by Mlieo.mi-
vs,-—are placed between the Tarfus and  lining of the Eye-lids,
and are formed of a fl-ries of white lines  or Follicles, miming in
ferpentine directions, which,  when viewed through a magnifier,
appear like rows of Pearls, from  which   an Oily or Sebaceous
Matter, refembling little worms,  miy  be readily fqueezed out 
                            2.3

through the Foramina or pun eta Cilaria', placed upon the edges
of the Eye-lids.
  The Matter of the Sebaceous  Glands facilitates  the motion of
the Eye-lids, and prevents their accretion during fteep.
                           Cilia.
  The Cilia, or Eye-lafhes,  are ftiff Hairs placed in the edges of
the Eye-lids.  Thofe of the upper Eye-lid are bent upwards, and
are confiderably longer than thofe of the under Eye-lid, which
are bent in the oppofite  direction.  In  both Eye-lids, they are
awanting near the inner Angle.
  The Cilia prevent duft,  infects,  &c. from getting into the
Eye, aflift in moderating the quantity of light fent into  it,  and
add to the beauty of the Face.

                Glandula Lacrymalis.
  The Glandula Lacrymalis, called, till  of late years, the Glan-
dula Innominata Galeni,  is fituated upon the upper and outer
part of the Eye,  in a  hollow behind the outer end of the Superci-
liary Ridge of the Frontal Bone.—It is a Gland of the Conglo-
merate kind, of a yellowifli colour,  of an oblong form, and a
little flattened, with  one  end pointing to the Nofe, the  other to
the outer angle of the Eye.
  Befides this, there is a chain of Smaller Glands, lying between
the principal Gland and upper Eye-lid,  and connecting them to-
gether.
  In the direction of the Smaller Glands, there are feveral Ex-
cretory Ducts,—defcribed by Dr. Monro,  1758,—which  run
nearly parallel to, but do not communicate with each other.
  The Excretory Ducts,  on account ot  their fmallnefs,  are not
often fcen, and are difficult  of injection.   They terminate on the
inner fide of the upper Eye-lid,  near the outer angle of the Eye,
and upper edge of the Tarfus.
  The ufe of this gland is to fecrete  the Tears, which arefpread
ever the Surface of the Eye by  their own weight, and  by the
motion of the Eye-lids, for the purpofe of preferving the delicacy
of the Eye, and particularly the tranfparency of the Cornea.
                  Puncta Lacrymalia.
  The Pun3a Lacrymalia are two fmall Orifices placed near the
inner angle of  the Eye, one in the upper, the other in the under
Eye-lid,  at the extremity of the  Tarfus, and  oppofite to each
other.
  Each Punctum is feated obliquely upon a fmall eminence, and
is furrounded with a Cartilaginous Circle, which  keeps  it con-
ftantly open,
  The Puncta Lacrymalia are  the Orifices of two fmall Canal",
wlr'chrun in the direction  of the edges  of the Eye-lids towards
    Vol. II.            C 
 the fide of the Nofe, where they approach each other, and termi-
 nate together in the, Lacrymal Sac.
   The Tears which remain after moiftening the Eye are abforbed
 by the Puncta, after the manner of Capillary attraction, and are
 conveyed through their Ducts into the Lacrymal Sac by th« im-
 pulfe of the Eye-lids.
                Caruncula  Lacrymalis.
   The Caruncula Lacrymalis is a fmall Gland of a rcddiih colour,
 of the Conglomarate  kind,  fituated between  the inner angle of
 the  Eye-lids  and  Ball of  the Eye, which fupplies  Sebaceous
.Matter to this part of the  Eye-lids,  and ferves in particular to
 feparate the Puncta Lacrymalia, and to direct the Teais to them
 while the Eye-lids  are fliut.
   Minute Hairs are found upon the Sui face of this body, ferving
 to entangle fmall objects which get into the Eye.
                 Valvula Semilunaris.
   The Valvula Semilunaris is a fmall  doubling of the Tunica
 Conjunctiva, which lies between the Caruncula Lacrymalis  and
 Ball of the Eye.
   It is larger in the Ape and other Quadrupeds than  in  the Hu-
 man fpecies, and (till larger in  Birds, in  which, as well as in
 Quadrupeds, it is called membrana NitTitans.
   It is in form of a Crefcent, the horns of which are turned to-
 wards the Puncta Lacrymalia, and aflifts the Caruncula in con-
 ducting the Tears to the Puncta.                     ,
                THE BALL OF THE EYE.
   The Ball,  Globe, or Bulb of the Eye, is of a fphe/ical form, to
 collect the rays of  light into a proper Focus, and is  furrounded
 behind by a quantity of foft Fat, to allow the Eye and its Muf-
 cles to move with facility.
   The Bali of the  Eye is compofed  of C.ais, Humours, Veffels,
 and Nerves,  to be  next dtferibed.
                        COATS.
                    Tunica Adnata.
   The Tunica Adnata, or Cnjunilive, named from  its connec-
 t'ng the  Eye to the Orbit,  is a reflection of the Skin continued
 from  the Eye-lids  over the whole fore-part of the Bull of  the
 Eye.                 *
   It  adheres  flightly fry  means  of  Cellular Subftance to the
 White of the Eye,  but fo firmly to the Cornea, as to be feparated
 from it with  difficulty.
   It is fo remarkably thin,  that the colour  of the fubjacent parts
 mine readily through it.
   Between this Coat and the white part of the Eye, there  is,a
 quantity of  loofe  Cellular  Subftance, which is veiy Vafcular,
 and is the common feat ,f Ophthalmia. 
27
  The Tunica Adnata fuppcrts  the Ball of the Eye,  prevents
extraneous bodies from getting to the back-part of it, and forms
a l.nboth covering to left-en the friction between the Eye and Eye-
lids.

                          Cornea.
  The Cornea, fo called from its refemblance to Horn, is termed
by many Authors Cornea Luiida, to diftinguiih it from the Scle-
rotica, named Cornea Opaca.
  It forms the antcr or Pellucid Covering of  the Eye, is more
convex  than the reft of the  Ball,  and  is joined to the Tunica
Sclerotica, like the Segment  of a fmall Sphere to that of a  lar-
ger one.   The convexity,  however,  varies in  d fit rent  perfons,
fo as  to form a fliort or long lighted Eye, according as  the Cor-
nea is more  or lefs  prominent.
  In  a recent  fub^d, it is  lnrd, denfe,  and  tranfparent ;  but
after  maceration in  water, it  becomes foft and  opaque,  and may
be readdy feparated,  efpecially  in  young Animals, into  differ-
ent Lamellae, the anterior of which is the continuation of the
Tunica Adnata.
  By a (light degree of putrefaction, it  may alfo be feparated
from  the Tunica Sclerotica.
  In  the Whale, the edge of the Cornea is received into a diftinct
Groove formed by the Sclerotica.
  In  a found  ftate, it has  no  Veflels  which  carry red Blood,
though fuch are frequently feen on it when  the Eye is inflamed.
  Its nerves are  too fmall to be traced;  yet it poflefles  exquifit:
fenlibility.
  It  collefls  the rays of light,  and tranfmits them to  the Eye,
protects the tender  parts within  it, and contains  the Aqueous
Humour.

                            Iris.
  The Iris, which is named  frort) be;ng in fome perfons of  dif-
ferent colours, is the only Coat which pofTeffes motion.   It  was
confidered as a continuation of  the Choio.d Coat, until defcribed
b\ Z nn,  who fliews that it  is  only connected  to this  Coat by
the medium of the Ciliuiy Circle.
  It is place !  at a lit;lc diftance  from the Cornea, begins a fmall
way behind the junction < f  that Coat  with the Sclerotica,  and
running   acrofs,  it forms a  Septum, a little convex  anteriorly,
and peiforatcd in the middle  by  a HoIeV called the Pup.I, or
light  of the Eye.
  The term Pupil is applied,  beeaufe it reprefents objects no lar-
ger than a Pupilla or Puppet.
  In  the Foetus, the Pupil is cove; ed with a Vafcular Membrane,
termed Membrana Pupillaris, which generally difappears  between
the fever.th  and ninth month  of geftaiion. 
2S
  Upon the back-part of the Iris, there is  a dark-coloured Pig-
ment, confidered by the Ancients as  a  pofterior Layer  of  the
Iris, called by thtm Uvea, from  its refemblance in colour to
the Grape.
  When the Paint is waflied off, the Iris exhibits two fcts  of
Fibres,—concerning which Authors  have entertained  various
opinions,—one in  the foim of Radii, tht different colours of
which give the diverfity of colour to the Eye ;  the other circular,
and furrounding the inner edge of the Iris,  and confidered  by
Dr. Monro as the Sphincter Mufcle of the Pupil.
  The Iris has alfo many Blood-\tflels,  which can be readily
injected ;  and has a greater proportion of Nerves than almoft any
other part of the Body.
  It floats  in the Aqueous  Humour, and  is  of fuch a nature,
that upon expofure to a ftrong light, or when the Eye looks upon
a near object, the diameter of the Pupil is diminifhed; and vice
verfa.
  The different motions of the Iris are  fuppofed  to be excited  by
the  fenlibility  of the  Retina, and the quantity  of light falling
upon that Nerve.
  The Iris  ferves to  regulate the quantity of light fent to the
bottom of the Eye.

                  Tunica  Sclerotica.
  The Tunica Sclerotica,  which is  named from its hnrdnefs, is
the largeft  and ftrongeft Coat of the Eye,  covering the whole
Ball,  excepting the parts occupied by the entrance  of the Optic
Nerve behind, and by the Cornea before.
  It is fo firmly fixed to the edge of the Cornea,  as to have been
confidered by many Anatomilis as  a continuation of the fame
fubftance;  but it differs from the Cornea in the following parti-
culars ;  it is of a pure white colour, i  foimed of Fibres running
in every direction,  and clofely  interwoven  with each  other, is
not  divifible into Layers,  and may be  feparated fi.-m it by art,
as has been already mentioned.
  It is  tlnckeft pofteriorly, and receives  a  little  time on  the
inner Surface, from the Choroid Coat, with  which it  is in con-
taa.
  It gives form and ftrength to  the Eye, and fupports the tender
parts within it.
  The Tendons of the four  Recti Mufcles of the Eye  are fixed
to the fore  p^irt of the Tunica Sclerotica ; and thefe, or the Cel-
lular Vaeinx covering them, have been fuppofed to give an  ad-
ditional  v\ hitenefs to the Eye; and thenar! giving this whitenefs
has been termed Tunica Albuginea:—But  the Sclerotic Coat is
every whereof a puie white, and can receive  little additional
bright in. fa from any fuch coverings. 
29
                   Tunica Choroides.

  This Coat derives its  name  from the Veffels with  which  it
abounds,  forming" a Chorus; or from its  fuppofed refemblance
to the Membrane called Chorion, which furrounds the Foetus in
Utero.
  The Choroides lies under the Sclerotica,  and is connected to it
by the Trunks of  Veffels  and Nerves which pafs  from the one
Coat to the other, and alfo by a tender Cellular Subftance, of a
brown colour, with which the inn?r Surface of the Sclerotica is
tinged.
  It begins at the entrance of the Optic Nerve into the Eye, runs
between the Sclerotica  and Retina,  nearly to  the  Cryftaliinc
Lens, where it is  more firmly  connected  to  the  Sclerotic Coat
than it is elfewhere, by means of the Ciliary Circle.
   The Ciliary Circle, or Ciliary  Ligament as it is called, is com-
pofed of a quantity of condenfed Ihining Cellular Subftance, which
forms a white Ring connecting the  fore-part  of the Choroides,
and  the root or outer Margin of the Iris, to the Sclerotica."
   The Choroid Coat is much thinner and more tender than  the
Sclerot'c, and is one of  the moft  Vafcular  parts of the Body,
feeming at fiift fi-Jit to be entirely compofed  of  Veffels.—The
gna;.er number of thofe on  the out tide run  in whirls ; while thofe
on the infuie,  running nearly parallel to each other, gave rife to
the fuppoled exiftence of the Membruna Ruyfchiana.
   It is  alfo fumifhed.with numerous Nerves, which are united
with its Veffels by a fine Cellular Texture.
   In the human Eye, the Choroides is of  a dufky brown colour,
 both externally and internally ;  Out the colour varies con fid era -
bly in the eyes of different annuals.
   I he inner Suiface of this Coat, which  is Villous, was defciib-.
ed by Kuvsch as a dijlinS Lamin,z,  and h  s  been  termed by
many Amu^nifts Tunica Ruyfchiana ;—Haller however, and
ZlNN, and many others who fo.lowed them, have dcmoiiltratcd
this Coat  to  con lift  of  only one  Lamina ;   though   in Sheep,
 ar,d  n fome other animals, it appears to be double.
   Upon  the inner lide of the Choroides, there  is a daik-culoured
 Mucus, called  Pigmentum Nigrum,—fuppofed  to  be  produ. cd
 from the Veffels of this Coat,—wtveh is bla::keft and thickeft at
 the  fore-put of the Eye, where it adhercf fo tcnacioully as to be
 removed  with difficulty ;  but  behind it  is thinner, more fluid,
 and more ealily removed ;  becoming gradually lefs evident,  and
 almoft difappearing round the Optic Nerve.
   In advanced a^e,  the Pigmentum Nigrum  becomes more  di-
 luted, and of a 1 .titer colour;  fo  that the Vcffeis of tf- Cho-
 roid Coat may be feen ihining through the Vit.eous Humour.
Vol.  II.
C2 
30
  Though HaLLER denies  that the  Membrana Ruyfchiana can
ever be feparated, in the Human Eye, f.oin the Choro de«,—he
retains the name, to denote the black Suiface of this Coat.
  In  grimeniverous animals, in fifties,  and  in  ihofe  animals
which rro in queft of prey in  the nighf, the Paint is of a light jmd
fluning colour in the bottom of the Eye, and is called Tapetum.—
In an entiiely wlvte Rabbit,  the Paint is awantiner,  and tht Eye
has a red cof.ur from the Veffels of the  Choroid Coat ;  but the.
lv.icefs dilip, ears when the animal is dead.
  A  the fore-part of the Choroid Coat, and oppofite to the Cili-
ary Circle, there is  a black radiated Ring, called Corpus Ciliare,
which is  about  the  fixth part of an inch  in breadth towards the
Temple,  b.it fomewhat narrower towards the Ncd'e.
  In the pofterior portion of the Corpus  Ciliare,  there  are nu-
merous pale radiated Ciliary  Stria, but fo covered with the P'g-
mentum Nigrum, as not to be diftinctly feen till the Paint is re-
moved.
  Near disconnection of the  Corpus Ciliare with the root of the
Iris, thefe Striae become gradually broader and more ele\ ated, and
form about feventy white Plica or Folds, termed Proctffus ( iliares,
the  intervals of which are  alfo covered with Pigmentum Ni-
grum.
  The Proccffus  Ciliares, which obtain their name from their re-
femblance to the Cilia of the Eye-lids, are commonly formed each
of two or  more  Striae,  are not all  of an equal fize, and many of
them forked at their extremities.
  The Corpus Ciliare, formed of the Ciliaiy Stria; and C liary
Proceffes,  has no appearance of Mufcularity, though the contrary
has been fuppofed by fome Authors.   A fine  Injection fhew, it
to be chiefly formed of a continuation of the Blood-veflels of  the
Choro'd coat, the branches of which divideinto fuchm nute partf,
as to give the whoie a Villous appearance.
  The Corpus Ciliare is glued to the Retina,  at the fore-part of
the  Vitreous Humour,  and a' little behind the edge of the Cry-
stalline Lens ;  but the Ciliary Proceffes float in the Aqueous Hu-
mour in the pofterior chamber of the Eye, at the inner  fide of the
root of the Iris,  and may be readily turned back behind the edge
cf the Lens, to which they are contiguous,  but do not adhere.
  The Choroid  Coat, with its dark Pa'nt, ferves to fuffocate the
rays of light which pals through the Retina,  and thereby to al-
low a diftinct image to be formed upon the bottom of the Eye, and
to prevent the rays from  being reflected fo as to  form a fecond
im '•.:/-.
  In thefe animals in which this Coat or its Paint is of a bright
eolour, it acts as a minor to reflect light, and make the impreflion
ftronger. 
31
                Optic Nerve and Retina.
   The Optic Nerve, in  its paffage through the Orbitr  is cover-
 ed by a continuation  of the Membranes which  furround  the
 Brain.
    At  the Foramen  Opticum, the Dura Mater is  divided  into
 tvjo Lamina, one of which affifts in  forming the Periofteum  of
 the Onm;  the other, which is again divided into two Laminae,
 furnifhes a fheatli to the Nerve, and accompanies it to the Tuni-
 ca Sclerotica, to which it is fo firmly  connected by Cellular Sub-
 ftance, as to hav; induced fome Authors  to defcribe the Sclero-
 tica  as a continuation of the Dura Mater
    The Boay of the  Nerve  is ftill more clofely inverted by the
 Pia Mater,  which  alfo forms (heaths round  the Neivous Fafci-
 culi,  and accompanies the Nerve into the E)e.
   At the back-part of the Ball of the Eye, and a little removed
 from the Axis,  towards the  Nofe, the Fafciculi of the Optic
 Nerve pafs through a Cribriform part of the Sclerotic Coat.
   The Nerve is contracted  at  its entrance through the  Sclerotic  -
 Coat,  but immediately^ after its ingrefs,  it expands to form the
 Retina,—lb called from its fuppofed Reticular appearance.
   In the middle of the en_rance of the Optic  Ne, ve,  the Artery
 is i'een dividing into  branches, which are difpeifed  upon the in-
 ner Surface of the Retina.
   The Retina advances between the  Choroid Coat and Capfule
 of the  Vitreous  Humour, to  the  fore-part  of the Eye,  and ter-
 minates or difappears upon the anterior part of the edge,  or great-
- eft diameter of the Capfule of the Cryftalline  Lens.
    The Retina is  contiguous to the Choroid Coa and Capfule  of
 the Vitreous  Humour, but does not adheie to either, by Blood-
 vcffels or otherwil'e,  till it reach the Corpus Cii  are.
   Under the Corpus Ciliare,  the Retina is lb  cove.ed externally,
 with the Pigmentum Nigrum, and adheres internally  fo cJofely
 to the Capfule of the Vitreous Humour, as to be prevented fiom
 being feen till the black Paint be waftied off, orti-1 all the Coats
 be removed poftei iorly, and the Eye viewed through the medium
 oi the Vitieous Humour.
   The Retina is compofed of a tender and Pulpy-like Subftance,
 isfemi-tranfparent,  and of a  light-grey colour, refembling that
 ofgiouhd glafs.
   From the entrance of the Optic Nerve, to the e-djrc of the Cor-
 pus Ciliare, the Retina is  of an equal and  uniform  Subftance,
 and is fo eafily torn and feparated from the edge of  that  body,  as
 to be defcribed by many Authois  as terminating there.
  _ Undei the Striae and  Pioceffes of the Corpus  Ci lare,  the  Re-
 tina is thinner than in  the pofterior part of the Eye,  and  is fo im- 
3:2
preffed by thefe bodies, as alfo to have the appearance of Striae,
vhich terminate in  numerous minute  Fibres, like Nerves  in
other parts of the Body.
   The Retina is the  ll it of  Vifion, and therefore the primary
partot the Eye,  to which all the other parts within the Orbit are
fubfervient.

                       HUMOURS.
                   Aqueous Humour.
   The Aqueous Humour is lodged in the fpace between the Cor-
nea and Cryftalline Lens.
   This fpace is  divided into two Cavities, called Chambers,  the
anterior of which -s  fituated between the Cornea and Iris, and is
the larger of the two.
   The pofterior is placed between the Iris and Cryftalline Lens,
and  is fo much fmaller than the former,  that  its exiftence has
been denied by fome Authors, though it is a diftinct Cavity,  de-
monftrable, m,t only in the Adult, where the Pupil is open, but
in the Foetus  before the Pupil is formed.
   The Aqucjus Humour is clear as the pure ft  Water,  but is
fomewhat heavier, pofl'elTes a  fmall degree of  vifcidity,  contains
a little Salt, and is about five grains in weight.
   In the  Foetus, and for the firft  month after birth,  it is reddifh
and turbid.
   When evacuated, it is qtrckly renewed  ;  for  within forty-
eight hours after it has been let out by a  puncture, the Cornea is
obferved to be again reiftcliy diftended.
   It is fuppofed to be fecreted from the  neighbouring Arteries,
particularly  fiom thole on the feie-pai:  of the Iris and Ciliary
Proceffes.
   I  ferves to keep the Cornea diftended, and, by its  roundifh
form and pell .cidity,  it col Lets and tranfmits the  rays of light
to the inner parts of the Eye.  It likewife  guaids  the Ins  and
Lens,  and ud/mits of the'm.tions of the forme..
                  Crys i alline Lens.
   The Cryflalline Lens, wh.ch has its name from its refemblance
to Cryftal, and fiom  it-* Lenticular form,—th.ugha foiid  body,
which may  be moulded into various fhapes,—has  always been
ckflVd among the Humours of the Eye.
   It is  fituated behind the  Aqueous Humour, oppofite  to the
Pupil, and the whole of  its pofterior pai;  is  received into a de-
prtflion on the forepart of ihe Vitreous  M irnour.
   Like a common Lens,  01 magnifying Glafs, it has two convex
Surfaces, the anterior of which is in  general lefs convex than the
pofterior, the two being formed of fegments of fpheres of an un-
equal fize. 
33
  The anterior Suiface, according to the experiments of Petit,
forms the fegment of  a fphere, the diameter of which is between
i't\en or  eight lines, or twelfths  of  an inch ; while the pofterior
Surface is only equal to the fegment of a fphere of about five lines
in diameter.
  It has  been obferved by Zinn,—that the  figure of the Lens
varies at  different periods, being in the Foetus almoft of a fpheri-
cal  form, but becoming gradually flatter on the anterior and pof-
terior Surfaces,  till about the age of thirty, after which its form
does not  appear  to vary.
  As the figure, fo alfo  the colour and confiftency are found to
change at different times of life—In  the  Foetus, not only the
Capfule,  but the Lens alfo is of a reddifli colour ; but, imme-
diately after birth, they become  perfectly tranfparent.—In a per-
fon confiderably advanced  in years, the Lens is  obferved to ac-
quire a certain degree  of yellownefs, which appears firft in the
centre, and afterwards extends gradually  to the  circumference;
and in extreme old age, this  yellow tinge becomes fo  deep as to
refemble Amber.
   An  Aqueous Fluid is  defcribed as betig fituated  between the
Cryftalline Lamellae, which  is fuppofed to  decreafe in quantity,
and to become yellowifli, the Lens at the fame time increafing in
folid ty as  the perfon advances in life.—This difference however,
of convexity, colour,  and  confidence,  according to  the difference
of  age, is not uniformly met with.
  The Lens becomes opaque foon  after death,  and acquires an
additional opacity when put into  fpirit of wine.
   It is compofed of  cancentric  Lamellse,  laid over each  other
like the coats of an Onion.   Thefe Lamellae are  connected by a
fine Cellular Subftance,  and are  more clofely compacted the near-
er they are to the centre.
   Th's lamellated ftructure may be readily obfeived  in the Eye
of an Ox, or any other large animal, but is moft evident when the
Lens has been macerated in Water or Vinegar.
   When the maceration  is continued  for fome time, the Lamel-
lae  put on  a radiated appearance, the  Radii running in a vertical
manner,  or iflfuin - from the centre to the circumference, dividing
the Surface into Ilofcular Triangles.
   The Lamellae were difcovered  by LEUWENHOECK,  to be of a
Fibrous ftructure.   By a late writer, thefe  Fibres have been con-
fidered as Mufcular,—hut this opinion of the Mufcularity of the
Lens,  feems to have  ained very few profelytes.
   The fubftance of  the  Lens fomewhat refembles half-melted
Gum, is very loft and tender on the  outlide,  but becomes gra-
dually firmer and tougher towards the centre, wiur. it  forms a
Nucleus.
  The Lens is  furrounded  by a very pellucid proper Capfule,
called Tunica Aranca, or Cryflallina,  which is much thicker and 
                             34

 more elaftic than the Capfule of the Vitreous Humour,  but ad-
 heres fo flightly, and  is fo eafily lacerated,  that after  a finally
 puncture is'made in it, the Lens ttarts out, upon applying gen-
 tle preffuie to the Capfule.
   The  pofterior part of the Capfule is much thinner, fofter, and
 weaker than the anterior ;  but is quite a dijlincl Membrane from
 the Tunica Vitrca ;  yet fo  fit inly connected to it by Celiulai Sub-
 ftance, that it is d.fficult to feparate them whhoi.t lacerating both
 the Vitreous Coat and its Humour.
   Some Authors defcribe an Aqueous Humour as feated between
 the Lens and its Capfule; while others, of no fmall refpe6>abili-
 ty, deny the exiftence of  this Humour,  as  well as of that  which
 is faid to be fituated between the Lamelhe of the  Lens.
   The Vcfftls of the Lens are not  to be feen  in  the  Eye  of nn
 Adult; but in  that of a Foetus,  Petit  found Veflels pafling  jf
 from  the Corpus Ciliare,  over  the fore-part of the Capfule of the
 Lens.
   Winslow afterwards obferved, that in the Foetus, and in new-
 born children, a fine injection fucceeued fo well as to difcover the
 Veffels  of  the Membrana Cryftalina and Vitrea ;—and in  a Foe-
 tus of about fix months, the injected liquor feemed to him to have
 penetrated  a part of  the Cryftalline and Vitreous Humours.
   Albinus derives thefe veflels from  a double fouice.—In the
 Eye of a Whale, he demonftrated Veffels pafling from the  Cilia-
 ry Procefl'es to  the Subftance of the Lens ;—and, at a later peri-  J
,od, he injected  in the human Eye, a fmall  branch arifing from
 the Cential Artery  of  the Retina, which proceeded in a ftraight
 direction through the Vitreous Humour, and divided in the pofte-
 rior part of the Capfule into numerous branches, many  twigs ct
 wh ch plunged  into the Subftance of the Lens.
   This artery and its branches, have been frequently andfuccefs-
 fully  injected by fucceeding Aiiutomifts.

                  Vitreous Humour.
   The Vitreous Humour,  fo called  from its ief mbhnce to melted
 Ghfi, is fitu-.ted in the back-part of the Cavity of the Eye,  which
 it occupies from the inferrioii of the Optic Nerve  to'the Surface of
 the Ciyftaline Lens.
   It is round at the back-part  r.nd fides, where  it is covered by
 the R'-tina, but is concave before, wiieie it  forms a bed for the
 Cryftalline Le i=.
   It  is by much the largeft cf the three  Humours, occupying
 upwards of n:ne-tenths of th"e whole E . .-, and has a Gelatinous
 appearance,—oi' is fomewhat like the ^ia;re c-t an Egg.
   In  an Adult  it is always very tranfparent,  and in an Old Per-
 fon it does not like  the Lens, degenerate into a yellow, or any
 o;her colour. 
  In the Foetus, like the Aqueous  Humour,^ it is of a reddifh
colour.
  The liquor with  which the Vitreous  Humour,  is filled,  is
fnnilar to the Aqueous,—very fluid,  tranfpires readily through
the Capfule,  though  that Coat be entire, and,  like the Aqueous
Humour, is  fomewhat thicker,  heavier,  and more vifcid than
Water.
  When this Humour is evacuated by puncture, in the living Bo-
dy, it is very feldom, though  fomelimes renewed.
  Upon the Surface of this Humour there is a Coat, termed Vi-
trea, as tranfparent as  the Humour itfelf, and  fo thin and Cob-
web-like,  as to have the name of Aranea.
  The Tunica Vitrea is remarkably fmooth on its outer Surface;
but within it fends Pro effes into the body of the Humour.
   Seme Authors, and among thefe WiNSLOW,  have defcribed
this  Coat  as confifting of two  Laminae, but  Sabatier, and
other late writers, ftem fufliciently fatisfied that  it is a  fingle
Layer ; and even this fingle Layer cannot be raifed  but with dif-
ficulty, though it is demonfti able by making a  puncture to allow
the Humour to efcape, and by afterwards diftending the part with
air.
   The ftructure of the humour coniifts in a fet of delicate Cells,
which contain  the liquor within them, as may be feen  by the
affiftance of Acids, or by boiling Water, or by Congelation.
   The Cells of the Humour communicate freely with each other,
as appears from the liquor oozing out by the  fmalleft puncture
made in the general  Capfule.
   Under the Corpus Ciliare, the Capfule of the  Vitreous Hu-
mour fends ofF an external Lamina,  which  accompanies the Re-
tina, aiid is inferred with it into the fore-part  of the Capfule of
the Lens,  a  little before its anterior  edge.   It is termed Mem-
branula Corona Ciliaris,  or  Zomula Ciliaris,  from its Striated
appearance and Circular form,  and affifts in  fixing the Lens to
 the Vitreous humour.
   After fending off  the  Ciliary  Zone, the Coat of the Vitreous
Humour goesfeehind the Capfule of the Lens,  to which it firmly
 adheres.
   Between the Ciliary Zone  and part where the  Capfule  of  the
 Vitreous Humour adheres to  that of the Lens,—which is at  the
 fame diftance behind the edge of the  Lens with the diftance of the
 infantum of the Ciliary Zone  before it,—a Paffage is formed, na-
 med Can.r/is Petitianus, after  Petit, who difcovered it.
   The Membranes  forming  this Paffage are pervaded by  tranf-
 verfe Fibres, in fuch a manner,  that when air is-introduced,  it
 trues fieely round the  edge of the Lens; but the Paffage has a
 C'llular appearance,  being contracted and dilated alternately, 
                             36
                                          V
   The Canal of Petit is nearly of the  fame breadth  with the
Corpus Ciliare, is always empty and has no communication with
the Gapfules of the Vitreous or Cryftalline Humours.
   No Veffels are to he feen in the Vitreous Humour of an Adulr,
but in the *Eye of a Fretus,  an artery is  obferved to arife from
the central one of the Retina,  which paries through the middle of
the Vitreous Humour,  fending twigs to the Cellular Texture of
this Humour while the principal Trunk is continued to  the Cap-
fule of the Cryftalline Lens, as has been  already obferved.
   The Vitreous Humour ferves to give fliape to the Eye, to keep
the Coats properly expanded, to preferve the due diftance of the
Lens, and  direct the rays of light to the Retina.

         MUSCLES OF THE BALL OF THE EYE.
   The Ball of the Eye is moved by fix Mufcles, which  are divi-
ded, on account of  their drection,  into Jour ftraight  and  Ivjq
oblique Mufcles, obtaining their refpective names from their fize,
fituation, direction, or ufe.
   Of the ftiaight Mufcles, one is fituated above the Eye, ano-
ther helow it, and one on each fide.  Of the oblique, one  is  placed
at the upper and inner, and the other at the under and outer part
of the Eye.
   The RecliMufcles are not ftiaight, as the name implies ;  for,
on account of the fituation  of the Eye and fliape of the Oibit, the
internal,  or that next the Nofe, is the only one which runs in a
ftiaight direction.
   Neither are they all equally long, the internal being the fliort-
eft, the external the longeft, and  the other  two nearly of  the fame
length.
   The four ftraight Mufcles,  which bear  a ftronj; rtilmblance to
each other,  arife by  a narrow beginning,  a little Tendinous and
Flefhy, from tin edge of the Foramen Opticum,  where  they em-
brace the Optic Nerve at its entrance into the Orbit.
   In their  paffage  foi wards, they form  Flefhy  Bellies,  which
fend off broad and very thin Tendons,  to  be inferted  into the
Sclerotic  Coat, under the Tunica Adnata, about a quarter of an
inch behind the edge  of the Cc.::ea, and at equal diftances from
each other.
  At the  place of their infertion they are fo  intimately connected
with the  Sclerotica,  that they cannot be feparated from  it,  % be
brought as  far as the Cornea,, without evident laceration.
   The different Mufcles of the Ball, of the Eye,  where thev lie
upon the Ball, aie covered with a Cellular  Sheath, which after-
wards degenerates into that Cellular Subftance which is interpo?
fed between -\x Sclerotica and Conjunctiva.

                                                  « 
37
                    Levator Oculi;
               Or Reel us Attollens, or Super bus.
  Origin : From the upper part of the Foramen  Opticum, below
the Levator Palpebral Superioris.
  Infertion:  Into the upper and fore-part of the Tunica Sclero-
tica.
  ABion :  To raifethe fore-part of the Ball of  the Eye.
                   Depressor  Oculi ;
              Or Retlus Deprimens,  or Humilis.
  Origin : From the inferior part of the Foramen Opticum.
  Infertion:  Op;>«.iie to the former.
  Ailion :  To pull the fore-part of the Eye downwards.
                   Adductor Oculi;
              Or ReJIus Adducens, or Bibitorius.
   Origin : From  th': Foramen Opticum, between the Obliquus
Superior and Depreffor.
   Infertion :  Oppofite to the inner  angle.
   Ailion : To turn the fore-part of the Eye towards theNofe.
                    Aeducpor  Oculi;
            Or Reelus Abducens, or Indignabundus.
   Origin : From the  B jny Partition between the Foramen Opti-
cum and Licerum.
   Infertion:  Into the Ball  of the  Eye, oppofite to  the outer
Angle.
   Ailion : To turn the fore-part of the Eye towards the Temple.
   W:icn two of the oppofite Rjcti  Mufcles,  or all of tliem act
together, they draw the Eye into the Orbit.
   When two of the adjicent Recti Mufcles act, they turn the
fore-part of tli'j Eye  obliquely in a direction towards their Ori-
gins.
                  Obliquus Superior;
              Or Obliquus Major,  or  Trocklearis.
   Origin: Lik.- the ftraight Mufcles, from the  edge of the Fo-
ramen  Opticum,  between the Levator  and Adduit r  Oculi.
From thence it runs ft.aigh  forward, fends oft" a  long round fen-
don,  which  paftes through a Cartil igmous Pulley  fixed beh nd
the Internal  Angular Procefs  of the Os Frontis :  tro.n this it
rundpi little downwards, and  retui ns  backwards and outwards,
paffnv;  under the Levator Oculi, to have its
   Infertion :  By a Broad thin Tendon,  into the Tun'ca Sclerotica,
about half-way between the infertion of the Levator Oculi an I
entrance of the Optic Nerve.
   Aefior. : To roll the  Ban of the Eye,  by turning the Pupil
downwagds and outwards.
   Vol? II.           D 
3S
                  Obliquus  Inferior;
                    Or Obliquus Minor.
  Oririn: By a narrow beginning, from the nntciior edge of the
Orbitary Procefs of the Superior Maxillary How;,  near the La-
crymal Groove, from which it paffes obliquely outwards,  back-
waids and upwaids,  round the Ball of the Eye.
  Infertion :  By a broad thin Tendon, into the Sclerotic Coat,
bctv.e^n the entrance of the Optic Nerve and infertion of the Ab-
ductor Oculi,  and oppofite to the iniei tion of the Superior Ob-
lique Mufcle.
  Ailion : To roll the Ball of the Eye, by turning the Pupil up-
wards, and  inwaid*, and, with the affiftance of  the  Superior
Oblique Mufcle, to pull the Eye forwards, thereby  becoming an
antagonilt to the Recti Mufcles.
  The two Oblique Mufcles, on account of rolling  the Eye, and
nflifting  it in the ex predion of certain paflions, have been called
Rotatores, or Amatores.

                  VESSELS OF THE EYE.
  The  Frontal,  Fafcial,  and  Temporal  Arteries, which  are
branches of the  External and Internal Carotids,  fupply the Pal-
pebral, and communicate  with  thofe v.hich are difpeifed within
the Orbit.
  Some  fmall branches  of the  Internal Maxillary Artery  pafs
through the Inferior  Orbitar Fiffure,  to be difpeifed chiefly upon
the Periofteum of the Orbit and Fat  of the Eye.
  The Ocular Artery, which is a branch of the Internal Carotid,
paffes though the Foiamen Opticum,  in company  with the Optic
Nnve, and fupplies the Fat, Mufcles, and Ball of  the Eye, and
alfo the  Laciymal Gland and Tunica Conjunctiva.
  The branches which belong to the Ball  of the Eye,  have the
name  of Ciliares :—They perforate  the  Sclerotica in  different
places, and are afterwards difperled chiefly upon the Choroid Coat
and Iris.
  One branch of  the Ocular  Artery,  called  Centralis Retina,
peifolates the Optic Nerve, and is difpeifed up n the  Retina.
  The Veins  which  conefpond- with the  Arteries cf the  Eye,
communicate freely with each othc, and pais partly  to the Exter-
nal Jugular Vein, by branches fituated about the fore-part of the
Orbit, and partly to the Internal Jugular Vein by ihe Cavernous
Sinus.

                  NERVES OF THE  EYE.
   Befides the Optic Nerve, already taken  notice of, the Eye re-
vives tiit Third and Fourth Pairs,  and branches  frorriythe firH 
39
part of the Fifth Pair, together with the Sixth Pair, and branch-
es from the Seventh.
   The  parts about the fore-fide of the Orbit  are  fupplied  by
branches from the Fifth and Seventh Pairs;—the Ball of the Eye
by Nerves called Ciliary,  which come from the Third and Fifth
Pairs ;—the fat,  Mufcles,  Lacrymal Gland, Sec. are fupplied by
the Third, Fourth, Fifth, and  Sixth Pairs.
   The ufe of the Eye is, to receive and collect the rays of lio-fit,
in fuch a manner as to form upon the Retina the image or picture
of the object which the  Eye looks at; and the point where thefe
different rays meet is called the Focus.
   The object is painred upon the Retina  in an inverted manner,
the rays from  above falling upon its  under,  and thofe from be-
low upon its upper pait; and  it is fuppofed  to be by habit,  or
rather by inftinct, that we judoe of the real fituation of any ob-
jea.
   That the rays of light may terminate diftinctly on the Retina,
it is  neceffary  that both the Cornea and  Cryftalline Lens ftiould
have a certain degree.of convexity.
   If  either the one or the other be too prominent, the Focus will
be formed before it reach the Retina, as is the cafe in fhort-fight-
ed people, who require concave glaffes to  enable them to fee ob-
jects diftinctly, at the proper and ordinary diftance.
   If, on the  contrary, the Cornea or Lens  be too flat, or the
refractive power of the Humours be in any way  diminilhed, the
Focus will then  be imperfectly formed, till the object is viewed at
a greater diftance than ordinary, as is the cafe with perfons ad-
vanced in life,  to whom the affiftance of  convex piaffes  becomei
neceffary.
   How an object,  viewed  with bo;h Eyes,  appears finale, has
been afcribed by the generality of" Authors to cuftom and habit;
and  by others to inftinct,  which regulates the uniform motion of
the Eye, and the accurate application of both to one point.
   The Eye is  enabled  to judge of,  or accommodate iifelf to ob-
jects at different diftances,  by the action cf its Mufcles  increa-
ling or dimiivftiing the length of its Axis,  and by the nvtonr of
the Iris allowing a grea.er  or fmaller quantity oi' light to  h*
thrown into the  Eye. 
40
OF   THE NOSE.
  The Nofe, which is the Organ of Smell,  and contributes  f«
the general purpofe of  Refpiration,,  is divided into the External
Prominent Pait, and the Internal Cavity, which is feparated by
the Septum Narium into two fmaller Cavities^—or,  it is divided
into Hard and Soft parts.
  The External part, or Nofe, properly fo called,  is cempofed   '.
fuperiorly of Bones,  interiorly of Cartilages, and has a  partial
covering from the Mufcles,  and a general one fiom the common
Integuments.
  On theoutfideof the Nofe are obferved,—the  Radix,  or upper
part;—i!-e Dorfum, or middle prominence ;—the Apex, or point ;   - j
—the Ala, or  latnal moveable  parts;—and Columna, or under
part of the Partition next the Upper Lip.
  The Offcons part of the Nofe is formed by the Offa Nafi,  pro-
peily  fo called, the Offa Maxillaria and Os Frontis, whieh con-
ftitute the upper and fore-part :
  By the Os Ethmoides and Offa Unguis,  which form the  tipper,
inner,  and lateral parts :
  And by the Offa Maxillaria Superiority Offa  Palati, Os Sphe-
noides,  Offa Spongiofa Inferiora, and Vomer, which form the un-
der, inner, and  back-part.
  The tivo Cavities, or Noftrils, terminate anteriorly in the Face,  *J
and pofteriorly in the Fauces, and are much enlarged by  the dif-
ferent Sinufes which communicate with them.
  The  under and fore-part of the Nofe confifts of five Cartilages,
of a fomewhat regular figuie, and of fome fmaller pieces, which
are  more irregular, and cf an in.letermina e number.
  Of the five Cait  lages,  one is fituated in the  middle,  and the ■
other four laterally.
  The  middle  Cartilage is the moft confiderable, ar.d  fupports
the  relt : It conftitutes the Cartilaginous  part of the Septum Nari-
um, and is joined to the anterior ed .e of the Nafal Lamella of the
Ethmoid  Bone, to the anterior edge of the Vomer, and to the
fore-part of the Spinous Procefs  of the  Superior Maxillary
Bones.
  Of the  lateral Cariihres, two are placed  anterioily,  form'ng
by thci - curved  union the I'ip of the Nofe ;  ami two poftencrly,
which form the Ai« Nafi. 
II
  Between  the  anterior and  pofterior  Cartilages, are  fpaces
filled with  additional Cartilages, the number, fize, and figure,
varying in different bodies.
  The ehfticity of the Cartilages contributes to the defence of
the Nofe againft external injuries.
  The Nofe is covered  by the common Integuments,  and per-
forated at its  under and outer-part  by the Ducts of Sebaceous
Glands,  the contents of  which may be readily fqueezed out  by
the preffure of the Fingers.
  The Cartilages of the Nofe are moved in  different directions,
by the following Mufcles,  which have  been already defcribed,
viz. the Compreffbr Narium, the Nafal part of the Frontal Mufcle,
the Levator and* Depreffbr Labii Superioris  Alaqtii  Nafi.—The
Nofe  may  alfo be  moved by the neighbouring Mufcles, which,
in many inftances,  become afliftants to the others.
  The internal Nares or Cavities of the Nofe extend upwards to
the Cribriform Plate of the Ethmoid, and to the  Body of  the;
Sphenoid Bone.
  At the  inner  fide they are  bounded by the feptum  Narium,
which is  formed by  the Nafal Lamella of  the  Ethmoid Bone,
by the Vomer, and by the middle Cartilage of the Nafe.
  On  the outfide,  or that next the Cheek,  the Offa  Spongiofa
project a confiderable way into their Cavities, and  increafe  the
Surface of the Membrane of the Nofe, for enlarging the  Organ
of Smell.
  In  animals  which fmell  acutely,  the Offa Spongiofa  are  re-
nin kably large and complex.                                 *
   The bottom of  the Noftrils runs  directly backwards, fo that a
ftraight  probe may be paffed through either  of  them  to  the
 Throat.
   In  the fore-part of the Noftrils  there  are ftiff Hairs, called
Vibriffa, which  pi-event the Mucus from conftantiy flowing out,
and infects, or other extraneous matter from  entering.
  The general Cavity of each Noftril is divided by the Offa Spon-
giofa into three Meatus, or Paffages,  which run fiom before back-
wards, and are defoibed  by  Haller according to their fitua-
tions, viz.                                                  ^
   The Meatus Narium Superior, placed at the upper, inner, and
back-part of  the Superior Spongy Bone.
   The Meatus  Medius, fuuated between the Superior and Infe-
 rior Spongy Bones.
  JThe Meatus  Inferior,  fituated between the Inferior  Spongy
Bone and bottom of the Nofe.
   Tiie in fide  of the Nofe is lined with a thick  Spongy Membrane,
termed Mucofa, or Pituitaria of  Schneider, or Schneideri-
 *>ia, which lines the whole internal Nares,  and  is alfo continued
                           *

   Vol. II.    '   *D2 
*
42
  to the different Sinufes, to the Lacrymal Sacs and Palatine Ducts,
  to the Pharynx, Palate, and Euftachian Tubes.
    This Membrane is very Vafcular and Nervous, and is the pri-
  mary Organ  of Smelling.   It is  coniiantiy lubricated  and pic-
  ferved in  a proper degree of moiftuie by the Mucus of the Nofe,
  which is difcharged  upon its Surface from numerous fmall Fol-
  licles.
    The different Sinufes of the  Bones of the Hejd,  after  havirc,'
  run obliquely backwards in a fhorr winding direction,  terminate
  by fmall openings in  the Cavity of the Nofe.
    The Frontal Sinufes pafs downwards into the anterior  Ethmoid
  Cells, w'.iich  terminate in  the upper part  of the Nofe,  behind
  the beginning of the Lacrymal Sacs.         '
    Befides the Paflages common to  the Frontal  Sinufes and ante-
  rior Ethmoid Cells, there are others proper to the Pofterior Eth-
  moid Cells,  which terminate in the upper  and back-pait of the
  Nofe, near the openings of  the Sphenoid Sinufes.
    The SpbenoitLgSinufes open,  behind the Cells of  the  Ethmoid
  Bone, into the upper and back-part of tiie Nofe.
    The Maxillary Sinufes open at their upper and inner  fides, by
  flne, and  fometimes  two paflages, into the nvddle of the fpace
 "between  the  Superior and Inferior Spongy Bones,  nearly oppo-
  fite to the under ed^e of the Orbit;.
    At the upper part of the Maxillary Smufes, Appendices, defcri-
  i-e.l by Haller, are fometimes found, which communicate with
  the Ethmoid  Cells.
 %  Ti.e Sides, or Walls of the Maxillary Sinufes,  are formed of
  thin  Plates  of Bone,  excepting where the Proceffes project  and
  £ive them additional ftrength.  Below,  they have only thin Plates
  between them and the Dentes Molares,  the roots of" which  are
  fometimes  found to perforate the Septum.
    The different Sinufjals are  lined with a continuation of the Mem-*
  hrana Schneideriana  ; but in thefe it is thinner, lefs Vafcular and
  Nervous,  than that part of  the Membrane which lines the gene-
  ral Cavity  of the Nofe.
    They are conftantly moiftened,  but not filled with a fluid.
     The  Sinufes increafe and modulate the voice : Their hollow
■* ftructure  renders the Bones lighter;  but they do not  appear to
  tonftitute part of the Organ of Smell.                        • ''-.
     Their paflages being direaed backwards, prevent any kind of
  extraneous matter from getting into them.
     The Lacrymal Sac is a  Membranous Canal, fituated in  the
  Lacrymal  Groove, formed  by the Superior, Maxillary, Lacry-
  mal, and Inferior  Spongy Bones.
     The Offeous Duel, in its  defcent, runs a little obliquely bnck-
  wards to  the lower and lateral part of the Cavity  of the Nofe
  where  t  terminates at the  inher and fore-pp;t of the  Antrum
   i'r« Hare, under  flie  Os  Spongiofum Inferius, a little behind 
43
  the anterior extremity of that Bone, and in a direct line upwards
  from the fecond Dens Molaris.
    The ueip:r part of the Offeous Paffage forms only a femi-canal,
  the under end a complete one.                    ..■■
    The Lacrymal Sac is fituated  in the upper part of the Lacry-
  mal  Groove, behind the Tendon of  the Orbicularis Mufcle of
  the Eye-lids.  About a fourth part of the Sac  is  fituated above
  the-Tendon, forming a kind of Intejlinum Cacum, and the reft is
  placed below.
    Towards  the inner angle of  the Eye, behind  the Tendon of
  the Orbicularis Mufcle, the Sac is perforated by the  Lacrymal
  Duas.
    The under part of the  Sac  becoming a Utile narrower, but
  without forming any Valve, paffes into  the Nofe, under the name
  of Lacrymal Duel, Canalis  Nafalis,  or Duel us  ad Nafum, and
  terminates at the^inferior extremity of the Offeous Canal.
    The fubftanee of the  Lacrymal Sac  and Dua is  fimilar to that
  of the Membrana Schneideriana, is defended with  the fame kind
  of Mucus with which this Membrane is lubricated, and is firmly
  conneaed to the Periofteum of the Offeous Canal.
    The ufe of this paffage is,—to  convey the fuperfluous  Tears
  to the Nofe, fo as to  prevent them from raffing over the Cheek.
    The Duclus  Incijivus, or NaJ'alo Palatinus of  St^no,  is a
  fmall Canal, which,  as has heen already obferved in  the defcrip-
  tion  of the Bones,  is  only fometimes met with  in  the Human
  Body, though it is always to be found in the Ox, Horfe,  Sheep,
  &c.
     When prefent, it takes its origin from a fmall Pit,  formed in
  the fore-part of the b*<?|tom of the Noftril,  under the termination
  of the Lacrymal Dua." It runs  obliquely downwards and for-
fc wards, placed in fuch a manner as to receive and condua Tears
  into the Mouth.
     The Arteries of the  Nofe come chiefly  from the external Ca-
   rotids.
     Thofe of the outer part of the Nofe come from  the Facial and
  Internal Maxillary  Arteries;—thofe of  the  inner,  from the
  Maxillares  Interna?;—and a few twigs are furnifhed by the Ocu-
  lar Arteries.
 >f«   The Veins go  to t'ie  External Jugulars ;—they likewife  com-
  municate with the Ocular veins,  and  of  courfe with the Lateral
   Sinufes and Internal Jugul is.
     The, Nerves with  which the outer  part of the  Nofe is chiefly
   fupplied, come  from  the  fecond branch of the Fifth, and from
  the Portio Dura of the  Seventh Pair.
     The inner part is principally fupplied by the Firft, or Olfaaory
  Nerves, and by fome branches from the firft and fecond portions of
   the Fifth Pair. 
44
OF  THE  EAR.
  The  Ear,  or Organ of Hearing, is divided into the External
and Internal Ear.                                         '

                    EXTERNAL  EAR.
  The External Ear comprehends the Auricle, or Ear, properly
fo called,  and the Meatus Auditoiius Externus.
  It is again divided  into the Pinnet,  or Ala, which conftitutes
by much the greater part of  it j—and  Ltbus,  which is placed at
its under end.
  The Pinna or Ala, is. chiefly compofed of  Cartilage, and is
divided, at its  fo.e-part, into  feveral Eminences and Cavities,
which have obtained paiticular names, viz.
  The Helix, or outer B ir, or Margin, fo called from its wind-
ing diic-a.on.   it ariies behind at the Lobe of the Ear, furrounds
its upper edge,  and terminates below, nearly oppofite to its ori-
gin,  div dn •. the Concha into two paits.
  The Antihelix, Anthelix, or inner Bar  or Margin, which is
fituated  with n  the former, and is  compofed fuperioily of two
Ridges, un'ting together below.          ,
  The Tragus, fo -.ailed from the Hairs which frequently grow
from it hav.ig a refemblance  to the beard of a Goat.
  It  is a fm 11 Em nmce which lies over the  Meatus Externus,
and is conneaed to the under and  fore-part of the Helix.
  The Antitragus, fo named from it-, beinij oppofite to the Tra-
gus, behw the pofterior ext.tmity of the  Antihelix.
  The Cavitas Innominata,  utuated between the Helix and An-
tihelix.
  Tlie Scapha, ox Foffa \avicularis,—compared in fhape to thaju.*
of aB,at,—fuua ed between  the two I mbs of the Antihelix.
  Tne Concha, fo . .die I  from  its refemi lance to a Ffh-fliell of  *
that name.  It is a la,ge Cavity under the Antihelix,  divided •
by the Helix nto two parts, the inferior of which leads  to  the
Mea ue Amlitorius.
  The back-pait of the  Externd Ear exhibits  only one confi-
derable Eminence, which is the convex Surface of the Concha.
  The Lobus,  which is the inferior foft part of the Ear,  is com-
pofed of Ctilular  Subftance,  witrfa  fmall quamity ct  Fat. 
43
  The Ear is covered by a continuation of the common Integu-
ments, which is thinner here than on the reft of the Body, and rs
perforated  in many  parts by the  mouths  of Sebaceous Duas,
which  are placed immediately under the Skin.
  The motions of the Ear, which are very limited, are regulated
by  feveral  Mufcles,  fome of  which are common to the Ear and
Head,  and others proper to the Ear itftlf.  The common Muf-
cles have been already defcribed.   The Mufcles  proper  to  the
Ear lie clofe upon the Cartilage, and,  in the -generality of fub-
jeas, are fothin, wh'te,  and indiftinct, as to receive from fome
Authors the name of Mufcular Membra,us.—They are as follow.
                     Helios Major.
  Origin:  From the anterior  acute  part of the Helix, upon
which it afcends.
  Infertion ■.  Into the Helix.
   Ailion:  To pull that part  into  which  it  is inferted a little
downwards and forwards.
                     Hflicis Minor.              n
   Origin .- From the under and fore-part of the Helix.
   Infertion :  Into the Helix, near  the Fiffure in the Cartilage op-
pofite  to the Concha.
   Ailion:  To contraa the Fiffure.

                         Tragicus.
   Origin : From the middle and  outer part of  the  Concha, at
 the root of the Tragus, along which it runs.
   Infertion : Into the*point of the Tragus.
  i Ailion : To pull,  the point of the Tragus  a  little forwards.

                      ANTITR AGICUS.
   Origin.  From the internal part of the Antitragus,  upon which
 it runs upwards.
   InJ'ertion : Into the tip of the  Antitragus,  as  far  as the  in-
 ferior part of the Antihelix,  where there is  a Fiffure in the Car-
 tilage.
    A:lion:  To turn the  tip of  the Antitraglis a little outwaids,
 and deprefs the extremity of the Antihelix u w^rds it.
                   Transversus  Auris.
    0< igin From the prominent part of the Concha, on the Dor-
  fum, or back-part of the Ear.
    Injertion -. Into thcoutfide of the Antihelix.
    A'iion: To draw the  parts to which it is conneaed towards
  each  other,  and to  ftretch the Scapha and Concha.
    The uj'e of  the External Ear is to  a Ilea the found, and con-
  vcv  it to the Meatus Externus,—the Mulcles giving tcnlion to
  it, fo as to render the founds more diftina. 
4 (j
   The Cartilage  of the External Ear is  connected to the Tem-
poral Bone by  the common Integliments, and by  its Mufcles;
and is furnifhed with Ligamentous Membranes,  which fix  it to
the roots of the Zj^ma and of the Mafto'd Procefs.
   The Meatus  Audi's--;,,:. <  Externus leads iuwaids,  from  the
Concha, and in iis courfe proceeds forwards and  upwards, turn-
ing a little downwards at its faitheft exticmity, and terminating
a? the Meinbrana I'vmpani.—The turns,  however, are  fo  in-
confiderablei  that the bottom of the paffage can  be readily feen in
a clear light, upon pulling the ear backwards.
   It is fomewhat  of an oval form, a l'.ttle contraaed iri the mid-
dle,  and upwards of an inch in  length.
   Its outer end, which is a continuation of the Conc'ia, is C.r-
.-.'.■ginous, and ha- twoorthice Interruptions or Fiffures in it.
   On the upper and back-part of   its  circumference, there  is a
Large Interruption*teiminating in an oblique M :.uin, which is
fixed to the rough edge, at the under part of the  Offeous poition
o'. the Meatus.
   At the upper and back-part of the Meatus,  the Cartilage  has
but  little conneaion  /.'.h the Bones, being there fixed  by the
Skin  which lines  the  Canal.
   The Offeus Canal is continued from the Cartilage of the Mea-
tus,  and is the longer of the two,  particularly at the upper and
back-part of the Paffage.
   The Meatus  is lined with a continuation of the Skin,  which
fills up the interruptions in the Cartilage, but is  thinner than
on the reft of the Body.
   Under the Skin of the Meatus,  and near its outer  end, there
are numerous fmall glands, of  a yellowifli colour, placed  in a
Reticular Subftance, formed of the  Corpus Mucofum, and  termed,
Glandula Ceruminofa,  which difcharge  the  Wax  of the Ear
through fmall Excretory Duas-
   The nrteries of the  External Ear come  anteriorly from  the
Temporal, and  pofteriorly from the Occipital,  both of which are
blanches of the External Carotid Artery.
   The Veins  pafs  partly  to the External, and partly to the In-
ternal Ju5ulars.
   The fore-part of the Ear is  fupplied  with Nerves from the
third  of the  Fifth, and from the Portio Dura  of the Seventh
Pair; the under  and back-part, by branches from the firft'and
fecond Cervicles.
   The Meatus  Externus conveys  the found from the Outer to-
wards the Inner Ear, and is fuppofed to  do this to greater ad-
vantage, on account of the winding nature of'the Paffage.
   The Wax lubricates  the Paffage, and defends  it from  the in-
juries of the air, and  being of a vilcid and bitter quality, aflift*
in the exclufion of infeas. 
47
  In the Foetus, the Meatus is entirely Cartilaginous,  and only
adheres to an imperfea Bony  Circle,  in which the Membrana
Tympani is fixed.
  At the innei  end of the  Meatus Externus, the Membrana
Tympani is fituated, winch has its name from covering  the outer
part of the Tympanum or Drum of the Ear.
  It is firm, almoft tranfparent, and of an oval form.
  It is fixed in a Groove  which  divides the Mctus  from the
Tympanum.
  It is very tenfe, but  has a fmall  depreffion in the middle next
the Meatus, with a correfponding convexity towards the Tym-
panum, where the extremity of the Malleus is fixed to  it.
  Its fituation is fomewat oblique, the upper part being turned
outwards, and  the under inwards, fo that the  lower fide of the
Meatus is  a little longer than the upper.
  It forms a complete Septum, and h-s no hole in if, fuch as has
been defcribed by fome Authors.
  It is formed partly of a continuation of the Lining of the Mea-
tus, but chiefly of the Periofteum.
  The Membrana Tympani has numerous fmall Veffels from the
Temporal and  Stylo-maftoid Arteries, which run in  a radiated
manner,  and which are moft abundant in the Foetus.
  It is the  Conduaor  of Sound  from the Outer  to  the Inner
Ear.
  In  the Foetus,  this Membrane is fixed in an imperfea  Ring
of Bone, and, along  with the Meatus,  is covered  with a  Mu-
cus Membrane, which defends  the parts  from the too ftrong
impulfe of Sound.

                  THE INTERNAL  EAR.

   The Internal Ear comprehends the Tympanum, Labyrinth, and
 certain Paffages leading into thefe.
   The Tympanum, or Drum of the Ear, is fituated at the  inner
 lide of the Membrana Tympani,  approaches to a hemifpherical
 figure,  and is about half an inch in width.
   Btwecn the Tympanum and Cavity called Labyrinth, there is
 an Offeous Septum, which forms the bottom of  the Tympanum,
 where there are feveral Eminences, viz.
   The Promontory,  which  forms  the beginning  of  the  Scala
 Tympani, and  divides  the Tympanum into anterior and pofterior
 regions.
   A Protuberance at the upper and back-part of the Tympanum,
 formed by the Aquaeduaus Fallopii.
   A Projetlion, called Eminentia Pyramidalis Tympani, fituated
 behind the  Feneftra Ovalis, in which is the Paffage for the Sta-
 pedius Mufcl*. 
43
  An Eminence at the upper and fore-part  of the Tympanum,
containing a femi caaal,  for lodging part of  the Tcnfor Tym-
pani Mufcle.
  In the Tympanum there are vaiious Paffages, which communi-
cate* with the neighbouring parts, viz.
  The he.- a Palato ad Atticm,  or Eujlachian  Tube,  which goes
off from the upper and fore part of the Tympanum,  and  runs
obliquely forwards and inwards to  the pofterior opening of the
Noftrii, and terminates at its outer edge, above the arch of the
Palate
  The pofterior part of the Tube is formed  in the Pars Petrofa,
at the upper and outer part of the Canal tor the Carotid Artery.
  The anterior portion is  formed above,  by  the Spinous Piocefs,
and root of  the Pterygoid Procefs of  the Sphenoid Bone ;—and
below, by Cartilage and Membrane.
  It is narrow next the Ear, where  it can only admit  the point
of ri Surgeon's probe ; but becomes  gradually wider towards the
Noie, where it tei initiates by an oblique opening with prominent
fides, fufficiently lar^e to admit a Goofc-quill.
  It is lined by a  Membrane  fimiiar  to that of the Nofe, of
which it appears to be a continuation ;  and en the edge of the
Mouth of the Tube,  it is fo thick  as  to add confulerably to its
prominency.
  The Euitachian Tube preferves the balance of Air between the
Outer and Inner Ear,  and prevents  it  fiom  pr fling too tor ibly
upon the different Membranes  placed in the fides of  the Tym-
panum.
  It  has been fuppofed to  convey the found of a pet Ton's own
Voice to the Inner  Ear; but experiment  does  not  favour this
opinion,  nor i it found to render Sound more diftina  when the
Mouth is open ;—thou h pcr.ons who are dull of heaiing are ob-
ferved irequently to 1;den  alte>  this  manner.
  The Cells of the Mafloid Procefs, wlvch  open  into the  upper
and lack-part of the Tympanum, oppofite to,  but a little higher
than the Euftachian Tube.
  They aie very irre; ular, and  have many windings  and  turn-
ings,  which  communicate  treelv with  each  o'her,  and  are
lined, l;ke th, Cells  of other Bones, with the  Puiolleum In-
ternum.
  They afiifl the Tympanum in rifhaing the Sound.
  In O^u  drupeds which he; r acutely,  there are  larc,t  Cavities
conneaed with the 1 ympanum, which lcem to fupply  the place
of Maftoid Cells.
  Above  the Promontory, a  Hole, called Fenefi<a Ovclis, tne
upper and under edges of  which aie convex upwaids,—tor lodg-
ing  the Bale of the Stapes.
  The inner  edges of this Hjle are contraaed by a narrow bor-
der,  upon which the end of the St: pes iefb. 
4*
   Below the  Feneftra Ovalis, and at the under and  back-part of
 ihe Promontory,  a Hole,  fmaller than the former,  called Fenef-
 tra Rotunda.
   It is placed obliquely backwards, and outwards,  leads to the
 Cochlea, but is fhut  up by a Membrane  which affifts in  com-
 municating Sound to the Labyrinth.
   The Sides, or IVallsof the Tympanum,  whch likewife afliftin
 conveying Sound to the  Labyiinth, are lined wifh Periofteum,
 which is refleaed into the-different Paffages leading from it.
   The Cavity  of the Tympanum contains four fmall Bones,
 called Officula Auditus, which form a chain ftietching acrofs from
 the Mem!), ana Tympani to ihe Labyrinth.
   The Officula Auditus are,—the Malleus, the Incus,  the Os Or-
biculare, and the  Sjapes;—thefe names  bein^ derived from fub-
 ftances which they are fuppofed ^o refemble in fliape.
   The Malleous,  or  Hammer, confifts of a round Head, a fmall
 Neck, a Manubrium or Handle, and twj fmall Proceffes, one in
 the neck,  long and very llender, and therefore  called Gracilis;
 the other in the upper end  of  the Handle, called  Proceffus brevis.
   The Handle is  by  fome  Authors confidered as one of the Pro-
 ceffes, and is  then called  the longeft of  the three.  It forms an
 angle with the Neck, becomes gradually  fmaller, and  is bent, at
 its extremity, towards the Membrana Tympani.
   In the natural fituation,  the Head is turned upwards and in-
wards, and the Handle down  upon the Membrana Tympani, to
 which it adheres.
   The Incus,  compared in fliape to an  Anvil, but  more refem-
 bling one of the Dentes Molares, with its roots widely feparated,
 is fituated  behind the Malleus, and  is  formed  of a Body, and
 tvjo Crura of unequal lengths.
   The Body has a Cavity and two Eminences, correfponding to
that part of the Malleus with which it is  articulated.
   Tacjbort Crus  extends  backwards,  and is joined by a Liga-
ment to the edge of the Maftoid opening.
   The long  Crus  is turned downwards, with the point a little
flattened, and bent inwards.
   The Os Orbicularc is the fmalleft Bone of the Body, bein»
confiderably lefs than a grain  of Mu (fa id-feed.
   It is articulated with the point of the long Procefs of the Incus,
and is fo firmly fixed to it,  that in feparatmg the fmall Bones of
the Ear from each other, it is  apt to adhere to the Incus,  and  has
on this account been frequently confidered as a Procefs  of that
Bone.
  The Stapes  is named from a ftriking  refemblance it  has to a
Stirrup.  It is divided into Head, Crura, and Bafe.
  The Head is placed upon a  fmall flat neck,  and is articulated
with the Os Orbicukue.

   Vol.  II.           E 
sn
  The Crura, like thofe  of the Incus,  are  unequal in length,
and have a groove within, which is occupied  by a Membrane.
  The Bafe  is of an  oral  fliape,  and has no  perforation in it.
Its  edges correfpond with thofe of the  Fenwftra Ovalis,  with
which it  is articulated.
  The Stapes is placed horizontally, being nearly at a right angle
with the inferior Crus of the Incus.—Its two  Crura are placed
in the fame plane,—the longeft backwards.
 • The fmall  Bones of the  Ear are  articulated with each other
by Capj'ular Ligaments, proportioned to their fize, and are cover-
ed by the Periofteum, which  likewife fixes  them  to the Mem-
brana Tympani and Feneftra Ovalis.
  The fmall  Bones have the following  Mufcles fixed  to  them,
which ferve for thtir different motions.

           Tensor T v m p a n i ,  or hit emus Auris.
  Origin: From the Cartilaginous extremity  of  the Euftachian
Tube, near  the entry of the Artery of the Dura  Mater.  From
thence, its Fk'ftiy Belly runs backwards in  a  Canal peculiar to
it,  at the upper  and  inner  part of the Offeous Portion of the
Tube, being covered only by a thin plate of Bone.   It fends off
a flender Tendon, which makes a turn in the Tympanum, and
paffes i.utwards.
  Infertion :  Into the pofterior part of the Handle of the Malleus,
a little below the root of its long Procefs.
   Ailion: To pull  the  Malleus  and Membrana Tympani in-
 wards by which the Membrane  is rendered  more  concave and
 tenfe,  and better adapted for the impieflion  of weak founds.
                   Laxator  Tvmpani.
   Origin .•  By a very fma',1 beginning, from the extremity of the
 Spinous Pio'.-tf, of the Sphenoid  Bone, behind the entry of the
 Artery of the Dura Mater ; after which it runs backwards and a
 Litle upwards, at the outfide of the Eultachian Tube, in a Fiffuie
 of the Os Trmporis, near the Foffa which lodges the Condyle of
 the Lower Jaw
   Infertion: Into the long Procefs of  the  Malleus, within  the
 Tympanum.
    ALuon ■. To draw the Malleus obliquely forwards and outwards,
 and thereby to render the Membrana  Tympani lefs convex, or ta
 lelax  it  when Sounds are too ftron-.—Haller d.nie? the ex-
 iftence of M'c.fcular Fibres in this Subftance.—Sabatilr  de-
 ic.ibes it, but doubts of its Mufcularity.
                        Stapedius.
    Origin:  By a fmall Flefliy Belly, from a little cavern in the
  Pars Petrofa, near the Cells of the M.ftoid  Procefs.   Its Ten- 
                             31

d-n paffes forwards  through a fmall Hole in that Cavern* and
goes into the Tympmum.
  Infer ain .- in to the pofterior part of the Head of the Stapes.
  Ailion : To di.c-v  the  Head of the Stapes obliquely.upwards
at;d bacL'VT- ;s,'. by which the » ulterior part of its Bafe is  moved
inward.,  ,nd the anunor  part  outwards, and  the  Membrana
Tympani thereby put upon the ftretch.

                        Labyrinth.
  The  labyrinth,   fo  called from  its  Sinuofuies  and wind-
ings, is fituated \t the inner-part  of the  Tympanum,  and is
formed  of the Vijltble, Cochlea, and Simiarcular Canals, together
with the Canalis Fallzpii and Meatus Auditorius Internus.
  The Vejlible,  nc.med from  it,  forming a poreh or entry  to the
Cochlea a« d Semicircular Canals, is of an oval figure, nearly of
the fize and lhape of a clean  grain of Barley, and is fituated at
the inner lide of the  Bale of the  Stipe*.
   There are three conuguou-. Cavities  in the  VcfliMe,  one of
 which,  the  Semi-oval,  is  fituated  above;  another, the  Hemi-
fpberical, below ;  and the third,  or Stdciform, which is the orifi'.e
of the Aquxdiiclus  Velt.buli, is placed behind.
   In ihe Veftible there aref-veiai Holes which communicate with
 the  neighbourin . paits,  viz.
   The  Femflra Ovalis fitu 'ted at the outfide, by which  it com-
 municates witn the  Tympanum.
   A round Hole, fituated at the fore and under-part, by which it
 communicates  with one of the Calais of  the Cochlea.
   Five Similar Foramina behind, by which it communicates with
 the Semicircular Canals.
   Next the Meatus  Auditorius Intemus, it  has four or  five
 Cribriform Perj'orations, for the tranfmiflion of Nerves.
   The Cochlea is fituated next the anterior extremity  of the Os
 Petrofum,  and at the fore-part of the Veftible,  in fuch a man-
 ner as to have  its Bafe towards  the  Meatus Auditorius Intemus,
 and its Apex in the oppofite direaion,—or facing outwards.
   It has two Canals or Gyri, called Scala,  from a fuppofed re-
 femblance  to Stair-cafes, ihe Gyri  or turns of which  are very
 clofe to each otner,  and iuii in  afprd  direaion, like the Shell
 of a Snail,  from which the pari  has obtained its name.
   The Cochlea forms tvjo Circumvolutions or Turns and a half,
 the firft of w'u.h is much larger and widei than the other Tumi
 and a half, which become fuddenly fmaller.
    The two Canals are upon the  fame level, the inner one next
 the Bafe, and the outer next the po nt of the Cochlea.
    The Gyri go round a Nucleus,  Ax s, or central Pillar, which
 is  nearly  horizontal,  and is formed of  tnuo hdh-vj Cones, with
 their points turned to each other, the ane termed Modiolus, from 
V
 t- .cfemblance to the Spindle ©f a winding Stair-cafe, the oth<y
Tnfundibulum, or Funnel.
  The Mcd-.olus forms the inner and larger portion of the central
Pillar, and is that Cavity feen in  the under  and fore-pait of the
Meatus Auditorius Internus.
  It lodges that branch of the Portio Mollis of  the Seventh Pair
of Nerves,  which goes to the Cochlea,  and is Cribriform, or full
of fmall Holes for the paft"'^e of the twigs  of that branch.
  The  Modiolus  confifts of  tvuo Plates,  with numerous Cells
and Paffages between them, and terminates  in the middle of thf
fecond Gyrus of the  Cochlea.
  The Infundibulum is an impei fcSi Funnel,  the Apex  of which
is common  with tha; of the Modiolus, and  the Bafe  is covered
by the Apex of the Cochlea, which is termed Cupola.
  Between  the  Scalae of the Cochlea there  is a Partition, called
Lamina Spiralis,  or Septum  Scala, the larger portion of which,
next the Modiolus, is formed of Bene : The lemainder,  or  that
part next the oppofite fide of the  Scala;,  is Membranous,  and
termed by Valsalva ZonaCochla.—This drops out by macera-
tion,  fo as  afterwards to leave only a partial  Septum.
  The Offeous part of the Lamina Spiralis is compofed of  tnvo
extremely thin Cribriform  Plates, which gradually approach each
other at their oppofite edges, where they are perforated by numer-
ous Hol-.'S.
  The  termination of the  Lamina Spiralis, and of  the Scala
Tympani, forms a Hamulus, or fmall Hook, which projeas into
the Infundibulum.
  One of the Canals or Scala? of tha Cochlea, opens into the un-
der and fore-part of the Veftible,  and is termed Scala Veftibuli;
The other,  which is the  fmaller of the two,  communicates with
the Tympanum  by the Feneftra  Rotunda,  and is called Scala
Tympani.
  The Partition between the two Gyri or Turns of the Cochlea,
like the Offeous part of the Lamina Spirars, is foimed  of  tvso
Plates,  with a fmall Cavity between them.
  The Volute, or Spiral of the Cochlea, begins below, runs for-
wards,  and then round,  fo as to form, as has been already men-
tioned,  two Circles or Turns and a haif,  the  direaion  of the
Gyri coi reJpt nding with thofe of the Shell  of a Snail.
  The  Canal, of the  Cochlea are conical,  becoming  gradually
fmaller towards the Apex, where they communicate freely with
each other, through the  medium of  he Infundibulum.__This
communication  is called by C assebohm,   who gives  the fulleft
Treatife upon the Cnr, Canalis Scalarutn Communis.
  The Semicircular Canals  are three in number,—the Superior or
Vertical,—the Pofterior or Oblique,—and the Exterior or  Hori-
zontal. 
53
   The Superior is placed tranverfely,  in  the upper-part of the
Pars Petrofo,  with its convex fide upwards.
   The Pofterior is farther back than the former one,  and is pa-
rallel to the length of the Pars Petrofa, with the convex fide turned
backwards*—One of its extremities is placed above, and the o' her
below, the upper extremity joining with the internal one of the
Vertical Canal, by which a common Canal is formed.
   The Exterior is Iefs than the other two, which are more of an
equal fize, is placed next the Tympanum, and has its extremities
and curvatures nearly upon  the fame  plane;—with  the curve
placed backwards.
   Each of the Canals  forms Upwards of three-fourths of a circle,
can admit the  head of a  fmall  Pin, and has an Enlargement,
Ampulla, or Cavities Elliptica,  at one  end, the other extremity
being nearly of the fame fize with the reft of the Canal.
   The Orifices are only five in number, two of  the Canals ha-
ving a common termination.   Of thefe  Orifice^, three are fitua-
ted at the infide, and two at the outfide of the Veftible, into the
pofterior part of which they open.
   In the bottom of the Meatus  Auditorious Tnternus, which is
fituated in the pofterior Suiface of the  Pars Petrofa,  there is a
large under,  and  a fmall  upper Foffula, feparated by a  (harp
Ridge.
   The fore-part of the inferior  Foffula leads towards the Coch-
lea, and is perforated with m\mbtv\cl\ fmall Holes, through which
branches  of the Portio Mollis  of the  Seventh Pair of Nerves pafs
to the Cochlea.
   One Hole in the centre, larger than the reft, tranfmits a branch
of thar Nerve to  the Infundibulum.—This Hole, however, is
frequently enlarged,  in confeqnence of  the Bone, which is ex-
tremely thin,  being broken while preparing it.
   In the  back-part of the inferior Foffula, three  or four Cibri-
form Holes appear, for the tranfmiffion of branches of that part
of the Portio Mollis  deftined  for the Veftiblj and  Semicircular
 Canals.
   In the upper Fo.Tda of the Meatus Internus, there are tivo
 Paffages, one pofterior and fmaller, tranfmitting Nerves into the
 Elliptical Cavity ot the Veftible.
   The  other, the  anterior and Iargeft,  i« termed  Canalis or
 Aquaduflus  Fathpii,—from a refemblance  it bears to an Ital an
 Aqueduct,  and ferves for a tranfmiffion of the Portio Dura of
 the  Seventh Pair of Nerves.
   The Canal of Fallopius goes through  the upper-part of the
 Pars Petrofa,  paffes  downwards and backwards between the
 Foramen Ovale and external  Semicircul :r Canal, and terminates
 in the Foramen Stylo-Maftoideum.

    Vol. II.         E  2 
54
   In its paffage through the Pars Petrofa,  it communicates with
the Foramen Inn: minium, fituated on the  upper and fore part
of the Procefs.
   In Children, the Lab, rinth is almoft as large as in Adults, its
Subftince complete and hard, while the Bone .which fun  muds it
is foft and fr...n..-y ; on which account it is eafily fepaivted from
the reft of the Pars Petrofa.
   The different Cavit es rnd Paffages of the Labyrinth are lined
with the  Periofteum, which in the Veftible fills  the Feneftra
Ovalis,  an-* of confequence covers the Bafe of the Stapes.
   The Peri >ftea of the two Canals of the Cochlea form, by their
Tinion, the Membianous portion of the Lamina Spiralis, which,
together with the Offeous part, completes the Septum between the
two Scalae.
   The Periofteum of the  Cochlea alfo affifts that of  the Tym-
panum, in forming  the Membrane of the Feneftra Rotunda,
and which  is fometimes called  Membrana Tympani Secundarii,
from a refemblance to the Membrana Tympani, and from being,
like it, a little  concave on the  outer, and convex on the inner
Surface, or where it faces the Scala to which it belongs.
   Befides the Periofteum,  the Veftible,  Cochlea, and Semicir-
cular Canals contain a Pulpy Membrane,  upon which  the Portio
Mollis is irregularly difpeifed.
   In the Veftible, the Pulpy Membrane forms a Sac, in  fhapc
refembling that of the  Ofleous Cavity which contains it, and
which is defcribed and beautifully deliniated by Scarpa.      9
   When the Sac is laid  open upon the  upper and outer-part,  a
Partition appears, of the nature of the  Sac,  termed by Dr.
Meckel, Septum Veftibuli Nervofo ■ membranaceum.
   In the Cochlea, the Pulpy  Membrane is in cont»a with  the
Periofteum, but can  be  feparated from that Membrane  without
much difficulty.
   In the Semicircular Canals,  it is at fome diftance  from  the
Periofteum of thefe Bones, and is confiderably fmaller, but, like
them, it forms diftina  Tubes, which  communicate with  the
Veft ble.   Like the Offeous Canals alfo, the Membranous Canals
form Ampullae,  or Elliptic Cavities at one end.
   The Arteries  of the  Labyrinth arife  by one or   two  fmall
branches, chiefly from the  Veitebral Artery, and  pafs through
the Cribriform Plate,  at  the bottom  of  the Meatus Externus
which belongs to the Labyrinth.
   From the Labyrinth one or two Veins return,  and terminate in
the end of the Later J Sinus.
   The Cavity of the  Veftible contains no Air, but is  conftantly
illed with a Watery Fluid, fuppofed to be fecreted  from  the Ar-
teries of the Periofteum,  and  which is found  to  referable  the
Aqueous Humour of the Eye. 
55
  The Aqueous Fluid fills the Veftible and Scalar  of the  Coch-
lea, and likevvife furrounds the Membranous  Semicircular Ca-
nals.
  The  Aqua Labyrinthi is  confidered as  a medium by  wh ch
founds are communicated  from the Membrane filling the round
and oval Holes,  and from the  Bafe of the  Stapes to the  Pulpy
Membrane placed in it.
  The fuperfluous part of the Aqua Labyrinthi is fuppofed by
Cotunnius to be carried off by two fmail Conical Duels,  more
particularly defcribed by him  than by fome pieceding Anato-
mifts, who were partly acquainted  with them, bui confidered
them as Blood-veflels.
  One of the  Aqueduas of  Cotunnius, called  Aquaduilus
Cochlea, begins  at the under-part of the Scala  Tympani, near
the Feneftra Rotunda,  and after pafling through the  Pars Petro-
fa,  is feen, in the figures he gives of it, terminating by  a wide
triangular opening,  upon the furface of the Dura Mater, be-
tween  the paflages of the Seventh and Eighth Pair of Nerves.
  The other Dua, called Aquaduilus  Veftibuli, begins under the
termination of the  common Canal,  in the Veftible,  from which
it defcends, and terminates by a triangular opening  between the
Layers  of the Dura Mater, behind the Meatus Internus,  and
halfway between the upper edge of the Pars Petrofa and Diver-
ticulum of the Internal Jugular Vein.
  For ajull account of thefe Duels, and of the other  parts of the
Labyrinth, fee a Defcription of them by Dr. Meckel of Berlin.
  The  Nerves of the  Labyrinth  are derived entirely from the
Seventh Pair.
  The  Auditory Nerve is  compofed of two branches, one of
which  is called Portio Dura,  and is harder than the other, ter-
med Portio Mollis.
  The Trunk of the Auditory Nerve paffes into the Meatus Ex-
ternus, covered  by the inverting Membrane of the Brain.
  The Portio  Dura  goes  through the Canalis  Fallopii, fending
off, in its paftace, branches through Perforations  in its fides, to
the Stapedius Mufcle and Maftoid Cells.
  One■refle^ed branch paflingthrough the  Foramen Innomina-
tum, in the Pii» Petrofa, forms a conneaion  between ihe Por-
tio Dun and the fecond pait of the Fifth Pair.
   Anoiher, called Chorda Tympani, paffes aerofs  the Cavity of
 the Tympanum,, between  the inferior Crus of the Incus and
handle of the Malleus, and at the outfide of the Euftachian Tub;-
to join  the Lingual  '.nanch of the Fifth Pair.  In its  oaffa ^ it
fupplies the Mufcles of the Malleus, and Membranes,  Sec. of
the  Tympanum.
   Tha rem«-nder of t'ie Portio Dura is difperfed upon the Face.
   The Portia M-lr  s divided into  two principal parts,__one to
the Cochlea, the oiher to the Veftible. 
56
   The branches of the  Cochlea pafs through  the Crib, if,; m
 Plates of the Modiolus, to the Pulpy Membrane  lying in the
 Seals.
   The branches run between,  and likewife on the out-fide of
 the Parti ions wh.ch  devide  the  Cochleae  into  Gyri, and the
 Gyri into Scalae, and are large and  numerous in  proportion to
 the part they fupply.
   The largeft and moft numerous of thefe branches arc difperfcd
 upon the Lamina Spiralis, where they form an intricate Plexus,
 theThieads of which are at firft opaque, but are  afterwards of
 the colour of the Retina of the Eye.
   The  branches terminate, and appear alfo to  meet upon that
 part of the Pulpy Membrane, which is moft diftant  from the Mo-
 d olus.
   Through the Cribriform Plate,  common to the Modiolus and
 Infundibulum, the laft  branches of  this  portion of  the  Nerves
 pafs, to be fpread out upon the Membrane  lying within  tie In-
 fundibulum.—For  a  particular defcription oj' that part of  the
 Portio Mollis  diftributed to  the  Cochlea  and oj  the Cochlea  it-
felf, fee  Dr.  Monro's Treatife on the Ear.
   Of that  part  of the  Portio Mollis deftined for the Veftible
 and Semcircular CanaK, one branch  goes  through the pofterior
 Hole in the upper-part of the Meatus Internus ;  the reft pafs
 through the holes in the under and  back-part  of the Mc.tus,
 already pointed out in the defcription of that Paffage.
   After perforating the  Foramina,  the  Nerves  are feen firft in
 diftina Piexus,  but become afteiwards tranfparent,  and are loft
 upon the Sac contained in the Veftible and upon  the Ampulla of
 the Membranous Semicircular Canals.
   The Portio  Mollis is  the primary part of the Organ of Hearing,
 to which all the other parts are fu. i.rvient,  and nay  be legard-
 ed as being of the lame fervicc to the Ear, as the Retina is to the
 Eye. 
57
      W  THE MOUTH,  Tongue,  AND


                      THROAT,


            WITH THEIR APPENDAGES.




                         MOUTH.
                                     m
   The Offeous Paris of the mouth are,—the Offa Maxillaria Su-
periora, the Offa  Palati,  the Maxilla Inferior,  and the leeth ;
—all of which have been  alieady defcribed.
   The Sojt Parts of the  Mouth confift of the Lips and Cheeks,
the Gums, the Palate, the Velum Palati, the Uvula, the Tongue,
the Membrane lining the Mouth and the Salivary Glands.
   The Lips and Cheeks are principally compofed of Mufcles, are
covered on  the outfide by the common  Integuments,  and lined
within by the Membrane  of  the Mouth, under which there are
numerous Mucous Glands, which obtain their names from their
fituations.
   The intervening fpace  between the Maffeter  and Buccinator
Mufcles is occupied by a large quantity of Fat, which gives form
to the Face.
   The Membrane of the Mouth is covered with fine Villi; but
thefe are moft confpicuous upon the edges of  the Lips, as may
be readily feen after a fine injeaion, or after macerating the parts
till the Cuticle can be feparated.
   From the edges of the  Lips, the Common  Integuments (now
become extremely thin) are converted into  the Membrane which
is continued into the Cavity of the Mouth, and which, oppofite
to the Dentes Iucifores of the Upper and Under Jaws, forms a
fmall Doubling or Franum, which fixes the Lips more firmly  to
the Jaws.
   The Lips are ferviceable in the general purpofes of Speaking,
Eating, Drinking, &c.
   The Gums cover the fides of the Alveolar Border of both Jaws,
pafs  in between  the different Teeth, and  funound and  adher*
firmly to the Collar of  each.
   The Subftance of the Gums is of a denfe natuie. very Vafcu-
lar, and the Veffels united by a compaa  Cellular Subftance. 
oS
  They may be faid to confift of the Common Membrane of the
Mouth and  the Peiiofteum of the Jaws intimately conneacd.
  They ferve as a covering to the Jaws and affift  in the feciuity
of the Teeth,
  The Arteries of the Lips,  Cheeks, and Gums, are* from the
Facial, Temporal, and Internal  Maxiilaries, which are derived
from the External Carotids.
  The Veins go chiefly to the External, and partly to the  Inter-
nal Jugulars.
  The Nerves  come from the firft and fecond  branches  of tit
Fifth Pair,  and alfo from the Portio Dura of  the Seventh Pair.
  The Palate 's divided  into the Palatum Dure and  Palatum
Molle.   The former is compofed of the Palate-plates of the  Up-
per Jaw,  and is covered by the Peiiofteum and  common Mem-
brane of the Mouth, which prevent the Bones from being in-
juied.
  The Membrane which covers  the Bones of  the Palate forms
numerous Rug<r, which affift in the divfion of the Food.
  It is neaily of the fame ftrufturc with that of  the Gums, but
perforated by the Duas of the Palatine Glands, for th.'excretion
of Mucus,  which ferves to  lubricate  the Palate, and aff.ils  in
d if living the Food.
  The Palatum Molle,  Velum Pendulum Palati, or Soft Palate,
is that  pait which depends from  the pofterior edge  of the  Offa
Palai, and from the Pterygoid Procefl'es of the Sphenoid  Bone,
and forms a Partition between the Nofe and Mouth.
  It is compofed of the Membranes  which line the Nofe arid
Mouth, and of t!ae expanfions of the  Circumflex  and Levator
Palati Mufcles, and  numerous  Mucous Glands  which feive  to
lubricate ihe Mouth and  Fin oat, and  facilitate deglutition.
  The Palatum Molle condufts  the  Fluids of the Nofe into the
Mouth, and aas like a Valve in preventing what we fwallow from
pafling into the nofe.
  In the middle of the pofterior  edge  of  the Velum  Palati, the
Uvula or Pap of the Throat,  takes its orgin, and hangs  pen-
dulous, from the Velum over the root of the Tongue.
  It is of a Conical form, is  covered  by the Membrane  of the
Mouth, and has a fmall  Mufcle within it,  by which  it Is eleva-
ted and ftiorteneJ,—its other nations, depending  upon the Muf-
cles of the Pala e.
  The ufe < f the Uvula in Speaking and  in De-dutition,  is evi-
dent from the inconveniencies which refult from its being deftroy-
ed  by <)ifeafe.
  The Arteries  of the  Palate, &;. come from the Facial, and
Internal Maxillary.
   The Veins go the External and Infernal Jugulars.
  The Nerves aie  chiefly  fr.m the fecond  of the  Fifth,  with
fome twigs from the Eighth Pair. 
«,«
                         Tongue.
  The Tongue  is of an Oval form, and is divided  into Bafe,
Body and Apex.
  The Bafe,  or pofterior part of the Tongue, isconneaed to tha
Os Hyoides,  and by the medium of  this,  to  the adjacent Bones
and Mufcles.
  The Body, or middle part of the  Tongue, terminates  anteri-
orly in the loofe moveable point.
  On theDorfum or upper Surface, there is a Linea Mediana, or
middle Groove, running longitudinally, and dividing it into two
lateral convexities.
  The inferior  Surface, which reaches only from the  middle of
the Tongue to the point, is conntaed to the parts below it by the
Sublingual Ligament, or  Franum Lingua,  which is a doubling
of the Skin, or lining of the Mouth.
   The fides of  the Tongue are fixed to the Lower Jaw and Sty*
 loid Proceffes,  and  parts adjacent, by Membranous Ligaments.
   The Ton. ue is chiefly  compofed of the Fibres of the Mufcles
 which ferve  for its motions.—Thefe Fibres are difpofed  in vari-
 ous direaions,  and intermixed with  a Medullary Fat.
   The upper and lateral parts of the Tongue are compofed of the
 Stylo-Glofli.—Its middle  portion, between the two former Muf-
 cles, is formed  of  the  Linguales.—The lower  part  is  chiefly
 formed of the Genio-Glofli ;—and behind,  the  Stylo-Glcfli en-
 ter into its compofition.
   The Tongue is covered  by a continuation of the common In-
 teguments,  which are preierved foft and moift by the  Saliva.
   The Cuticle forms Vagin.t for receiving the Subftances called
 Papilla.
   The Corpus Mucofum  of the Tongue is thicker than  in other
 parts of the Body,  but more moift.
   The third  covering of the Tongue, the Cutis Vera, is remark-
 ably Nervous.—The Papilla?, which take their origin from it aie
 very Vafcular, efpecially  near the Apex of the Tongue,  but arc
 awantingon its  under furface.
    The Papilla are divided into three kinds, the Maxima, Media,
 and Minima.
    The  fiift  clafs,  called Papilla Maxima,  Lenticulares,  or
 Lapitata, are by much the  larueft, and of a Lenticular form,
 having round  Meads  and  fhort Stems.
    They are placed at the Bafe of the Tongue, in fupcrficial Fof-
 fula?, . nd are difierfeJ in fuch  a  manner-  as to form an angle
 with its  point backwards.
    They  are Glands of the Salivary kind, and have each of them
 a fmall Perforation in the middle of its convex  Surface, for the
 excretion of Mucus.                                       * 
60
  Befides the Papillae Capitatae,  there are numerous  Mucous
 Follicles, which cover the greater part of the Surface of  the root
 of the Tongue.
  At the root of the Tongue, and behind  the  angle  formed by
 the Papillae Maxima?, there is a Hole, called Foramen Caecum of
 Morgagni, by whom it was firft defcribed.
  It penetrates only a fmall way into the Subftance of the Tongue,
 and receives the Mouths of feveral Excretory Du&s which termi-
 nate in it.
  The fecond clafs called  Papilla Media, or  Semi-lenticulares,
 are much fmaller than the former, and aie fcattered over  the up-
per Surface of  the Tongue, at fome diftance from each other.
  They are of  a Cyndrical form,  and terminated by a round ex-
 tremity.
  The third clafs,  termed Papilla Minima, or  Conica,  or  Vil-
 hfa, are by much the moft numerous, but verv minute.  They
occu iy almoft the whole upper Surface of  the  Tongue,  but are
 moft abundant towards the Apex,  where the fenlation of Tafte a
moft acute.
  This and the fecond clafs have been fuppofed to  be  formed
cniefly of the extremities of Nerves, and to conftitute the  real Or-
gan of Tafte ;  though  other parts, as  the  Palate, and even the
Pharynx and Efophagus, poffefs the faculty of Tafte in a certain
degree.
  The principal Blood-veffels of the Tongue are large in  propor-
tion to the fize of that Organ.
  They are called Linguales, or Ranina, on account of the dark-
coloured branches which appear undei the Tongue.
  The Arteries, which are bianches of the External Carotids, are
not found to communicate fo freely on ihe oppofite fides of the
Tongue,  as they do in other parts of the Body.
  The Veins open chiefly into the External Jugulars.
  The Nerves like the Arttries,  are  large  and numerous,  and
have little conneaion on the oppofie fides.
  They come from the Fifth, Eighth, and Ninth Pairs.
  The firft fet fupply the parts next, the  point of the Tongue,
and are therefore confidered as being principally concerned in con-
veying the fenfation of Tafte.
  The fecond let fupply the root and  the third the middle of the
Tongue,  and are  cniefly difpeifed upon its Mufcles.—There is
a confiderable  intermixture,  however, between the  three fets on
the fame fide.
  Befides being the principal Organ of Tafte, the Tongue is the
chief  inftrument of Speech, and of the aiticulaiion of the Voice,
—It  alfo affifts in  Manducation, Deglutition, Spitting, Suck-
ing,  &c.
  The Salivary Glands confifl of three large  Glands on each
ride of the Face, viz.—the Parotid,  th"  Submaxillary,  and the 
61
Sublingual;—befides many fmall Glands,  named from the parts
to which they belong.
  They are of a yellowifli colour, and irregular on their Surface,
being of the Conglomerate kind.
  The Parotid Gland, which is the largeft of the Salivary Glands,
is named  from its fituation near the Ear.
  It occupies the whole fpace between the Ear, Maftoid Procefs,
and the angle of the Lower Jaw.
  It extends  fuperioily to  the Zygoma, and  anteriorly  to the
Maffeter Mufcle, part of which it  covers.
  The under end of it lies contiguous to the Submaxillary Gland.
  From the different parts of the Gland, numerous fmall branch-
es arife,  which join together to form a  large  Dua, fometimes
called  Steno's Salivary Dud, or Duilus Superior, which paffes
from the upper and fore-part of the Gland.
  The  Parotid Dua is of a white  colour and large  fize, but,
from the thuknefs  of its  Coats, tin Cavity  is fmfcll in propor-
tion to the outfide of the Dua.
  It paffes anterorly, in a tranfverfe direaion, over the Tendon
of the Maffeter Mufcle, by which it is free from coinpreflion, and
defcends a little to  perforate the  Buccinator  Mufcle, oppofite to
the fecond or third Dens Molam of the Upper Jaw.
  In  crofting the Maffeter Mufcle, it  receives fometimes one,
fometimes  two minute Duas, from an  equal  number  of fmall
Glands, called by Haller, Glandula Accefforia.
  The Inferior Maxillary, or Submaxillary Gland, is fmaller  and
rounder thtn the Parotid,  and is fituated on the infide of the  an-
gle of  the Lower Jaw,  between it and the Tendon of the Digaf-
tric Mufcle.
  From  the upper  and fore-part of this Gland,  aDuaarifes,
called  by fome Authors Duilus Whartonii, or Duilus Inferior,
which  is much thinner in  fubftance than the former Duct,  but
longer.
  It paffes forwards between  the  Mylo-Hyoideus and Genio-
Gloffus Mufcles, alon? the under  and  inner edge of the Sub-
lingual Gland, to the fide of the Frsenum Lin jus, and terminates
behind the Dentes Incilores, by a fmall  orifice, in form  of a  Pa-
pilla.
  The Sublingual Gland is fmaller and fofter than the Submaxil-
lary,  and is flat, and of an aval form.
  It is fituated under the anterior portion of the  Tongue,  above
the Dua of the inferior Maxillary  Gland near the Lower Jaw,
between  the Mylo-Hyoi:les and Genio-hyogloffus  Mufcles,  the
former of wlvch f.iftains it.
  Its extremities are turned forwards and backwards, and the
edges obliquely inwards and outwards.
  It is covered by a continuation  of the Skin  of the under fide of
the Tongue, which  fixes the Gland in its place.
   Vol. II.           F 
62
  It opens by feveral orifices arranged in 'a line near the Gums, a
little to the outfide of the Fiaenum.
  In many Quadrupeds, there is a  diftina duct belonging to this
Gland, like that of the Submaxillary.
  Sometimes this Gland fends off a Branch which communicates
with that of the Submaxillary,  but generally it is othtrwife.
  The fmaller Glands of the Mouth are in great nnmbers, lying
between the  inner lining of the Mouth and its Mufcles,  and de-
living  their names from their fituations.
  They  are fmall  fimple  Glands,  each fending a dua, which
perforates the Skin  of the  Mouth, and opens into its Cavity.—
They con fill of—
  The Buccales, which are placed all over the  Cheek, but moft
plentifully near the  termination of the Parotid Du&;
  The Labiates, lying on the infide of the Lips  ;
  The Palatina,  upon the Palate ; and
  The I.inguates, at the root of the Tongue.
  The Arteries of the Salivary Glands are from different Branch-
es of the External Carotids.
  The Parotid is fupplied from the Temporal, the Inferior Max-
illary from the Facial, and  the Sublingual from the Lingual Ar-
tery.
  T\\t Veins of thefe Glands goto the External Jugulars.
  Their Nerves  are chiefly from the third part  of the Fifth,
and from ihe P«itio Dura  of the Seventh Pair.
  The  Salivary Glands ferve for the fecretion  of the  Saliva,
which  they pour out in large quanfty, and which is promoted by
the motion of the Lower Jaw.—The Saliva  affifts in the folution
of  the food in the Mouth, in lubricating the throat for its paffage
downwards,  and in the digeftion of  it in the Stomach.
'O'
                       THROAT.

  TV Throat eonfifts of the Arches of the Palate, of the Pharynx
e.nd Larynx, with the Mufcles, Veffels, Nerves,  Sec.  which fur-
iound them.
  The Arches of the  Palate are two in number, in each fide of
the Throat, one of which is termed the Anterior,  the other the
Pofterior.
   Fi.ey are formed of a Doubling of the Skin,  with a few feat-
ured  Mufcular Fibies.
  The Anterior arifes fiom the middle of the Velum Palati, at the
fide cf the Uvula, and is  fixed to the edge of the Bafe of the
T«ngue, 
63
  The Pofterior has its origin likewife-  from the lide of the Uvu-
la, and paftes downwards,  to be inleried into  the fide of  the
Pharynx.
  The Anterior Arch contains the Circumflex Mufcle of the Pa-
late,   and,  with  its fellow on the oppofite fide, forms  the open-
ing into thfi'Thioat,  called Ifthmus Foucium.
  The Pofterior Arch has within it the Levator Mufcle  of the Pa-
late.
  Between the Anterior and  P-ifteror Arches, and clofe by  the
fides of the Bafe of the Tongue,  the Amygdala,  Tonjils, or Al-
monds of the Ears are fituated.     i
  They are of a reddifti col..in, of the figure of Almonds,  full
of Cells wh.ch commumca.e  wall each other, and have lar.;e  ir-
regular openings, which.convey 'he Mucus into the Threat,  the
dii'ehaige of  wh.ch is promoted by the motion of  the  furroUnd-
ing  pans.
                         Pharynx.
   The Pharynx, fo called  from  its convevingFood to the Sto-
m ich, and Air to the Lune;s, is a large Mufcular Bag, in form.
of an irregular Fun ie!, with the Tube called Eftphugus defcend-
iiv; from it,  and forming :he under end of that Funnel.
   It is bounded  ibove by tii   Cuneiform Procefs of the Occip'tal
Bone, the Pterygoid Proceffes of the  Sphenoid Bone, and back-
part of the Jaws, with all of which u is intimately conneaed.
   The anterior  margins of its Flefliy  parts are conneaed to  the
edges of the Larynx, and its fides  are covered by the great Blood-
veffels of the Neck.
   The fore-part of the Pharynx is formed by a Membrane com-
•mon  to it and to the  back-part of  the Larynx.
   Behind, it lies flat up.m the Cervical Vertebrae, and upon the
Mufcles which  cover the fore-parts of the  fides  of thefe Verte-
brae.
   It has feveral Openings by which it communieates with neigh-
bouring Cavities.
   Two  of thefe lead  upwards and  forwards by the pofterior
Nare-s into the Nofe ;—two go laterally by the Euftachian Tubes
to the Ears;—one  paries forwards  through the  large opening,
termed Fauces,  or Top of the Throat,  to the Mouth ;—one goes
downwards and forwards, thron^h the Larynx and Trache3, to
the Lung* :—and another direaiy downwards by the  Efophagus
to the Stomach.
   The Pharynx is furrounded by a loofe Cellular Subftance, and
confifts of 'different Layers of Muliles,  called ConftriHores Pha-
rymris, which have been already defcribed.
   On the  inner fide, it is  lined by the continuation of  the Mem-
brane of the Mouth, wh'ch is perforated by the Duas of nume-
rous Glands,  for the fecretion of Mucus.               '  " - 
1-1
   The lower end of the Pharynx, oppofite to the under edge of
 the  Cricoid Cartilage,  defcribes  a  complete Circle,  which
 forms the beginning of the Efophagus.
   The Phaiynx is fupplied  with  Blood by the Pharyngeal
 Branches, which come  direaiy or indireaiy  from the External
 Carotids. It returns its  blood to both Jugular Veins.—Its nerves
 are from  the Eighth Pair.
   The Ufe of the Pharynx is,—to receive the  Aliments from ihe
 Mouth, and by the ;.ction of  its  Mufcles to convey them to the
 Efophagus. It muftlikewifeaffift in the modification of the Voice.
                         Larynx.
   The Larynx,  fo called  from its being the principal Organ of
 Voice,  is fituated at the upper and fore-part of the Neck  imme-
 diately under the Os Hyoides,  which is placed at the root of the
 Tongue.
   It is compofed of Cartilages and Mufcles,  Ligaments,  Mem-
 branes, and Mucous Glands; and  is  conneaed  above to the
 Tongue and Os  Hyoides, and behind to the Pharynx.
   The Cartilages of the Larynx are geneially  coniideied as being
 five in number,  though, befides thefe, fome choofe to enumerate
 fmall Projections which  are conneaed with them.
   The  Five Cartilages are,—the Thyroid,  the Cricoid,  the Tvjo
 Arytenoid, and the Epiglottis.
   The Thyroid,  Scutiform, or Shield-like Cartilage, is placed at
 the upper  and fore-part of the  Laiynx, and is the largeft of the
 whole.
   When fpread out, it is of  an oblong fliape,  but,  in  the natu-
 ral fituation, it  confifts  of two lateral Wings or Portions,  of a
 quadrangular  form, uniting  before in a  Ion itudinal  angle,
 which can be readily felt in the  fore-part of the Throat, and
 which,  from its  projeaing  more  in  Men than  in Women,  has
 obtained the name of Pomum Adami.
   The upper part of the  angle is formed into a Notch,  from
 which,  and  from the upper edge of the  Cartilage in  general, a
broad Ligatnent  afcends,  to fix it to the  under part of the Os
 Hyoides.
   From the pofteiior corners four proceffes projea, called Cornua,
 two of which termed Superior, are long, and  alcend to be joined
 by round  Ligaments'to the extremities of the Cornua of the Os
 Hyoides.
   In the middle of thefe  Ligaments,  one or two fmall Cartilagi-
 nous, or even Offeous Subftances,  are frequently found.
   The other two Cornua, called  bferior, are.fhorter than  the
 Superior,  andcuived backwards,  to  be fixed to the fides of  the
 Cricoid Cartila;e.
   The Thyroid Caitilage ferves for the  proteaion  of  the other
 Cartilages, and,  along with the Os Hyoides,  preferves  the Paf-
 fage open, for the tranfmiffion «f the Food to the Stomach. 
•
                             65

  The Cricoid, or  Annular, or Ring-like, Cartilage,  is placed
below, and likewife  behind the Thyroid, and like it, may be
readily felt in the fore-part of the Throat.
  It is narrow before, where it lies under the Thyroid Cartilage,
and thick, broad and ftrong pofteriorly, where it is  placed be-
hind that  Cartilage.
  Its Pofterior Surface is divided by a Ridge into tivo lateral Ca-
vities, for the reception of  the  pofterior  Cricoarytenoid Muf-
cles.
  Its under edge is horizontal, and fixed to  the beginning, or
fii ft Cartilage of  the Trachea.
  The upper edge  flants confiderably,  and has its anterior nar-
row  part  fixed to the under edge of the Thyroid Cartilage.
  It has four  fmall Articular  Surfaces, with  diftina Capfulaf
L'gaments, of which two are placed above, for  he articulation
of the Arytenoid  Cartilages,  and two  at the  uader  and lateral
parts, for the conneaion of the iuferior Cornua of the Thyroid
Cartilace.
   The Cricoid Cartilage forms part of  the general Tube of the
Trachea,  conftitutes  the Bafe of the Larynx, and gives a firm
fupport to the Arytenoid Caitilages.
   The tvjs Arytenoid Cartilages,  named from  a fuppafed refem-
blance to an Ewer, or Drinking-cup of  the Ancients, are mu.b
fmaller than  the other Cartila es, and are placed upon  the up-
per  pofte ior, and  lateral  parts  of the  Cricoid  Cartilage,  at  a
fmall diftance frcmeach other.
   They  are of a triangular form, and a Utile twifted, and are
bent back, fo as to have a broad concave Suiface  behind.
   Their upper extrem'ties aie turned towards each othei, and are
confidered by fome Authors as diftina Cartilages.
   Their Ba.es are  broal and hollo-w, where  they are articulated
by Capfular Ligamems  with the C'icoid Cartilace, upon .vmch
they  are  moved  in different  direaions,  by  the  action of vari-
ous  Mufcles.
   They are conneaed to each other, and to the adjacent Cartila-
ges,  by  different Mufcles  and  L-^amcts.
   The Aiytenoid  Cfirtila^es form a part of  the opening called
Glottis, and give attachment o its Ligaments.
   Tli? Epiglottis, obtaining its name from \t> fituation ab.ive th^
Glottis,  is of an  oval form when furrounded by its Ligaments
and Membianes, but, wi.cn diveiled  of thtfe, it is fouul to be
narrow below,  broad above, and rounded  at its upper exive-
mty.
   It  is qpnvex  towards the Tongue,  and Concave towards the
Glottis,   with its point refleaed a Intl.-  forwards.
   It is placed behind the upper part of  the Thyuid Cartilage, is
fituated obliquely ovei the Glottis, and  may be fetn and exami --
f-' i ypreffing down the root of the Tongue.
  Vol.  II.         I  j 
66
   Its under end is fixed by a broad and fhort L'gament to the mid-
dle Notch of the Thyroid Callage, and by  two lateral Liga-
ments to the whole length of the Arytenoid Cartilages.
   It is fixed to the roots of  the Os Hyoides and Tongue by ano-
ther  Ligament, which is a doubling  of the  inner Membrane
running along the middle of its anterior Sui face, and forming the
Franum Epiglottidis.
   It is  very elalbc, and is much more pliable than the other Car-
tilages, being of a C.trtilago-ligamentous nature.
   It is  foumf to have a number of Fiffures, in which Lacuna are
placed, and to be perforated by numerous Foramina, which  are
the Mouths of fo many Mucous Follicles, and which are in  a
great meafure concealed  by the Membrane which  covers it.
   It breaks the current of the  Air coming from  the Mouth and
Nofe, and prevents it from rufhing too forcibly into the  Cavity
of theLun,'s.—In fled  and drawn  down by  the Tongue  and
by fmall Mufcles,  it defends the Glottis,  and ftiuts it com-
pletely  in the time of  fwallowing.—After the action of fwallow-
ing, it  is  railed  by  its own  elafticity,  and  by the root of the
Tongue to which it is fixed, returning to its former p> fition.
   Ligaments of the Glottis.—From the fore-part of the body of
each of  the Arytenoid Cartilages, a Ligamentous Cord paffes hori-
zontally forwards, to be fixed by its other extremity to the infide
of  the anterior angle  of the Thyroid Cartilage.
   The  opening formed between thefe Ligaments is called Glottis,
from the Greek:  It is  alfo called Mouth  of the larynx,  and
Rima  Glottidis, and  is  of a triangular figure,  the  Ligaments
being at a  greater diftance behind than at their anterior extre-
mity.
   Under  thefe two Ligaments there are two others, larger and
more diftina than the former and which are commonly confidered
us the proper Ligaments of the Glottis.  They arife from the Bafe
of the Arytenoid Cartilages, and run  in the fame direaion with
the former, to be fixed alfo to the Thyroid Cartilage.
   In  the  Interftice of the Superior and Inferior Ligaments, on
each fide there is  a Fiffure,  which leads to a fmall Membranous
Cavity  or  Deprcflion, with its bottom turned outwards.
   Thefe are the Ventricles of the Larynx of Galen.—They are
chiefly formed by  the inner Membrane of  the Larynx.
   They differ in fize in different people, have  Mucous  Follicles
opening into them, and are found to be ferviceable in the modula-
tion of  the Voice.
   On the anterior Suiface of the Arytenoid Cartilages, there is a
fmall Depreflion filled by  a Glandular Body, which  not only
covers the fore-part of thefe Cartilages, but is  continued over the
pofterior extremity of the Ligaments of  the Glottis.
   The Arytenoid Glands are larger in fome fubjects than in  others.
They were difcovered, and  are particularly defcribed and  deline-
ated,  by Morgacm. 
67
   The  Ligaments  which connea the Epiglottis to the Notch of
 the Thyroid Cartilage, and to the under fide of the Os Hyoides,
 and one which ties the Bafe of the Os Hyoides, form a triangular
fpace, which is alfo occupied by Cellular Subftance and by Mu-
 cous Glands.
   The  Cavity of the Larynx is lined by a membrane which is
 extremely irritable, and is.every where perforated by the Mouths
 of fmall Mucous Glands, for the purpofe of moiftening it.
   The  Larynx has a number of Mufcles, for its different mo-
 tions; all of which have been already defcribed.
   The  Arteries of the Larynx  are the two fuperior Laryngeals,
 which come from the  External Carotids,  and the  two inferior
 Laryngeals,  which are fent off from the Subclavian Arteries.
   The Veins return to  the External Jugulars.
   The Nerves are chiefly the fuperior and inferior Laryngeals,
 which are branches of  the Eighth Pair.
   The Larynx ferves the purpofe of Refpiration, forms and mo-
 dulates the Voice, and is alfo ufeful in  Deglutition.
   It is  the principal Organ of Voice;—for,  if a hole be made in
 the Trachea, and the paffage  of the Larynx  flopped, the Air
 efcapes by that opening without producing Voice.
   Voice is formed by the Air, in its paffage through the Glottis,
 aaing upon the Ligaments of the Glottis and Cartilages of the
 Larynx and Trachea,  and thus  producing a Tremour;—and is
 different in different perfons,  according to the Form and Struaure
 of the Larynx.
   The  ftrength of Voice is in proportion to the quantity of Air
 expired,  and the narrowntfs of the Glottis.
   A Tone is acute in proportion to  the tenfion of the parts of
 the Larynx  and Trachea in general, and  of  the Ligaments of the
 Glottis in particular.
   A Tone is grave in  propostion to the reverfe of the above.
   Speech is performed  chiefly by the different parts of the Mouth,
 aflifted  by the Cavity of the  Nofe,—the Larynx moving only in
 a fmall degree.
   When the Air paffes through the Larynx without producing a
 Tremour it occafions  a Whifper.
   When a perfon fpeaks during infpiration,  the voice  is thereby
 very materially altered ; and, by praaice,  may be made to ap-
 pear as cociing from o:her places than the mouth of the fpeaker j
 as is the cafe with thole who call thcmfelves Ventriloquifts. 
6S
OF  THE  THORAN.
                    ---—o—    —

  The  Thorax, or  Breaft, extends  from the neck to  the Dia-
phragm,  and is divided into External and Internal Parts.

         EXTERNAL PARTS OF THE THORAX.
  The External Parts of the Thorax, befides the common In-
teguments and Mammae, are,
  The Mufcles, con! (Tug of the Peifcralrs, Subclavii, and un-
der end of the Platyfma Moyodes on each fide, which aie fituated
anteriorly.
  The Serati Magni, which are placed laterally.
  The Trapzii, Latiffimi Dorfi, and numerous other Mufcles on
the Back, which are placed  pofteriorly.
  The- Intercoftales  and Sterno-Coftales, which are fituated, 'the
former between, and the latter on the inner fide of the Ribs'
  The Bones, confifting of Sternum, Ribs, and Dorfal Vertebra.
—All thefe Parts, excepting the Mammae, have been already
defcribed.
                 *       Mammje.
  The Mamma are two Glandular  Bodies, of a circular form,
fituated on the anterior, and a little towards the lateral  parts of
the Thorax, adhering loofely by  Cellular Subftance to  the Sur-
face of the large Peaoral Mufcles.
  The term Mamma is peculiar to the Breafts of Women.—In
Men thefe parts are called Mammilla ;—and in the Brute-kind,
Uberm.
  In the  Ape, and a few other animals,  they  are placed,  as in
the Human body,  upon the  Thorax ;—but, in the ceneiality of
Qu drupeds,  they aie fituated under the Abdomen.
   The cor. mon number A the M  mmae,  in the Human fpecies,
is well known to be two.—Barthcli.. e, however, mentions the
cafe of a  Woman, who had  two  Mammae on  the left fide, and
one on the ugh ;  and  another, where theie were two  on each
fide.
  Dr. Vaug::an narrates the cafe of a Woman he has examined,
who nas  a iupernum'.rary N:i,>le,  at the ;n,der fide of  the right
Mamma, from  wh-ch  mdk flowed wnui  the central  one  was
preffed, and vice verfa. 
   The Mamma? vary in fize in different Women, and in  the
fame Women at different periods of life.
   In ,Girls, previous to the age of Puberty, they are remarkably
fmall.
  About  the  age of  fourteen,  at which time the Menfes, in
this  climate, moft commonly begin to appear, they evolve and
become prominent.
   During Geftation they incrcafe in fize, and foon after Delivery
they arrive at their greateft extent.
   After the age of forty-five,  or from that to fifty,—the period
when the Menfes generally difappear,  they decreafe in fize, and
become foft, pendulous, and flaccid.
   Under the Skin, there is a large quantity of Fat which confti-
tutcs a confiderable portion of the bulk of the Mamma,  and  de-
fends the Glandular Part,  and is not found to pafs into, or com-
municate with, the Laaiferoos Duas.
   The Glandular Part  of the Mamma is of  a whiiifti colour
of the Conglomerate kind, and therefore  irregular in its Sub-
ftance.
   It is compofed of a number of fmaller Maffes or Glands, which
are alfo  feparated by Fat;  and  thefe  agin  are  divided  into
ftill fmaller parts, in  which the Milk is originally fecreted or
formed.                                   •
   Near the  centre of the Mamma,  is the  Papilla  or Nipple,
which is of a Cylindrical form, and of a redder colour than the
reft of the Skin of the Breaft.
   It is of different fizes in different ages and conftitutions, and is
always larger in the time of Geftation, or of Nurfing.
   It is capable of diftention from titillation, or when influenced
 by the paflions of the Mind.
   It is compofed of a tough Cellular  or  Ligamentous  Subftance,
which inclofes the Laaiferous Tube?, and  which is  fo  elaftic,
ihat after the part is drawn out or diftended,  it readily recovers
its former dimenfion,  when the caufe  of  diftenfion has ceafed to
act.
   Upon the Apex of  the Nipple,  the  Orifices of the Laaiferous
Duas appear  and  are of the fame  numbei w.th thofe which enter
its Bafe.
   Around  the Nipple, there is a Circle  or Difk,  called Areola,
—of a different colour from the reft of the Skin of the  Breaft.
   This Difk,  however, varies in colour at different times of life,
being florid in young G;rls, of a  pale-brown in  Women a lit-
tle more advanced in life,  and in  old age,  of a livid  and dull
colour.
   During Pregnancy, it is of a darker colour than at other times,
in confequence of a change which takes place in the Corpus Mu-
cofum which forms it. 
TO
  Under the Skin of the Areola,  there are numerous Sebaceous
Glands, or Follicles, the Orifices of wbich difcharge an oily Mu-
cus, to defeuJ the N'ppleand Areola arou d it.
  The Arteries of the  Mamma aie partly from the Internal,  and
partly from the External Marhmaries or  Thorac cs,  the  former
of which are fait off from the Subciav ac.  and the latter from the
Ax llary Artery,—the  Branches entering the Mamma at many
d.fferent places.
  The Veins accompany the Arteries, and are diftinguifhed by
the fame names-
  The Abforbents of the Mamma are alfo numerous,  the  greater
part of which pafs through the Axillary Glands, others penetrate
the IrHerltices  of  the  Ribs, near  the Sternum, and enter the
Glands which beljng to the Internal M .mmary Veffels.
  The Nerves  are' chiefly  from  the  Axillary Plexus,  a  few
Blanches being alfo fent off from the Interc.dials.
  From the extremities  of the Arteries in the Subftance  of  the
Mamma,  nuruiierlefs Tube.-> arife, called Duilus or Tubuli Lac-
tij'eri,  which gradually  unite  into Trunks, and run in a radiated
manner tow,.ids the root of the Nipple.
  They  become grealy enlarged in the  time of  Suckling,  and
ferve as Relet voir* in which the Milk is contained.
  The Laateroift  Duas are accompanied,  in iht Subftance of
the Mamma, by a tough white elaftic  Subftance,  which  follows
them to the Nipple.
  At the root of the N-'pple,  they  become contraaed,   and 3ie
there from Twelve to Eighteen in number.
  Either from the want of  uniformity, however, with refpea to
their number in different fubje-as, or fiom the difficulty  of  ptr-
ceivng them, they have been  varioufly eftimated by different
Authors.
   Near the root of the Nipple,  they have been fuppofed by Dr.
Meckel, to form a circle of  communication ;—but this  has
Ken afcribed by ft II later Anatomifts, to a laceration of Vcffeis;
and numerous  preparations and experiments,—particulaily  that
of throwing in  an  injeaion at one Dua,  and finding that it  fills
ore part only of the  Mamma, with cut  returning by any other
Duct,—'ecm fufficientiy to indicate, that there is no fuch ciicu-
lar communication.
   In  the Subftance of  the Nipple,  the Laaiferous Tubes are at
a  little diftance from each other,  and  are coiled up in  fuch a
manner, that the fpontaneous flow of the Milk is prevented, un-
lefs it be accumulated in a large quantity.
   But  when the Nipple is drawn out and extended,—as  by the
application of  the  Child's Mouth,—the  Duas become  ftraight
and parallel to eavh other,  fo as to  allow  an  uninterrupted  flow
of the Milk. 
71
  After the aaion of Sucking, the Nipple, and of eonftquence
its Duas, immediately recover their former fituation.
  Sometimes one or  more of the Laaiferous  Duas terminate
upon the Surface of the Areola, from  which, Morgagni  fup-
pofed,  that ihe Glands there were of t'.e Lactiferous kind.
  In Children of both fexes, the Mammx are merely Cutaneous
Tubercles,  and at the time  of birth contain a  Milky-like Fluid,
which can be readily fqueezed outr
  This Fluid commonly disappears a  fhort  time after Birth •—
but there are various examples  on record, where Milk has  been
brought to the Breads, both  of youngG rls and old Women, by
the frequent application of  a  Child to  the Nipples, and where
there was no caufe for fufpicion of Impregnation be ng  prefent.
Nor are inftances awanting of Milk being brought to the Mam-
millae of Men,  by the fame apphcation.
   The Mamma: add much  to the ornament of the  perfon, but
ferve in particular for furn fhing nourifhment to the Child, which
is conveyed to  it through  the medium  of the Nipple.
   The  Secretion begins  foon  after Delivery,  and  continues to
flow for many  months, and even for fome years,  if the Woman
fuckle her Clvld ;  and the more frequently the Milk  is extraaed,
the c reater is the quantity  received in a given time.
   The  operation of Sucking depends  upon the principles of the    ^
Air-pump.—The child embraces the Nipple clofely with  its Lips,
which prevents the external Air from entering, draws the Duas
 to a ftiaight line,  and prepares a fpace  for the Milk,  which is
 forced from  the Breaft by the preffure of the Atmofphere, and
 flows to the Mouth in the manner a  Fluid follows the Piftern of a
 common Pump or Syringe.

          INTERNAL PARTS  OF THE THORAX.
   The Mammae and Mufcles, covering  the fore and lateral pails
 of the Thorax, being  turned afide, and  the Ribs  afteiwards cut
 from the  Sternum and turned back,  the  Internal Parts of the
 Thorax are brought into view.
   They eonfift of ihe Pleura,  which lines the  Thorax;__the
 Mediaftinum, which divides it into right and  left Cavities, and
 contains feveral Veflels, Nerves, &c.  between  its Layers;—the
 Pericardium and  Heart, which  occupy the middle,—and the
 Lungs, which  furround the  Heart, and fill the greater part of the
 Thorax.

                      The Pleura.
   The Pleura is a Membrane of confiderable ftrength, which
 lines the inner fide of the Thorax, and  covers the moft of its
 contents.
   Its External Surface is Cellular, and adheres  clofely to the
 parts which furround it. 
Tl
  Its Internal Suiface is fmooth andpohJheJ, being moiltened by
a Sereus Fluid, which exfudes from its Arteries.
  It is divided into two lateral Sacs or Pleura, the form of which
correfponds exaaiy with that of the  furrouuding  Bones  of the
Thorax.
  The Pleurae adhere to the Periofteum of the Ribs, line theln-
tercoftal and Sterno Coital Mufcles, the Sternum, and  Dorfal
Vertebrae, and cover the  Pericardium, Lungs,  and Lateral or
Flefhy parts of the Diaphragm.
  Behind the Sternum, the Pleurae are contiguous to each other,
and form a Partition called Mediaftinum, which  extends between
the Sternum and Vertebrae,  but is intercepted by the  Heart and
Root of the Lungs,  and divides the'Thorax into two diftina
Cavities, which have no communication with each other.
  The Arteries ot the Pleura are from thofe of the adjacent parts,
viz.  from the  Intercoftal,  Mammaries,  Diaphragmatics,  Bron-
chial, and Efophageal.
  The Veins, which return the Blood, accompany the Arteries,
and are diftinguifhed by  the fame names.
  The Nerves are  from the Inttrcoftals and Diaphragmatics, but
too fmall to be traced without difficulty ; and the Membrane it-
felf is not obferved to poffefs much fenlibility in the found un-
inflamed ftate.
  The Pleura ferves to render the infide of the  Thorax fmooth,
for the eafy motion of the  contiguous parts, to divide it into Ca-
vities,  and to ftrengthen the containing and  contained  parts of
the  Thorax.
                        Mediastinum.
  The Mediaftinum, fo named from its fituation  in the middle of
the Thorax, is fo'med by a refleaion of the Pleura, and is of
comfe double.—It contains between its Layers a confiderable
quantity of Cellular Subftance,  by which they are united.
  It is divided into Anterior and Pofterior Mediaftinum, the for-
mer of which is fituated at  the fore,  an J the latter at the back-
part of the Thorax.
  The Anterior Mediaftinum is conneaed  before,  to  the Ster-
num ; and behind, to the  Pericardium and large Veffels  of the
Heart.
  The two Layers of the Anterior Mediaftinum are clo'Vly ap.
plied to each other, excepting at the upper-put  of  the  Thorax,
where they are fepaiared by the remains of the Thymus Gland.
  At the upper-part of the Thorax, it  lies  e^aiy bthmd the
middle of the Sternum ; but in its defcent, it inclines gradually
to the left edge of  that Bone.
  In confequence of its obliquity, a pointed  inftrument, pufhed
through the centre of the  Sternum, is generally found to  pafs
into the right Cavity of the Thorax. 
73
  Frequent deviations, however, from this general rule, have been
met with.—In particular,  Lieutaud and Sabatier relate fe-
veral inftanccs where  the Anterior Mediaftinum wts found to
defcend along the middle of the Sternum;  and others,  though
rare, where it defcended even to the right fide of this Bone.
  The Pofterior Mediaftinum reaches from the root of the Lungs
and back-part of  the Heart, to the Dorfal Vertebrae.
  Between the Layers of the  Pofterior Mediaftinum, a triangu-
lar fpace is formed, in which are fituated the under end of  the
Trachea, the Efophagus, the Aorta Defcendens, the Vena Azy-
goa,.and  i horacic Dua,  with the Eighth Pair of Nerves.
  The Blood-veffels of the Mediaftinum  are  from thofe of  the
neighbouring parts :'— The Anterior Mediaftinum is fupplied by
Branches from the Subclavian,  Internal Mammaries, and Dia-
phragmatic->,—and the Pofterior Mediaftinum, by Branches from
the Intercoitals and Efophageals.
   The Veins  ccompany the Arteries, and have the fame names.
   The Mediaftinum divides the Thorax  into two Cavities, fup-
 ports its general Contents, hinders one Lung from prefling upon
 the other, when the perfon lies on his fide,  and prevents Fluids,
 ■—which, in conlequence ox accident or difeafe, may be contain-
 ed in the Cavity of the Thorax,—from palling  from one fide to
 the other.  4          ^
                      PERICARDIUM.
   The Pericardium,  Sac, or Capfule of the Heart, is one of the
 ftrongeft Membranes of the Body, and its fize fuch as to be pro-
 perly adapted to that of the Heart, which it contains.
   It is formed of tvoo Layers, the External of  which is  a conti-
 s nation  of the Anterior Mediaftinum, which afterwards paffes to
 the Lun^s and lateral parts of the Diaphragm.
   The Internal Layer is fmooth,  tendinous-like, and polifhed oa
 its inner Surface, and is ftronger than the other.
   It adheres fo firmly to the  Tendinous part of the Diaphragm,
 as not to be feparated from it without much difficulty.
   The Pericardium extends  a confiderable way beyond the Bafe
 of the Heart, and includes the large Blood-veffels, as far as the
 roots of  their firft principal Branches, in confequence of which
 it forms feveral angles, which have been  termed Comua of the
 Pericardium.
   While the  External Layer is refleaed to cover the parts which
 furround it, the inner one is alfo refleaed,  fit 11 over the  roots of
 the large Blood-veffels, and then  over  the  Heart,  to  form its
 proper covering, in the fame manner the Tunica Conjunaiva is
 refleaed from the Eye-lids to cover the fore-part of the  Eye.
   From the ends of  the Extreme Arteries, upon its Surface,  a
 Fluid, called Liquor Pericardii, is difcharged, by which it is lu-
 bricated, and the effeas of Friaion diminifhed.

    Vol. TJ.           G
h," 
74
  The Liquor Pericardii is commonly found, after death, in the
quantity of a few drachms, though  not unfrequently of  one or
two ounces.
  Its colour is redder in a young fubject, than in a perfon ad-
vanced in life, in whom it becomes paler,  or more of a ftraw-
colour.
  The Arteries of the fore-part of the Pericardium are from the
Internal Mammaries and Diaphragmaties;  thofe of its fore-part
from the Bronchial and Efophageal.
  The Veins correfpond with the Arteries,  and have the  fame
name.
  The Ufe of the Pericardium is, to preferve the Heart in fitu,
to defend it from being injured by the parts which furround  it,
and to refhain its inordinate motions.




                    OF  THE HEART.

  The  Heart is a hollow Mufcle, divided into different Cavi-
ties, and inclofed in the Pericardium.
  It is fituated in the Cavity of the Thorax, behind*the Sternum,
between the Right and  Left Lungs.
  It is of a Conical figure, flattened at one fide,  and is divided
into Bafe, Body,  and Apex, with a Superior and Inferior Surface,
and a Right and  Left  Margin.
  The Bafe is placed backwards next the Spine, while the Body
and Apex are  turned  forwards, and obliquely over to the left
fide.
  In Quadrupeds, the Heart is placed upon a line  with the  Ster-
num,  the point only  touching  the Diaphragm :—In the Human
Body,  the Apex, or  Point of  the Heart,  is but little lower than
the Bafe, and projeas between the two lobes of the left Lung,
behind the  Cartilages of the Fifth  and Sixth True Ribs of the
left Side, or a little  below the left Nipple, where the Pulfation
may be felt.—The  fituation, however, varies a little, according
to the polition of the Body, and ftate of Refpiration.
  Though  this be the common fituation of the Heart, a few rar«
and fingular inftances have occurred, where it has been found (o
occupy  the light fide of  the  thorax; and a difplacement has
fometimes  happened,  in confequence  of different kinds of tu-
mours  n the left fide of the Thorax.
  The Superior or Anterior Surface of the  Heart is convex, and
is oppofed to the Pofterior Surface of the Sternum,  the anterior
ed^es of the Lungs intervening.
  The Inferior or Pofterior Surface  is flat, and refts upon the
Teidon of the Diajpnragm, which fupports it; the Heart is not 
73
much affeaed,  however, by the motions of that Mufcle in time
of Refpnaion, its  Tendon  moving oniy in a fmall degree.
  The right fi.le of the Body of the Heart is fharp, and is cal-
led  Vlargo Acutus,                 ~
  The left fide of the Body of the Heart is round, and is termed
Mar go Obtufus.
  The Bii'e is formed of a right and left Auricle, and the Body
of a right and left  Ventricle.
  When the Heart is diftended, the right Auricle, and part of the
correfpondmg Ventricle, occupy the right, and the reft of the
Heart the left Cavity of the Thorax.
  The Heart is conneaed above and  behind to  the  upper and
back-part of the Thorax, through the  med'um of the great Vef-
fels wh.ch go into, or pafs out from it.       ,
  The other parts of the  Heart are free, being merely contigu-
ous to ihe infide of the Pericardium.
  The External  Surface of  the  Heart is  covered  with a thin
fmooth Membranous Coat, which is a lefkaion of the inner Layer
of the Pericardium, and which gives  additional  ftrength to  its
Flefhy Fibres.                                           *
   Between the Coat and Subftance of the  Heart, th?re is com
monly a confiderable quantity of Fat,  which lubricates ?.,  and
fc ibtates its motions.
  The Sundance of the Heart confifts of Mufcular Fibres, firm
and more clofely conneaed than the generally of Fibres cf Muf-
cles in other parts of the Body.
  The Fibres run in different direaions, longitudinal and tranf-
verie, but moft of  them oblique.
  Many of them run over the Point of the He:;;t from one Sur-
face to the other, and the whole fo much twilled and folded, and
fo varioufly intermixed,  as to be difficult to be unravelled or de-
icribod :—In general, however,  their  courfe is fuch as  to leffen
the Cavities of the Heart in all their dimenfions.
  The Civities cf the Heart are lined w:th a Membrane extreme-
ly thin, but d-.-nfe and ftrong,  to defend them againft the pref-
ix re of the Blood.
   The Heart is formed of an anterior  or right and a pofter'nr or
left fide,  or of a right and left Heart,  joinetktogether by a Par-
tition, which prevents the two fides from having any dirta com-
munication with each other.— The terms Right and Lefr^TV w-
 ever, are moie applicable to the Heait of  the Quadruped,* and
 tlioi'e of Anterior and P< ftcvior to the  Humnn Heart.
   Ei.l-  lide of the Heart is furnifiled  wih  a iet of Vet :s, with
an Auricle, a Ventricle, and  an Artery, and alfo with two fets of
 Calves,—one between the AuiiJe and Ventricle, the other be-
tween the Ventricle and Aitery.
   At the ri. ht lide cf the Heart  are two Veins, called from their
 large fize Vena  Cav.e,  the one Superior, the other InJ'e.-lrr.
ki 
76
   The Superior Vena Cava, called alfo Vena Cava Defccndens,
 returns the Blood from  the  upper  parts of the Bodv ;  and the
 Injtrior Vena Cava, termed likewife Afcendens, returns it from
 the lower parts ; and both'terminate in the right Auricle.   It is-
 prevented from returning by the fullnefs of the Veins, and by
 the preffure of the Blood a tergo.
   The Auricle is fituated upon-the right,  and partly  upon the
 back-part of  the Heart,  and is divided into the right Sinus Veno-
fus and  proper Auricle.
   The Sinus  Venofus  is  formed by  the union of the two Vena1
 Cava?, which fweil  out towards the anterior  and left fide.  It is
 notched at its anterior edge, is a Mufcular Bag of confiderable
 ftrength,  aid is  uniform and fmooth, both upon its  outer and
 inner Suiface.
   At the upper  and left  fide of the Sinus, is  the projection or
 Appendix, termed Proper Auricle,  from its fuppofed refemblance
 to the Ear of a Quadruped -.—It is formed by a blind Sac, which
 is ferrated and  notched on its pofterior edge, and convex or
 rounded on the  other,  and terminates obliquely in an  obtufe
 point.
   The Sinus and proper Auricle form one common Cavity, have
 no Valve between them, and are therefore fillad and emptied at
 the fame time.
   Where the t^vo Cavities meet in  the Hearts  of  Quadrupeds,
 there is a Projeaion feen in the Sinus Venofus, called Tuberculum
 LowERl, which is fuppofed  to prevent the Blood of the one Ca-
 va from rufhing  upon that of the other, and  to direa it into the
 Auricle.
   At the meeting of the two Cavoe in the  Human Heart, an an-
 gle is formed, which alfo has fiequently got the name of Tuber-
 -culum Loweri :—That fubftance, however,  is peculiar  to the
 Hearts  of Brute-Animals.
   Under th's Angle,  < r  joining of the Vena; Cava*, there is the
 Vcft-ge of the Foramen Ovale, which, in the Foetus, forms  a
 communication between the  right and left Auricles ; but,  in the
 Adult, is filled  up  by its Membrane,  and forms the Fofa Ova-
 lis.
   The  Foff'a Ovalis has thick  and  ftrong fides, called  Column*
 Foaminis Ovalis, lfthmus Vieussenii,  or  Annulus ilcff^  Ova-
 lis.
   At the left fide of the  Mouth of the Inferior Cava,  where   it
 joins the Sinu-,  is the Valve of Eustachius.
   It s  in form of a Crefcent, with the convex edge fixed to the
 union  f ihe Sinus and  Cava, and the concave edge turned ob-
 liquely upwards, reaching about  half way  ovei the Mouth of
 the Cava.—Its fize and appearance, however, vary  much in dif-
 feient Subjeas. 
7?
   Its porcriov Cornu is continued with the left fide of the Ifth-
mus of the Foramen Ovale; the other end vanifhes in the oppo-
fite fide of  the Sinus.
   It is equally diftina in the Adult as in the Fcetus ; but in the
former  it is frequently  found reticulated, or Cribriform,  which
appearance  is feldom, though fometimes, met with in the  latter.
   In the Adult^ it is fuppofed to prevent the Blood of  the Au-
ricle from  pafling into the Inferior Cava; and in the Fcetus, to
direft the Blood of the  Inferior Cava to the Foramen Ovale.
   Upon the left lide of the Valve of Eustachius, in the under
part of the Auricle, is  the Orifice or Termination  of the g.eat
Coronary Vein of the-Heart.
   Over the  Orifice of this Vein, there is a Semilunar Valve,  to
prevent the  Blood in the Auricle from paffing into the Vein.
   The inner fide *jf  the proper Auricle  is readily d itimuifhed
from the  Sinus, by having a  number of Columna Carnea, or
FleJ1;; P'dlars in it,  which, from their fuppoied  refembh'ice to
the T'-uh  of a Comb, femctimes obtain  the  name of Mufcult-
Auricula  Petlinati.
   The Mulculi PecVnati have fmaller Columns running in d f-
ferent  direaions,  giving the whole a  reticulated appeararce.
   Between  the Columnae Carneas, are Depreffions  or Furrovjs, in
which the  fides of the Auricle are  thin, and  lemi  tranfparent,
being chiefly formed by  the outer and iiiwti- Membrane  of the
Aunclj.
   At the  under and kit  fide of the Sinus Venofus, and oppofite •
to a Groove, fituated externally between \\\c: Auricle  and Ventri- v,
cle, ther,e is a Hole, above an inch in diameter, which opens in-
to the  upper and right part of the  correfnoiiding Vcn ricle.
   The right A uicle receives  the Blood  from the  Vena;  Cavae
and Coronary Veins, and, by i's Mufcular contraai n, difchar-
ges it  into  the correfponding Ventricle, out of wh.ee.  t  is pre-
vented from returning by a Valve, called Tricufpid, placed.with-
i.i the  Ventricle.
   The Right or Pulmonary Ventricle,  is fituated on the  fore-fide
cf the Heart, is of  a tiiangular form, and  much  thieiter and
ivrongcr than the corivfponding Auricle.
   It has many ftrong Eminences,  Columns, Lacertuli,or Cords,
 called Columna Carnea.
   The Columna run in different direaions, but the  ftronreft^pf
 tiiem longitudinally, and  are of various fize9, foimin  fo many
diltina Mufcles,  which are extremely compaa  in  their   ftruc-
 ture,  and  coinpofe a beautiful,  intricate, and  irregular Net-
 work.
   In general, they adlv.-re through their whole length to each o-
ther, or to the fides of the Ventricle ;  but many or' them arc icofe
in their middle, ai.d maybe raifcd by a p.'jbe put under  than.

    Vol.  II.           G 2
4 
73
  Thes a<Ti$ the Ve  trcle in  its Syflole or contraaion,  and pre-
vent ;  i.om  icing oveiftieched in it  Dyaftcle or dilatation, and
agitj . .he BlooJ in its paffage through the Ventricle.
  T:»ty ait fui.^.ffd to  bnnc the oppofite fides of  the Ventrich
Completely to,_edier,  during us contraaion.
  Between the Columns: aie many deep Grooves,  Pits, or Fo-
vea?, into all of  which the B ood readily enters.
  Around the Paffige, between the Auricle and Ventricle, there
is a Tendinous Margin or Ring,  from the whole  edge of which
a circular Membrane is fent off, called Valvula Trieufpis, or Tri-
glochin, from its having thiee principal points or  divilions.
  Fiom  the edge  of the Tricufpid  Valve,  many fmall round
Tendinous Cords  are fent off, of  unequal  fize.
  The Cho-da Tendinea defcend obliquely within the Ventricle,
in the  fame diicction with the Valve from whiph  they arife.
  They  are fixed to the extremities of a few ftrong  Papilla: or
Colum. ae Carneae, which are joined by their other  extremilcs to
the corrcfponditig  fides of the Ventiicie.
  The Tricufpid Valve prevents the  reflux of the  Blood to the
Auricle, during the contraaion of the Ventricle.
  The Tendons allow the Valve to be pufhed back by the Blood,
until a Septum or  Partition is formed  by it at the Mouth of the
Vtntriclq, during the contraaion of the latter.—The Papillae, by
their contraaion,  prevent the Valve from going into the Auri-
cle.
  The Valve is  opened and preffed back by the Blood in its paf-
fage from the Auricle to the Ventricle.
  The upper and left fide of the Ventricle becomes fmooth  and
uniform, and leads to a large Opening,  about an inch in diame-
ter, which is  the Mouth of the  Pulmonary Artery.
  The right Ventricle,  by its dilatation,  receives the Blood from
the,Auricle, and  fends it, by  a ftiong  and  fudden  convulfive
contraaion, to the Pulmonary Artery,  from whence it is pre-
vented -from retuining, by three Valves placed in  the Mouth of
the Artery.
   The Valves at the Mouth of  the Pulmonary Artery are called
 Valvula  Semilunares, or Sigmoidea, from  the  refemblance of
 their edges  to thefe of a Crefcent.—Two of them are placed in
the fore, and one  in the back-part i f the Aitery.
   Each of them forms  a fmall Sac,  one edge of which adheres
 to a third ;^art of  the circumference of the infide of the Artery;
 the other e <ge is loofe in the Cavity of that Veflel,  and is fome-
 what thicke■• and ftronger than th« reft of the Valve,—the thick-
ened edp;es  icrving as Ligaments to it.
   The loofe edge  has a general Curve, divided into tvjo fmaller
ones, which meet in a point in fh  middle.
  The Valves are chiefly foimed of a doubling  or extcnfion of
the inner Coat of  the Artery. 
79
  In the middle point or loofe edge of each of the Valves, there
is a fmall hard triangular Granula, of a fomewhat redder colour
than the reft of the Valve, called,  from its reputed difcov,lies,
Corpufculum Aurantii, or Corpufculum Morgagn* ; 01 from
its refemblance in fliape to the Sefamum feed,  Corpufculum Sefa-
moideum.
  The Corpufcles complete the Valves at the centre of the Arte-
ry,  and enable them to make a  ftronger  refiftance againft  the
Blood,  while the Artery is in aaion.
  The Semilunar Valves are concave towards the Artery, convex
towards the Ventricle, and,  when fhut,  their  loofe edges are op-
pofed to each other, fo as to enable them to form a complete Par-
tition between the Ventricle and Artery.
  Oppofite to the Semilunar Valves, the Artery bulges out, and
forms three Projeclions, which  have correfponding Pitts or De-
preflions within, and are called,  from their defcoverer, Sinus
 Valsalva.
   The Sinufes of Valsalva are of the fame nature with thofe Di-
latations which are found in the Veins and Lymphatics, between
their fides and Valves ; and, like  them,  are partly formed by the
preffure of the Fluids upon the  fides of the Veffels.
   The  Pulmonary Artery  receives the Blood  from the right
Ventricle,  and by its contraaile power, affifts the Ventricle in
driving it through the Lungs.
   The Semilunar Valves, preffed back  by the Blood in the Ar-
 tery, prevent its return into the Ventricle.
   The Valves are opened again by being driven towards the fides
of the  Artery by the current of  the Blood,  upon the next con-
 traaion or ftroke of the Ventricle.
   The Pulmonary Artery pafi'es behind the Sternum, and fepa-
 rates into right and left Branches, which go to the correfponding
 pars of the Lungs.
   The two Branches of the Pulmonary Artery, like thofe of the
 Arteries of the Vifcera in other parts of the large Cavities, fud-
 denly divide into ftill fmaller Branches.
   From the extreme Arteries of the Lungs, coirefponding Veins
 arife, and are merely the  continuation or  reflea on of the Arte-
 ries, without any intermediate Cell  or Dilatatons.
    The Pulmonary Veins,  in the  Subftance of the Lungs, gradu-
 ally unite, and form four principalTrunks, which terminate in,
 and carry  the Blood to  the left  Auricle.
    Of the Pulmonary Veins, tiuo comefnm  the right, and  tvuo
 from the left lung, and teiminate n the coneipond ng fides of the
 left Auricle.
    The left Auricle is confiderably thik<r an < ftionger than the
 right,  and,  rkc  ii,  is divided intj bin-is V<;. i-.s and  in per
 Aui-ic.Ii-,  which  from one common Cavity without the interven-
 tion of any Valve. 
80
   The lejt Sinus Venofus,  called alfo Sinus Pulmonalis, is turned
 towards the Spine, is moie of a cubic form  than the right  one;
 but refembles it in the uniformity and fmoothnefs- of its  outer
 and ii.ner«6uifaces.
   From  the fore and  left  part of the Sinus,  the Proper Auricle
 proj^as,  and forms a diftina flat Appendix,  or Bag, with  dif-
 feicnt  Curvatures or Indentations upon its edges.
   The inner part of the Proper Auricle is longer,  but narrower
 than that on  the right fide-, like  it, however, it  is formed of
 Columna? Carneae,  with Furrows between them.
   The Proper Auricle is  fomewhat  lefs  capacious than  that on
 the right fide ; but the Sinus is as much larger as  to tender the
 two common Cavities  of the  right  and left  Auricles nearly
 equal.
   The two Auricles have a Flejhy Septum between them, in which,
 as has  been already mentioned,  there is the Foramen Ovale in (he
 Foetus ;—but in the adult the Partition is generally perfea.
   From the under part of the  Sinus Venofus, a  Paffage  leads
 down  to  the Cavity of  the  Left Ventricle, and is  oppofite  to a
 Grove feen  externally  between the Auricle and  Ventricle, fimilai
 to that on the right fide.
   The Left Auricle receives  the  Blood from the Pulmonary
Veins, and by its Mufcular contraaion, drives it into  the L ft
 Ventricle, from which it is prevented  from returning, by a Valve
m the Ventricle, called Mitrahs.
   The Lejt Ventricle  is fituated in the pofterior and left part of
 the Heart.
   115 fides are about three times thicker ant1, ftronger than thofe of
the Right Ventricle, being in proportion to the t rce required to
 propel  the Bl jod to the moft remote par's of  the Body.
   It is nanovjer and rounder, but con idtr.bly longer, both on
its External Surface and in its Internal Cavity, than the Right
 Ventricle, md generally defcends fomeway below the other, and
forms the Apex  cordis, or  Point of the Heart.
   The Cavity is commonly defcribed as  be ng  lefs than that of
the Ri. lit Ventricle ;—But the  apparent  difference, which  takes
 place after death, is accounted for wnh feeming propriety by fome
 Authors,—from the left Ventm lc being then  for the moit part
 found  empty,  and the Right one full, and fiom the greater de-
 gree of contraaiiity in the former.
   That me capacity of  the Cavity of the right and left Sides of
 the Heart is  more nii ly   qua! during life than after d-ath, or
 than  c is ger.er.lly fuppofed to be, is evident  from the appearance
 of the  Heart cf the Human and aifo of the Brute k nd, and  from
 ini'Sims into the two fi'.f-s cf the  Heart, where  the  force ap-
 plied is m propemor to ihe lei  v.vt ftrength  of  each fide.
   The inner  Sn  i:re ^f  the Left Ver-tnc'e h iS the fame general
 appeal ance With tht Ventricle  of the right fide, and only d ffers 
si
from it in having its Columnje Carneas larger, firmer and ftrong-
er.
  In the Paffage of communication  between the Auricle and
Ventricle, there is  a Ring,  from which  a Circular Valve  goes
off, with all  its apparatus fimilar to that between the right Au-
ricle and Ventiicle,  and d ffering in no refpea from it in flruaure
and ufe,  excepting  in being ftronger,  and in being divided into
two principal portions only.
  This Valve  has  been fuppofed to bear fome refemblance to a
Bifhop"s Mitre,  from which it has been called Valvula Mitralis.
  One of the portions  of this Valve is larger than the other, lies
over the Mouth of the Aorta, and is  fuppofed to cover it  while
the Ventricle is a filling.
  The Valvula Mitralis prevents the reflux of the Blood during
th^ contraaion of the  Ventricle.
  After the contraction is  over,  the Valve returns to  its former
fituation by the impulfe of a freih current of Blood from the Au-
ricle.
   Between  the Right  and Left Ventricle, there is a thick  ftrong
impervious Partition, which forms a fhare of the general Septum
Cordis, and is  compofed partly by the wall of the Right,  but
chiefly by that of the Left Ventricle,  the Right being uniftd to
fhe Left, almoft in the form of an Appendix.
  The Partition prevents any direa communication between  the
two Ventricles.
   Oppofite to the outer edge of the Septum, both upon the up-
per and under Surfaces of the Heart, there  is a Groove in  which
fome of  the principal Trunks of the Coronary Veffels are fitu-
ated.
   At the fore and right fide of the Valvula Mitralis, and behind
the beginning of the Pulmonary Artery,  there is a round Opening
which is the Mouth of tie  Aorta,  and  which is  nearly of  the
fame fize wiih that  of the Pulmonary Artery.
   Under  this opening, the  Surface  of the Ventricle becomes
fmooth, and equal,  having none of  the  Columnae  Carneae which
are fcen on the other par's of its Cavity.
  .The Left Ventricle  receives the Blood fent to it from the Au-
ricle, and by a contraaion  fimilar to, but much  (iron er than
that of the Right Ventricle, propels it to the Aorta.
   At the Mouth of the Aorta, there are three Semilunar Valves,
with  their Corpufcula Aur antii, perftaiy finiiia.  to thofe of the
Pulmonary Artery;—hut a Utile ftronger.
   On the outlideof the Semilunar Valves, arc the Sinufes of Val-
 salva,  like thofe  of the Pulmonary Artery,—but a  little more
prominent.
   The Semilunar Valves are preffed back by t!   Blood, and pre-
vent  its  reflux during the  contraaion of the Aorta.—They are 
Si!
returned towards the fides  of  the Aorta, in the fame manner,
and fiom the fame caufe, as in the Pulmonary Arteiy.
   The Aorta paffes upwards from the top of the Lef. Ventricle,
and is fituated firft behind, and then  on the  right  fide  of the
Pulmonary Arteiy, and betwen it and the Superior Cava.
   It bears nearly the fame  proportion in thicknefs and ftrength
to the Pulmonary Artery,  wh.ch  the fides of the Left Ventricle
do to thofe of the Right.
   When the Aorta is about to  fend off the  fii ft of it.; large
Branches  at the top of the Thorax, it is of great fize, and is
fumet-mes called the Large  Sinus of Valsalva.
  The Aorta receives the Blood  from the Left Ventiicle, and by
its Mufcular contraaion re-a6ts upon  it, and affifts the Ven-
tiicle in fending it  by numbeilefs Branches throu0h the dfteient
paitsof the  Body,  from whence it is  returned by the Veins^o
the Ri-. ht Auricle.
  Befides the Blood-veffels alrcttdy taken  notice  of, and which
are common to the Heart and the reft of  the  Body, the Heart is
funvfhed with Veffels peculiar to itfejf,  termed Coronary from a
Cirona which they foun upon its fm face.
  The Coio:iary Veife-is ccniilt of t-wo Arteries and one principal
Vein
  The Coronary Arteries arife from the Sinufes at the Mouth of
the Aorta, opp^fne to two of tiie Semilunar Valves.
  One runs  in a Groov« between the  Right Auricle and Ventri-
cle, and fupplies chiefly the right fide of the Heart.
  The other paffes partly between the Left Auricle and Ventri-
cle, and pai tly in the Groove between the Ventricles, on the fore-
fide of the Heart,—-fupplying the left fide of the Heart, and com-
municat ng w:-.h the Branches of the other Artery on its upper
and under Surfaces.
  The Coronary Arteries are entirely difperfed upon thefubftance
of the  Heart, and u-.-nn the roots of the great Vcffeis,  forming
upon thefe fome cf the minute Branches, termed, Vafa Vaforuv:.
  The  Coronary  Arterii•■■-, from their  fituation  oppofite  to the
Vahes, have bi-en  fuppofed to  be filled at a different tune from
that of the reft of the Arterious  Syftcm ;—but from  experiment,
it fecms now niflrticntly evident, that the Coronary  Veffels have
then-  puliation at  (lie fame indent  v.iih  the other  Arteiics.
 *Vi.e Coronary f<f/,7j»return the Blood from  their con ef.onding
Arteries :  The greater  part of  them join into a  Trunk,  called
the Great l\> ;,ia>- Vein, which,  after  making a turn from the
left lide, and  running between  the Left Auiicle and Ventrch-,
teiminates in the under part of the  Right Auricle,  where it  i,
cow.red by  its Semilunar Valve.
   Other Coronary Veins,  mn h fmaller than the former, termi
nate in different parts of the right fide of the Heart. 
83
  The Abforbents of the Heart go to the neighbouring Lympha-
tic Glands.
  The Nerves are from  the great Sympathetics and Eighth Pair.
  With refpea to the Circulation in general :—The Ve ns  re-
turn the Blood from  II  ti.e different parts of the Body by a flow
and equal motion, and without pulfation, to the Au.icle , which
on account of the quantity and ftimulatmg quality of the Blood,
contraa  fuddenly and at the fame time, and fend it to the Ven-
tricles.
  The Ventricles, from the fame caufe which ft'mulates  the Au-
ricles, and from the ftroke they receive from them,  contraa con-
vulfively, with a force proportioned to the thicknefs of their fides,
and fend the Blood to the Arteries ; and, du. ing their contraaion,
they are thiown by the dilatating Aur cks againft h*. il bs, where
the ftroke occ.fioned by the Pulfe of the  Heuit m..y be felt.
  The Arteries,  by their contradlile power and eiafticity,  feud
the Blood fuddenly to the Veins,  through which, by the united
force of  the Ventricles and Arteries, and bkewife, as is fuppofed
by fome,  by a contraaiie power of the  Veii^ and preffureof the
furrounding parts, 'it is driven agrin to the  Auricles.
  Initscouife the Blood  peiforms a double  Circulation,—one
called the Lefler  or  that through  the Lungs ;—the  other called
the Greater, er that  through  the Body.
  In the former  it paffes from the Right Ventricle to the Lungs,
and  returns  to the Left Auricle.—In the latter, it goes from the
left Ventricle to  the different parts of the Body, and returns to the
Right Auricle.
  During this Circulation, the Auricles and Arteries, and the
Ventricles and Veins, aa in concert, contraaing and dilating at
the fame time.
   Ufe of the Heart.——The Heart is the centre of  the  Vafcu-
lar Syltem,  and  thafl#rincipal agent in the  Circulation of the
Blood.
  The right fide of  he Heart receives the Blood, which is con-
taminated in pafling through the Body, and/ends it to the Lungs,
where it is purified through the medium  of  the Air.
  From  the Lungs, the Blood, now puiified,  is returned to the
left  fide  of  the Heart to be circulated through  all the other parts
of  'he Body, thereby  imparting  Noui ilhment, Growth,  and
Strength to the general S.ftem ; being found alfo to be the fource
of Senlibility, Irritability, and Motion, and likewife  of the Ani-
mal Heat. 
<^ !
                    OF 7HE LUNGS.

  The Lungs are two foft fpongy bodies, which occupy by much
the greater part of  the Cavty of the Thorax.
  They completely fill the two bags of the Pleura, and are every
wherein contaa with the parts adjacent; no Air intervening be-
tween them and the Thorax.
  In figure,  they have been compared to that of the Foot of an
Ox, with the back part turned forwards ;—or, their fhape cor-
refponds exaaiy with  the   nfide of the Tho ax, being  rounded
next the Ribs, hollow  towards the Diaphragm,  and  irregu-
larly flattened and depreffed next the Mediaftinum and Heart.
  They are of a reddifti or pink colour in Children, of a  light
blue or greyifh  colour in Adults, and more of  a purple and li-
vid colour in Old A^e, at which period they are alfo obferved to
be tinged with black fpots,  proceeding from a matter fecreted in
the r Subftance.
  They are joined  to the Neck, by the Trachea;  to the Spine,
by the  two Layers of the  Mediaftinum,  which ferve  them as
Ligaments;  and to the Hc.ut,  by  the Pulmonary Veffels;—the
reft of them  being  free and  unconneaed,  unlefs an adhefion has
taken place in confequence of inflammation.
  They are divided  into  Right and  Lejt  Portions, or Lungs,
which  are feparated from each Other by the Heart and Medialti-
rum and which have no communication,  excepting  through the
Medium of  the Trachea.
  Each of the Lungs is again divided into large portions, called
Lobes,  which facilitates their motion and the dilatations of their
Cells.                                  $"•
  Of thefe Lobes, three belong to the Right Lung, ennefpond-
ing with the larger Bag of  the Pleuia, and tvjo to the left, be-
tween which there  is a Notch  or Sinus, occupied by the Point of
the Heart
  Each of  the Lobes  is fubdivided into  many  fmaller parts,
termed Lobules, which are of different iizes, and of an  irregular
an/ular form.
  The Lobules diminifh in fize, and degenerate at  laft intofinall
Veficles or Cells, which conftitute a large fhare of the Lungs, and
which are merely  viiible to  the naked Eye.
   The Cells of the Lungs are purely  Membranous, of an irregu-
lar figuie, compreffed and  clofely  conneaed,  and  have  3 free
communication with each other.
   Between  the different  Lobes, Lobules, and  Cells,  a  large
quantity of  common Cellular Subftance,  deftitute of Fat, is  in- 
$5
terpofed, which unites and  ftrengthens them, and  allows the
Blood-veffels to be minutely difperled over them.
  The Cells  of the Lungs  have no communication  with this
common Cellular Subftance; for when Air is blown  into it, the
Lobules are compreffed ; but when the Air is blown in through
a Branch of.the Trachea, the Cells are again diftended,  and the
Lobules lecover their former dimenfions.
  In the Foetus, the Cells  are empty and in a collapfed  ftate;
—but as icon as Refpiration begins, they become diftended,  and
continue fo during life,  and  in every ftate of Refpiration,  and
even in  the  recently dead  Body :—But if an  opening be made
into the Cavity of .the Thorax,  whether in  the  living or  dead
Body,—and  the Air in this or in any other  way admitted, they
immediately  collapfe by  their own weight and  eiafticity, the
prefTure of the air being then the fame on the outer Surface of
theLuiujs, and inner Suiface of the Trachea.
   The Lungs are covered  by tvuo Coats, an External or  Com-
mon,  and  an Internal or Proper one.
   The External or Common Coat \>  a continuation or  refleaion of
the Pleura, is extremely thin,  but denfe, and, like the other parts
of  the Pleura, is found to poffefs little  Senlibility,   It forms  a
general covering to the Lungs, but does not enter between their
different Lobules.
  The Internal or Proper Coat adheres  fo firm!*.- to the former,
as to appear  to  conftitute part cf its Subftance.  It not only co-
vers the Lungs, but inlinu lies ufelf ber-ween their  Lobules,  and
is intimately conneaed with their Cellular Subftance.
  Befides the Cells,  various kinds of Veffels,  viz. the Air vef-
fels or Branches of the Trachea,  Bhod-veffcls and Abforbents, to-
gether with fmall Branches ot Nerves, enter into the  compolition
of the Lungs.

                         Trachea.
  The Trachea, or Ajpera Arteri.?, fo called from the inequali-
ty of its Surface, and from  its conveying At, begins at the un*-
dec part of the  Cricoid Cartilage,  and  defcends in the fore part
of  the Neck, between and behind the Sterno-hyoid and Sterno-
thyroid Mufcles.
   From the Neck, it paffes into the Thorax, where it is fituated
betvreen the  Layers  of the upper-part  of the  pofterior  Media-
 ftinum.
   Behind  the  Curvature of the  Aorta,  and oppofite  to the
third  Vertebra of the Thwiax,  the  Trachea divides into two
Lateral Branches, tenmd Bronchi, from the Greek, one of which
goes to the Right, and the other, which  is the longer  of the two,
to the Left Lung.
Vol.  [I.          H 
86
   The Bronchi are divided into Branches,  which by degrees be-
 come fmaller, and at laft  terminate in the Cells  of the Lungs,
 which communicate fo freely with each other,  that, upon intro-
 ducing Air into  any of thefe Branches, a large portion of the
 Lungs may be inflated.
   The Trachea confifts of Cartilaginous Rings, about fixteen or
 eighteen in numbei, which give ftrength and firmnefs to it, and
 preferve it conftantly open for the tranlmiflion of Air.  They are
 incomplete behind, where the Trachea is foimed of a foft Flefhy
 Subftance, which  yields to the Efophagus in the time of Deglu-
 tition.
   Each Cartilage  forms a large fegment of a circle, about a  line,
or one-twelfth of an inch  in breadth, and one-fourth of a line in
 thicknefs.
   The Cartilages are fituntcd horizontally,  with their edges op-   I
 pofied to each other, fmall fpaccs intervening between them.
  They are united  to each other, by a Ligamentous Subftance,
which is  fo elaftic, that  when the Lungs are  taken out of the
Body, it draws the Caitilages clolely  together.
   At the upper end of the Trachea, two or three of the Cartila-
ge- arc frequently joined  by an union  of  Subftance ; but below
rhis,  they are peift-aiy difttia from each other.
   The beginnings of the Bronchi  have the fame kind of Cartila-
 ges with  the Trachea ;  but after they enter  the Lungs,  they ai*
\ oken no two or ihree pieces, which go completely  round the
Bronchi,  and are fo conneaed to each  other, as to keep the  Paf-
fage open and fiee from compitflion.
   The Tiachea ha6 feveral Coats entering  into its  compofition,
 feme for llrengthening it, others for giving it a certain degree of
motion,  viz.
   A Cellular Coat, which, in the Thorax, is covered by the Me-
d:aftinum.
   An Elaftic Ligamentous Coat,  which paffes along the Trachea,
 and  alio  upon  the  different Branches in  the  fubftance of the
 Lungs, adding  much to the elafticity of thefe.
   A  M'.fcular Coat,  placed between the Cartilages, and in the
 back-pait of the  trachea,  and  compofed of Circular  Fibies   !
 without,   and  Longitudinal Fibres  within ;—the former for
 ftraitening, the- other for  ftiorteiiing the general Paffage,
   The Longitudinal Fibres arecolleaed into bundles, wihich are
 diftir.aiy fcen through the inner Coat, and may be  traced  <on-
 fiJ.et-'.biy farther,  in the Subftance of tha Lungs, than the Carti-
 lages. K
   The inner fide  of  the Trachea  is lined  with  a very Vafcular
 mid Irritable Mevibrane,  continued from the Mouth, and term-
 ing at laft the ex'reme Branches of the Trachea, which terminate
 in the Cells of  the L-jh;-s. 
87
  The inner Membrane of the Trachea is every where perforated
by the  Duds of  Mucous Glands, and by the Mouths of the Ex-
halent Arteries, the foimer  pouring out Mucus to  lubricate the
Lungs, the other the Vapour  which is thrown off in  Perfpira-
tion.
  Three dfferent kinds of  Glands are conneaed  with the Tra-
chea,—the Thyroid,  the Tracheal, and the Bronchial.
  The Thyroid Gland has its nam: from its conneaion with the
Thyroid Cartilage,  though more immediately  conneaed  with
the Trachea.
  It is  a large reddifh  mafs,  fi uated at the under and  fore-part
of  the  Larynx,  behind the Sierno-hyoid and  Sterno  thyroid
Mufcles.
  It h is two Lobes  placed  at the under and lateral parts of the
Larynx, defcending a certain way upon the Trachea  and Efo-
phagas.
  The Lcbes are joined by  an intermediate  portion, which  lies
acrofs the upper and fore-part of the Trachea.
  Sometimes a Procefs from the middle portion afcends between
the Sterno-hyoid Mufcles,  and  is loft behind the Bafe of the Os
Hyoides.
  This Gland has a Grandulous appearance within, and  a vifcid
Liquor is fometimes obferved in it, which has been fuppofed by
Sabatier  and others,  to lubricate the parts  in the neighbour-
hood.
  It is  fupplied  with large Blood-veffels,  and  with feveral
Nerves, from  thofe of the Larynx ; it is likewife furniftied with
numerous Lymphatics,—but no Excretory Dua has yet been ob-
ferved  to come from  it; nor is its office yet underftood.
  The Tracheal Glands are fm .11, but numerous, and cf different
fizes, furrounding the  Mufcular Coat of the  Trachea,  and its
Branches in the Longs ; the largeft of them  are  placed in  the
Flefhy Subftance behind.
  From each of thefe Glands a fmail Dua iffues, and  throws
out a Mucus,  to defend the inner Surface of  the  Trachea from
being injured  by the Air, or  by  the extraneous particles which  it
cariies along  with it.
   The Bronchial  Glands are placed  in  the Cellular  Subftance
round  the under end of the Trachea and roots of the Bronchi,
where  thefe penetrate into the Subftance< f the Lungs
   They arc of various fizes, from that of the point of the Lit-
tle Finger to  that of a Millet-feed, and have a bluifh or black
colour, correfponding in a great mcafure with the colour of the
darketl parts of- the  Lungs.
   They were  formerly confidered by many Authors as fending
Fluids to the Trachea, but are now fufficiently known fo be entire- 
                            33
                           *
ly of the Lymphatic kind,—the  Abforbeiits of the Lungs paffing
through them in their way to the Thoracic Dua.
   The Trachea is lurnifhed with Blood-veffels from the  Inferior
Laiyngeals, and Nerves fiom  the  Recuntnts and great Sym-
pathetic Pair.
   The Trachea ferves to convey  Air into,  or out from the Cells
of the Lungs,  during Refpiration,  and to carry cff the  I'erlpir-
able Matter from their Arteries in time of  Expiration.
   The Blocd-Veffels cf the  Lungs confift of the Pulmonary and
Bronchial Vefftls ; the one for the general Circulation, the other
proper to the Lungs.
   The Pulmonaiy Aitery arifes from the top of the Ris  lit Ven-
tricle,  divides,  like the Tiachea, into Right and Left Branches,
which are difpeifed through the  fubftance cf the Lungs.
   The minute Branches running in the  ccmim n Cellular Sub-
ftance, foim at  laft  a  Plexus upon the proper Cells, fometimes
called Rete M-rci-ile,  and  Rete  Vafculofum Malpighii, fiom
which that  llalitus is deiived which is expelled by  the Lungs in
Expiration.
   The Pulmonary Veins are commonly obferved to be fmaller in
proportion to the correfponding Arteries, than Veins are to Ar-
teries in other parts of the Body, which  has been fuppofed to be
owing to the large quantity of Fluids expired.—They join into
four principal Trunks, which terminate  in the Left Auricle.
  The Bronchial Arteries arife by three  or four fmall Branches,
one of which is from the right Superior Intercollal, the left from
the Trunk  of the Aorta.
  They are  difpeifed upon the Bronchi  and Bronchial  Glands,
and fubftance of the Lungs in general,  and  are found  to com-
municate with the Pulmonary Artery.
  The Bronchial Arteries are fuppofed to  ferve for the nourifli-
ment of the Lungs and fecretion of the Mucus.
  The Veins return  the Blood to the Vena Azygos, and  left fu-
perior Inurcoftal Vein.
  The Lymphatics form a Plexus upon the Surface of the Lungs :
—They  communicate ficcly  with  the  dtep-featcd Ablorbenls,
and pafs through the Bronchial Glands.
  The Nerves of the Lungs are partly  from the  great Sympathe-
tics, but chidfcy from  die Eighth Pair,  and  are rather ,Jgall  in
proper'ion to the bulk of the organ on  which they are difperfed.
  The Lur.cs ferve the general   purpofe cf  Refpiration, which
confifts of Infpiration and Expiration, or the  paiiape of  the Air
into or*out from the Lungs by the alteruate dilatation and con-
trail ion of  the Thorax.
  Infpiration is  performed in confequence  of the Thorax being
dilated by the  aaion  chiefly of  \\\e Diaphragm and, Inlercoftal
Mufcles; the  Lungs,  which aie paffive, and  in  contaa  with 
89
the Thorax,  following it, and the Air rufhing into the Trachea
by its own gravity.
  Expiration  is performed in confequence of a relaxation of the
Mufcles which dilate the Thorax,—of  the aaion of the Abdo-
minal and a few other Mufcles,—of  the elafticty of the Cartila-
ges of the Ribs, and likewife of the Lun ;s, by which the Cavity
of the Thorax is diminifhed, and  the Air  is expelled from  the
Lungs.
  Upon the alternate ftates of Infpiration  and Expirat;on,  de-
pend the formation of the Voice, the  fenfation of Smell,  and all
the other  funaions of the Body: but the great and principal
office of the Lungs, which was formerly fuppofed to be that of
cooling the  Blood over-heated  by friaion, is, during Infpira-
tion,  to receive from the  Atmofphere pure  Air, upon which the
principle of heat and  life depends ; and,  during Expiration, to
carry off an impure Air,  which is  noxious to Animal Life.
  According  to  late experiments, it appears, that the Venous
Blood pafling to the Lun ,s, of a  dark red or purple colour,  is
charged with Carbon or Charcoal, and Hydrogen, or Inflamma-
ble Air;—that while  circulating  upon the Bronchial Cells, one
part of the Oxygen, or Vital Air, contained in  the common Air
which has been infpired,  unites with  the Carbon and Hydroge-n,
and  forms Fixed Air and a Watery Hahtus, which are carried
off by Expiration ;—that another part of the Oxygen is imbibed
by  the Blood, which,  in confequence of thefe changes, returns
from the  Lungs,  of  a florid red  colour, and full of heat in a
latent ftate, which becomes fenfible  in the  courfe of the general
Circulation,  and is diffufed over the  different parts of the Body ;
and,— hat the Blood  thus changed alfo affords a Stimulus to the
Arteries,  and promotes the different  Secretions.

                        Esophagus.
  Tue Esophagus, called  alfo Gula  or Gullet, derives its
name from canying what is eaten  into the Stomach.
  It is a Fleftiv Canal,   which begins from  the inferior part of
the Pharynx,  defcend^ along the Neck, and  through the Thorax,
follow, ng nearly the direaion of the Spine.
   It is fituated between  the Trachea and Veriebr.e ; and in  the
Thorax, it proceeds behind the Bafe  of the Heart,  and between
the Layers of the Pofterior Mediaftinum, from which it receives
a lateral covering.
   Soon after entering the Thorax, it makes a flight turn to the
right, and partes down upon the fore  and riLjht fide of the Aorta,
by  which  they are prevented from injuring each ether.
  In 'ts progrels, it inclines more forwards and to the left  fide;
and about the Ninth Vertebra of the  Thorax, it perforate*  the
Mufcular  part of the  Diaphragm, and terminates in the  upper
Orifice of the Stomach.
Vol.  II.
H 2 
oo
  It has feveraltCoar/ rroper to it, the firft of which is Cellular,
and  conn as it t> the adjacent parts.
  The ficond Coat Is Mufeular, and is  fometimes termed Vagi-
nalis Gula.—\t confifts  of  two Layen- ; the external of  whch
has  thick, ftrong, longitudinal F bres ;  the internal is formed of
c rcnlar and  tranfverfe Fibres,  and  is thinner than the former.
—The outer Layer  is fined for fhorten.ng and relaxing, and the
'inner for contraaing the Canal, during Deglutition.
  The third Coat is termed Nervous, but is properly Cellular,
being formed  of loofe Cellular  Subftance, which  conneas the
Mufeular to the Inner Coat.
  The Inner Coat is continued from the Lining of  the  Mouth  :
It confifts of many  longitudinal Plica or Folds,  which are
f'.arcely vifible when the Efophagus is  dilated,  and is furnifhed
•vi' h numerous Foramina, which  difcharge a Mucus for  lubri-
cating the paffage,  and facilitating Deglutition.
  The  Arteries of  the  Efophagus are  Branches of tht Inferior
Laryngeals, which  fupply  the  Cervical part of it,  and Efopha-
geals and Branches of the Bronchials,  which  are derived from
 the  Aorta Defcendens, and fupply the Thoracic part of it.
   The Veins go to  the Inferior Laryngeals, to  the Vena Azygos,
and left Superior Intercoftal Vein.
   The Abforbents  are numerous, and intermix with thofe of the
 Heart and Lungs.
   The Nerves are chiefly from the Eighth Pair.
   The ufe of the Efophagus is, to receive the Aliments from the
 Pharynx, and convey them to the Stomach.
                    Thoracic Duct.
   The Thoracic Duct is a fmall Membranous-like  Canal,
 fituated  in  the back-pait of the Thorax, and is  the  principal
 Trunk of the Abforbent Syftem.
   It begins upon the third  Vertebra of the Loins,* and paffes be-
 hind the Aorta, croffing obliquely from left to right, till it gets to
 the right fide of that Artery.
   Upon the firft Lumbar Veitebra,  it forms an Oval Sac, term-
 ed  Receptaculum Chyli, which is placed behind the  Right Crus
 of the  Diaphragm, and  a  little  higher than  the Right Renal
 Arttry.
   The Dua afterwards paffes between  the Crura of  the  Dia-
 phragm,  and afcends in the Thorax, on the anterior part of the
 Spine,  between the Layers of the Pofterior Mediaftinum, on the
 right fide of the Aorta, and between it and the Vena Azygos.
   It croffes behind the upper part of the defcending Aorta, and
 emerges  fiom the Thorax,  to  reach the  under part  of 'the
 Neck.
   In the Neck, it paffes behind the  Internal Jugular Vein, and a
 little higher than the Subclavian. 
91
  It then turns downwards,  forming an  Arch, which termi-
nates in the upper pari of the Angle, between the Internal Jugu-
lar  and Subclavian of the Left Sde.
  The Thoracic Dua rccivcs the Chyle from the Laaeals, and
Lymph from the Lymphatics, and difcharges thefe  into the red
Veins.
OOOOOOOO €I>00O0O000
OF  THE  ABDOMEN.
                     ---   — Q«l---


  The Abdomen or Belly extends from the Thorax to the under
part of the Trunk.
  It  is bounded above, by  the Diaphragm,  and the Bones to
which that Mufcle is fixed;  below, by the Pelvis; behind, by
the Lumbai Vertebra? and Mufcles of the Loins;  anteriorly, by
its  Proper Mufcles ; and laterally,  by the Falfe Ribs,  Offa Hii,
and Mufcles conneaed with thefe;—all of which  have been de-
fcribed in their places.
  It is diftin^uiflied into three Divifions or Regions, termed Up-
per, Middle, and Under Region ;  each of which is fubdivided
into three others.
  The Upper Region begins oppofite to the Cartilag-o Enfiformis,
at a fmall  depreflion called Scrobiculus Cordis,  or Pit of the Sto-
mach, and extends to about a hand-breadth from  the Umbilicus
or Navel.
  The middle of this  Region is termed Epigaftrium,  or under
part of the Belly, and the two lateral pairs  Hypochondria, from
their lying under the Cartilages of the  Falfe Ribs.
  The Middle  Region occupies an  equal  diftance above and be-
low the Umbilicus.— Fhe middle part of it is called the Umbilical
and itsjateral parts the  Lumbar Regions or Loins.
   The Under Region begins where  the m'ddle one  terminates, or
at a line drawn between the fuperior anterior  Spinous Proceffes
cf  the Oila Ilii,  and forms in the middle, the Hypogaftrium or
bottom of  the Belly ;  and at the fides, the Iliac Regions.
   The Abdomen is covered on the outfide by the common Integu-
ments, and lined within by the  Peritoneum,  in the manner the
Thorax  is lined by the  Pleura, but without being divided by the
 intervention ef a Partition.
   The Abdomen contains  the Chylopoetic and Affiftant Cbylopoetic
Vifcera or  Organs of Digeftion,—the Organs of Urine,  and part of 
92
thofe of Generation,  with the Veffels  and Nerves which belong,
fome of them to thefe Vifcera,  and others to the lower parts of
the Body.
  The Ghylopoetic Vifcera comprehend the Stomach, which is fi-
tuated in the Upper and left part of the Abdomen,—the Intefiines,
which fill the greater part of it,—and the Membranes, termed
Omenta and Mefentery, which are conneaed with thefe.
  The Affiftant Lhytopoetic Vifcera conlift of the Liver, which is
placed in the upper  and  right; of the Spleen, which is fituated
in the upper and left fide of the Abdomen ;—and of the Pancre-
as, which lies urn ei the Stomach.
  Of the Organs of Urine,  the Kidneys  are placed in the back-
part of the Abdomen, and the Bladder, with fome of the Organs
•f Generation in the  Pelvis.

                      Peritoneum.
  The Peritoneum,  named from its being ftretched or fpread a-
round the Bowels, is a firm  but fimple Membiane, by which the
Abdominal Vifcera are furrounded, and  partly fupported.
  Its External Surface is rough  and Ceilular,  and clofely con-
neaed with the parts to which it belongs.
  The Internal Surface is  remarkably fmooth, and lubricated
by a Liquor which is exhaled from its own Veffels.
  It is very elaftic,  and admits of great  extenfion,  as happens
in Geftation, Corpulency, or Afcitesj  but, upon the caufes, of
extenfion he"ing removed, it returns to its former dimenfion^.
   It Ines the Diaphragm,  paffes downwards, adhering firmly to
the Abdominal Mufcles,—lines the  containing, and covers  the
con.ained parts of the Pelvis, from which it is refleaed in  the
back-part of the Abdomen, lining its Mu.cles,  and, by its  re-
duplications, covering the Bowels and great Blood-veflels of that
Cavity ;—though, ftrictly /peaking, the Abdominal Vifcera may
be faid to lie on the  outfide of it.
   In its  paffa. e fiom one Bowel to another, it  forms doublings
which  ferve as Ligaments  to fix them  to each other,  and like-
wife to the Body.
   It gives a general covering to  moft of the  Bowels, a partial
one to a  few, and to thofe which are deep-feattd, and project leaft,
a ftill more partial covering.                                       #
   It forms a large Sac, the pofterior part of which adheres firm-       \
Jy to the different Vdcera, and the anterior to the  Abdominal
Mufcles ;— he part lining the Abdomen being merely in  contaa
with its  cdtents, and allowing a fmall degree of motion.
   The Cellular Subftance, on the External Suiface of this Mem-
brane, is not every wheie of equal thicknefs, being in fome parts,
 a> upon  the  Bowels,  remarkably thin ;  in others,  as over the
 Kidney*, filled with a confiderable quantity of Fat. 
93
   The Cellular Subftance forms various Proceffes or produaions,
 fome of  which,  as thofe on the Spermatic Cords, pafs through
 Foramina, to be conneaed with the neighbouring parts ; and the
 Proceffes are fent off, without affeaing the Internal Membrane,
 the one not  accompanying the other.
   The Veflels and Nerves of the Peritoneum are from thofe which
 fupply the contiguous parts; its Veffels,  however,  are not  very
 numerous ;  neither does it  poff-fs  much Senlibility  when  free
 from difeafe.
   The Arteries come from  the Internal Mammary, Epigaftric,
 Lfer or Intei coftal, Lumbar,  Sacral,  and Ueo-lumbar Arteries,
 and from thofe which fupply the Abdominal Vifcera.
   The Veins have the fame courfe,  bear the fame names, and in
 "general pafs to the  Inferior Cava.
   The Abforbents are numerous, and run chiefly to  the Iliac and
 Lumbar Plexus.
   The Nerves,  which are few in  number and fmall, are  from
 the  Inferior Dorfal, the Lumbar,  the Great Sympathetic  and
 Sacral Nerves.
   The ufe of the Peritoneum is to line and ftrengthen the Cavity
 of the Abdomen ; to inclofe and affift in fupporting its different
 Vifcera; to  furnifh moft of them with an External Coat; to con-
 nca  them to the Body,  and, by its fmoothnefs  and flippeiinefs,
 to prevent the effeas of Friaion.
   Upon  the outfide of the Peritoneum are Four White Lines, or
 fmall Cords,  three of which are Veffels in the Foetus,—one of
 them a Vein,  and two of them Arteries; the fourth is the Ura-
 chus.—In the Adult, they are fhrivelled up,  and ferve as Liga-
 ments, the  Vein forming the round Ligament of the Liver,  the
 ■hree other  Cords,  forming Ligaments of the Bladder.




                         STOMACH.

   The  Stomach is  a lar^e  Bag or  Refervoir, fituated obliquely
 acrofs the upper and left part of the Abdomen, in the left  Hy-
 pochondriac and Epigaftric Regions.
   It is turned downwards and fo, wards,  fo as to form an  angle
 with the Efophagus, the angle becoming more conipicuous, ac-
 cording to  the diftenfion of  the Stomach.
   The right part of the Stomach is  fituated under the left part of
 the Liver, the reft of  it  is placed  immediately under the  Dia-
 phragm, its extiemity being in contaa with the Spleen.
   The Stomach is long,  round,  and tapering,  and has  been
i compared in  fhape  to the Bag of a  Bagpipe. 
91
   The fize is in proportion to the quantity of Aliment it  has
been accuftomed to receive, and therefore is commonly l.rger in
Jvlen than in Women.
   It has a Large and Small Extremity, an Upper and Under Sur-
face, a Great and Small Curvature,  a Lejt and  Right Orifice,
and confifts of feveral Layers or Coats.
   The Large, called alfo the Lejt Extremity, is fituated in  the
left fide of the Abdomen, and  is confiderably higher than  the
Right.
   The Upper Surface is turned towards the Diaphragm, the  Un-
der towards the Interlines;     hut when the Abdomen is laid o-
pen,—unlefs the Stom ch be confideiabiy diftended,—the Supe-
rior Surface becomes anterior,  and the Inferior Suiface pofterior.
   The Large Curvature is turned obliquely forwards and down-
wards towards  the Abdominal  Mufcles, and extends  from  one
Orifice to the other.
   The  Small Curvature  is  oppofed  to  the  other, and turned
backwards  and upwards, towards the Spine,  extending alfo be-
tween the two Orifices.
   The Orifices are next the Small Curvature.  The left is termed
Cardia, or  Os Ventriculi,  or Upper Orifice of the  Stomach.—It
is oppofed to the Spine, at a  little diftance  from it, and is  for-
med by the termination of the Efophagus.—It allows a free Paf-
fage for the Food into the  Stomach,  the  return of  which is pre-
vented by the Angle formed by this  part of  the Stomach,  and
by the Flefhy Parts  of the Cardia, and of the Diaphragm in
which it is fituated.
   The Right,  or Inferior  Orifice, is  commonly termed Pylorus
from its office as a Porter.
   It is fituated under the fmall Lobe of the  Liver, a little to
the right fide of the  Spine,—is turned more forwards than the
Cardia, and is confiderably lower, but rifes in proportion to the
diftenfion of the Stomach.                                ,.-
   The  Stomrxh is conneaed by the Cardia to the  Efophagus,—
by the Pylorus to the beginning of the Inteftines,—by the Peri-
toneum and Blood-veffels to the Spleen,—and by a refleaion of
the Peritoneum to the root of the Liver and to the great  Intef-
tines.
   The  StruSlure of  the Stomach is  in general fimilar  to that of
the Efophagus,  of which  it is  a kind vf Expanfion.
   The Coats of the Stomach  are four in number.
   The firft or External Coat, called alfo Peritoneal, is a Refleai-
on of that  part of the Peritoneum which comes from the root of
the Liver.
   It ftrengthens the Stomach ; by its fmoothnefs  it diminifhes
the effea of Friaien, and paffefling few Nerves or  Blood-veffels,
it is not very fufccptible of pain or inflammation. 
96
  The Cellular Subftance under the Peritoneal Covering, is def-
cribed by fome  Authors as a diftina Coat, called Tunica  Celln-
lofa  Ruyfcbiana ;—but ought  not  to  be numbered among the
Coats of the Stomach.
  The  Second or Mufeular  Coat is  compofed chiefly of two
Planes of Fibres varioufly difpofed.
  The External Plane is lonDitudinal,  extends from the longi-
tudinal Fibres of the  Efophagus,  and follows  the fame general
courfe with  that of the Stomach from the Great to the Small Ex-
tremity.
  Upon each fide of the Small Curvature, the longitudinal Fi-
bres form a  thick, ftrong, Mufeular Band.
  The fecond Plane is chiefly  tranfverfe or circular, and  confi-
derably thicker and ftronger than the other.
  Its Fibres are  interfeaed by many  fmall,  white, Tendinous-
like Lines ;—thefe, however,  are in a gieat  mealure formed of
that Cellular Subftance by which the two Coats are united.
  The Mufeular Coat affifts  in the Digeftion  of the Food,  by
giving a gentle motion to the Stomach, accoi din   to the  direction
of its Fibies, the one fet fhortenin», the other rendering it nar-
rower.
  The  Pylorus is formed by  a doubling of the two inner Coats,
which projea into the Paffa e between  the Stomach  and Intef-
tine,  and contain a Ring of Mufeular Fibres,  which  form a
Sphinaer, called Sphiniler Pylori.
  This fubftance, by contraaing, prevents the greffer ind gefted
parts of the Aliment from efcaping, and, by dilating, allows
the Pulpy digetted part to pafs to the Inteftmes.
   The Third Coat, commonly called Nervous, but properly Cel-
lular, confifts of a large quantty of fine Cellular  Subftance,
without Fat, and is  intermixed  with, and fupported  by fmall
Aponeurotic like Filaments, which crofs each other obliquely,
bur which are alfo of a Cellular nature.
   This Coat ftrengthens the  Stomach, and allows the Veffels to
be diftributed to the Inner Coat, with  which it  is intimately con-
neaed.
   The Fourth or Inner Coat,  called alfo Villous,  from its refem-
blance to Velvet, is continued from the Inner Coat of the Efo-
phagus, but is  much  more Villous.—It  is formed of  fine, fhort,
 prominent Villi,  which are  crowded with Small Veffels, fome for
 furnifhing a Mucous Liquor to the Stomach, others for abfoi bing
 a portion of the thinner part of the Food.
   The two laft Coats are more extenfive than the reft, and form,
 upon the inner  part  of  the  Stomach, many doublings, termed
 Ruga, the  greater number of which  run in a waving tianfveife
 direaion, and are afterwards divided into a fort of  Net-ivork. 
*  96
Near the Orifices, however efpecially towards the upper one, they
run more in a longitudinal direaion,  and have a radiated appear-*
ance at the  Cardia.
  The Rugae, like  the Plicae of the Efophagus, are moft diftina
when the Stomach  is'empty ;—when full,  they  are  much  lefs
evident.
  They admit of diftention without endangering  the Veffels and
Nerves difperled  in  them, and affift a little in detaining-the Ali-
ment till properly digelted.
  From the Inner Surface of the Stomach a Liquor iffues, which
is'found to approach  to the nature of Saliva, and is termed Gaf-
tric Juice.—This was  formerly  fuppofed to come from Glands
feated in the Third  Coat, but is now more fiequently confidered
as a Secretion from the Arteries of the Stomach,  no Glands be-
ing evident there, at  leaft in the found ftate of this Vifcus.
  The Arteries  of  the Stomach  are derived  from the  Cceliac
Arteiy.  They confift of the Superior Gaftric, which fupplies the
place next the fmall Curvature ; the Right Inferior Gaftric, which
is a bianch  of  the  Hepatic;  the Pyloric Arter'es, which are
fmall branches from  the Gaftrics  and from the Hepatic ; and of
the Left Gaftric and Arteriae breves,  which are branches of the
Splenic Artery.
  The Veins have  the fame  names, and  nearly the fame courfi
with'the Arteries.  The whole  of them terminate in the Vena
Porta?.
  The Abforbents of the Stomach are numerous and large.   Th?y
pafs through fmall  Glands fituated upon the Curvatures, and go
afterwards  to the Thoracic Dua.
  They appear  to cari*y Lymph only, no Chyle having been de-
teaed in tli.n,  even  in cales where the Laaeals  were found full
of it.
  The Nerves are chiefly from the Eighth Pair, and partly from
the Great Syinpathetics, and are moft numerous upon the Cl->jr-
dia.
  The Stomach receives the Food from the Efophagus, and af-
terwards prepares it,  by digeltibh, for the Interlines.
  The d'geftion  of the Food in the Stomach is found to be effec,
ted,—by Triture,  which is performed  by the motions of the
Stomach and furrounding Mufcles,—by dilution,—by a partial
fermentation,—but chiefly by the aaion  of the (' iftric Juice fer*
ving as a Menftruum. 
97
                      INTESTINES.

  The Inteftines eonfift of a long Cylindiical Canal,  which be-
gins at the Inferior Orifi:e of  the Stomach, and, after winding
in various direaions, terminates in the Anus.
   In general they are about fix times the length of the Body to
which the*y belong ;" though, in a perfon of fhort ftature, the pro-
portional len th of the Inteftines i, greater, and vice verfa.
   They occupy a  large part of the  Abdomen, and are conneaed
to tie  Body through their whole  extent, by  a  doubling of the
Perironeum.
  On account of the inequalities of their fize, they are divided in-
to Small and Large Inteftines,  and each of thefe  is fubdivided in-
to others.
                   Small Intestines.
   The Small Inteftines are fmooth  on their outer Suiface, and of
a tapering  form,  becoming gradually lefs  in their diameter from
their upper  to their under  extremity, and  are  divided  into the
Duodenum,  Jejunum, and Ilium.
   The Duodenum, fo called from  its being about twelve fingers-
bitadtii in length, begins at  the  Pylorus, and makes a  fhort
tijr'n upwards and backwards,  by the Neck of the  Gall-bladder,
to which it is contiguous, hav ng the  Anterior  Layer of the
Omentum fixed to its inferior part,  and the Omentum Minus to
its oppofite fide.
   It then paffes obliquely downwards and to the  right fide, before
the great Veffels which go into the Liver,  and likewife before the
Renal Artery and Vein, included  in the  Cellular  Subftance of
the Mefocolon.
   Oppofite to the under part of the Kidney, it makes  a turn to
the left iide,  where it is lodged in the common  root of the Me-
focolon and Mefentery,  and receives into  its back-part the ends
of the Biliary and PaucreaticDufts, and goe» over the  Aorta and
Vena C iva, oppofite the laft Vertebra of the Back.
   In pafling acrofs thefe Veffels, it is involved in the root of the
Mefentery,  and  afcends a little till it gets to the left  fida of the
Spine, where it perforates the common root of the Mefentery and
Mefocolon, and makes  a turn forwards,  where' it obtains tha
name^-of Jejunum.
   The Jejunum fo named from its being commonly more empty
than the other Inteftines, in confequence of the thinner parts of
its Contents being fooner  abforbed,  begins  at the laft turn of
the Duodenum, and forms numerous Convolutions, which run in
nil direaions, and are  fituated in the  upper part of the Umbili-
cal Region.

   Vol.  II.           I 
*   98
   The Ilium, named from  its numerous Turns, begins where
 the Jejunum terminates, or where the Internal Plicae become lefs
 confpicuous, and is diftinguifhed externally from that Gut, by
 being fmaller, thinner in its  Coats, and paler, and from its
 forming about three-fifths of the length of the two Inteftines.
   The Ilium,  like the  Jejunum,  forms many Convolutions,
 which are fituated on the under part of the Umbilical Region, and
 extend as far as the Hypogaftric and Iliac Regions,  and not un-
 frequently, efpecially  in Women,  into the Cavity of the Pelvis.
   Iffurrounds  the lateral parts of the Jejunum, and is fupport-
(ed by  the Offa Ilia; and,  the laft turn of the  Gut paffing acrofs
towards the upper edge of the Right Os  Ilium,  it terminates by
a Valve  in the left fid; of the beginning of the Colon.
   Through the  whole of this courfe, the Jejunum and  Ilium
are fixed to the Spine by a continuation of the Mefentery.
                   Great Intestines.
   The Great Inteftines, like the Small, form one continued Ca-
nal,  which tapers  from its upper to near its under extremity;
but differ from  them in being confiderably larger,  fhorter, and
 iliaighter,  and  in  being  irregular  in their Outer  Suiface, and
 tacked up  into  Cells, having  befides many Proceffes depending
from them, termed Appeudicula Pinguidenofa.
   Like the Small  Inteftines, alfo,  they are divided into three
parts, termed Caen/;;, Colon, and Reilum.
   The Intcftinjim Cacum, or  Blind Gut, forms a round fhort Bag,
only about three or four  Fingers-breadth in length, and  nearly
the fame in diameter.   The  Caecum, properly fo called,  is that
part of the Inteftine which lies under the Infertion of the  Ilium,
through  frequently the dilated beginning of the Colon is diftin-
guifhed by the fame name.
   It is fituated  in the Right  Iliac Region, refting on the  Cavity
of the correfponding Os  Ilium, at  the under end of the Right
 Kidney, and'is  concealed by the laft Convolutions of the  Ilium.
   The bottom  of it  is turned downwards, end  forms  a  fliut
 Sac,  the mouth  of which is turned  towaids the Colon, and may
 be confidered as foiming  the Cacum Caput Coli.
   At the pofterior and left fide of the Caecum,  there is a fmall
 Procefs,  about the fame length  with the  Caecum itfelf, but the
 diameter not larger than that of a Goofe-quill,—termed  Appen-
dix Vermijbrtn^s, from its refemblance to  an  Earth-worm, and
 Appendix Caci,  from  its  conneaion with the Ca?cum.
   It is convoluted, and fixed by its fides to the Caecum.
   It has two extremities,  one of which it impervious, the other
 opens obliquely into the back-part of the  Caecum.
   The Colon, fo called from the Gieek,  is by much the'longeft
 of the Large Inteftines.   It encircles the  Small Guts, and  is con-
 tiguous  to mofl of the Abdominal  Vifcera.
# 
93
  It is a continuation of the Caecum, beginning at the termina-
tion of the Ilium.
  It afcends in the Right Lumbar Region,  over the Kidney of
that fide to which it is conneaed.
  From the  rlid'.ey, it paffes forwards, and croffes the  Abdo-
men in the Epigaftric  and Hypochondriac Regions,  conneaed to
the Duodenum, under the name of Great Arch of the Colon.
   Fiie ri_;ht portion of the Great Arch is fituated under the Li-
ver and Gall-bladder,  wh-ch, after death, commonly iicges part
of  it  and of the Duodenum with Bile.
  The left portion is fitua.ed under the Stomach;  and immedi-
ately  below the Arch are the Convolutions  of the Jejunum.
  In  the Left Hypochonrlrium, it  turns backwards under  the
Spleen,  and Lfcends  in the  Lie Lumbar Region, on the fore-
fide of the K'dney, to which  alfo it is clofely conneaed.
  In  the  Left  Iliac Region, it forms two  Convolutions, com-
pared in  fliape to the  Greek Sigma,  and  hence called Sigmoid
Flexwe of the Colon,  which afteiwards conltitutes the Return.
  The Sigmoid Flexure varies confiderably in  length in different
perfons,  extending frequently into the Hypogaftric Region,  and
in fome inftances, as far as the Inteftinum C<ecum.
  The Colon,  through its whole extent is fixed to the Body  bi-
rr., ans of the Mefocolon.
  The Reelu/u begins  at the laft Lumbar Vertebra, and  has its
name from appearing  ftraight when  viewed  anteriorly.
  Itdsfcends upon the fore-fide  of  the Os  Sacrum and Os Coc-
cygis, and terminates in the Anus,  a little beyond the extremity
of  the laft named Bone.
   In  its  courfe, it follows  the direaion of the Bones over which
it paftes, turning firft downwards, then a little backwards, then
forwards, and is. fixed to them by the Meforeaum.
   The Reaum differs  front  the other Inteftines, in becoming
wider in its pijpgrefs  downwards, and forming below a Refer-
voir for the Faeces.
   At the Anus,  it contraas into a narrow  Orifice, the  fides of
which are difpofed in  clofe longitudinal folds.
   Upon  the Outer Surface of the  Great  Ineeftines, but  more
•fpecially upon the Colon,  are the Appendicula Pinguedinofa, fi-
tuated at different diftanccs from each other,—thin at their roots,
 becoming thicker in their bodies/ and projeaing from  the Intef-
tines like fo many pendulous Papillae.
   They are covered  by the Peritoneum, and are of the fame
 ftructure and ufe with the  Omentum.
   Befides the  Appendicular, ihere are on both fides of the adhe-
 fions of the Mefocolon, Adipofe Strata, which are of the fame
nature with the others.
   The Colon  is divided, longitudinally, into three parts, by as
many Ligamentous-dike Band;., which run vnon its Surface- 
100
  One of them goes along each fide of the Colon j and that moil
expof'ed to view when the Omentum is feparated, is  the largeft :
The thiid,  which is the fmalleft,  and which was  difcovered  by
Morgagni, ;s concealed by the attachment of the Mefo-colon.
  Thty begin at  the root cf the Append.x Vermiformis, and,
after running along the Cascum and Colon,  unite into two, and
then terminate on  the Reflum.
                       Mesentery.
  The Mefentery 's formed by  a doubling  of the  Peritoneum,
which is detached forwards, and includes the  Inteftines as in  a
Sling.
  It is named from its  fituation in the middle  of  the Inteftines,
and is divided into two  parts,  one conneaing the Small Intef-
tine«, and i mining the name of Mefentery;  the other, the Great
Inteftines and termed Mefocolon.
  The Mefentery  begins at the laft turn  of the Duodenum, and
runs obliquely downwards and  towards the right  fide, along the
Vertebrae of the Loins, to the firft, fecond,  and thiid of which
it is chiefly conneaed.
  Between the two Layers of the Mefentery, are inclofed a con-
fiderable quantity of Ce'llular Subftance  and Fat, the numerous
Blood-vefl'els and Nerves, with the Laaeals and  Glands of  the
Jejunum and Ilium.
  Its anterior edi^e is much more extendve than the pofterior, be-
ing plaited and folded,—the Plaits correfponding with the Con-
volutions of the Inteftines to which it is  fixed.
  The Mefo-colon is* the continuation of  the Mefentery, which,
after reaching the lower extremity of the Ilium, contraas, and
obtains this name.
  It follows  the cour|£of the Great Inteftines,  and fixes them
in their place.
  Under the Right  Kidney,  it is narrow and firm, and  forms
the  Right Ligament of the Colon.    .-            ---      ^.
  Oppofite to that Kidney, it appears to be loft by the immedi-
ate  adhefion of the Colon to the Kidney and Duodenum.
  It then  nuns acrofs,  and forms a broad expaniion, which  in-
clofes the Arch of the  Colon  at  its anterior edge;  and  behind,
it fi:paratcs and inclofes the anterior part of the Duodenum, and
is fixed to the Spine.
  It adheres  a little to the under part of the  left extremity  of
the Stomach, and afteiwards defcends over the left Kidney,  at
the under end ct  which it forms the left Ligament of the  Colon.
  It afterwards expands, adheres t- the large Pfoas  Mufcle, and
forms a loofe fold, which  retains the  Sigmoid Flexure  ot  the
Colon.
  At the laft Vertebra of the  Loins,  it  forms the  Meforeilum,  ■
which by de0rccs  becomes narrower, and difappears towards the 
101
under part of the Pelvis, the Reaum being then immediately
conneaed to the Os Sacrum.
  Between the Layers of the Mefocolon are placed the Arteries,
Veins, and Nerves, with the Abforbents'and Glands of the Co-
lon.
  The ufe of the Mefentery,  in general, is to fufpend, connea,
and retain the Inteftines in their places,—to fuinifh  them with
an  external Coat,—to receive their Glands, Veflels, and Nerves,
and to allow the two laft to be properly diftributed.
                        Omentum.
  The  Omentum or Caivl, formerly called Epiploon, from  its
feeming to float upon the Inteftines, is a fine Membranous Bag,
intermixed with much Fat,  and covering a large portion of the
Anterior Suiface of the Abdominat Vifcera.
  It is divided into Omentum Gaftro-colicum, and Omentum Coli-
cum,  the former comir.on to the Stomach  and  Colon, the ratter
proper to the Colon :  They are, however,  a continuation of one
and the fame  fubftance.
  The Omentum Gaftro-colicum confifts of  an anterior and pofte-
rior part, each of which is formed of two Membranes intimate-
ly united.
  In young fubjeas,  the Omentum forms  a diftina Bag, but in
old people, the layers of which it is compofed become more or
iefs incorporated, and Cribriform or Reticular.
  The Anterior Layer is aconfinu tion of the Peritoneal Coats,
produced from the upper and  under Surfaces if the Stomach.
  This Produaion arifes from the  whole length of the  large
Arch of the  Stomach,  and beginning of  the  Duodenum ,— ts
ori,in extending as far  as the Spleen, and  defcending to  » little
bti iw th«.  Umbilicus, efoecially in fat people,—but without ad-  *
he'ring to the Abdomin .1 Mufcles behind  which  it is  fituated.
  fts underedge is refleaed, to form the Pofterior Layer, which
afcends without adhering to the Small Inteftines over  which it is
fpread,  till it reaches the Arch of the Colon,  to the greater oart
of  which  Arch, and to  the  V-fl'els of the Spleen,  it is connc-aed.
  Tie Omentum  Colicum ariies  from  the right part of the Ar:h
of  the Colon,  in the manner the other part cf  the Omentum a-
rife-s from the Stmntich, and fends downwards and to the  right
 fide a Cuneiform Piocefs, to be conneaed  to the,C .cum.
   Befides the Omentum, there is a Memurane much fmaller than
 the former,  fituated  between the Liver and  Stomach,  termed
 Omenfkm  Hepato-gaftricum,,or Omentum  minus  of Wixslow,
 or  Membrana Macilentior of Haller.  from its having little Fat
 in  it.
    It paffes from the fore-part of  the Sinus of the Porta, to the
 under and back-part of the Liver, to be conneaed" to the whole

    Vol. II.          I 2 
10.!
  edge <-T the fmall Curvature of the Stomach,  and to the begin-
  n.";: t the Duodenum.
    1. ke the dhtr Omentum, it i* compofed of  wo Layars, but is
  thinner, lei's F .f,  and  moie uniform in its flruaure, and alfo
  difteis fivm it in having; n> iefleaion upwards.
    After the Omentum M nus  teaches the Stomach,  its two
  L-yers fepante from tach other, inclofe that  Vncus, and form
  its Extemal Cot.
    At the great Curvature of the Stomach, they rejoin, and form
  the Anterior, then the refleaed or pofterior part of the Omentum
  Maju*.
    The  pofterior part feparates  again into  two Layers, which
  inclofe the Cole n, and  form its  External Coat.
    At the oppofite fide  of the Colon, the Layers re-unite, and
  form the Me fo colon.
    ]'v the M.mbrane thus continued, a large irregular Bpg is
  founcd,  of wheh the Omentum Minus, Stomach,  and anterior
  portion of the Omentum Majus, conftitute the anterior, and the,
  refleaion of the Large Omentum,  the Colon,  and  Mefo-colon,
  the pofterior part.
,    At the upper and right fide of the Sac, there is a Paffage large
i. enough to  admit a Finder,  termed Foramen  Winslowi.
    It i- fituated immediately behind the Coid.of the  great Veffels
  which lead to the Liver, and is of a Semicircular form.
    It is compofed of the Peritoneum, under the appearance of two
  Ligaments which connea the furrtounding parts to each  other.
    The Foramen of Winslow  maintains a communication  be-
  tween the Large Sac of the Omentum and common Cavity of the
  Abdomen, from which circumftance, Fluids generated by dif-
  cafe iriay readily pafs from one of thefe Cawies to th« other.
  ■  The Omentum, by its Fatty nature, ferves^ro lubricate the Vif-
  cera, and prevent them from being injured by friaion.
   Structure of the  Small Intestines in  General.
    The  Structure of the Small Inteft nes is nearly fimilar to that
  of the Stomach, and the number of their Coats the  fame.
    The Extemal Coat,  exeepting in a portion of the Duodenum,
  is a continuation of that part ofthe Peritoneum which forms the'
  Mefen'.ery.  It clofely furrounds the Inteftines, adheiing to them
  by fine Cellular Subftance.
    The Second, or Mufeular Coat, as in the  Stomach, is compo-
  fed of two Planes of Fibres, the External or Longitudinal of
  which are more minute than the  Internal.
    The Circular Fibres  are diftina and numerous :   They confift
  of Segments of Circles,  which unite at different diftances, fo as
  to furround the Canal.
    The  Longitudinal Fibres fhorten, and the Circular contraa the
  Inteftiues j and upon the alternate relaxation" and contraction of 
103
thefe Fibres, depends that Vermicular motion, called Periftaltic,
by which the Contents are pufhed th.ough the Canal.
  Twe Third commonly called  Nervous Coat, like that in the
Stomach, is white and firm and compofed of Cellular Subftance,
without Fat ;—its firmnefs givin  ftrength to the Inteftines.
  The Fourth,  or Villous Coat, differs from that of the Stomach,
in forming, with the Cellular Coat, numerous tranfverfe F tds,
termed Valvula Qpjfniventes,  from their fervmg, as a kind of
Valves, to  retard the motion of the Food.
  One edje of theie  Valves is fixed to the Inteftine, the other is
loofe.—[hey are much  deeper than the Rugae of  the  Stomach,
and placed oppofite  to the Interllices of each  other, and are of
different lengths, not forming entire Circles.
  The Villi of the Inner Coat are  much  more confpicuous than
in the Stomach, being compofed not only of  the extremities of
Arteries, Veins, and Nerves, but particularly of the Mouths of
Laaeal Veffels,  the  Origins of which  are extremely fmall, and
have a fungous appearance.
  Numerous Duels of Simple and Compound Glands terminate on
this Coat,  for the fecretion of Mucus.
  The former are called Solitary, and the latter Congregate ;—
an I,  form their defcribers, Glandula Peyeri, and  Glandula
Brunneri.
  They are in  the  form of Papillae,  but fo minute as feldom
to be feen,  excepting in  the dtfeafed ftate,—though they are fup-
pofed to be difpeifed  over the whole of the  Canal.

Structure of the Small Intestines in Particular.
   The Duodenum is the laxeft and ftraighteft of the Small Intef-
tines,  and  fo large  as  to have been confidered as a Ventriculus
Succenturiatus, or secondary Stomach.                 ■—     m
   It is of a redder colour than the  reft, has  a thicker Mufeular
Coat, receives only a partial covering from the Peritoneum, and
is fixed more clofely to the Body, without floating like the other
Inteftines.                                                ■>.
   It is perforated at the diftance of three or four fingei s-breadth
from the   Pylorus,  by  the enls of the  B.liary and  Pancreatic
 Duas, for the reception of Bile  nd Pancreatic Juice.
   In the Duodenum, the L iaeai Veffels  begin to make their ap-
 pearance,  and  numerous Mucous Giands are found in itefpeci-
 ally near the Py ,01 us
   The ufe of  lie Duodenum ii to receive the Food from the Sto-
 mach, and detain it till mixed  with  the Bile and Pancreatic
D«a.
   The Jejunum d'ffers from the  Duodenum in deriving it^ com-
 mon Coat  wh  lly ti m the  Peiitoneum, 1:1  being  fin.Tier,—in
 having a weaker M if ula  Cat, the xternai  Fibres of  which
 are extremely minu  e,—in the Valvui.t Connivences, being  larger 
104
 and more numerous,—and in the Villi and Laaeals which pro-
 ceed from them bctiit, much more confpicuous.
   The Ilium d Hers  from the  former  in being lefs in diameter,
 and it-. Co its thinner and of a paler colour, and in having fewer
 and fmailer Laatal Velu-is.—In this Inte, ine the Valvula? Con-
 nivc-ntes gradually decreale in fize and number, and at length en-
 tirely  difupear.—At its  under end,  the  Mucous Glands are
 diftina and numerous.
   The ufe of the Small Inteftines in general is,—to promote tha
 forma ion  ol the Chyle,—to allow it to be abforbed,  and—to
 propel the remains of the Food into the Large Inteftines.
 Structure  of the  Great Intestines in  General.
   The Great have the fame number of Coats with the Small In-
 teftines, hut differ from them in being thicker and ftronger.—The
 Valvulae Connivenies are deep,  and placed oipoi.te to each other,
 and, as in the Sm.-il Inteftines, diminifh m number and in fizj
 towards the under extrenvty.—The Villous  appearance  is much
 lefs diftina.—The Mucous Glands are larger,  but Ampler than
 thofe of the Small Inteftines.
       Structure of the Great Intestines in
                       Particular.
   The Inteftinum Cacum is of the fame general flruaure  with the
 reft of the Great Inteftines.  lis Villi are very  fhort ; and it has
 a number of folitary  Mucous Glands, broader than thofe of the •
 Small  Inteftines, which,  when difeafed,  fometimes appear like
 fmall-pox, with  a perforation in ea< h.
   The Appendix Vermijormis is of ihe  fame flruaure  with the
 other Intttines, contains no i';e.es, but is fuiryflicd with nume-
 rous Glands finilar  to thofe of the Duoderiun?, the  contents of
 which pafs into the Caecum, a little below the Valve of the Co-
^Jon, and affift in  lubricating that Inteftine,  and in facilitating
 the cxpulfion of the iaeculent Matter.
   In the Caecum, and beginnin ; of the Colon, the Food coming
 from the Ilium is retained for fome time, and, in'confequencc of
 abforption, acquires  a gfea.er degree of confiltency, and rtce.vcs a
 fceiid  fmall.
   The Valvula Colt, fometimes called Valvula-llei, <r Valvula
 Baughim, from its fuppofed difcoverer, and Valvula Tut pii
 fiom the  Author who gives a particular defaiption of it, is iitu-
 ated at the beginning of the Colon, and is placed tranfvuTeiy in
 the. pofterior and left part cf that Inicllne.
    It is formed of a piojeaion of the Vtlous and Nervous  Coats,
' and Circu'.t'r Mufculat Fibres of the Ilium,  Caecum, and (J km,
 and has iwo Folds or Lips, with an aperture in form of  a Mouth
  or  Chink between thr-in.                                     ¥
    At the ends  of the Valves a.e two cords, termed Retinacula, or 
IOj
Frana Morgagnii,  which  retain the Valve in its proper fitu-
ation.
  The Valve of the Colon allows a free pafface for the Contents
of the  Small into the  Large Inteftines, but completely prevents
their return.
  The Colon is of a  fimilar  flruaure with the Caecum.—The
Longitudinal Mufeular  Fibres are coll aed upon it  into three
Fafciculi  or  Bands,  which  arife at  the root of the  Vermiform
Procefs,  and are continued along the Colon to the Reaum.
   The Longitu final Bands are ftiortei than the inner parts of the
Colon, and  of confequence affift in contraaing it, and forming
it into Plicae, which lie acrofs the Gut,anfwering to the Valvulse
Conniventes; only they are at a greater diftance from each  other,
and much larger, dividing the Colon into little apartments,  called
Cells.
   The Cells of the Colon, with their Partitions, have a threefold
order, the Inteftine being aimoft quite fmooth or plain, oppefite
to the Longitudinal Bands.
   The Cells affift  in preventing  the too quick defcent of the Fae-
ces.
   The ufe of the Colon is,—to receive the Excrementitious parts
of the Aliment,—to  retain th-m,—to change them into  Faeces,
and  then, by the  periftaltic  motion of the Inteftines  and power
of Refpiration, to pufh  them,  by flow degrees, to the Reaum.
   The Rectum  difteis from the Colon in being covered only an-
teriorly and  laterally by the  Peritoneum:—its Mufeular  Fibres
are ftronger and thicker,  and  f4 read uniformly over the Inteftine.
—The Circular Fibres are fo thick at the end of the Reaum, as
to have been  named Internal Sphincter.
   It has  no  Cells like the Colon''} but the Cellular  and  Inner
Coat are fo much  'larger here than they are higher up, as to fall
into tiantVerfe folds, which, however, difappear in proportion to
the detention of  the  Inteftine.
   The middle  and under end of the Reaum has numerous large
Mucous Glands or Follicles.
   The extremity of the Reaum forms a firm Circle,  which aas
as a Vaive>  and aflifts the proper Sphincter in preventing the in-
voluntary difcharge of the Fieces.
   The Verge of the Anus is furrounded with deep Follicles, the
 contents  of  which prevent the teftder Skin of the Anus from be-
 inj>  excoriated  by  hard or acrid Fie es.
   The Anus is alfo furrounded \ ith a : reat deal of Fat,  which
 admits of the  dilatation of the Reaum, and  facilitates the dif-
 char.e of the Faeces.
   The Reaum receives  the Fares from the Colon,  retains them
 for  a certain time, till,  by  their weight and Acrid nature, it is
 flimulatcd to difcharge them ; which it does by the powsr of its 
106
I
Mufeular Coat, and of the Levator Ani, aflifted by the aaion of
the Diaphragmat c and Abdominal-Mufcles.
  The Blood-veffels of the Inteftines are large and numerous, and
are derived fiem different fources.
  The Duodenum receives Branches from the Splenic and Hepa-
tic Arteries.
  The Jejunum,  Ilium, and right half of the Colon, are  fup-
plied by ihe Superior Mefentric Aitery ; and the left half of the
Colon with the Reaum, by the Inferior Mefejitric Artery.
  The Veins of all the Inteftines fend  iheir Blood  to the Vena
Portae.
  The Abforben'.s of the  Ttv'dines are large and numerous.—
They aide from the inner Surface of the Inteftines, run  in  the
Mefentery  and Mefo-colon,  pafling  through  their numerous
Glands.—'I he Abforbents of  the Small  Inteftines terminate in
the receptacle of the Chyle ; thofe of the Large Inteftines, which
are final ler than the former, go partly to the Thoracic Dua,  and
paitly to the Lymphatics of the Loins-
  The Nerves of the  Inteftines are  fmall,  but numerous,  and
are derived  partly from the Eighth  Pair, but chiefly from the
Great Sympathetics.
  The Veflels and Nerves of the  Omenta are Branches of thofe
which fupply  the  Stomach,  and have  the name  of  Gaftro-
Epiploic.
                        LIVER.

  The L/tw is a large folic! Mafs, of a duller red colour,  fitu-
ated immediately under the Diaphragm,  extending downwards
to the margin of the Thorax,  but not going bc-yond it.
  It is pl'ced partly in the Right Hypochondiium, which it in a
great meafure fills, and partly in the Epigaftrium,  reaching over
a little way into the Left Hypochondiium.
  It is convex m.d \ery fmooth on the upper Surface, where it  is
oppofed to the Diaphragm,  though  a l.ttle flattened on the  up-
per part of its  left fule, where it is placed oppofite to the Heart.
  It is irregularly concave on the under fide,  where it refts upon
the Stomach and Inteftines,  and  is perforated  by feveral large
Blood-veffels.
  It is thick on its right and pofterior  part, and becomes gradu-
ally thinner towards the left fide ; \& obtufe or blunt ■ n its p iter,or,
and acute orJharp en its anterior edge,—and conilaerably broad-'
er from one lide to the other, than from before backv c.i ^ . 
107
  It is divided into Prominences or Lobes, two of which, called
Great *no\ Small,  or Right and Left Lobes, are fo confiderable as
to form  the Body and whole  upper part of the Liver—The
others are fmall, and are placed upon  the  under fide of the for-
mer.
  The Great Lobe is placed obliquely in the Right Hypochondriac
Region,  following the Curve of  the Diaphragm, and rells upon
the Pylorus, Colon, and top of the Ri ,ht Kidney.
  The Small Lobe, diftingu-fhed from the Great one by a broad
Ligament, is placed almolt horizontally, chiefly in the Hepeaftic,
and reaching only a little way into the Hypochondriac Region.
                  —-The other Lobes are,—
  The Lobules Spigelii, which is fmall when compared with the
two former Lobes,  but is the principal one below.
   It is fituated near the Spine, upon the left fide of the Great
Lobe, and  is of a Pyramidal form, projeaing like a Nipple, at
the fmall Curvature of the Stomach.
   The Lobulus Cuudatus, which is merely the root, or one of the
angles of the Lohulus Spigelii, advancing towards the middle of
the lower fide  of  the Great Lobe.
   The Lobulus Anonymus, or S^uadratus, which is placed between
the paffage of  the round Ligament and the Gall-bladder,  and  is
lefs prominent, but broader than the former Lobule.
   From the Lobulus Anonymus, a bridge called Pons,  or Ifth-
mus Hepatis,  runs acrofs the  Paffage for the Round Ligament, to
be joined to the Left Lobe -.—It is fometimes aw3nting.
   Upon the under fide of the Liver, there are feveral Fiffures, of
which the following are the principal.
f   The Great  Fiffure, called Foffa Umbilicalis, between the Right
and Left Lobes,  at the under and tore-part of the Liver.
   This  is terminated by a Notch at the fore-part of the Liver,—
of different depths in different bodies,—and behind,  it  is com-
monly covered with the Bridge above mentioned.
   The  Principal Fiffure, termed Sulcus Tranjverfus,  or Sinus
Portarum, extending from right to lef, between the Great and
Small Lobes,  and bounded by thefe Lobes at its extremities, and
by the  Lobulus  Anonymus before, and by the L >bulus Spigelii
behind,  the  two latter forming  parts compaied by the An-
cients to  a  Gate, and therefore  called Porta.
   The Depreffion between the Great Lobe  and Lobulus Spigelii,
 for the  paflage of  the Inferior Vena Cava, which has frequently
 a bridge over it,  forming it into a Canal.
   A Small Depreffion, called  Foffa Duilus Venoft, between  the
 L|ft Lobe and Lobulus Spigelii,  running a little obliquely from
 right to left fide,  and receiving a Ligament,—wivch is a Branch
 of the Umbilical Vein in the Fcetus. 
10S
  The Ljyer is conneaed to  the  Body  by different Proceff^,
termed its Ligaments, all of which, excepting one, are formed by
doublings of the Peritoneum, viz.
  The Ligamentum Latum, or Sufpenj'orium Hepatis,  placed be-
tween the Right and Left Lobes above,  and extending below into
the Foffa Umbilicalis.
  It is fixed obi 'que y to the Diaphragm and tip of the Enfiform
Cartilage, and thrn defcends in the fame oblique direaion, ad-
hering to the inner part of the V .gina of the Right Reaus Abdo-
minis Mufcle,  as far as the Umbilicus.
  The Ligamentum Rotundum,—which is the Umbilical Vein in
the Fcetus,  placed in a doubl.ng  at the under part of the  Liga-
mentum Latum,  and fixed to the Umbilicus.
  Thefe two Lig iments have been fuppofed to referable a Falx,
with the edge turned uppermoft, from which circumftance the
Ligamentum Latum is fometimes  alfo called Falcijorme.
  The Ligamentum Dextrum, or Right Lateral Ligament,  which
is fhort,  and conneas the back-part of the right extremity of the
Gr-at Lol e to the Diaphragm.
  The Ligamentum Siniftrum,  or Left Lateral Ligament,  which
is longer than the former,  and  conneas the left extremity of the
Small Lobe to the Diaphragm.
  The Ligamentum  Coronarium,  confidered  by fome as merely
Cellular Su'iftance, and by others as a refleaion of the Peritone-
um, or both.—It unites the root of the Liver to the Tendinous
Portion of the Diaphragm.
  Befides the Ligaments already mentioned, two others are de-
fcribed by Hallkr ;  one called Hepatico-colicum, which paffes
from  the Gall-bladder and contiguous Sinus Portarum, acrofs
the Duodenum,  to the Colon; another called  Hcpatico-renale,
which  defcends  from the  root of the  Liver to the  Kidney.—
Thefe,  as  well  as the oti er Ligaments of the Liver  in gene-
ral, are produaions of the Peritoneum.
  The Ligaments of  the Liver  preferve it  in its proper fituation,
and of courfe prevent  it from inclining too  much in any direaion.
The Stomach and Inteftines ftippoit it'when the Body is upright
and the Diaphragm,  when  the Body is  inverted.
  Tie Liver has a fimple Coat adhering clofely to it which it de-
rives from  the Peritoneum, and  is every where covered by this
Membiane, except-ngbehind, where itadheies to the Diaphragm
by Cellular Subftance.
  The Subftance of  the Liver  is  com-cfed cf feveral kinds of
Vcffeis, the extreme  Branches of  which are intermixed in  fuch  a
manner, as  to form numberlefs Pulpy Corpufcles, named Acini,
from a refemblance to fmall Stones or  Kernels of Fiuit,  wrrtch
when minutely examined, are obferved  to be compofed of Veffels
in the form of radiated Villi or Penicilli. 
109
  The Veffels of the Liver are,  the Hepatic Artery,  Vena Porta-
rum, Vena Hepatica,  Abforbents, and Biliary  Duels.—It  has
likewife numerous Nerves.
  The trunks of the Hepatic Artery, Vena Porta;, Biliary Di^s,
and Nerves, with the Abforbents and Lymphatic Glands of  the
Liver, form a large Cord at its  under part.
  The Arteiy is fituated in  the left pirt of the Cord, the Vein
in the right, with the Trunk  of the Biliary Duas before it  ;—
the Nerves and Lymphatics furrounding the great Veffels.
  The Coid of Veffels and Nerves  is intermixe^ with much Cel-
lular Suhftance and covered externally  by a refleaion of the  Pe-
ritoneum, which has obtained the name of Capfule  o/"Glisson.
  The  Branches of Veffels and Nerves accompany each other
through the fubftanceof the Liver, forming fmall Fafciculi, in
a manner fomewhat fimilar to that by which the Cord is formed
by their Trunks.
   In  their courfe through  the Liver, the Branches of the different
Veflels and Nerves, but particularly thofe of the Vena Portx, are
inclofed in a large portion of Cellular Subftance, which  is  alfo
frequently called Capfule o/Glisson,  from that Author fuppo-
fing it to be a  continuation of the Capfule which covers the Vef-
fels before they enter the Liver.
  The Hepatic Artery is derived from the Caeliac, and is difperfed
throughout the whole  fubftance'of the Liver,  and  alfo upon the
Coat which covers it,  and is fo fmall  when compared with  the
bulk of the Liver, as to have been generally fuppofed to  be def-
ined for the  nourifhment  merely of  that  Vifcus;  but from in-
jea ons pafling from the Artery to the Biliary Duas, and from
other caufes,  it has been fuppofed by fome Anatomilis,  that  the
Hepatic Artery is not only intended to  nourifh the  Liver, but is
capable  of fecretiug parted7 the Bile ;—and this fuppofuion is
farther confirmed from the Vena Porta?  having,  in a recent cafe,»
been found awanting, while, at the fame time,  the Hcpaic  Ar-
tery was larger than ufual, and the Veins which commonly form
the Vena Porta?, terminated in the Vena Cava.
  The Vena Porta  is named from its fituation with refpea to  the
Porta of the Liver.
  It partakes  of the nature of an Artery and a Vein :__Like the
former it carries the Blood from the Trunk to the Branches, and,
like the latter, it carries  it  to the Heart;—or it is peculiar in  the
Blood,  in one part  flowing from the Branches to the Trunk, and
in another from the Tiunkto the Branches.
   It is formed by the Veins of the Stomach and Inteftines, joined
to  thofe  of the Spleen,  Omentum,  and  Pancreas, and  ap-
proaches to the nature of an artery in the thicknefs of its Coats,
though it his  no pulfation.
  It paffes to  the Po ta, where, from its great fize, it is named
Sinus of the Vena Porta?, and divides into Branches which ac-
   Vol.  II.            K 
no
    company thofe of the Artery in their coui fe through the fubftance
m  noi  the Liver,  termin .t.ng at laft in  the Pulpy Corpufcles.
      'The /-ena Porta  ferves to carry Venous Blood  to the  Liver,
    for the l'ecretion of  the B le.
      The  Vena Hepatic* are numerous.   They are refleaed partly
    fiom the extremities of the Artery, and part.y from thofe of the
    Vena Porta?.  They unite by degiees, and  accompany the  other
    two fets of Veffels ;  but at the  roo. of the Liver they form two or
    three large Tiunks  which term nate  in the Vena Cava, where it
    is about to peiforate the Diaphragm.—They likewife  fend  off
    fome fmall  Branches which terminate  in the Cava, where that
    Vein  iies behind the Liver.
      The Ve  re Hepatica? receive the Blood from the Hepatic Ar-
    tery and  Vena Portse, after the liile has bren fecreted, and return
   it to the Vena Cava, to be conveyed by it  to the Heart.
     The lymphatics of the Liver are fo numerous as to cover al-
   moft the whole of its outer Surface.  They difcharge their con-
   tents, partly into the beginning of the Thoracic Dua, and partly
   to a Plexus fituated  in the fore-part of the  Thorax.
     The Nerves of the Liver are alfo numerous.   They arife from
   the Great Sympathetics  and  Eighth Pair, and accompany the
   Blood-veffels.
     The Biliary Duels arife by extremely minute Branches, termed
   Pori Bilarii or Tubuli Bilijeri,  chiefly from the extremities of the
   Vena  Porta?, in the  Suoftance  of the Corpufcles,  through the
   whole of  the Liver.
     The Pon Bilarii run in company with the  Branches of the Ar-
   tery and  Veins, and  unite into  larger and larger Branches, which
   afterwards go into two, and thefe  again into a  fingle Tiunk  in
   the  Sinus Portarum, called Duilus Hepaticus.            41
     The Duilus Hepaticus ferves to carry the  Gall or  Bile, which
   K of a yellow green  colour, from  ihe Liver,—and  to convey  it
   by the power of the  Heart, Hepatic Artery, and  Vena  Portae,
   -iffidtd by the preffnre of the i'unounding Mufcles, to the Duo-
   denum, and  partiy to the Veficula Fullis.
     The Veficula, or  Cyftis Fellis, or Gall-bladder, is a fmall ob-
   long,  Pynform Bag, confifting of a Bottom, Body, and Neck,
   fituated upon the concave fide of the Great Lobe of the Liver,
   and  placed in a tranfverfe direaion from behind forwards.
     It extends from the Sinus Portatum, where the  Neck is  fitu-
   ated, to the anterior  edge  of the Liver, and  when full advances
   beyond the edge of the Liver, fb  as  fometimes to have its Fun-
   dus  oppofed to the foft parts of the Abdomen, under the edge of
   the  Falfe Ribs.
     The bottom  is a  little  lower than the Neck,  when the  Body
   is  in  the  erea pofture.   It inclines  alfo  a little to the right
   fide, a.d refts upon the Colon  at the beginning of the Duo-
   denum. 
111
  It is compofed of feveral Coats, the external of which  is a
continuation of the Membrane of the Lntr: 1 his however, is
only a partial Coatcoveiing that part of the Gail-bladder, which
projcas  beyond  the  Surface of the L ver.—It  fcives to give
ftrength to the Gall-bladder, and to fix it to the Liver.
  Under the former Coat,  a few pale fcattered Fibres,  running
in various  direaums, are fometimes obferved, which have  been
confidered as a Mufeular Coat ; and under this is a fmall quanti-
ty of Cellular Subftance, which has obtained the  name of  Ner-
vous Coat.
  The Inner Coat, fometimes called Villous, is full of fmall Re-
ticular Rugae or Folds,  which become extremely minute towards
the Ceivcx, where they run in a longitudinal  direction.
  The  Su. face  of th s Coat i, every  where pen-rated by the
Duas of fmall Follicies, which difcharge a lifcid  Mucus, to de-
fend the Surface of the Inner Coat from the  Stimulant  nature of
the Biie.
   The Gall-Bladder is conneaed through  its whole length to
the Liver by Cellular Subihiiice,  Blood-veffels, ;i..d Abloibents,
among which  the Hepato-cyftic Duel,  fimilar to  thofe  found in
many Animals,  were in former times defciibed,  and  fuppofed
to carry the Bile found in the Gall-bladder immed.ntely from the
Liver.   It i;  now fufficiently afcertamed,—that no fuch Duas
efift in the Hum in Body
   The Gall-Bladder has Blood-vcfl'-ls, abforbents, and Nerves,
in common with thoi'e of the Liver.—Its Veins pafs into the  Vena
 Porta;.
   The Neck of the Gall-bladder is twilled and folded againft k-
felf, and afterwards con.raas and fends out  a  Duct called Cyfiicus,
which runs near the Ductus Hepatieus,  and then joins it, to  form
the Duilus Communis Choledochus.
   The Dui~lus Cifticus is fmaller than the Duilus Hepatieus, and
differs from i: alio in having a number cf .niperfea Paititions or
Plica,  running in a fomewhat fpiral direaion, and forming  it in-
to Cells which retard the flow of the Bile.
   The Gall-bladder ferves as a leceptacie  for the Bile, when the
Stomach and Inteftines are empty anddiave no need of it, and ic-
tains it till wanted for the purpofe of digeftion.—It is aherwaidi
 discharged from the Gill-bladder,  when the Stomach is full in-
 to  the Duaus  Communis, and  from that to the Duodenum,
 chiefly by the preffure of the furrounding Vifcera,  and partly as
 fome Anatomilis fuppui'e, by a contractile power in the Gali-olad-
 der itfclf.
   The whole of the Bile contained in  the Gall-bladder is found,
 by experiment,  to pafs from the Liver  through the Hepatic  Dua
 to the Duaus Communis, and from that by  the Cyftic  Dua into
 the Gall-bladder.
   The Bile returning  from the  Gall-bladder isobfeived,  from
 the thinner parts being  abloibed,  tube thicker,  moieaciid and 
112
 bitter, and cf a deeper colour, than that  which flows from the
 Liver.
   The Duilus Communis Choledochus, called Choledochus from its
 conveying Bile, is about the fize of a Goofe-quill,  and  is  con-
 fiderably larger than either of the Duas which open into it.
   It defcends at the pofterior and left part of the Duodenum, and
 pafl'es for fome  way obliquely between the Mufeular and  Inner
 Cons of that Gut,—the obliquity anfwering  the purpofe of a
 Valve.
   It terminates in the left,  pofterior, and  near to the under part
 of the fecond Turn  of  the Inteftine,  by a  projeaing Orifice,
which is  rounded above, and pointed belovx.
  The Struaure of the Duaus Choledochus  and of the Biliary
 Duas in  general, is of the fame nature be'ng  entirely Membra-
 nous : The Inner Surface of the Duas alfo agree in  being per-
 forated by numberlefs pores, wh.ch are the Mouths of Mucous
 Follicles, fimilar to thofe upon the infide of the Gall-Bladder.
  The Bile ferves to mix the different parts of the Food properly
 together,  for  the formation  of the Chyle,—to  correa too great
 a dilpofition to acidity,—and to excite the Periftalic motion of the
 inteftines,

                         SPLEEN.
  The Spleen  is a  foft and very Vafcular Subftance, and  of  a
purple colour.
  It is fomewhat depreffed,  is of a long oval form, and of a con-
fiderable  fize, but varying in this refpea in different fubjeas.
  It is fituated in the  Left  Hypochondriac Region, between the
 large extremity of the Stomach and  correfponding Falfe Ribs;—
 Its under end  lying behind  the Colon, and over the top of the
 Left Kidney.
  The fitintion of the Spleen  varies  a  little, according to the
 ftate of Refpir;.tion, and to the ftillnefs or emptinefs of the Sto-
 mach ;—riling  or falling as  the Lungs are lefs or more dilated,
and becoming more oblique  in its fituation,—with its inferior ex-
 tremity turned  more  forwards,—in proportion as the Stomach
 becomes  more diftended.
  Its External Surface is convex and unifoim, like  that of the
 Ribs, &c. to which it is oppofed.
  Its Internal Su.rj'ace,  or that next the Spine,  is irregulatly
 concave; and is divided into an Anterior and  Pofterior Plane, by
 a longitudinal Groove or Fiffure,  where  the  Veffels and Neives
 enter.
   The Anterior Plane is more concave than  the Pofterior, cor-
 refponding to the contiguous convexity of the Stomach.
   The Spleen has frequently deep Fiffiires upon its edges;—fome-
 times it has fmall Appendages attached to it, and not unfrequent-
 ly there is one or more Small Spleens conneaed with it. 
  At the under fide,  it is fixed to the Omentum,  and, by means
of that and Blood-veffels, to  the  Stomach and Pancreas.—Be-
hind, it  is conneaed to the Diaphragm ;  and below,  to the Left
Kidney and  Colon, by  refleaions of the  Peritoneum, and  by
Cellular Subftance.
  It is covered by a double Membrane, one Layer of which is a
produaion of the Peritoneum,  the other  proper to the Spleen  it-
feVf ; but fo clofely conneaed to the common Coat, that they ap-
pear to be one and the fame Membrane.
  The  fubllance  of the  Spleen  is  remarkably  foft,  and is by
much the moft tender of the Abdominal Vifcera.
  It Confifts  of a Congeries  of Blood-veffels, Lymphatics, and
Nerves, joined together and fupportedby a larae quantity of Cel-
lular Subftance.
  The extreme Branches  of the Blood-veffels put on the appear-
ance of  Penicilli, or fmall Brujkes, which huvc  been  miftaken
tor Glands.
  Thefe Veflels are fo tender,  th.it when an injeaion is forcibly
thrown into  either Arteiy or  Vein,  it burlls into the  common
Cellular Subftance,  and  gives the  appearance  of Follicles  or
 Cells.
  The Blood-veffels of the Spleen  are among the l.irgeil  of  the
Body, in proportion to the Vifcus on which they are dilperfed.
  The Artery is a principal Branch of the Caeluc.—It run-, in a
ferpentine  direaion,  and, after fending Branches to  the Pancre-
as, &c.  and the Arteria  Breves to the It ft end of the Stomach,
it goes into the fubllance of the Sple.n, wiie'ie it is fubdivided  in-
to Branches, which are crowded together, and run in every direc-
tion, forming at length Plexus and Penictili, winch  terminate in
 the  Branches of the coriefponding Vein.
  The Vein,  like that in moft other Vifcera, is   larger  thun  the
Arteiy :—Ft  receives the Blood  immediately from  the  termi-
nations of the Artery, without the intervention of Cells.
   The Spienic Vein receives the Vena Breves of the Stomach, tlu*-
P.increatic Veins,  &c. and forms one of the principal  Branches
 of  the Vena  Poi tar.
   The Lymphatics from  the fupei ficitd  p-rts  of  the Spleen juiu
 the; deep L\:\.cd Abforbents at the Fiflure where the Blood-veffels
enter, and afterwards p.'.fs thiougli feveral Conglobate Glands
 lying over the Splenic Artery.
   Tney intermix  with lymphatics belonging to fV/erul  other
 Vifcera, and terminate in tho  Thoracic Duel.
   The Nerves of the Spleen, which  are fmall,  but coiTiderabls
 in number,  are Branches of  the Great  Sympathetic and Eiuhch
 Pair, and  form an irregular Plexus which furpunds the Veflels.
   No Exciet jry Duct has bc;n found to proceed from the Spleen,
 in  confequence of which very various opinions  hive been enter-
 tained with icfp.a to the ul'c of that Organ.
    Vol.'II.           K s2 
114
  Mmy of the ancients were of opinion,—that befides  the Bile
of the Liver, there was an Atra  Bilis,  or  Black  Bile, and that 4
the Spleen was the receptacle of the latter.
  Others have thought a particular Menftruum\va% fecreted in it,
and conveyed to the Stomach for the purpofe of digeftion.
  Others again,—that the Blood of the Spleen promotes the flug-
gifh circulation of the Blood of the Vena Porta?.
  The late Mr. Hewson, who has written particularly on the
Spleen,  was of opinion it concurred with the Thymus and Lym-
phatic Glamh, in forming the led Globules of the  Blood,  and
that thefe Globules were rendered complete in the Spleen.
  It has been alfo fuppofed,—that as the Stomach becomes full,
the Spleen is compreffed by it, in confequence of which a greater
quantity of  Blood is fent to  the Pancreas,  for  the Secretion of
the Pancreatic Juice.
  But the prefent moft prevalent opinion is,—that the Blood un-
dergoes fome change  in it,  which renders it  ufeful in  the  fe-
cretion  of  the  Bile ;—and  the opinion is fupported from  the
great  quantity of  blood with which this Organ is known to be
fupplied, and from  its Vein, not only in Man,  but in other ani-
mals, paffing to the Vena Porta?.

                       PANCREAS.
  The Pancreas, i. e. AllFlefh, or the Sweat  Bread, is a long
flat Gland  of the Conglomerate kind,  and of the fame  nature
with  the Salivary Glands, of which it may  be reckoned  the
largefl.
   It is fituated in the  Epigaftric Region, and  is placed tranfverfe-
ly in  the back-part of the Abdomen, between the Stomach and
Spine.
   It has a large or Right Extremity, and a fmall or Left one, an
Anterior and Pofterior Surfaee, and an  Upper and Under Edge.
   The Right Extremity is attached to the  left  fide of the fecond
Turn of the Duodenum,  or to  that part  where  the Inteftine is
about to go acrofs the Spine.
   From the under  part of  the Right Extremity, the Pancreas
fends down an  Elongation or Procefs,  which adheres clofely to
the Duodenum.
   This Procefs was difcovered by Winslow,  and termed by
 him Pancreas Minus.—It is alfo called  Head of the Pancreas.
   The Body of the Pancreas  paffts before the  upper part of the
 tranfverfe portion of the Duodenum, and over the Aorta, Vena
 Cava, and part of the Splenic Veffels,  to  all of  which it is at-
 tached.
   The fmall extremity, which is rounded, is fixed to the  Spleen,
 through the medium of the  large Omentum.
   The Pancreas is covered anteriorly by  the two Layers of the
 root  of the Mefo-colon ;—pofteriorly, it is only covered  with
 Cellular Subftance, which connefts it to the Vertebra?. 
                            I 15

  It is compofed of Acini, which form fmall Glands or Lobes 5
and  thefe are conneaed loofely by Cellular Subftance,  in fuch a
manner as to give an appearance of uniformity and fmoothnefs
to the External Surface.
  The Arteries of the Pancreas are derived,  partly from the He-
patic, but chiefly from the Splenic, by feveral fmall  Branches,
which pafs at various places  into its Subftance, in a  tranfverfe
direaion.
  The Veins correfpond in name and  courfe with the Arteries,
and  affift in forming the Vena Portae.
  The Lymphatics run to  the Splenic Plexus, and terminate in
the Thoracic Dua.
  The Nerves of the Pancreas are fmall :  Like thofe of the o-
ther Vifcera of  the  Abdomen, they are derived from  the Great
Sympathetic and  Eighth Pair.
  From the  different Acini of the Pancreas,  fmall Duas  arife,
which join into larger ones running tranfverfely in the Subftance
of the Pancreas,  and forming a common Dua,  called Duilus
Pancreaticus.
  The Pancreatic Duel, termed alfo Duilus Wirtsungi, after
the difcoverer of it in the Human Body, is remarkably thin, of a
white colour, and femi-tranfparent.
  It begins at the Left Extiemity of the Pancreas, runs in  the
fubftance of the Gland, a little below its middle height, and be-
comes gradually larger in  confequence of receiving the different
Branches which compofe it,—and is at laft about the fize of a
Raven's-quill.
   At the Right Extremity of the Pancreas, it receives the  Prin-
cipal Dua of the Pancreas Minus, and terminates obliquely in
the Duodenum along with the Duaus Communis Choledochus.
—In fome rare cafes, however,  it terminates  at a little diftance
from the Biliary Duct; and fometimes alfo,  the Dua of the Pan-
creas Minus ends feparately in the Duodenum.
   The Pancreas fecretes a Liquid or Juice,  refembling Saliva in
quality and appearance, and  difcharges it by  its Excretory Dua
into the Duodenum.
   The Pancreatic Juice incorporates  the B !e with the Alimen-
tary Mafs, and may be faid alfo to anfwer the fame purpofe to the
contents of  the Inteftines, which the Gaftric  Juice doe* to thofe
of the Stomach ;—or, it finifhes  that digeftive Procefs in the In
teftines which was be^un  iii the Stomach. 
11G
                          OF THE


 ORGANS  OF  URINE AND  GENERATION


                    IN THE  MALE.


                    -i--«^BO«»---


                        KIDNEYS.

   THb Kidneys are two Glandular bodies, of a pale red colour,
fituated in the upper and back-part of the Abdomen, in the Lum-
bar Region.
   They are placed one  on each fide  of the Spine, extending from
the Eleventh Pair of Ribs to near  the  Offa Ilia; and reft upon
the Diaphragm, large Pfoa?, Quadrati Lumborum, and Tranf-
ver'fales Abdominis Mufcles.
   The Right Kidney is fituated at  the  under  and back-part  of
the large Lobe of the Liver,  behind the Colon, and is common-
ly a very little lower than the left.
   The left Kidney is placid at the  under and  back-part  of the
Spleen, and behind the left parts of the Stomach, Pancreas, and
Colon.
   The Kidney  is about five or fix fingers-breadth in length, but
confiderably lefs from  the outer to  the inner fide, and lei's  than
that ftill from before backwards; or, it is compaied in fhape to
a French or Kidney bean.
   It is rounded anteriorly, flattened pofteriorly, convex and uni-
form at its outer margin,  and has a deep depreffion or Sinus to-
wards the Vertebra?, furrounded with unequal edges, where the
ivtnal Veffels and Nerves enter.
   it is a little broader behind  than  before, and  a little broader
and more curved above than below,  from which circumftance,
but more particularly from the difpolition of the Veffels to be af-
terwards mentioned, it is ealy to  diftin.uifti the Right fiom the
Left Kidney when taken out of the Body.
  The .Ritrht Kidney is conneaed to  the Liver and Duodenum,
the Ltfi. to the hpleen,  and both to the  Mufcles on which  they
arc placed, and.to the Renal  Glai.ds  and Colon, by Cellular
Subftance and  by the Peritoneum.
  Tiny arc alio cor neaed to the Aorta and Vena Cava by the
t-    •  „*-„..,  .,..Jt0 tht gladder ot- Urine by the  Urdus.— 
in
They accompany the motions of the Liver and Spleen, in the dif-
ferent ftates of Refpiration.
  Each Kidney is furrounded by loofe Cellular Subftance, which
commonly contains a confiderable quantity of Fat,  from which
it is termed Tunica Adipofa.
  The Tunica Adipofa  covers not only the Kidney, but  large
Veffels,  and defends them from the preffure of the  furrounding
Vifcera.
  Under the Tunica Adipofa, there is a Membrane  compofed of
the original  proper Coat  and Cellular Subftance incorporated,
which adheres clofely to the Kidney,  and  is refleaed  over  the
ed.es of the Sinus, to be joined to  the Pelvis and large Veffels.
  The fubllance of the  Kidney is commonly fmooth and  uni-
form, though  fometimes it  is irregular,  in confequ-.ucc of  the
Lobes which originally  form it not  being completely incorpora-
ted.—It confifts of an outer  part called  Cortical, and an inner
termed Medullary.
   Theȣortical Subftance, termed alfo Secerning,  furrounds the
Kidney, and  forms about a third  of its  breadth;—it likewife
fends in Proceffes or Partitions,  wiiich feparate the Medullary
parts from each other.
   The Medullary, termed alfo Uriniferous Subftance, is of a red-
der colour than the former,  and is divided into a number of dif-
tina  Columns, each ot which terminates  in a projeaion called
Papilla,  or Proceffus  Mammillaris.
   The  Papilla are merely the continuation of the  Uriniferous
part j though frequently confidered as a third divilion of the fub-
 llance of the  Kidney.
   Each  Kidney has  one, and  fometimes more Arteries, which
 run tranfverfely from the Aorta, and  a  Vein ftill larger, which
terminates in  the Cava.— They enter at the Sinus of the Kidney,
 and aie included in Cellular Subftance, which accompanies  them
 throughout their courfe.
   The Right Renal  Arteiy  is longer than the Left,  in confe-
quence of the Vena Cava, behind which it paiies,  being placed
 upon the Rip.ht Side of the Aorta.
   The Artery,  as  it  approaches  the Kidney, is  divided  into
 Branches,  which  are  afterwards  minutely  diftributed through
 the Coitical Subftance, forming Arches and  Anaftomofes;—-but
 t'u-fj are found to be much lefs frequent  than are commonly  de-
 fcribed.
    The fmall  Branches, after turning  and winding in varous  di-
 reaions,  pafs partly towards the  Suiface of the Kidney,  where
 they form irregular Stars, fome of which  fupply the proper Mem-
 brane.                              %
    Others turn inwards in a waving direaion, and form Corpuf-
 cles, which are difpofed fomewhat after the manner  of  Clufters of
fmall Berries, which can only be feen diftinaiy by  the affiftance
 of Glaffes, after a minute injeaion. 
I 18
   The Corpufcles wete confidered by Dr. Nichols as the Glo-
bular-termination of Blood-veffels, and termed  by him  Globuli
Arteriarum Termini;—but thefe  Globuli  were afterwards ob-
ferved by Mr. Hewson to conlift of fmall Veffels intimately in-
termixed.
   The Veins returning from the extremities of the Arteries unite
in the Cortical Subftance of  the Kidney.
   The Branches of the Renal Vein are much larger  than thofe
■of the Artery,  but correfpond with them in their courfe.— They
form a large Trunk on each fide,,  which lies antciior  to the cor-
refponding Arteiy, and runs tranfverfely to the Cava  ;—the left,
which is the  laiger of the two,  pafling acrofs the fore-part of the
Aoria,
   The Lymphatics of the Kidney run from without inwaids, and
terminate in  the Lumbar Glands, and afteiwards in the Thora-
cic Dua.—The Superficial Lymphatics are fo fmall, as ieidem
to be feen, exctptin   in the difeafed ftate of the Kidney.
   The Neivts are from the Semilunar Ganglion formed  by the
great Sympathetic and Eighih Pair.   I hey form a Plexus which
furrounds theBlood-veflcls, and accompanies them in the Kidney.
   From the minute  Extremities of the Renal Artery,  in the  Cor-
pufcles  feated in theCoitical  Subflance, the Urinijerous Tubes
arife.  They are mixed with fome extremely fmall Blood-veffels.
and  conftitute the Medullary Subftance of the Kidney.
   By degrees they unite into larger Tubes,  which run in a ra*
diated manner, the direction being from the outer idge or ciicum-
ference, towards the inner put or Cavity of the Kidney.
   The radiated Tubes, becoming ftill  larger in their paflVge, ter-
minate  in ihe Papilla, which are  of  a comprefled conical form,
and  are at  a  little diftance from each other.
   The Papilla are twelve or more in  each  Kidney,  the number
varying accoi ding to that of the original  Lobes  of which the
Kidney is compofed,  and  likewife from lime of the Papillae be-
ing  incorporated  with each other.
   Upon the po.nts of  the Papiiirr are the terminations  of the Ui i-
nTeroiis Tubes,—large enough to be  dillinguiflied by the naked
Eye,—through which the Urine diftils fiom the Subftance of the
K'dney.
   Round  the root of each Papilla, a Membranous Tube arifes,
termed Injundibulum or Calix, which receives the Urine from the
Papilla?.
   The  Infundibula are commonly the fame  in number with the
Papilla? ; the number, however, varying in different fubjeas, two
or more of the Papilla? fometimes  opening into the fame Infundi-
bulum.
   The  Infundibula join into two or three larger Trunks, which
 afteiwards fonn a Dilatation of confiderable hze, of  the fhape of
 an inverted Cone, and termed Pelvis of the Kidney. 
119
  The Pelvis is placed partly within, but the greateft part of it
without the body of the Kidney, and contraas into a long Tube,
about the fize of a Writing-pen, called Ureter.
  The Ureters  are commonly one  to  each  Kidney,  though in
fome r-.re inftances they are double on one or on both fides.
   The Artery of  the Kidney is placed uppeimoft,—the Vein in
the middle and  lore part,—and  the  Pelvis and beginning of the
Ureters at the under and back-part of the Blood-veflels.
  The Ureters defcend obliquely  inwards  behind  the Perito-
neum, and go over the great Pfoa? Mufcles and Iliac Veffels, op-
pofite to the anteiior and lateral parts of the Os Sacrum.
  They  pafs afterwards into the Pelvis, and  terminate in the un-
der, outer, and back-part of the Bladder.
  In their defcent, they are not ftraight,  but form turns which
are commonly compared to the  Italic f;—~neither are they cylin-
drical, as they form  flight dilatations and contraaions  in  their
courfe, two   of which contraaions  ae more obfervable in their
paflage/>yer  the Pfoa? Mufcles, and at their infertion into the
BladdeW
   The Ureters  are covered anteriorly by the Peritoneum, and
compofed of an External  Membranous Coat, a middle Mufeular
one,  formed chiefly of  circular Fibres,  and  an  Internal Coat,
fometimes called Villous.
   The Inner Coat is very Vafcular,  and is  perforated by the
Mouths of fmall Ducts, which  line it with a Mucus to defend it
from  the Urine.
   The Veffels  and Nerves of the Ureters are from thofe of the
contiguous parts.
   The Ufe of the Kidneys is to fecrete the Urine from the Blood,
and convey it by means of the Ureters to the Bladder.

                    RENAL  GLANDS.
   The Renal Glands, termed alfo Capfula Atrabilaria, Capfula
Renales, Renes  Succenturiati, and Glandula Suprarenale.', are two
fmall, flat, Glandular-like bodies of a dark-yellow-colour, ly-
ing in the upper and back-part of the Abdomen.
   They  are fituated at the upper,  inner,  and fore-part  of the
Kidneys, over the large Pfoa; Mufcles and Diaphragm, and high-
er than the Renal Veffels.        *
   They are of an irregular figure, and are about a couple of fin-
gers-breadth in  length, but much  lar.ei, proportionally, in the
Foetus than in the Adult.
   The Right one  is conneaed to the Liver, the Left to the Spleen
and Pancreas, and both  to the fmall Mufcle of the Diaphragm,
and to the Pfoa? Mufcles and Kidneys,  by Cellular  Subftance.
They are likewife retained by numerous Veffels and Nerves which
are fpread over them. 
120
   They are furrounded by Cellular Subftance,  which is part of
the Tunica Adipofa of the Kidneys, and have a thin proper Coat,
wh'di adheres firmly to them.
   They are frequently obierved  to be  hollow,  and to contain a
dark-coloured Bilious-like matter, which is confidered by many
Anatomilis as the Internal, very Vafcular and tender parts melted
down by pc-trefaaion.
   Thei< Aiteries come from thofe of the adjacent parts,  particu-
larly  fiom  the Renal, and alfo from the Aorta,  and Diaphrag-
matic Artepes.
   Of the principal Veins,  the Right goes to the Vena Cava, and
the Left to the Renal Vein.
   The Lymphatics go chiefly to thofe of the Kidneys.
   The Nerves come principally from  the Renal Plexus.
   Tluy have no Excretory Du6ls.
   The Renal  Glands have been fuppofed to furnifh  Lymph for
the dilution of the Blood  leturning in the Renal Veins, after the
fecretiun of the Urine ;
   Or,—to reltore to the Blood of the Vena Cava the irritable parts
which it lofes in the fecretion of the Urine and Bile ;
   Or,—to  convey fomething ufeful to the Thoracic Dua ;
   Or, in the Fcetus,—to divert the Blood from the  Kidneys, and
thereby ltffen the quantity of Urine.
   But their ufe is (till undiscovered ;  though it is fuppofed from
theii vicinity to the Kidneys, not only in Man, but in many o-
tht-r animals, that they  are fubfervient to  thefe Organs, and par-
ticularly to thofe of the Foetus.

                  VESICA URINARIA.               fc
   THE Vefica Urinaria, or Bladder of Urine, is a large Sac fitu-
ated in the Pelvis of the  Abdomen, in  the bottom of the Hypo-
gaftric Region.
   It is placed in the fore-part of  the Pelvis, behind the Offa, Pu-
bis, and before the upper, and  above  the under portion of the In-
ternum Reaum.
   When empty, it is contiaaed into a fmall fize, which occupies
the under and forepart of the Pelvis; but, when  fully diftended,
it rifes above the brin. < f  that jCavity,  and fometimes afcends to
within a little  d fiance of the Umbilicus.     ,.
   When  moderately dilated, it is of a loundiih, or irregular ob-
long form, but a little flattened before,  more convex behind, and
broader at its anterior and polttiioi,  than towards  its.hueral
parts,—a little more capacious, alfo, below than above, efpecially
at its  pofterior part.
   It is diftingirfhed into Fundus, Body, and Cervix,  the firft of
which is placed {fpvards and a little forwards;—the laft at the un-
der and fore-part.
* 
:_•!
  It is conneaed-below to the  Reaum, and  at the fides to the
PeivisJsy the refleaed  Peritoneum and Cellular Subftance, the
former of which, when the Bladder is empty, has the appearance
of lateral Ligaments.
  It is attached, at the fore-part of its  Body, by Cellular  Sub-
ftance, to  the Offa Pubis, without the intervention of the Perito-
neum.
  It is alfo fixed to the Umbilicus by  three Ligaments  fituated
between  the Peritoneum  and Abdominal Mufcles.—They are
formed of the Urachus running upwards from the  Fundus, and
the ihrivelled Umbilical Arteries pafling obliquely from the fides
of the Bladder.
  The firmed connection is by  means of a Ligamentous expan-
fion, which runs from each fide of the Neck of the Bladder and
Proftate Gland, to be fixed to the infide of the Arch of the Offa
Pubis.—It  is conneaed, alfo, at this pjacc, to the Penis, by the
Urethra,
   It is compofed of different Coats  joined together by Cellular
Subftance, the firft of which is only a partial one continued from
the Peritoneum.
   The Peritoneal or Common Coat, recedes from the Abdominal
Mufcles at  the top of th$,Pubes, and paftes over the fuperior, and
down upon  the pofterior and lateral parts  of the Bladder, to near
the termination of the Ureters, where it is about a finger's-length
from the Anus,—and  is  there refleaed upon the Reaum and
back pait of the Pelvis.
   When the bladder i j much diftended, it carries the Peritoneum
with it,  and  leaves a fpace between  that Membrane and the
Pubes, of fuchiength, that an incifion has frequently been made
here, and large Calculi extraaed from the Bladder,  without pe-
netrating into the Abdomen,  or wounding the Peritoneum.
   The fecond Coat is termed  Mufeular.—It is compofed of dif-
tina Flefhy Fibres,  interwoven with  each other,  and forming
Fafciculi.
   ■The External Fibres  run chisfly in a longitudinal direaion,
and are  conneaed, at the under and fore-part of the Bladder,
 with the OfTa Pubis.
   More internally, are Fibres which run  in  all direaions, and
are intermixed with each other in the form of Net-work.
   The Mufeular Fibres  are contraaed  about the Neck of the
 Bladder, and  form  what has  been termed Sphincter Vefica ;—
 ihefe, however, are meiely the continuation of the other Fibres.
   The Mufeular Coat, by its contraaion, occafions the complete
evacuation  of the Bladdtr.— The Fibres  about the Neck of the
Bladder, by aaing feparately  from the reft of thj Mufeular  Coat,
prevent the involuntary difcharge of the Urine.
   The Cellular Subftance, under the Mufeular Fibres, U fre-
 f; if ntly ternjad Nervous Coat.
    Vol.  U.             I 
122
  The Inner Coat, though often called Villous, is fmooth like the
infide of the Peritoneum, and, though thin, is fo denfe as to pre-
vent the exfud^tion of the Urine.
  This Coat is rendered fomewhat unequal by the projeaing of
the Fafciculi of the Mufeular Fibres ; and when the Bladder is
emptfl| it forms large wrinkles or Ruga?.
  The infide of the  Bladder is very irritable, in confequence of
which a defire to expel the Urine is occafionally excited.   It is
lined, however, by a Mueus, difcharged from its Arteries, which
prevents it from being conftantly iiritated by that Fluid.
  The under part of the Bladder  is perforated by three Openings,
of which one is placed anteriorly, and two pofteriorly.
  The Anterior Opening is the beginning of the Paffage called
Urethra, and is furrounded by the Neck of the Bladder.
  It comes off almoft at a right angle from the lower part of the
Bladder, without any tapering of that Vifcus.
  The other two openings are formed by the termination of the
Ureters, which run  obliquely  foi vards  and inwards,  between
the Mufeular and Inner Coat of the Bladder.
  They terminate  in the Bladder at a little diftance from each
other, and at the fame diftance behind the beginning of the Ure-
thra, each  by a fomewhat oval Opening,  which is more  contraa-
ed than the Ureter  is immediately above  it.
  The Arteries of  the Bladder come from various fources, but
chiefly from the Umbilical  and Pudenda Communis.
  The Veins return to the Internal Iliacs :—They form a Plex-
us of confiderable fize upon each  fu\e of the Bladder.
  The Lymphatics accompany the principal Veins on  the Blad-
der, and, at the under part and fides, pafs into the Iliac Glands.
  The Nerves are Branches*of the Great Sympathetic and Sa-
cral Nerves.
  The Bladder receives the Urine from the Ureters by drops, and
fometimes by fmall  thread-like ftreams or fquirts, till  by its ac-
cumulated  quantity and acrimony, it forces that Vifcus to con-
traa and expel  it.
  The Urine is expelled, partly by the contraaion of  the Blad-
der itfelf, and partly by the aaion of the Abdominal Mufcles and
Diaphragm prtfling the Inteftines againft the Bladder.
   The frequency of the evacuation depends upon the fize and
fenfibdity of the  Bladder, upon  the quantity of Urine fecieted,
and the degree  of acrimony it pcfteffes.

                         TESTES.
   The Teftes, formerly termed Didymi or Gemini, are two Glan-
dular Bodies fituated in the Cavity of the Scrotum.
   The Scrotum,  which furnifhes an external  covering  to the
 Teftes, is  a continuation of the  common  Integuments, has the
* 
121
fi.me Stru6""tu'T  with the Skin in general, but is more plentifully
fupplied with Sebaceous Follicles, has no fat in its Cellular Sub-
ftance, and isoccafionally relaxed and corru, ated in a greater de-
gree than t»e Skin in the other parts of the Body.
  Upon the Surface of the Scrotum, there is a fuperficial, longi-
tudinal projeaing Line,  which divides it into two equal parts,
and has the name of  Raphe.
  Tin- inner Surface of the Scrotum is lined with Cellular Sub-
ftance, wh ch is firmer and more Vafcular than  in other places.
  The Cellul  r Subfttuice of the  Scrotum,  in  confequence  of
its  rednels, Fibrous appearance, and fuppofed power of contrac-
tion^  has, by many Auatomift-., been confidered as a Mufcle, and
called Dartos.—This opinion, however, has of late years been re -
jeaed.
  The Cellular Subftance  of the  Scr  turn involves each Tefti-
cle fingly,  and forms a Septum or Partition "beiween  the two,
which prevents A'r or  Water from pafling readily  from one fide
of  the Scrotum to the other.
   The Veffels and Nerves of the Scrotum are chiefly  from thofe of
the neighbouring parts.
    The  Blood-vefllls  are  Branches  of the Pudendal  and Fe-
 moral.
   The Lymphatics go  moftiy to  the Inguinal,—but fome of them
accompany thofe of the Teftes to the Lumbar Glands.
   The anterior part  of the Scrotum derives Nerves  from  the
Lumbar, and  the* pofterior fiom the Pudendal Nerves.
    The Scrotum affifts in fupporting and pruteamg the  Teftes.
    Under the  Scrotum are two Membranes or Coats, proper to
 each of the Teltes, the one termed Vaginalis, the other Albuginea.
    The Tunica Vaginalis, named from its forming a (heath, is of
 the fame nature with the Peritoneum, being originally a Procefs
 of that Membrane, which in the Fcetus defcends with the Teftti-
 cle from the Abdomen.
    It forms a fliut Sac, which has no communication with any o-
 ther part.
    It inclofes the Tefticle, as the Pericardium does the Heart, and
 lies loofe every where, excepting behind, where  it is continuous
 with  the Albuginea.
    It  is confiderably  larger than  the  Teftis  which it inclofes,
 reaching as far above and below it as to allow  it a certain degree
 of motion.
    It  is conneaed by  its external Surface to the Cremafter Muf-
 cle,   and partly, by means of  that, to the inner Surface of the
 Scrotum.
    It  affifts the Cremafter in fupporting  the Teftis, and, by being
 conftantly moiftened within by  a Fiu:d exhaled fiom its Surface,
 and  from that of the Tunica Albuginea,  it allows the Tefticle
 to move eafily. 
U4
  The Tunica Albuginea, fo called from its u lie colour,  «; like
the former Coat, a continuation of the Peritoneum,  and invet'^
the Body of the Tefticle clofely.
  It is a thick, ftrong, denfe, and inelaftic Membrane, of a glif-
tening appearance.
  It is remarkably fmooth on the outfide, but  internally it is
rough and unequal, adherinsr'every where  fiimly to the Body of
the Teftis.    H
  It covers both the Teftis and Epididymis,  conneas them to
each other, gives ftrtnjgth to them, and  conduas their  Vcffeis
in the manner the Mcftntery does thofe of the  Inteftines.
  The Body of the Teftis is of a yellowifli colour, and has a Pul-
py appearance,—is of an oval form, a little flattened at its outer
end inner Suiface ;—and frequently one Tefticle is a little larger
than the other.
  The Teftes are placed obliquely, with one end upwards and
forwaids, and the other end backwnids and downwards.
  At the outer and back-part of the Teftis,  there is an Appen-
dix named Epididymis, from its fituation upon  the Teftis or Di-
dymis, which is inclofed in the fame  covering with  the Tefti.
itfelf.
  The Epididymis begins at the  upper part  of the Tefticle, im-
mediately above the entry of the Blood-veffels ;  and this part of
it being hire and of a round form, is termed Globus Major, or
Head of the Epididymis.
  In its defcent, it oecomes fomewhat fmaller  and flatter, and is
attached behind  to  the Body of the Tefticle,  where the Blood-
velfels go in ; but forwaids it is loofe, the Tunica Albuginea
dipping in this place, and forming a Cavity  or Pouch.
  The under parr of it becomes more firmly attached to the Bo-
dy of the Tefticle, and foims the Cauda, or Globus Minor ; it is
then turned backwards upon  itfelf, after which it fends out the
Excretory Duct of the Tefticle.
  The Body of the Teftis has numerous Arteries, Veins, Abfor-
bents, and Nerves ;  but is principally compofed of a colhaion
of minute, tenrier, elaftic Filaments, intricately  convoluted, tci til-
ed Tubuli Seminiferi, or Vafa Seminalia.
  The Tubuli Seminijeri  are difpofed in  Fafciculi or Bundles*
between Partitions, which are formed of  Blood-veffels ar.d Cel-
lular Subftance.
  Thefe Septula? begun at  the root or Nucleus,  fituated  at the
back-part of the Tefticle,  fometimes  termed  Corpus  Highmori-
anutn, and extend in a radiated manner to the Tunica Albu-
ginea.                                                  TP
  The Titlis is  fixed behind by its  Veffels, which are colkaed
into a Cord termed Spermatic, but  is  loofe  and free  before, to
prevent it from being pinched. 
125
  The Spermatic Cord, properly fo called, extends from the Ring
of the External dblique Mufcle to the Body of  the Teftis, and is
compofed of the Trunks of the different Veffels belonging to the
Tefticle, and of a quantity of Cellular  Su  fiance.—The Cord is
covered by the Cremafter Mufcle; and within thu», by ihe f.me
Piocefs of the Peritoneum which forms  the Tunica Vaginalis
Teftis.   This  part of the Procefs,  however,  is fo incorporated
with the common Cellular  Subftance of the Cord, as to appear to
form part of it.
  The  under part of the Vagina of the Cord is feparated by a
Partition formed by the  upper end of  the*  Vaginal  Co.it of the
Tefticle, and  by condenfed Cellular Subftance, fo that no liquor
can pafs eafily from the Cord to the Tefticle, and vice verfix.
  The Arteries  of  the   Teftes, termed A^teria Spermatica, and
Arteria Preparantes, arife, one on each  fide, from the fore-part of
the Aorta, a little beloV the Renal Arteries.
   The  Spermatic  Artery  croffes over the Pfoas Mufcle and
Uieter, and defcends, behind the Peritoneum to the under part of
the Abdomen.
   At the lower part of the  Abdomen, it perforates the Ring of
the Extern d Oblique Mufcle, and  paffes  in the Spermatic Cord
to the Tefticle.
   In its defcent, it gives branches to the adjacent parts, and is
 fo intei laced with thofe of the correlponding Vein, as to have been
 fuppofed by the Ancients  to  have  large lateral communications
 with them.
   After palling the Ring, it divides into  Branches which go to
 the  Teftis at  its pofteiior  edge.   They are partly difpeifed  upon
 the  Epididymis, but the larger  Branches run in aicrpentine di-
 reaion into the Subftance  of the Teftis, where they are minutely
 diftnbuted upon the Surface of the Seminal Tubes.
   Befides the Spermatic Artery, there is a fmaller one from  the
 Hypogaftric, which accompanies the Vas  Deferens,  and  is dif-
 perfed along with the other Artery.
   'The Veins are much   larger   than  the  correfponding  Arte-
 ries, and have feveral Valves in  them,  efpecially without the Ab-
 domt-ii.
    They  form a Plexus, which accompanies the Artery on each
 fide, and -is fometimes called  Corpus Pampynijorme,  being com-
 paied to the fhoots of the Vine,  or Corpus Pyramidale, from giv-
 ii^f a Pyramidal form to the Cord.
   The Plexus afcends  in the Abdomen,  and upon the Suiface
 of the Pfoas Mufcle ; and about the part where it recedes from
 the Artery, it  forms a fingle Trunk, which, in the tight  lide,
 termi iates in the Vena'Cava, nearly oppofite to the Arteiy, and,
 in the left fide, goes into the Renal Vein.
   There is  alfo a  fmall inferior Spermatic Vein, which accompa-
 nies its Artery, and ends io the Hypogaftric Vein.
     Vol. II.    „       L2 
126
  The Tubuli Seminiferi in the Body of the Tefticle confift of
numbei Ids txtremeiy minute Luas, which are of a Cylindrical
fonn, have no divifion into Branches, and when  drawn out, aie
found to be feveral  feet  in leng h.
  They are firft collected  into Bundles, between the Septula? of
the TeiicJe, r>nd thefe again into others ftill fmaller, each of the
fmaller being formed of'a fimple Tube, coiled up into a Conical
foim, with its Bafe forwards) and its Apex towards the pofterior
edge ef the Tefticle.
  From the convoluted  Seminal Tubes, an equal number of
ftraight Vcffeis are lent out at the back-part of the Tefticle, under
the name of Vafa Reila.
  At the upper and l>avk-part of the  Tefticle, the Vafa Reaa
communicate, and form an inegular Plexus or Net-Work, called
Rete Vafculofum Teftis.
  The Rete Teftis  fends  out  from twelve  to  eighteen ftiaight
Tubes, teimed Vaffa Efferentia, which carry the Semen from the
Telticle to the Epididymis.
  The Vafta Lflt'entia  foon become convoluted, and form Coni-
cal  Bundles, teimed Coni Vafculofi.
  The Coni Vafculofi aie fiimly conneaed by Cellular Subftance,
and aie  obferved by Dr. Monro, in his  Treatife De Tefiibus,
to compofe lomewh^t more than a  third part of the Epididymis.
  The Vafcular Cofies gradually unite into a fingle Tube, which
conftituies The reft of  the Epididymis, and though only about the
fze of a Hog's Bnftle, tranfmits the whole of the Semen.
  The fingle Tube becomes larger in its  courfe and lefs convolu-
ted, and at laft, expanding its convolutions, it comes out greatly
increafed  in fize, and almoft in a ftraight  direaion, under the
name of Vas Deferens.
 _ Befides the Duas  already defcribed, a Vas Aberrans is fome-
times obferved, which is one cf the Vafcular Cones, wandering
off, and terminating in the Epididymis lower than ufual.
 At other times, the fame kind of Vefl'el forms a  Proceffus Cacus,
or blind Dua, with a dilated  Extremity which  does  not com-
municate with any other part.
o
 VESICUL^E SEMINALES  AND PROSTATE GLAND.

  The  Veficula Seminales are two  fmall Pyriform Receptacles,
fituated between the under and late.al parts of the Bladder and
the Inteftinum Reaum,—about three fim-eis-bieadth in length,
and the third part of that in breadth, and a little flattened.      ' 
127
  They are at  a confiderable  diftance from each other behind,
but anteriorly they converge, and become contiguous;, forming a
fliarp angle.
  Each of them is compofed of a convoluted Tube, with irregu-
lar Proceffes, and furrounded by a quantity of  tough  Cellular
Subftance, and by many Veffels and Nerves.
  Internally, they have a Villous appe^-a'iee and are formed of
irregular Cells which correfpond with  the  irregulai ities on their
External  Surface, and  communicate  freely with e&ch  other.—
Their fhape, fize, and ^eneml appearance, however, vary  in dif-
ferent fubjeas, and not  unfrequently in  the fame peifon.
  Between  the Veficula? Seminales,  the ends of the Vafa  De-
ferentia, now  become larger  and  Cellular, pafs forwards  till
they arrive at the Proftrate Gland, where each Vas Deferens joins
the Veficula ot that  fide, and communicates fo fieely wiih it,
that injeaed Fluids readily pafs from the one to the other.
  From each. Veficula Semmalis  and  Vas  Deferens of the fame
fide, a fmall Canal, about a Finger's breadth :n length, paffes out
which is fiimly conneaed to its fellow,  without communicating
with it, and becomes gradually fmaller, piercing, obliquely,  the
Proftate Gland, and terminating in  the under part of the Neck
of the Bladder.
  The Orifices of thefe  Canals are feparated from each  other by
a Caruncula, or round Projeaion of the Membrane" of the Ure-
thra,  termed Veru montanum ;—■ r, from being broad behind and
roftriform  before, it is  compared  to the Head  and beak  of the
Wood cock,  and called Caput Gallinaginis.
  The Veficula; Seminales are commonly confidered as Refrrvoira
of the Semen, receiving it from the Vafa Deferentia, and after-
waids,—by a power inherent in themfelves, affifted by the aaion
of the neighbouring Mufcles,  particularly of the Levatores Ani,
—propelling it to Jie Urethra.
  The Semen  is  prevented from pafling into  the  Bladder,  the
opening from it being fliut while that Fluid is expelled.
  Various experiments   11uvt*  been made on the Veficula?  Semi-
nales by  the late Mr..  Hun i er, from which  he  was of opi-
nion, that they are not  Refcrvoirs of Semen,  but Glands,  fe-
creting a particular  Mucus ;—that,  with  other  parts,  ihey  are
fubfervient to the purpofes of Generation ;—and that the Bulb of
the U'vihra is the re.epticle  ot  the  Semen in which it  is ac-
cumulated previous to its ejeaLn.
  The  Proftate Gland, named  trom its fiuiation before  the Vefi-
cula?.  Sein mlcs,  lies   mmediately beh  nd  the  under end cf the
Sympnyfio of ih  Pubis, ;n 1 refts upon ihe Lutftnum R.-flnm,
  It furrounds and clsiely ?mb ace-* the  Nf-ck of the Bladder, or
beginning of ihe U\ethi a;  but tiie gr-uer p.:r   it  it i*.  placed
pofteriorly and iaiduli^, navmj  a  Lobe projranig  on each nde. 
1  C-c?
  It ig about the fize of a Walnut, and of the figure of a Spanifh
Chefnut,—or it refemhlesa Heart as commonly painted op Play-
ing-cards,, with the  Bafe towards the Bladder, and  the Point
towards the Penis.
  I.  has a Spungy Subftance, but is one of the firmed  Glands of
the Body,  and generally fends out ten or tiuelve Duds, which
open obliquely  at the beginning of the Urethra, at the  fides of
the Caput Gallinaginis, and near the teinunation of the Seminal
Duas.
  From the Duas of the Proftate Gland, a  thin white Liquor
is difcharged,—i om  the fame caufes, and at the fame time  with
the Semen,—into the Uiethra,  and is fuppofed to be ufeful  in
the procefs of Generation ;—or,  accordn g  to fome Authors,
this  Fluid  facilitates  the  pafl^ge of  the  SeuKn  through  the
Uiethia.
  The Blood veffels,  Abforbents,  and  Nerves of the Veficula?
Seminales and Proftate G and, aie in common w,.h thofe of the
parts which furround  them.

                        PENIS.

  The Pent', which has obtained  a variety of other names,
fuch  as Membrum Virile. Mentula,  &c. coniins of three S ongy
Subftances, two of whicii foi m the upper part and lid. s,  01 Body
of the  Penis  and aie teimed  Corpora CavemoJ'a  Penis,  the
third funounds the Urethra,  and has the name ot Corpus Jptn-
giofum Urethra.
  The Penis is covered with  a continuation of the common Inte-
guments,  which are thinner than elfewhere, and,  nltead of Fat,
there is as in the Scrotum,  a Reticular Subftance only under the
Skin.
  At the anterior extremity of the Penis, the Integuments  form
a loofe fold, temed Prepuce, which is conneaed to the anterior
and  undei  part, or Glans of the Penis, by a triangular  fold,
called Franum P>eputii.
  The Corpora Cavernofa Penis refemble two equal but  irregular
Cylinders, (clofely applied  to t.ie  ,ut-  of each other, and  each
coveied by a (long,  elaftic,  Ligamentous  Sheath, the Fibres of
which run in  a tranfveife,  and p itly n. an oblique direaion.
   Thev anfe one on each fide, by two bind Conical extremities,
called then Crura, from the  inner part of the Crura of the Ofla
Ifchia and Offa Pubis, to both of wh.ch  they are very firmly
conneaed by Ligamentous Subftances.
   At the under part of the Symphyfis ,l  the Pubis,  they are uni-
ted to  each other, and continue lb till tr.ey  ;each  the Gl nds
where -hey tei cinate in a rounded extumity.
   At the  u(pei  pait<f the  root of  the Penis, the Ligamentous
Sheath of the Ccipora Cavei nofa fends up a Procefs of a triangu- 
1?!)
Iftr form, to be connected to the Symphyfis of the  Ofla Pubis,
under the name of Ligamentum Sufpenforium, by which the Body
of the Penis is fupported, and prevented from  preffing too  much
upon the Scrotum.
  The Corpora Cavernofa leave a Groove above,  for the princi-
pal Vein of the Penis, and'a Channel below for  the Cavernous
Subftance of the Urethra.
  The  internal  fubftance of the Comma Caverncia confifts of
loofe reticular Plates, fomewhat fimilar, to the Cancelli in the ends
of long Bones, and, like  them, readily  communicating  with
each other.
   Upon the Cells of the Corpora CavemoiV., the Arteries are plen-
tifully difperfed,  and open fieely  into  them, the  Blood  of the
Arteries tinging the Cells in the relaxed  ftate of the Penis,  and
filling them completely when it is diftended.
   The  Corpora Cavernofa are united  to each other by 3 Septum
or Partition, formed by a continaation of the Klaftic Ligament
which coveis thefe Bodies.
   The  Septum Penis is compofed of Cords, extending, nearly in
-1 parallel direaion, from the Dorfum, or upper pert of the Penis,
to the Corpus Spongiofum Urethiae.
   Between the different Cords, Fiffures  are left,  through  which
the Blood, or an  injeaed Fluid, priffes without obftruaion from
one of  the Corpora Cavernofa to the other.
   The  Corpus Spongiofum Urethra is fituated  under and between
the  Corpora Cavernofa Penis,  but  projeas confiderably beyond
 them.                                         '•
   It begins a little behind the part where the  Corpora Cavernofa
are  united, adheres to them by condenfed Cellular Subftance, and
terminates at the anterior extremity of the Penis.
   It has an external covering fimilar to that of tha Corpora Ca-
vernofa Penis, but more delicate and more of a Membranous ap-
 pearance.
   The pofterior  part of the Corpus Spongiofum is dilated into
 a longitudinal Prominence, of a Conical form,  fituated within the
 Skin of the Perineum, and termed Bulb of the Urethra.   It ex-
 tends from the root of the Penis to mar the Anus, projeas moft
 towards the under and b.xk  put, and is divided anteriorly by a
  Septum.
   The Corpus Spongiofum  is continued along the under  part of
  the Corpora Cavernofa, and at the end of thefe expanus into the
  Subftance called Glans Penis,  which covers and inclofes the ends
  of  the Corpora Cavernofa.
   The Glans or Nut,  named from its  refemblance to an Acorn,
 is feparated from the Corpora Cavernofa by a  continuation of the
 Ligamentous Sheath which covers  them,  and is  encircled at its
 pofterior part by a prominent margin,  called Corona Glandis, be-
  hind which is a Cervix or Neck. 
1 it)
   The Surface of the Glans is covered with  a Plexus, chiefly of
 Venous Veffels, and with Nervous Papilla, which give it its fen-
 fibiliiy ;  and thefe  are  inclofed in a fine Membiane  continued
 from the infide of the Prepuce.
   About-the Cervix and Corona of the Glans, are many Follicles,
 termed Glandula Odvirtr.-, which ducharge a  Sebaceous Mat-
 ter,  to preferve the feniibidty of  the Glans,  and allow the Pre-
 puce to move backwards and forwards upon it with facility.
   The InternaLStruaure of the Bulb of the Ure.hra and Glans
 of the Penis, is of the iunru  nature with  that  of the Corpora
 Cavernofa ; and the Internal Struaure of the reft of the Corpus
 Spongiofum differs from that of the  Corpora Cavernofa only in
 this, that the Cells are fmaller and of a more delicate  texture.—
 Some Anatomilis confider the greater pait of the Corpus Spon-
 giofum as merely a Plexus of convoluted Veins.
   The Urethra, named from  the Urine pafling  through  it,  is a
 long Canal, the Diameter of which is nearly equal  to that  of  a
 wntiiig-pen. It begins at the under and fore-part of the Bladder,
 runs through the   Corpus  Spongiofum, and terminates in the
 pcint of  the Penis by a longitudinal Orifice.
   At its onjjin, it  defcends a  I ttle, and then  paffes forward^,
 under the  Symphyfis of the Cffa Pubis, to which it  is clofely
 conneaed by Celiulir Subftance : It then afcends at  the under
 and  fore-part of the Offa Pubis, varying in the remainder of its
 courfe, according to the different degrees of  relaxation or diften-
 fion of the Cells of the Peni6.
   There are commonly three Dilatations in  the Urethra ; one of
 which  is at the Proftate Gland, the  fecond in  the Bulb of the
 Urethra, r.rci the third about the beginning of the Glans.
   In general, it has alfo the fame number of ftight Contraclions ;
 the  firft at  its origin  from  the Bladder,  the  fecond  between the
 point of the Proftate Gland and Bulb of the  Urethra, and the
 third at the point of the Glans.
   Between  the point of the  Proftate  Gland and part where the
 Urethra penetrates the Corpus SppnHofum,—including nearly the
 fpace of  a FingerVbreadth,—the Urinary paffage is entirely Mem-
 branous, and covered only with the common Cellular Subftance.
   As the upper fide of the Bulb, the Urethra enters the  Corpus
 Spongiofum, in which it L  inclofed to its termination in the point
 ol the Penis.
   The infide of the Urethra is lined  by a very Vafcular and fenfi-
 ble Membrane, which is obferved to poffefs  a certain degree  mi
 contiaadity, and  is  therefoie prefumed by feveral Anatomilis
 to be endowed with Mufular F'bres.
"  Between the Corpus Spongiofnn and Membrane which lines
 he U. dura, elpe.iaily towards the Septum of the  Penis, mime-
 reu, Lacuna cf different fnes are fituated,  one  or two of which
 in piiticular, next the Glands, are often confiderably larger than
 the  reft. 
1-1
  They run in a longitudinal direaion from behind forward, and
perforate the Uiethra by Orifices large enough to admit a Bridle,
—They  dncha.ge a  bland Mucus for the defence of the Uie-
thra.
  Befides the Lacuna3, two fmall bodies, each about the fize of
a Garden-pea, are frequently met  with,  and are  termed, from
their difcoverer,  Cowper's Glands.
  They are fituated at the fides of  the Membranous part of  the
Urethra,—between its Bulb and the point of the Proftate Gland,
—and  covered by the Accelerator Mufcles.
  When prefent  they are obferved to difcharge from their Duas
into the U.ethra,  a Fluid which  is  fuppofed to ferve  the fame
purpofe with that of the Lacunas.
  The Arteries of the Penis are chiefly from the  Pudicae Com-
munes, which  are  Branches of the Internal  Iliacs, and partly
from the Femoral Arteries.
  Each of the Pudic  Arteries having paffed out  of the Pelvis,
through  the great  Notch  of the  Os Ilium,  runs  between the
Sacro-Seiatic Ligaments to the  inner fide of  the Tuber Ifchii,
from which it pafl'es along  the Crus of that Bone, and of the Os
Pubis,  to the root of the Penis.
  In its couKfe,  it furniflies Branches to the adjacent parts,  and
afterwards gives  off three  principal Branches, which belong to
the Penis :—One of thefe goes 10 the Bulb of the Uiethra,  to be
difperled in the Corpus Spongiofum ;—the other two,  which are
larger  than  the former, go  to the Body of the Penis, one of them
penetrating its'Crus, and running in the centre of the Corpus
Cavernofum ; the other pafling between the Symphyfis Pubis  and
joining of the Crura Penis, and extending along the Dorfum as
fai  as  the Corona Gl.mdis.
  The Brariches of the  Femoral Artery to the Penis communi-
cate with thofe of the former, and are chiefly difpeifed  upon  the
Integuments.
  The Arteries  of the Penis are divided into  minute  Ramifica-
tions, wh'ch communicate with each other, and with their fellows
on  the  oppofite fide and terminate  partly in the correfponding
Veins, and partly in the Cells of the Penis.
   The Veins arife,  fome from the extremities of the Arteries, and
others by large open Mouths from the Cells of the Penis.
   The greater number of  the Veins unite into a  Trunk,  called
 Vena Magna Penis, which  runs in the fuperior Groove foimed by
the union of the Corpora Cavernofa, and  is fnrnifhed with Valves
 and with thick ftron^ Coats.
   The Vena Magna, at the under  end of the Symphyfis Pubis
 feparates into Right and  Left Plexus,  which pafs to the corre-
 fponding Iliac Veins.
   To an  obftrua;on  of the courfe of  the  Blood through  the
 Veins, by the preffure of the Mufcles at the root of the Penis, 
132
together with an increafed influx through the Arteries, is owin*
that accumulation of Blood in the Corpora Cavernofa, which
occafions a diftenfion of the Penis.           ft
  The relaxation  of  the Penis-happens  from the caufes which
produced the d ften&on  being removed ;—The Elaft c Ligamen-
tous Membiane which covers the  Penis again forcing the Blood
from the  Ceils into the Veins.
  Upon the  Surface  of the  Penis, there are fmall fuperficial
Veins,  which communica.e with thofe deeper feated, and  com-
mon^ terminate by  one or more Branches in the Veins at the
top of the Thighs
  Thefe Branches  affift in carrying oji the circulation, and return
part of the Blood during the diihnfion of the Penis.
  Of the Lymphatics of the Penis,  thofe from the Prepuce and
Skin, in  general, go to the right and left Inguinal Glands, while
the  Lymphatics from the Glans and Body of  the Penis  accom-
pany the  Arteries  into the under part of the Pelvis.
  The Nerves of  the Penis are large i-n proportion to the fize of
that Organ.  They come from the Hypogaftric Plexus, and  prin-
cipally from  the laft Sacral Neives,  and arediftributed chiefly up-
on the Ligamentous Sheath which inclofes the Corpora Cavernolh.
  They are fituated upon the Dorfum of the Penis,"more laterally
than the Arte, ies which lie between them and the principal Vein.
  For the Mufcles of the Penis, fee Part Ii.
  The Penis ejeas the Semen into  the Vagina, and ferves for the
conveyance.of the Urine from the Bladder.
i—OOOOOOOQ<frOOOOOOOO
                         OF THE

ORGANS  OF URINE AND  GENERATION


                  IN  THE FEMALE.

                    --—■«*0«M----

  The  Kidneys,  Renal Glands, and Ureters, have the fame fitu-
ation and flruaure as in the Male.
  The Bladder has alfo the fame fituation behind the Offa Pubis,
but rifes higher when it is in the diftended ftate.
  It is propoitionally larger than the Bladder of the Male, and
re broader from one fide to the other,  correfponding to that part
©f the Cavity of  the Pelvis to  which it belongs*.
» 
lie*
   The Urethra is much fhorter,—bcicc, fearcely two  inches  in
length,—and llraighter than in the Male, having only a flight
bend downward*.between its extremities.
   It is producerffrom  the moft depending part of the Bladder,
has no proftate Gland, but is turnifhed,  as  in  the  Male, with
Lacuna,  which open into it, and difcharge a Mucus  to defend
it  from the Urine.
   The Parts of Generation in the Female (which are here fup-
pofed to be in the unimpregnated ftate)  are divided into Internal
and External.  The former confift of the Uterus and its Appen-
dages, the latter are thofe which are feen without any Diffeaien#

                    Internal Parts.
   The. Uterus,  Matrix, or Womb, is a hollow Vifcus, fituated
in the Peivis, in  the Hypogaftric Region, between the Bladder
and Reaum, with which it is  conneaed.
   It is of a triangular figure, and a little flattened before and.be-
hind, but more  fo anteriorly; is large  above,  fmall below, and
has two angles at its upper and  lateral parts,  called Corners  of
the Uterus.
   It is diftinguifhed into Fundus, or upper part, which includes
the fpace above the infertion of the Fallopian  Tubes, the Body
ov middle,  and Cervix or under part, the two laft being nearly
of equal length.                          t£
   Tne extent and figure  of the Uterus varies confiderably in dif-
ferent fubjeas.—In Women who have never been pregnant, it is
commonly about  two inches and a half in length, from one inch
and a half to two inches in breadth at  the Fundus,  and about
h.ilf as broad at the Cervix.—It is near an inch in thicknef», and
is lager in Women who have  borne Children, than in the Virgin
ft-ite.
   The Cavity,  like the external part of the Uterus,  is of a tri-
angular Jorm, but is fmall in proportion to the  fize of the Organ,
—being fearcely capable of containing the Kernel of an Almond,
-—and has its fides clofely applied to each other.
   It is covered externally through its whole length, with a fmooth
p.difhed  Coat,  continued from the  Peritoneum, which,  at the
under part of the Cervix, is refleaed forwards upon the Bladder,
backwards over the Reaum, and laterally towards the Sides of
the Pelvis.
   Its Subftance is of a compaa, Cellular, and Flefhy nature,
and plentifully fupplied with Blood-veffels:  The Fleftiy Fibres,
however,  are feen diftinctly only in the  Giavid  Uteius.
   It is remarkably Vafcular in  its Body, lefs fo  in its Cervix, and
is nearly of the fame thicknefs throughout, excepting at its Cor-
ners,  where the Uterine or Fallopian  Tubes terminate.

   Vol. H.          M 
131-
   It is lined with a fine and very vafcular Membrane, of a fome-
what Porous and Villous appearance, in which the Arteries- ter-
minate which difcharge the Menftrual Fluid.
   The Cavty of the  Cervix has tveo fmall Ltyigitudinal Lines
projeaing in  it,  one in the anterior, the other' in the pofterior
part, on each fide of which are numerous Ruga.
   The Ruga run, in  an obliquely  tranfverfe  direaion, and are
formed not only  of the inner Membrane, but  alfo by the Fibres
which compofc the Body of the Uterus.
   Between the Ruga? are many fmall Follicles,  which difcharge a
Mucus for lubricating the parts near which they are placed :—
Some of  them, being  of a roundifli form, were miftaken by Na-
BOTH for Female Ovula.
   The under part of the Cervix projeas into the  Vagina, fome-
what in form  of  the Glans Penis, and  is perforated  by a tranf-
verfe  flit, termed Os Tinea, from its fuppofed relemblance to the
Mouth of the Tench Fifh.
   The Os Tinea,  in an Uterus which has never been impreg-
nated, is  about the fize of the orifice of the Urethra in the Male,
btit nearly twice as laige in the Uterus  of a  Woman who has
borne Children.
   It is fmooth on its external furface, is placed obliquely in a di-
rection towards  the back-part of the Vagina,  and is furrounded
with feveral Mucous Follicles.
             Appendages of the Uterus.
   The Appendages of the Uterus, are the Broad and Round Liga-
mints, the Ovaria, the Fallopian Tubes, and the Vagina.
   The Ligamenta Lata, 'termed fometimes Ala Vefpertilionis,
from their refemblance to the Wings of a Bat, are two  Membra-
nous  prcduaions, or Doublings of the Peritoneum, fent from the
fd^cs of  the Uterus and pofterior extremity  of  the Vagina, to be
rixed  to the fi les  of the Pelvis.
   Along with the Uterus, they feparate the Pelvis into anterior
and pofterior  Cavities- and are themfelves divided  into large and
fmall, or  anterior and pofterior Alae or Pinions.
   They contain and fupport the Ovaria and Uterine Tubes, with
part of the Spermatic  and Uterine  Veffels and Nerves.   They
likewife inclofe a portion of the Ligamenta Rotunda, &c.  con-
nea the Uterus to the fides of the Pelvis, and aflilt in retaining it   4
in its  place.  In  the time of Geftation they become effaced, by
furnifhing the Uterus with part of its external  covering.
   The Ligamenta Rotunda are two long and flender Cords, com-
pofed of Veffels  and Ligamentous Fibres, arifing from the Cor-   4
tiers of the Uterus, immediately before and below the  Fallopian
Tubes, from which they defcend obliquely   in  the Ligament
Lata, diminifhing a little in their courfe towards the  Groins. 
135
  They pafs through the Rings of the  Abdominal Mufcles, i»
the f-une manner as the Spermatic Cords do in the Male, and are
afterwards inf.rted by feparate Branches into the upper and late-
ral parts of theP_udendum.                    ,
  They affift the  Ligamenta Lata in preferving the equilibrium
of the Uterus.
  The Ovaria, anciently called Teftes Muliebres, are fituated at
the fides of  the  Fundus  of the Uterus, -about  an inch diftant
from  it, and are  contained in  the pofterior Pinions ot the Liga-
menta Lata, which form a Coat to them finnlar to the Tunica Al-
buginea Teftis.
  The Ovaria are plain above, and prominent and femi oval be-
low, flattened at  their anterior  and  poifeiior Suiface-,, and the
fize of each,  when in a ftate of the greeted maturity, neaily equal
to half of the Male Tefticle.                   fc.
  They are large, uniform, and fmooth, in the vigour of life, but
become final 1, unequal, and fhnveiled, in Old Women, or in thofe
who have borne many Children.
  They are attached to the Uterus by the Ligamenta L.-.tP, and
by two  fmall Cords, termed Ligamenta  Rotunda Ovarii, which
weremiftaken  by the Ancients  for Vafa Deftrentia, c.urying a
fecreted Liquor to the Uteius.
  They are compofed internally of a loofe whitifh Cellular Sub-
ftince, intermixed with Veffels and Neives, and contain a num-
ber of fmall Veficles, called  Ova, filled  with  a limp.d  Fluid,
which partakes of the qualities of the White of  an Egg.
  Thefe Veficles differ much in fize  in the fame Ovarium ;—the
largeft of them are feldom equal to the hzc of  a fmall Garden-
pea.                 *■
  The number of Ova  is differently  eftimtited by  different Ana-
tomilis,—from  ten to twenty and up vai'ds having been found in
one Ovarium.
  According to experiments made by Mr.  Hunter, it is ascer-
tained,—that the number of originally exifting Ova in each Ova-
rium, whether that number be greater or fmaller, may be dimi-
nifhed, but cannot be increafed.
  The Ovaria ferve for the nourifhment of the Ova, which con-
tain the rudiments of the Fee'us.
  The Uterine, or Fallopian Tubes, compared  in fh>,p> by Fal-
LOPius, to that of a Trumpet,  aie two Conical and Vermiform
Canals, attached to the Corneis of the Uterus, and  terminating
in it, each by a fmall Opening which foarcely admits the entrance
of a Bridle.
  They become gradually larger in their pafl'a e towards the fices
of the Pelvis :  Near their outer  extremity, they  are  convoluted
and confiderably dilated, but are afterwards fuddenly contraaed,
and terminate by open Mouths-fu&Lcitnily large to admit the point
of a-Goofe-quill. 
iJ'i
   Their outer ends are free and fluauating in the Pelvis, and ex-
pand into many irregvlar jagged  or pointed extremities, called
Fimbria, which are  confiderably longer at one fide of the Tube
than-the other.
   They  are  commonly  upwards  of a  hand-breadth in length,
and contained in  a Doubling  of the Ligamenta Lata.—In  their
natural  fituation,  they lie near the Ovaria ;  but when drawn out
andextended, are a Finper's-breadth diftant from them.
   The flruaure of the Tubes is nearly the  fame with that of the
Uterus, and, like it, they are capable of dilatation and contraaion:
Their inner fide, however, has a'different appearance, being fur-
nifhed with many fmall longitudinal Plica?, which are moft  con-
fpicuous Kwards the outer extremities.
   The Tubes are fuppofed to con\ey the prolific part of the Male
Semen  from the Uterus to the Ovar a, in order to fecundate the
Ova ; and by grafptng that part of the  Ovarium where  the iip«.ft
Ovum  is  fituated, to carry the Ovum, according to fome  Au-
thors, or its  contents only according  to  others,  to be mixed
with the Male Semen, and to be lodged in the Cavity of the
Uterus.
   The Vagina is a Membranous Canal, which extends from the
Neck of the Uterus  to the opening of the Pudendum.
   It is fituated behind the  Bladder- and Uiethra, and before fhe
under part of the IntefJtiium Reaum, to each of which it is clofely
connected by  Cellular Subftance.
   It begins a  little above the Internal Orifice of the Uterus, but
reaches  higher  at the  pofterior than anterior  part j from which
circumftance, together with a flight Curvature it has backwards,
the Canal is  found to be  longer in  its pofterior than anterior
Surface.
   From the Os Tinra?,  it paffes downwards and forwards, and
terminates  between  the Labia Pudendi, the Axis of the Vagina
forming a confiderable Aiule with that of the Uterus.
   The  dimenfions of the Vagina correfpond with the fize cf the
Ptnis in the  Male  ; but vary according to the temperament cf
the Body, and become larger in Women who have borne Chil-
dren.                                                       t
   The  Body of the Vagina is compofed of thick, ftrong, Mem-
branous parts, and furr.ifhed internally with humeious intgular
Ruga or Wrinkles, and Nervous  Papilla,  the  former  ot which
confiderably diminifh the capacity of the Canal, and the latter add
to its fenfibility.  ^
   The  Ruga run in a tranfverfe direaion,  and are fo difpofed as
to divide the Vagina  into anterior and pofterior Columns, which
jcin together laterally,  and produce a Raphe  or Suture at the
right and left fides.
   They are deepeft,  largeft, and moft crowded upon the anteror
and towards the outer part of the Vagina; are  molt  confpicuous 
137
in Virgins, lefs fo in married Women, and become more and more
effaced in thofe who have borne Children.—The Ruga? facilitate
the diftenfion of the Vagina during Child-birth.
  The whole extent of the Vagina, particularly towards its outer
extremity, is furnifhed with fmall Follicles,  the orifices of which
can frequently be feen.
   They fupply a Mucus, with which the Canal is  always rubri-
cated, and which is difcharged, in time of Coition, in fuch abun-
dance, as  to have;been formerly confidered as an emiflion of Fe-
male Semen.                   '
   The outer end of the Vagina is covered, on each  fide, by  a
Subftance compofed of Blood-veffels and Cells fimilar to thole of
the Penis, and defcribed by  De Graaf under the name of Plex-
us Reieformis, and by later Anatomifts under that of Corpus Ga-
vernofum Vagina.                            1  '
   The Corpora Cavernofa are covered by  the  Sphiinaer Vagina;
Mufcle,  the aaion of whxh, joined to the Dilatation  of thefe
Bodies, ferves  to contraa the entry of the  Vagiua  in the time of
Coition.                       ^
   The Ufe of  the Vagina is  to receive the Penis and Semen, and
to convey from the Uterus the Menitrual   Flux, the Foetus, the
Secundines, and the Lochia.      •
   The Uterus, with  its  Ligaments, Ovaria, and Uterine Tubes,
aie fupplied with Blood from the Spermatic  and Uterine Ar-
teries.
   The Spermatic Arteries arife from the Aorta, as in  the Male,
and run  in the Ligamenta Lata, to be difpepfc* upon the Ovaria
and Uterine Tubes, and afterwards upon the Uterus itfelf.
   The Uterine Arteries are  derived from the Internal  lliacs, and
are much larger than the Spermatics.   They dnea their courfe,,
firft to the under part of the Uieru6, after which they afcend along
its edircs,  and  near its upper part join the Spermatic Arteries.
   From  the Uterine chiefly, and partly from the Spermatic Ar-
teries, many fmall Branches are  furnifhed, which  run  in a Ter-
pentine manner,  and  communicatewith their fellows in the oppo-
fite fides of the Uteius.
   The Vagina is fupplied with an Artery on^ach  fide,—termed
Vaginal,—from the  Uterine, and with fmall  Branches from the
Umbilical, Middle H&morrhoidal, and Pudenda? Communes.
   The Spermatic Veins have the fame termiimtion as in the Male,
but aie confideiably larger.—The other Veins  run into the Inter-
nal  Iliac.
   The Lymphatics, like  the Blood  veffels,  run alfo in two Sets.
Thofe of the one let accompany'the Spermatic Blood-veffels, and,
like the Abforbents of ihe Teftes in the M de,  go to the  Lumbar
Glupds.   Thofe of  thtjMther  correfpond with the Hypogastric
B|pod-ve'flcK, and terminate in the Glands at the lateral pans of
the Pelvis.
    Vol. II.           M 1 
1.^
  The Nerves are from the Sacral and Great Sympathetica
  The Ufe of the Uterus is,—to  receive from the  Ovaria, by
means of the Fallopian Tubes, the Rudiments  of the Foetus,—
to nourifh it, and, after bringing it  to maturity,—to expel  it
through the Os Internum Uteri and Vagina.—From the Inner
Surface ot the Uterus,  the  Menftrual Evacuation  is  alfo dif-
charged.
                   External Parts.
  The External Parts, called Pudendum ot Vulva,  are formed
of two prominent fides, termed Labia Pudendi, Labia Externa,
or Ala Majores.   Thefe  are  contiguous, when the  Limbs are
not much feparated,  thereby preventing the accefs of Air  to
the Internal Parts, which they at the fame time protea and con-
ceal.
  The upper part of the  Pudendum, named Pubes or Mons Ve-
neris, is fituated on the fore-fide of the Offa Pubis, and is cover-
ed with Hair fimilar to that in the Male, and beginning to grow
about the fame period of life.
  The Pubes is compofed  of the  Common Integaments, under
which a confiderable  quantity of  Fat  is fituated,  rendering  it
thick, foft, and prominent.
  The Labia Pudendi extend  from the Pubes to within about an
inch of the Anus, the fpace between the Pudendum and  Anus
obtaining  the taame  of Perineum,  from a moifture  fuppofed to
flow about this part of the Skin.—It is fometimes alfo called An-
terior Perineum,  to  diftinguifh it from that  part which extends
from the Anus to' the Coccyx, termed by  fome Anatomifts Po-
fterior Perineum.
  The  opening  between  the  two  Labia has the name of Foffa
Magna ;—it increafes a little in fize and depth as it defcends, and
forms a fmall boat-like Cavity  at its under extremity, termed
Foffa Navicularis.
 • The Labia are thickeft above, become thinner below, and ter-,
mhiate in  a tranfverfe  fold of the Skin, named Franum, Furcula,
or Fourchette, which is  frequently lacerated in  the firft Child-
birth.
  The Labia are compofed of the Skin elevated by a large quan-
tity of Cellular Subftance and fome Fat,  and lined by a  very
Vafcular Membrane, which is thin, tender, and red like the in-
fide of the Lips, ami is furnifhed with numerous Sebaceous Fol-
licles', fecreting a Liquor, whereby the parts are preferved fmooth
and moift.
  Between the upper ends of the Labia, is tho Subftance named
Clitoris, and by fome Mentula Muliebris,—not exceeding an inch
in length, and little more than the third part of that in thicknefs,
and  tied down to the fore-part of the Symphyfis Pubis. 
U9
  It is extremely Vafcular and  Nervous» ancWs compofed, like
the Penis  in the  Male,  of two Crura and Corpora Cavernofa%
contained in a Ligamentous Sheath,  with a  Septum betweeu
them.                         ^
  The Crura are upwards of twice the length of the Body of tire
Clitoris, and, together with Mufcles belonging to them, arife, as
the Crura of the Penis do in the Male, from the Crura of the Ofla
Ifchia and Pubis.
  The Clitoris is alfo provided with a Ligamentum Sufpenforium,
by  which it is connected to the Ofla Pubis, and with a Glans,
which, like that of the Penis, is extremely fenfible,  but  has no
perforation in it for the paffage of the Urine.
  It is covered by a continuation of the Skin of the Labia, which
at its inferior extiemity, forms a Semilunar Fold, termed Prepu-
tium Clitorilis.        *
  The Prepuce is furnifhed with Glandula Odorifera upon its
inner Surface, and  with  a fmall Fraenum which fixes it to the
Glans.
  In the time of Coition, the Glans Ciitoridw is fuppofed to pro-
duce nearly the fame fenfation in the Female, as the Glans Penis
does in the Male.
  At the under and  outer part of the Clitoris  are two Bodies,
called Nympha, from their being fuppofed to prefide over and di-
rea the courfe of the Water proceeding from theBladder.
  The Nympha arife narrow from  the Prepuce and Glans, and
run obliquely downwards and  outwards along the infide of the
Labia, increafing in breadth, but fuddenly contraaing again at
their lewer extremity.
   They are chiefly formed by a production of the infide of the
Labia, have the fame florid colour with them, and in their natu-
ral ftate are contiguous, and cover the Orifice of the Uiethra.
   They  are fometimes of  unequal  fize, and not unfrequently,
particularly in warm  climates, they pfojea beyond  the edges of
the Labia.
   Their Internal Struaure confifts of Cellular Subftance, with
a large proportion of Blood-veffels.  Th*y have alfo many Ner-
vous Papillae, which render them very fenfible, and Sebaceous
Follicles, the contents of which prevent them from being injured
by the Urine.
   The Nympha? affift in direaing the courfe of the Urine  from
the Urethra, and in preventing the Air from entering the Vagina.
—They alfo tend  to enlarge the Paffage for the  Child in the time
of  Parturition.
   Between the Perineum and Nympha?, there is a fmooth Cavity
or Veftibulum, which is moft complete in Virgins,  and leids to
two Paflages, viz.  to the .Urethra above, and to the Vagina be-
low. 
«140
   The Orifice of the Utetbra is placed a  little below the Glans
 of theVClitoris, and between the two Nympha?, and is furround-
 ed by  a  Spongy Eminence, which projects  at its* under part,—
 called by fome Authors  Corpus Glandulofum, or  Glandula Pro-
ftata Mulierum.
■'  The Corpus  Glandulofum  is perforated by Lacuna, fome of
 which are of confiderable depth, and  difcharge a Vifcid Matter
 round the Orfice of the Urethra.
   The Orifice of the Vagina  termed likewife  Os Externum Uteri,
 is placed immediately under that of the Urethra,  and is natural-
 ly ftraiter than  the reft of  the Canal, but in the Virgin ftalejs
 ftillmorecontraaedbytheSubftar.ee  called Hymen, or  Circuits
 Membranofus, which partly furrounds  it.
   The Hjrntn approaches to a Circular Figure, but the Circle is
 frequently incomplete next  the orifice dt" the  Urethra, the broad
 part being fuelled towards the Perineum.
   When the Hymen is ruptured,  it degenerates into fmall Coni-
cal Papillae, termed Caruncula Mj/rtiftrmes,  from their fuppofed
 refemblance  to Myrtle-berries.
   The Hymen  has  been  confidered  as a Teft of Virginity  ;__
but neither the prefence nor abfence   of this Mttmbrane can De
 depended upon as a certain  Criterion.
   About the Orifice cf the Vagina  are feveral Mucous  Follicles,
 fimilar to thofe round the Opening of the Urethra.
   The Blood-veffels and Nerves of the External  Parts are from
the Pudic  Branches,  and are difpeifed  in numerous Ramificati-
 ons upon the end of .the Vagina,  Labia Externa,  and Clitoris.
   The Abforbents pafs partly to the Inguinal  Glands,  and partly
 to thofe placed at the fides  of the Pelvis,  or upon  the Lumbar
 Vertebra.
00000000*00000000'
          OF THE GRAVID  UTERUS.
                V f




  \^HEN  the Rudiments  of the Fcetus have been conveyed from
one of the Ovaria into the Cavity of the Uterus,  through the
medium of the -.oireiponding UwiuefTube, whether in the ftate
of a Fund oi-'.y, ''■. of a complete Ovum, lmpiegnation is fuicPto
have tiken place.   * 
141
  Some days after Impregnation has commenced, an Ovum, con-
fiftiqg of a Veficle filled with a limpid Fluid, is found in the Ca-
vity of the Uterus.
  The Ovum,  when firft vifible,  is obferved  to  have a  fmooth
Surface,  but in a  fhort  time thereafter  it fends off flocculent
Branches, the greater part of which are by degrees converted in-
to a Placenta at that part of the. Uterus where the Ovum happens
to be  firft  attached.
  The Rudiments  of the  Fcetus,^ however, are not  always
conveyed to the Uterus after  Impregnation, for fometimes a Foe-
tus is fouiiel in the Ovarium ; at other times in one of the  Uterine
Tubes ;  and fome rare Inllance* have occurred, where the Em-
bryo has dropped from one of the Ovaria or Tubes, into  the Ca-
vity of the  Abdomen,  where  a Placenta has been formed,  by
which  it  has been nouriflied.
  The Ovum, at an early period of Geftation,  confifts of athin
Membranous Capfule, which inclofes the Embryo  or  Germ with
the Umbilical Cord and Waters ;  and the Capfule, again,  con-
fifts of an internal  Membrane  called  Annios, on  the outfide of
which  is the  True Chorion, which is covered with a Filamentous
and Spongy Subftance, termed by Ruysch Tunica Filamentofa,
and by more modern Authors,  Falfe or Spongy Chorion.
  The Spongy Chorion is defcribed by Dr. Hunter as confift-
ing, in early Geftation, of tvjo Layers, ^B|ie lining the Cavity of
the  Uterus, and termed by him Membrana Decidua,  from being
fuppofed to  be caft  off from  the^Uterus: The other, covering
that part of the Ovum which does not adhere to the Uterus, he
terms Decidua Reftexa.
  The Decidua is leaft diftina between the Uterus and Placenta.
Near the edge of the Placenta, both it and that part of it called
Reftexa,  are thickeftand ftrongeft, and decreafe in thicknefs tow-
aids the  other end  cf the UterUs  and Ovum, in proportion as
thefe become more expanded.
  The Decidua and Decidua Reflexa unite into one  Membrane
in advanced Geftition.  They have been fuppofed to be formed
originally by an efil jrefcence thrown out upon the parts on which
they are  placed, in the manner it is thrown  out upon  inflamed
for faces.
  Between the Amnios and  Chorion,  a Gelatinous Fluid is con-
tained in the early Months,  at which period a  fmall Bag,  filled
with a milky-It-ke Fluid, isobfeivcu  on  the  Ammos,   near the
Umbilical Cord, and is termed Veficula Umbilicalis or  Alba.
  The Veficula  Umbilicalis  is  conneaed to the Cord by a  Fila-
ment confifting of an artery and Vein, which, with the Fluid and
B.i_r, foon diinppcar.  The ufe of this Velicie, which has fome-
times been miftaken for an Allantois, is not yet undcrftood.
  In  early  Geftation, the Ovum  is Luge in  proportion to the
Embryo; but towards the latter period of Pregnancy, the  propor-
tion is reverfed,  as  appears from the fallowing Obfervations. 
  No well authenticated account has been  yet received, of the
Embryo being obfervable till near the  end of the thud Week,
when it is found to appear like'an oblong Veficle floating in the
limped Liquor of the Ovum.
  In the fourth Week, the Ovum is about the fize of a Pigeon's
Egg,  and the Embryo not larger than that of a common Fly.
  About the end of the thinTMonth, the Ovum is  the fize of a
Goofe's Egg, and weighs eipft ounces, while the Embryo is be-
tween two and three ounces in weight, and thiee inches in length ;
—and  the Head and Extremities being now diftinaiy obfervable,
it obtains the name ot Fcetus, which it  retains, fiom  ibis lime till
the  end of Geftation.
  In the fixth Month the Placenta and Membranes weigh feven or
eight ounces, the Foetus, twelve or thiiteen, and  is eight or nine
Inches in length, and  puricct in all its external parts.
  AtBiith,  the  Secundines  weigh only between one and  two
pounds, the  Fcetus fix 01 feven,'and is from eighteen to twenty-
two inches in length.
  Still however,  from the difficulty of afcertaining  when Pi te-
nancy  commences,—from ihe^differences of Ftetufesof the fame
age in different Women, and in  the fame  Woman in different
Pregnancies, and—from the Fcetus being frequently retained  in
the  Uterus fome time  after it is dead, as well as from the fmall
dependance  to be placed upon  many  of the  Figures given  of
thefe Paits,—the above Obfervaiions are not altogether to be de-
pended upon.

   Changes  Prodvced in  the Uterine  System by
                    Impregnation.

  Immediately after Impregnation,  a  large Orifice is conftrmtly
oblervcd  in  the Ovarium, leading to a Cavity in that part ot  it
from whence the Rudiments of the Fee.us have been derived.
  This Cavity appe.us fiift lijcculent, and is afterwards rilled up
with  a Grai.ulous Suhftunce,  which has  the name of Corpus Lu-
teum,  from the yellow  appearance  it  aflumes,  efpecially  in
Quadrupeds.
  The Corpus Luteum,  confifts of an outer Vafcular, and an in-
ner Inorganic-looking Subftance, w hich has been confidered by
fome Authors as the remains of the Ovum. '
  The Corpus Luteum is not  found till after Impregnation. It
contines  during P; gnancy, and for  fome time after Delivery,
when  it  gradually vanifhes, but leaves  a  Scar  in the Qvarium,
which continues  for  life.—The number  of Corpora Lutea  cor-
refponds with  that of the Ova impregnated.
  After  the Embryo is received  into  the Cavity of the Uterus,
the Os Tine* is fliut up by a Ropy Mucus  fccreled from the Fol- 
14.0
licles in the Cervix Uteri ; the Menftrua ceafe to flovj,—ana\ the
Uutfusby degrees is changed from a triangular to an oval form.
  From the influx of  Blood, and the growth of the Ovum, the
Cavity of the Uterus gradually enlarges from a fize capable on-
ly of admitting an Almond, to that which contains  the  full-
grown Fcetus, the Secundines and Waters ; compofing together
a Mafs equal to nine or ten pounds weight.
   Some time after impregnation,', the Fundus and Body of the
Uterus,  being fofter and loofer than the Cervix,  firft yield to the
parts which it contains.
   For the two firft Months, the Uterus increafes fo little  as  to
remain in the Cavity of the Pelvis, and  it is generally after the
third month, before the Tumour formed by it can  be  felt above
the Symphyfis of the Pubis.
   During the firft three Months, the Os Tinea?  remains fmooth
and even, and its Oiihce  is  nearly as in the  un-impregnated
ftate;  but between the third  and fifth  Month, the  Cervix  and
Orifice begin to be dilated, the former becoming fofter,  and the
latter changing its common appearance, and projeaing more into
the Cavity of the Vagina.
   The Uterus continues to rife through the whole period of Gef-
tation, but frequently inclines a little to one fide.—In the feventh
Month, it reaches the Umbilicus, and at  laft touches the Scro-
biculus Cordis, Stomach and  Colon,  occupying the whole  of
the  Umbilical Epigaftric Regions.
   In the progrefs of Geftation, the whole  Uterus becomes fofter,
loofer, and more Vafcular, and the Veffels are greatly enlarged,
the proportional increafe being nearly  fimilar to that of the Ute-
 rus.
   The courfe of the  Arteries  is remarkably convoluted,—fully
as much fo as they are previous to Conception,—and greatly moie
 fo than  that of the correfponding Veins.
   The Veins  are much larger than the Arten'es, their diameters
being fuch as to have diftinguifhed them by the name of Sinufes ;
—and to them the great bulk-of the Uterus is chiefly  owing.
   The fubllance of the Uterus  wa* itt-merly fuppofed by fome to
 be thicker, and by others to be thinner  in the Gravid,  than in the
 unimpregnated ftate ; but the generality of Anatomifts feern now
 fufficiently fiuisfied,  that it  is nearly of  the  fame thicknefs in
 both ftates, and during (he whole  term of Pregnancy.
    In  the  latter Months, the Tubercle of the Os Uteri is confi-
 derably enlarged, and the firmnefs of its texture  converted  to
 tfte Spongy loftnefs  of the Body of the Uterus.  The  tranfveife
 Rima or Orifice is changed into an oval Ptt, and in Women who
 have borne feveral children, it is confiderably dilated near the end
 of Geftation.
   The fituation of the Appendages of the  Uterus is alfo confide-
 rably altered.   The Ovaria,  with  the Tubes and Ligaments of 
14 1
 the Uterus,, are lower fituated, in refpea to the Fundus Ulcri,
 in proportion 3S it afcends  ; and at the full time,  the Broad Li-
 gaments, by  aflifting  in  forming a covering to the Uteius, are
 nearly obliterated.
   In the  enlarged ftate of  the Uterus,  the Mufeular  Fibres are
 diftinaiy feen.—They form Fafciculi which run  in  various di«
 reaions, but cannot be traced) Jar without interruption.
   A defcription is given by Ruysch of a Circular Mufcle in the
 bottom of the  Uterus, for  the expulfion of the Placenta;—but
 the Placenta is found to adheieto other parts befides the Fundus
 Uteri j  nor  has  fuch  a Mufcle been obferved  by later Anato-
 mifts.
   The Mufeular Fibres of  the Uterus aflifl in the delivery of the
 Child and expulfion of  the Placenta ; and in a few days after-
 wards,  the Uterus, partly  by the contraaile power of thefe Fi-
 bres, and partly by that of the Blood-veflels, is reftored to near
 its former d menfions.


    Contents  of the  Uterus about the- end  of
                        Pregnancy.

   The Contents of the Uterus, towards the  end of Pregnancy,
 con lift of the  Fatus,  the Umbilical Cord Placenta, Membranes,
 and Waters.
   The Cord, Placenta, and Membranes, are named  the Secun-
 dines, or After-birth, with which fome include the Waters though
 thefe are difcharged previous to the expulfion of  the Child.
   The Cird\i  fixed by one  end to  the Umbilicus of the Foetus,
 and by the other it is attached to the  Placenta at a little diftance
 from jts middle,  from which circumftance the extraaion of the
 Placenta is more eafily tfteaed.
   It is commonly about two feet lon^,—in fome  inftances  mere,
 in others lefs ; but in general it is of fufficient length to allow thu
 Birth of the Child, while the Placenta adheres to the Uterus of
 the Mother.
   It> thicknefs is nearly equal to that of ones Finger,  but fmal-
 ler and weaker at the extiemity next the  Placentt.—It is feldoni
of a cylindrical form,  being marked with Sulci coiiefponding to
the courfe of its  Veflels.
   It is compofed of one Vein and tvuo Arteries, which twift about
each other in a fpiral direaion, and are covered by  a fmooth Coat
deiived from the Membranes.
   The Trunks of the Veffels are inclofed in a Gelatinous Cellular
Subftance, which adds to  the ftrength and elafticity of  the Cord,
and allows the Blood to pafs freely between the Fcetus and Pla-
centa, without being in danger of  interruption from preffure. 
145
  The Vein is much  larger than the Arteries; it is deftitute of
Valves, and fends off no Branches till it reaches the Fcetus.
  It arifes  from  the fubftance of the Placenta, and,  after perfo-
rating the Umbilicus, it paffes in the inferior part of the Li. a-
mentum Sufpenforium, to the under fide of  the Liver.
  The Arteries arife from the Iliac Arteries of the Foetus,  per-
forate the Umbilicus, and run to the Placenta, in the fubftance
of which  they divide into  their ultimate Branches, where the
Ramifications of one Artery frequently form large Anaftomofes
with th )fe  of the other, and both communicate with the Branches
of the Vein, in  the manner Arteries  and Veins do in other parts
of the Body.
  The Ufe of the Cord is, by means of the Vein, to convey pure
Blood from the Placenta  for the nourifhment of the Fcetus,  and,
through the medium of the Arteries,  to return what is not ufed
in Nutrition, again to be mixed with the  Blood of the Uterus.—
By the intervention of the Cord alfo,  the Placenta is more readi-
ly extraaed.
  The Placenta fo  called from its refemblance to a broad Cake,
is a fpongy mafs,  of  a round form, occupying near  a fourth part
of  the Ovum.
  It is about (even or eight  inches in  breadth, and upwards of
one inch in thicknefs, but is  thinner at the edges where the Mem-
branes go off.
  The external furfiice,  or  that next the Uterus,  is divided into
Lobules with deep Fiffures, while the internal, or that next the
Fcetus, forms a regular Mafs, which has numerous large Branch-
es of the Umbilical Veflels difpeifed upon it.
  In the Placenta  are to be obferved,—on the fide next the Child
the ramifications uf the Umbilical Veffels forming the principal
p.ut of its fubftance,—on the fide next the Mother,  Branches of
the Uterine Arteries,  almoft of  the fize of  Crow-quills, paffinrr
in a convoluted  manner  between the Uterus and  Placenta,  and
terminating!  in the latter ;—Veins correfponding with thefe Ar-
iel ies but flat and of great fize,  running  obliquely  to the  Ute-
rus,—and,  in the fubftance  of the  Placenta, an  Appearance
which  has been fuppofed by many Authors to be the common
Cellular Membrane,  of  a tender nature, and eafily ruptured by
injeaion,  but which is  confidered by late Authors  as a regular
Spongy Subftance, fimilar to that in the  Body of the Penis.
  The Placenta is conneaed to the Uterus on one fide, by Blood-
veffels  and by the Decidua, and to the Fcetus on  the other, by
means of the Umbilical Cord.
  The common place of attachment is  near the Fundus Uteri
though it is found  at different times adhering to all the other parts
of  the Uterus, not even  the  Os Tinea? excepted.
  In ihe cafe of Twins, there is fometimes only  one, but moft
frequently  two  diftina Placenta?, adhering together by the in
   Vol.   II.            N 
116  *
 fr-.vntion of a Membrane in which the  Veffels of  the two  Pla-
 centae occafionally communicate with each other.
   There are in thefe cafes alfo, twodiftma Apartments feparated
 by a Paitition, each Apartment  containing its own Waters and
 Cord.
   The Ufe of the Placenta is, t® receive Blood from the Uterus,
 and, according to  the opinion of modern Anatomifts, to purify
 it, (as  the Lungs do in  the Adult), for the nourifliment of the
 Feel us.
   The Membranes confift of the Spongy Chorion, the True Chorion,
 and the Amnios.
   They form a complete but flender Bag, which  line--  the Ca-
 vity of the Uterus, and inclofes the Fcetus, Umbilical Cord, and
 Waters.
  The Spongy Chorion is a thick opaque fubftance, which adheres
t« the Uterus, and forms the outer Layer of the Ovum, but fcarce-
ly penetrates between the Lobules of the Placenta.
  Between the  Uterus and Placenta, it is lefs  diftina than elfe-
where, being  perforated  there,  and in fome degree concealed by
the Blood-veffels proceeding from the infide of  the Uterus.
   It  has a Spongy and Villous  appearance,  and is full of fmall
Blood-veifels, which can be readily  injeaed   from thofe of the
Uterus.
  The True Chorion,—the term derived from Chorus a Company,
numerous  Vcffeis  being found to exift in  it in the Quadruped,__
is thinner, fmoothcr, and much denfer than the  former.
  It  is conneaed  with the Spongy Chorion as far as the edge of
the Placcntu, where it  fepaiates from  it, is refleaed  over the Sur-
face of the Plt.centa, which is oppofed  to the  Fcetus, and is af-
terwards continued over the whole cf the  Cord.
  It  is uniform in its texture, has a tranfparent appearance, ad-
heres to the Spongy Chorion and fur face of the  Placenta, by  a de-
licate Cellular Subftance, and has no  Veffels vifible  to  the naked
11;. e, or which can be injeaed.
   The Amnios,—fo oiled, according to fome Authors,''from its
fupp< led lefemblance to a Veifel ufed  by the Ancients for the re-
ception of Blood in Sacrifice,—lines the Surface of the True Cho-
rion, and, with it, is refleaed from the Plccenta upon the Cord
which it fupplies with  an externa! covering.
  It  is thinner, more denfe,  and  tranfparent,  than the Chorion,
to which it adheres every whereby a Je^iy.
   It is fmooth  and polifhed on the fide next  the  Fcetus, and is
deftitute of Blood-veffels.    t . .
  The Membianes, befides  containing  the Child  and Waters
 give origin to the  latter, and, in the time cf Labour, affift in open-
ing" the Orifice  of the Uterus.
   The Waters,  called Liq^.ur Amnii, are thinned- and  cleared in
the firft Months, after which they acquire fij.ne degree of colour
 and ropinefs. 
147
  The Liquor Amnii is  chiefly compofed of  the Serum of  the
Blood.   l,i  its natural ftate, it has all the Characters of the Li-
quor ^Pericardii, or of the Liqucrs exhaled from the Sui faces of
other Membranes fimilar to the Pericardium.—It is fuppofed to
be derived from the Exhalent Arteries of the Amnios.
  It is proportionally greater in quantity in the fiul than in  the
laft Months,  but the proportion and  quantity vary confiderably
in different  Women, and in the fame  Woman in different Preg-
nancies.
  Between the Amnios  and Choron, Water is frequently col-
Jeaed, but  in much fmaller quantity than in the Amnic.s, and is
termed Falfe Water, or  Falfe Delivery.—It  is  frequently dis-
charged fome time previous to  the B rth ot the Child, without any
danger.
  The Liquor Amnii defends  the Child and Umbilical Veffels
from the preffure of the.Uteru = ,  aflids  ;n. diftendinz the Uterus
during  Geftation, and ...Lws  the Foetus a cer.ain degree of mo-
tion.
  In  the time cf T..:;'.oui, it alfo afli/ls in dilating the Mouth °f
the Uterus,  and, by lubricating the Vagina, facilitates Delivery.
              PECULIARITIES  OF  THE FceTUS.
   All the Bones of the Body, excepting a few,  arc foj't,yield-
ing, and imperfect, and many of them entirely in a ftate of Car-
tilage.
   The  Head is large in  proportion to the red of the Body» and the
Bones of the Cranium are united by Membrane, which allows the
fize of the Head to be diminifhed,  whereby its Paffage is facilita-
ted in the time of De'ivery.                           ■
   Between  the Fronta"! and  Parietal Bones,  is the M.mbrane
caUed Bregma, formed by  the  Du.ti  Mater and  Pericranium,
which,commonly difappears before the Child is two years of age,
the margins of the Bones being then  united.
   —The other peculiarities of the Bones oj the Foetus are taken no-
tice oj in the Defcription of ihe Bones of the Adult.—
   There is  a large proportion  of fluids, and the Solids are gene-
rail y fofter  than in the Adult.
   The  Skin is of a bi ight red  colour, in confequence of its greater
 degiee  of Vafcularity.
   That part, chiefly of  the Cellular Membrane is Adipofe, which
is upon the Surface of  the Body  ;  frarcely  any Fat being found
in the interior parts, where it  gradually  accumulates as the per-
fon grows older.
   The  Brain, Spinal Marrow, and Nervous Syftcm, are propor-
tionally larger, hut fofter.
   The  Sanguiferous Syftein, and Glandular Organs, are larger.
   In the Eye is the Membrana f ■/Maris, which ariies  from the
inner margin of the Iris, and completely covers the Pupil. 
148
  It feparates the Camera? from each other, and is very Vafcular.
According to Blumenbach, it keeps the his expanded, during
theiapid iiicreafe of the Ball of the Eye.
  The Cryftalline Lens is almoft Spherical,  and has  numerous
Veffels difpeifed upon its Capfule.
  The Meatus Auditorius is wholly Cartilaginous, and adheres
by its extremity to an imperfea Bony Circle, in which the Mem-
brana Tympani is placed.
  The Meatus Externus, and Membrana Tympani, are lined by
a Mucous Membrane, which is caft off after Birth.
  The Thymus Glai.d, in  the Fcetus, is a large Subftance, fitu-
ated in the upper part of the Thorax, between  the Layers of  the
Anterior Mediaftinum.
  It lies over the Pericardium, and occupies the fpace where the
Aorta fends  off the Carotid and Subclavian Branches,  and ex-
tends a fhort way into* the fore-part of the Neck.
  It has tvjo long  Cornua above, and tvuo broad Lobes below,
is of a pale-red colour, and becomes afterwards of a darker hue.
  A ixihite ferous liquor can frequently be  fqueezed from its fub-
ftance ; but it has no Excretoiy Dua ; nor is the ufe of the Fluid,
or of the Gland itfelf,  yet afcertained.
  Some Anatomifts are of opinion, that the white Fluid is Chyle
fent by a retrogade motion  from the Thoracic Dua, and that the
Thymus Gland is  a Diverticulum to the Chyle, when too great
a quantity of Lymph is fent to the Subclavian Vein.
  In  the Adult, the Thymus Gland is fo completely abfoibed,
that fcaicely any  thing but  Cellular Subftance remains in its
place.
  The Blood-veffels of the Thymus are  Branches of the Sub-
clavian and Internal Mammary ; the Neives come from the Great
Sympathetics and Eighth Pair.
   Its Lymphatics have not yet been very accurately traced.
   The Lungs are fmall, firm, and  of a dark-red Coloui, and fink
when tin wn into water, in  confequence  of the Bronchial Cells
having  not vet received Air.
   Bui if Air be admitted  to  them by putrefaaion or otherwife,
they fwirn in Water, in the fame niamer as if Air had been con-
veyed to them in confequence  of Refpiration.
   The Valve of Eufbchius is diftinil in the Fcetus, but frequent-
ly Cr.biiioim in the Adult, is larger in proportion,  and is fup-
p  ud to d'uect  ihe Blood  of th^  Inferior Cava,  immediately
thiough the  Foramen Ovale to the^Left Auricle.
   In  the back-part  cf the Septum,  between the Right and Left
Auricles, is the  Foramen Ovale,  ne.rly  equal  in fize  to the
Mouth of the Interior C<;va, bounded by  a thick Mufculai u!< c,
teintud Airmdus FuaminisCvalis.
   U; on the left lice of the Foramen Ovale, a Membranous Valve
is pheed, which allows pait of the  Blood of  the Right Auricle 
141)
to pafs through the Foramen  Ovale immediately to the left one,
but which completely prevents its return.
   The Blood  g. ing through the Foramen Ovale, affifts in keep-
ing up the balance  of Ciiculation  between the two fides of the
Heart, till the Lungs be rer.dy to  receive it.
   ThePulmonary Artery divides  into three Branches, the r-ght
and left of which run to the Lungs, while the middle one, called
Duilus Arterioles,  larger than both the  other Branches, and its
Area nearly equal to that of the Foramen Ovale, paffes in an ob-
lique direaion to the beginning of the defcending Aoi ta.
   The Duaus, or Canalis  Arteriofus, forms nearly  one half of
the Aorta, carries part of the Blood of the RUTit Ventricle  nto
that Artery, without allowing it  to pafs to the Lungs ;  and the
Aorta, formed in this manner, receives the foice of both Ventri-
cles, by which it is more enabled  to fend Blood through the Um-
bil'cal Arteries to the Placenta.
   The Stomach is  of a rounder form than in the Adult,and com-
monly contains a fmall quantity of  a Gelatinous Matter.
   The Appendix Vermiformi3 is  larger in proportion, and is in-
feited  into the extremity of the Colon, which, at this time, does
net projea to form a proper  Caecum.
   The Colon, and  frequently  alfo the  end of the  Ilium, are
filled with a greenifh black Feces, of a vifcid confidence, termed
Meconium.
   The Liver is  fo large as  to occupy both  Hypochondriac  Re-
gions.
   The Umbilical Vein paffes from the Umbilicus, in a  duplicature
of the Peritoneum,  to the  left Branch  of the Vena  Portae,  and
carries the Blood from the Placenta to the Liver.
   From the Trunk of the Umbilical Vein, where it terminates in
the Liver, a Branch, called Duilus, or Canalis Venojus, runs  in a
fomewhat waving direaion, and  joins the Left Vena Hepatica,-
where that Vein enters the Cava.
   Ti c Duaus  Venofus is  much fmaller than the Trunk of the
Umbiltcal Vein, and.carries  part of the Blood of the Vein direa-
ly to the Heart, without allowing it to enter ths Circulation in
the Liver.   V'
   The Umbilical Vein fends Branches to the Right Lobe of the
Liver,  but is  principally diftribu'ed through  the Left LobeN;
while the Right Branch of the Vena Porta?  carries the Blood
of the Splenic and Mefentcric Arteries to the R Jit Lobe of the
Liver.                 J
   After Birth, the Left Lobe of  the Liver, which  was formerly
mi ire particularly fuppiiedb'y the Umbilical Wn, receives an ad-
ditional proportion of Blood from the  Vena Portarum.
   The reafon why the Umbilical  Vein goes partly to the Cava,
and not entirely1 to the Heart, is not underftood.
   \ OL. II.           I\ 2 
150
  The  K;dneys are irregular on their Suiface, being formed of
Lobes, each  i   hi ch con lifts of a Conic;-), a Medullary part, and
a Papilla, and U covered by aPioper Membrane.
  The Glandula Renalis is alm.lt as large as the Kidney, but af-
terwards rathe, dnmn.flies than  increafes in fize.
  The  Bi.Kidc.rof Urine  is of  a long form,  and extends almoft
to the Umbilicus. The gicater part of it is above the Pelvis, and is
more pnrticulnilv coveied by the Peritoneum  than in  the Adult.
  The Urachus, which i> of a Conical  form, afcends from the
bottom of the Bltdder, between the Umbilical Arteries, and be-
tween the Peritoneum and  Linea Alba,  to the Umbilicus, and
vanifhts by degrees  in the Umbilical Cord.
  It  is  tuimcd by a production of the Fundus  Vefica?, and in
the  litimtm Bcdy is generally folid, foiming a Sufpenfory  Liga-
ment < f the Bladder.
  It  has  been fometimes found hollow at  its beginning and
has been faid to be  fo,  in one  or two inftances, throughout its
whole lengih.
  In the Fcetal  Quadruped, it is a large Tube, which tranfmits
Ur  ne from the Bladder to a Bag  between the Amnios and
Chorion,  called Allantois.
  The common Iliac Arteries divide,  on each fide, into a fmall
External, and large Internal Branch.
  The principal part of the Internal Iliac is occupied in forming
the Umbilical Arteries, wh.ch mount by the fides of the Bladder,
on  the  outfide of the  Peritoneum, and perforate the Umbilicus
in their progrefs to the Umbilical Cord.
  Soonaft.-r Delivery, the Foramen Ovale, Duaus  Arteriofus,
and Venofus,  with the Umbilical Vein  and  Arteries, begin  to
contr: a,  and  are, in general, completely clofed,  and the Veffels
fhnveiled  into Ligaments within a year after Birth.
  This obliteration is produced by a contraaile power in the parts,
by a preffure in the fuirounding Vifcera, and by the Blood being
direaed through other channels.
  The Pelvis of the Fcetus is commonly fo fmall, that the  prin-
cipal parts of its Vifcera are contained in the  open cavity of" the
Abdomen.
  The Prepuce of the Clitoris is proportionally fo much larger in
a young Fcetus than  it is afterwards, that, in an Abortion, a Fe-
male 1'cetus has been frequently  miflaken tor a Male.
  The Teftes arehx'.ged during the greater part of Geftation, in
the  Caviiv of the A'>domen, over the Pfoae Mufcles, and a lit-
tle below the Ki-'neys.
  They  ' en coi ftitu ea part of the Abdominal Vifcera, and, in
a fmi'ar manner v i.-h  hem, are conneaed to the Body by a pro-
duect o.i  of the  Pemoncum, which forms  their Tunica Albu-
g nea. 
151
   Between the Tefticle and Scrotum, a  Fibrous and  Vafcular
Subftance, of  a  conical form,  is  extended,—called  by Mr.
Hunter, Gubernaculum, or Ligamentum Teftis, which hecon-
fiders as a principal agent in dirtair.g the courfe of the Tefticle,
and in making way for it in its defcent.
   About th,e eighth month of Pregnancy,  the Teftis, by means
not yet completely afcertiined,  paffes gradually along  to  the
Scrotum,  a Procefs of the Peritoneum  preceding it, which  af-
terwards forms its Vaginal Coat.
   The Teftis through the whole of its courfe, continues to be
covered by the Peritoneum,  is conneaed to the parts on which it
refts,  and has its  Veffels paffing to it from behind forwards,  the
fame as when fituated in the Abdomen.
   While the tefticle is pafling through the Ring of the Abdomi-
nal Mufcle,  the Ligamentum Teftis is found to be in fome mea-
fure inverted, and to form the under and fore-part of the Vaginal
Coat, on which the Cremafter Mufcle is expanded.
   After the defcent of the Tefticle,, the Peritoneal Procefs, which
defcends along with it, begins to contraa at the Ring, and a firm
adhefion of  its  fides, to* within a  little diftance of the Tefticle,
is commonly  found to be produced by the time of Birth.
                Position of the Fcetus.
   In the firft Months, the Embryo fwims in the Liquor Amnii,
free from the preffure of the furrounding parts ;—and from many
diffeaions and  obfervations made by the lateft Anatomifts, it is
afcertained,—that  the Head preponderates, and in general con-
tinues undermoft till the Child is delivered.
   Formerly it was fuppofed that the Embryo, in the firft Months,
was fituated with  the Head uppermoft,  and  that, in the latter
Months, the attitude of the Fcetus was inverted.
   The Fcetus is obferved to be coiled up into as round  a  figure
as poflible, fo as  to be properly adapted to the Cavity  of the
Uterus.
  The Head is bent towards the Thorax, and the arms are folded :
—The Knees are  drawn towards the Abdomen, and the Heels
towards the  Nates.
   The Spine  is bent into an Arch, and one fide of the Body of
the Fcetus is  frequently turned forwards.
   The Head  is  placed diagonally, with its long Diameter corre-
fponding to that of the  Pelvis, and the Occiput oppofed to  the
Os Tincae.
     Circulation  of the  Blood in the Fcctus.
   The Blood is fenr by the Arteries of  the Utdus  to  the Sub-
ftance of  the Placenta, from which according to iruft   r  rhe
ancient Anatomifts, i' pafl'.s  to  the Umbilical Vein 'e>y a  di-
rea communication of Branches ; cr, according t  tiif   pinion
of the greater part of  modern Anatomifts,—b\ Ablbrbhon. 
152
   By tha Umbilical Vein it goes principally to be circulated  in
the Liver,  and by  the  Duaus Venofus,  a  fmall portion of it
goes to the right Auricle of the Heart.
   The Blood fent from  the Inferior Cava  is tranfmitted by  the
Foramen Ovale to the left Auricle, and that fent by the Superior
Cava is tranfmitted to the right Auricle and Ventricle, and from
thence to the Pulmonary Artery.
   From the Pulmonary  Aiteiy,  one portion of it paffes through
the Circulation of the  Lungs,  and another goes  by the  Duc-
tus Arterioles lo the  Ao ta Defcendens.
   From the Lungs it >s  returned by the Pulmonary Veins to the
Left Auricle,  where it  nnxes  with that coming  from  the right
Auricle by the Foramen Ovale,  and is fent by the  Aorta to the
different parts of the Body.
   From the  Iliac Aiteries, it is conveyed  by  the  Umbilical
Branches to the Subftance of the Placenta, where one portion of
it  returns by correfponding Veins to the Fcetus,  the  reft going
to  the Uterus in the manner it was difcharged from the Uterine
Arteries to  the Branches of  the Umbilical Vein. 
153
PART    V.
               of The

ABSORBENT  STSTEM.
&
              Of the Absorbents in General.

     THE  Abforbent Syftem  confifts of the  Abforbent Veffels and
     Conglobate Glands, the former of which are divided into Lym-
phatic,and Lacteal Veffels.
  The Abforbents are fmall pellucid Tubes,  which have been dif-
covered in moft parts of the  Body, and are fuppofed to exift in
all.
  They begin  by numberlefs open Mouths,  too minute to be vifi-
ble to the naked  Eye; though, by the affiftance of Glaffes,  the
Orifices  of the Laaeals have been feen in  the  Human Body by
Mr. Cruickshank,  and thofe of the Lymphatics, in certain
kinds of  Fiflies, by Dr.  Momro.—See their Treatijes upon this
Subjea.
  They arife from the external Suiface of  the Body, from  the
Cellular Subftance, from the  Surfaces of the large Cavities, and
fiom the  Surface and Subftance of the different Vifcera;—but
have not  yet been obferved  in the Cavity of  the  Cranium, or in
the Placenta and its Membranes.
  In the  dflerent parts  of  the body in general  they run  in two
fets, one  fupeifitial and very numerous, the other accompanying
the Arteries,  and at leaft double then  number.
  The Laaeals are of the fame nature with the other Abfoibents.
They begin  from the  miide of the Inteftines, and, when thefe
conain Alitaeiu.ry  matter, they  carry  a  white Fluid,  called
Chyle, and at other times a Clear Fluid or Lymph, to be mixed with
the contents of the Lvmphatics. 
                            151-

  Moft of the Lymphatics,  and all the Laaeals, terminate  in
the Thoracic Dua, by which the Lymph and Chyle are conveyed
to the  Red Veins, to be mixed with the Blood.
  The common j lace of termination is in the large Veins in  the
bottom of the  N\ck;—to Faas  or obfervations having been yet
eftablifhed of their terminating in any  otlur part of  the  Venous
Syftem.
  The Coats of the Abforbents are  thinner and more tranfparent,
but ftrongerJh3n thofe of the Red Veins, being ab.e to fupport
a Column of'Mercury of confiderable weight;  but from their
thinnel, they cannot be enumerated.
  They are  geneially fuppofed howev'Li  to be formed of different
Membranous Layers, like the Blood-veffels.   Fibres can be feen
in them, and their Mufcul.uity is rendered pr-bable  by the Con-
traaile power which they  are  obfuved  to poffefs in  a living  or
moribund Anim il.
  By this contiaaility they convey  their contents from their Ori-
gins towaids their terminations,  in which they are aflifted by the
motions of the fun ou.uling parts,  imlependent of fuch a  Vis a
tergo as contributes  to propel the Blood through the  Veins.
  They arc  furnifhed with Blood-veffels for their nourimment, as
is fometimes obferved by  penetrating injeaions ;  and this is ren-
dered ftill more evident by their being fufceptible of inflamma-
tion and pain.
  Theprefence of Nerves alfo appears probable from the acute-
nefs of their feeling when in a ftate of inflammation.
  In general,  they form an irregular Net-vjork) having frequent
communications with each other ;  and thefe aie rnoft numerous
in the vicinity  of their Glands.
  Through  their whole extent,  they are intercepted by Valves,
which  are placed in pairs, and are of a femicircular form, having
one edge of  each Valve fixed  to the  fide of  the Veffel, and the
other ed  e loofe acrofs its cavity, but  turned towards the general
terminations.
  The Wives  are found, in fome parts, to be fituated  at equal
diftr.nces ; in  others,  more  irregularly.—Their number alfo is
very uncertain, amount:ng in  ('.me parts to thiee or four,  and
in others to feven or eight, or upwards, in the length of an inch ;
—hut  varying ftill  more with refpea to numbei,  in different
Bodies, and in diffeient parts of the fame Body.
   When the Abloi bents are  diftended, they appear largeft on the
fi le  of the Valves towards their  general terminatior, and the en-
largements are fuch as to give the Lymphatics a jointed, and the
Laaeals frequently a veficular appearance.
   In the termination of  the Abforbents, whether in the Thora-
cic Dua, or in the Red Veins, there is alway* one nnd common-
ly two Valves,  to  prevent the  contents of the Duel or  of the
Veins from pafling into them. 
155
  The Ufe of the V.dves is to promote the general courfe of the
Lymph and Chyle, and to prevent the retrograde motion of thefe
Fluids within their Veffels.
  Ufe of the Abforbents ■.  The Lymphatics take in the Fluids ap-
plied to their Orifices by Capillary Attraaion, and  by a power
inherent in themfelves,  and by  their contraaile  nature  condua
them into the Mafs of  Blood, whereby they pi event morbid ac-
cumulations.—The Laaeals,  in like manner, receive the Chyle
from  the Inteftines for the nourifhment cf the Body.
   The Conglobate Glands, or Glands of the  Abforbent Veffels,
are found in various parts of  the Body,  and are fituated in the
Cellular Subftance under the Skin, or over the Trunks of the
Blood-veffels belonging to the different Vifcera :—They are of a
round or oval form, and frequently a little flattened.
   They are of different fizes, from that of a Millet-feed to that
of  a Subftance near an inch in diameter ; and fometimes feveral
are colleaed into one mafs.
   Their colour alfo varies in different parts of the Body, and at
different times of life.
   In young fubjeas,  they are generally  largeft, and of a reddifh
or brown colour,  but  become fmaller and paler  with increafing
 age;  and immediately  under the Skin, they are redder and firmer
 than  within the large Cavities.
   They  have a  fmooth, denfe, Membranous Covering,  which
gives them a fhining appearance,  and are conneaed to the fur-
 rounding  parts by loofe Cellular Subftance.
    Their Coat  is  conneaed to the Glandular  part by a Cellular
 Membrane, which, .according to  Dr. Haller, is pervaded by
 a Succus proprius full  of Globules, which, Mr. Hewsqn  fup-
 pofed,  afterwards form  the Red Globules of  the Blood.
    L  ke  other  Glands, they have  Aiteries, Veins,  and Neives,
 entering their compofition.
    They are defcribed  by fome Anatomifts,  as being compofed of
 Cells internally,  while others conlider them as heing a Congeries
 of convoluted Abforbent Veffels.—Moft of the Glands have much
 of the former, but many of them  of the latter appearance.
    The Abforbents entering into the Glands,  are calied Vafa In-
 j'erentia.  When  they approach, or come in contaa with the Gland,
 they fplit into radiated Branches, which, after fpreading over ir,
 penetrate into its Sublt  nee.
    The  greater part of  the  Abforbents, approaching a Gland,
 terminate in  it in this manner, while otheis turn afide, or go over
 it, and terminate in other Abforbents or in other Glands.
    From  the oppofite fide of theGlands, Veffels j;c oat in theman-
 ncr they entered it, and are .termed  Vafa Efferentia.  They are
 frequently, though by no means always, fewer  m  number, but
 larger than the Vafa  Infcrentia. 
15G
   Moft of the Abforbents go through feveral Glands, but in fome
 parts through one only, before they reach their general termina-
 tions.
   The Lymph and  Chyle are ftrained  through the Glands,  by
 which they are fuppofed to undergo certain changes,—but the na-
 ture of thefe changes has not yet been afcertained.
           Of the Particular Absorbents.
   The  Superficial Abforbents of the Lovoer Extremities,  confift
 of numerous Veffels, which lie  between the Skin and Mufcles.
   They belong to the Integuments in general, and are much more
 numerous than the Subcutaneous  Red Veins.
   They can be traced from the Toes, round which they form a
 Plexus.
   From the Toes, feveral Branches, likewife forming a Plexus,
 run over the top  of the Foot,  to the inner part  of the Leg, and
 from that along the correfpondng part of the Knee.
   From the ou.er part of the Foot,  another Plexus arifes, which
 runs along the outfide of the Leg, where it fplits into two Divi-
 fions, one of which croffes obliquely over the fore-part of the
 Tibia, to the Lymphatics at the inner fide of the Knee.
   The other Divifion paffes partly to the Popliteal Glands,  fome
 afcending upon the outer and back-part of the Thish.
   The Popliteal  Glands are commonly two or three in number
 and are fituated near the Artery of the fame name, but frequent-
 ly thi y are fo fmail and fo much buried in Fat, as to be dilcover-
ed with difficulty.
   From the Sole, another Plexus of Lymphatics arifes, and joins
thofe upon the Leg already defcribed.
   From the infide of the Knee a Plexrn runs  up, confifting  of
 from twelve to twenty Trunks, which pafs afterwards on the fore
and inner-part of the 'Thigh to the Groin.
   The greater part of the Trunks of the laft Plexus, accompa-
ny the Vein called Saphena Major, and in their  paffage they re-
ceive many fma 1 Branches from the outer and back-part of th*
Thigh.                                          v
   In the Groin, they fplit into Branches which penetrate the In-
guinal Glands.
   The Inguinal Glands  are generally  from fix or eight to a do7en
in number, and are of  very different fizes; but  fometimes the
number is fmaller,  in confequence of two or more of them beiiv
united into one large Gland.                               °
   Of the  Inguinal Glands, fome lie in the angle  between the
Thigh and Abdomen, and  others a few inches  faither down  on
the fore-part of the Thigh.
   The greater number are placed upon the outer part of the Ten-
dinous Aponeurofis, the reft deeper, being in  contaa with th<>
great B!ood--veffels. 
157
  The juperficial Lymphatics of the thigh enter the lowed of thefe
Glands  ; one or more of them, however,  frequently pafs by the
firft Glands they meet with, and  penetrate others  higher in the
Groin, and fometimes a few do not enter  any Glands till  they
go into  the Abdomen.
  Into the  Inguinal  Glands enter likewife the fuperficial Lym-
phatics of the upper and  back-part of the Thigh, with thofe of
the Nates and of the Abdomen and Loins.
  The deep-feated Lymphatics of the Loiver Extremity are fitua-
ted among the Mufcles,—they accompany the BU?od-veffels, and
are few  in number when compared with the  Subcutaneous  fet-
  In feveral places,  one  only has been yet obferved on each fide
of the Trunks of the  Arteries, though,  in  others, they are
fomewhat more numerous, forming a Plexus  over  the Blood-
veflels.
  They arife from the fides of the Toes, and  from the deep parts
of the Sole, accompanying the Plantar Arteries ; and after reach-
ing the  Leg, they run up with the pofterior Tibial Arteiy to the
Ham.
   In the Ham,  they lie cl fe upon the Trunk of the Artery, and
enter the Popliteal Glands.
   Befides thefe, there are fimilar but fmaller Lymphatics, which
begin upon  the upper part of  the Foot,  and afterwards accom-
pany the anterior  Tibial,  and the Fibular Arteries, receiving
Branches from the deep parts of the fore and outer-fide of the
Leg.
   The anterior Tibial and the  Fibular  Lymphatics, terminate
with the pofterior Tibial in the Glands of the Ham.
   From the Popliteal Glands, two and fometimes more Trunks
of confiderable iize are fent  out,  which accompany the Femoral
Artery, and, at different diftances, communicate with each other,
by Branches which pafs obliquely acrofs the Arteiy.
   At the upper part of the  Thigh, they enter the undermoft of
the  Inguinal  Glands,  where the Lymph of the fuperficial and
deep-feated Abforbents of the Limb is mixed and incorporated.
   The fuperficial Lymphatics of  th» Scrotum enter the upper and
inner Inguinal Glands, thofe deeper feated pafling with the Lym-
phatics of the  Tefticle into the Abdomen.
   The fuperficial Lymphatics of the Penis begin at the Prepuce,
and form a few Trunks which run principally upon  the Dorfum
Penis, receiving in their paflage Branches  which turn round from
its interior furface.
   In fome Subjeas, they unite into Trunks in the middle of the
Doifum Penis, which afterwards feparate  into  right  and left
 parts.
   In others, they are more unconneaed,  and in all  they appear
to divide at the root of  the Penis into right and left Branches,
    Vol. II.           O 
15S
r fling into the correfponding  Inguinal  Glands, which lie next
the Symphyfis of the Pubis.
  The deep-feated Lymphatics of the Penis arife from  the Glans,
ai.d from the Body of the Penis, and accompany the Arteries into
the under part of the Pelvis.
  The Lymphatics oj' the Tefticle are numerous,  and are among
the largeft of  the Body,  fome ot  them exceeding the fize of a
Crow-quill.
  They arife from the Coats  and Body of the Tefticle, and from
the Epididymis, and run with  the Spermatic  Cord thiough the
Ring of the Abdominal Mufcle,  to  terminate  in the Lumbar
Gland-..—In their paflage, they have  few communications with
each other.
  The Lymphatics of the External Parts oj Generation in Women,
go partly to the Inguinal Glands of each fide, and partly through
the Rings of the external oblique Mufcles, in  company with the
round Ligaments of the Uterus, and terminate in the  Iliac or in
the Lumbar Glands.
  The  Superficial Lymphatics of the under part of the Abdomen,
thofe of the Loins, Nates, and verge of the Anus, pafs into the In-
guinal (ilands, each let terminating in fuch of the Glands as lie
neareft the parts to which the Veflels belong.
  The Inguinal Glands,  having received the Lymphatics  of the
Inferior Extremity,  and likewife  the Supeificiai  Lymphatics of
ihe Fxternal  Parts of  Generation, lend out  Trunks  fewer in
number,  but confiderably larger  than  thofe  which  entered the
Glands.
  The Vaffi T.fierentia of the Inguinal Glands enter the Abdo-
men under Pol part's Ligament, in company with theTnguinal
.nd Iliac Ai toy.                                         '
   Some <f them  <-o into the  Glands  fituated  about  the Iliac or
the Lumbar blood -veflels.  The Iliac Glands are frequently al-
moft as numerous as the Glands of the Groin, and one of them
is generally found larger than the reft,  and  placed  at the inner
(dge of Poupart's Ligament.  The Lumbar Glands are more
numerous ihan any of the chides already defcribed, and are placed
ovei the  Abdominal  Aorta,  Inferior Cava,  and bodies  of the
Lumbar  Vertebrae.
   'The left of  the Lymphatics  from the Lower  Extremity de-
f.-end at the fide of the Pelvis, near  the Internal Iliac Blood-
vtifcls,  and pafs thiough fome of the Glands  which  are fituated'
thtre.
   The  laft-mentioned Lvmphatics are joined  by  Abforbents
fiom the vifcera of the Pelvis  in  general,  efpecially by thofe of
-he Bladder and  Veliculae Seminales in the Male,and by a portion
of ihofe of the Uterus  and of the Vagina in the Female.
   The Lymphatics oj  the Bladder, in both fexes, accompany its
principal Blood  veffel*,  pafs through fome fmall Glands upon 
                             159           *

tiic fide of if, and, at the  u-idir part of the Pelvis,  go into the
Gunds  which furround the Internal Iliac Aitery and Vein.
   The Lymphatics of the Uterus run in t-vo bets ; one, which is
the larc;eft,  goes with the Hyp .gaitric,  the oti,er with the Sper-
matic Blood-veffels.
   The  Hypogaftric LymphatiM"form a Plexus which runs from
above downwaid;;-, into Giands fituated on the fule , of the Va-
gina.
   From thefe Glands they pafs to others which furround  the In-
ternal Iliac  Veflels, atad then, intermixing with the Trunks from
the Extremities, r'.ey terminate in the Th»racic Dua.
   The  Lymphatics, cor. eluding  with the  Spermatic Veffels.
term nale in the Lumbar  Gi. .ids,  as in the Mjtfi:.
   The  Lymphatics  of the  Uterus, like  its^Ptood veffels, are
much enlarged and of confequence eaiiiy ductmied,  i.t ihe Gra-
vid Itate.
   The  Lymphatics of i'.e P.r'Sinn go firft into fmall Glands which
lie between  it and the Os Sacrum, an.I afitrwaids terminate in ine
Lu.nbir Plexus of Glands and Veflels.
   Btfides  the Lymphatics which lie on the infide cf ihe  Exter-
nal Iliac  Artery, there are others  liui-ted on ihe vuiiide oi  it,
upon the Pfoas Mufcle.                                   *
   Of thefe, one part paffes up to the Lumbar Plexus, and goes
under the Aorta,  in different Branches which teuniuato in the
Thoracic Dua.
   Another part paffes  under the Iliac Arteries, and appears upon
the Os  Sacrum, forming a remarkable Plexus, wh.ch goes through
many Glands, and is chiefly fituated behind the Aoita and Vena
Cava.
   The Laileal Veffels,  fo called from conveying a fluid like milk,
whLh is termed Chyle, begin  upon  the inner Surface of  the In-
teftines.  Each L'iaeal takes its origin upon one of  the Villi, by
numerous fhort radiated  Branches,  aid each Branch is furnifhed
with an Orifiie for imbibing the ChyL.
   From the Villi the Laaeals run a confiderable way under the
Mufeular Coat of the Inteirmes, and ihen pais obliquely through
them, uniting in their courfe into larger Branches.
   They follow  the direction  of   the Blood-veflels,  and their
Trunks are double the nuni'.cr of the Aiter.es,—one being fitu-
ated on each fide of them.
   Upon the ouiiide of the Interlines an  External  Set appears.
They run bet^ve-en the Peritoneal and mu feu la rv Coats,  and com-
monly proceed fomew.iy in the direaion of the Inteftine,  and
with  few ramifications.
   The  Superficial  and deep-feated  Laaeals communicate in the
Subftance of the Inteftiues, and,  after leaviu.  them,  commonly
form a Plexus, which runs between  the plies or theMefentery and
Mefocolon,  without following the courfe of the Blood-veffels. 
160
    The Laileals of the J funum are  larger and more numerous
  than thofe of the Ilium, the principal  part of  the  Chyle being
  contained in this Inteftine.
    In their courfe, they pafs through a great number of  Laaeal
  or Mesenteric  Glands, which like the  Laaeals themfelves,  are
  largeft and moft numerous in that  part of the Mefentery which
  belongs to the Jejunum.       :•
    The Mefenteric Glands are feated in the Fat between the Layers
  of the MiTentery, neai the Branchings of the Blood-veffels.
    They aie  cemmonly fcattered over the Mefentery,  at a little
  diftance from each other ; but there are feldom any obferved with-
  in two or three inches of  the Inteftines.
    They are of different fizes  in different parts of the Mefentery,
  fome being about a half,  or  two thirds of an inch  in diameter,
  vi hie others are #b fmall as to be traced with difficulty.
    Their Stmaurc is ihe fame with that of the Abforbent Glands
  in other parts of the Body, but they are generally flatter,  and  Jie
  of a white colour when filled with the Chyle.
    They are confidered by fome Authors as dividing the Laaeals
  into different Orders.
    From the Inteftines to the Glands,  the Laaeals are called Vaffa
  latlea  Primi Generis, and from the Glands to the Thoracic
  Dua,  Vaffa  Lailea Secundi Generis.
   Some divide them into three Orders ;—the firft confiding of thofe
  which go from the Inteftines to the Glands,—the fecond, ot thofe
  winch  run from one fet of Glands  to  another,—and the third,
  of thofe which pafs from the Glands to the Thoracic Dua.
    The Lacleals of the  Small Inteftines,  after pafling through the
  different Glans in the Mefentery, form at  laft one, and frequent-
  ly two, three, or more Trunks,  which accompany the Trunk of
L_the fuperior Mefenteric Artery,  till they arrive at the right fide
  cf theAoita, where they fometimes  pafs into the beginning  of
  theThoiacic Dua:  At other  times they defcend  a little, and
  join the Trunks fr.m the Inferior  Extremities, to form that
  Dua.
   The Abforbents of  the Great  are of an inferior fize in  pro-
  portion to thofe of  the S?nall Inteftines,  and have feldom,  though
  fometimes,  been obferved to be filled  with  Chyle.
   In the r courfe they : o through the Mefoccilic Glands, wheh
 aie fituated  bttw-en the Laycis cf the Mefocolon, but are gene-
 rally much lefs numerous and confiderably fmaller than thofe of
 theM.fen'er; , or of molt other parts of the Body.
   The Abfui-benrs of the Cacum, ami of the right portion of the
 Colon, join  thole of the fmall  Inteftines,  about the root of the
 Melentery.
   Thole of the left portion of the Colon accompany  the Inferior
 Mefenteric  Arteiy, and  cemmun cate with  large  Lymphatics
 '• at its root. 
161
  They tei initiate at laft in the Lumbar Glands, or go direaiy
into the lower part of the Thoracic Dua.
  Of the Abforbents of the Stomach, one fet runs upon its f nail,
and another upon its great Curva.ure, but neither the one nor the
other are found to carry Chyle,  though a few have been obferved
filled with it in other animals,—as the Dog.
  The former of thefe, compofed of Branches from the upper and
under Surfaces of the Stomach,  accompany the fuperior Coronary
Artery.
  In their paffage, they  go through a few fmall Glands fituated
at the junftion of the Omentum Minus to the Stomach, and, af-
ter becoming larger t'ney enter other Glands in company with the
deep-feated  Lymphatics of the Liver, along with wh.ch they ter-
minate  in the Thoracic Dua.
  The  other fet paffes  from the great Curvature of the Stomach,
paitly to the right, and partly to the left fide, and, as on the fmall
Curvature,  are formed of  Branches from  its oppofit*' Surfaces.
  Thofe on the left fide receive the Lymphatics of the  middle
and  coriefpond'iig haif of ihe Omentum Majus.  Running to
the left fide of  the large  Curvatuie of the  Stomach, and pafling
through one Ur two  fi.nall Glan Is on it, they go with the Lym-
phatics cf the Spleen and Pancreas to the Thoracic Dua.
  Thole of the  right fide  receive  the Lymphatics  of the corre-
fponding half of the great  Omentum,  and alfo pafs through one
or two fmall Gland- which lie dole to the right Gaftiic Artery.
   In the;r defcent by  the  Pylorus,  they meet  the Plexus which
accompany  the fuperior Coronary  Aitery, and  run with  them,
and  with  the  deep Lymphatics of  the Liver  to the Thoracic
 Dua.
  The  Lymphatics of the Liver, as in other Vifcera,  run  in two
fets, the fuperfhhl of which are numerous, anei unite into Trunks
in the minner Roots unite to form the trunk of a tic.      *r
  The  fuperficial  ami deep fets communicate fo freely, that upon
inieaing the Lymphatics on the external Sinfice, the d«rtp-letted
Abf.ubents are readily filled from them.
  Thepiincipal part of the Lymphatics tipo,  the convx Sur-
face of the Liver,  go by  a right and left Piexus towards the Suf-
penibry Ligament.
  Running along this Ligament they direaiy perforate the Dia-
phra;m, after which they pttfs thivugh Glands fituated upon  the
anterior part of  the Pericardium.
  Other Lymphatics from the  convex part of the  liver run  to-
wjrds the lateral Ligaments,  where they form on each  fide one or
more Trunks of confiderable fize.
  From the lat-eial Liraraents they pafs through the Subftance of
the-Diaphragm,  and afterwards run forward on its c-.-nvex Sur-
fa:\ following  the  direaion  of  the Ribs.—>,oi  ur.fiequently,
Vol.  II.           0 2 
162
theie Veffels, inftead of perforating the Diaphragm, inn  down-
wtud, and  terminate in ihe  Thoracic Duel,  within the Abdo-
men.
  In their courfe upon the Diaphragm, they often fend  Branches
backwaids, which terminate in Glands upon the Elophagus ;
—in other inftanc.s, thefe Branches are obferved to go direaiy
into the Thoracic DucL
  They receiv. Branches from the Subftance of the Diaphragm,
and, after perforating two or three Gland; upon  its  Surface;
they join the Trunks from the Ligamentum Sufpenforium.
   The  Lymphatics  from the lateral Ligaments,  joined by thofe
from the  Ligamentum  Sufpenforium,  form  either a  principal
Trunk, or a Plexus, which runs up, fometimes  between the
Layers of the anterior Mediaftinum, and, at other times, in com-
pany with the internal Mammary Blood-veffels on each fide.
  When this tiunk or Plexus runs in the anterior Mediaftinum,
it  moft frequently tei mirutes in the upper end of  the Thoracic
Duct;—fometimes, however, it communicates with the general
:ci initiation in  the right fide of the Neck.
  When they  accompany the internal Mammary Veffels,  they
are obferved to terminate,  the left in the Thoracic DucT,  and
the right in the general termination of that fide.
  The Lymphatics on the concave Surface of  the Liver run to-
wards the Poi ta, and join the deep-feated Set.—One part of them
i(ocs over the  under  Suiface of the Gall-bladder,  from which
they receive numerous fmall  Branches.
  The deep-feated Lymphatics accompany the  Blood and Bil ary
Veflels, and communicating  with the Superficial  Abforbents al-
ready  mentioned,  they pafs through  feveral Glands fituated
; bout the Trunk of the Vena Portte, and terminate in the Tho-,
racic Dua, near the root of the fuperior Mefenteric Artery.
  The  Superficial Lymphatics of the  Spleen are remarkably
fmall.   They pafs from its convex to its concave  Surface, where
they j«in the deep-feated Lymphatics, which are very  considera-
ble in fize and  number.
  The Splenic  Plexus of-Lymphatics accompany the Splenic Ar-
tery, and go though feveral Glands of a  dark colour fcattered
airng the Surface of that Veffel.
  The  Lymphatics of the %pleen  receive thofe of the  Pancreas,
which run into them in a tranfverfe direaion.
  In their  courfe, they unite with the Lymphatics of the Stomach
«nd thofe defcending from the under part of the  Liver ;  and the
whole of them, near the head of the Pancreas, form a confidera-
ble  Plexus.  From this Plexus, Branches are fent off,  fome paf-
fing over the  Duodenum, and others under it, and all of them
going into  the  Thoracic Duft near the  termination of the Lac 
163
  The Lymphatics of the Kidney are feldom feen, excepting when
it is enlarged or ulcerated, ,n which cafe they may fometimes be
diftinaiy obferved.
  The Superficial  Abforbents run from its outer towaids its in-
ner edge, where, meeting with thofe deep feated, they commonly
unite with them, and form a Plexus which accompanies the Renal
Blood-veffels,  after which they pafs through fome of the Lumbar
Glands, and terminate in large Lymphatics near the Aorta.
  The  Lymphatics of the Capfula Renalis,  which are numerous
in proportion to its fize, terminate in the Renai Plexus.
  All the Abforbents already defcribed, excepting ihofe from the
convex  Surface of the Liver, terminate in the Thoracic Dua
near its beginning.
  The Thoracic Duel, at its under extremity,  is formed  by the
union ot three, or fometimes of more  principal Trunks, the firft
of which is  compofed of the  Lymphatics of the right, and the fe-
cond of thofe  of  the left Inferior Extremity:—the third  Trunk,
or fet of Trunks, belongs chiefly to  the Laaeals.
   Thefe large Abforbents unite fo as to form the Dua over the
th id Vertebra of the Loins.
   Sometimes they unite upon the fecond Vertebra of the Loins,
where the Dua formed by them is twice or thrice as large in dia-
meter as it is higher up.
   Commonly  it enlarges again  upon  the fiift Vertebra of the
Loins,  where  it has generally been called the  Receptacle of the
Chyle,  and confidered as the beginning of the Dua,  being often
found forming an oval, or Pyriform  ba^-,  about the third of an
inch  in diameter.
   Thefe large Trunks which form the Thoracic Dua lie  clofe
upon the Spine, thofe of the right fide being placed below the Right
Crus of the Diaphragm, and thofe of the left  between the Aorta
and Spine,  while the Thoracic Dua  itfelf lies at firft behind the
Aorta, but afterwards pafles from it  upwards,  and a little to the
right fide, till it gets before the  firft Vertebra of the Loins.
   Here it is fituated behind  the Right Crus of the Diaphragm,  a
little higher than the right Renal Artery,  from whence  it panes
upwards, and afterwards appears in  the Thorax, upon  the fore
and right fide  of the Spine, between the Aorta and Vena Azygos,
where it is fuppofed to be confiderably aflifted  by  the ftrokes of
the Aorta in impelling its Fluids.
   In the middle of the Thorax, it is fmaller than elfewhere, be-
ing only about a line in diameter.  After this it gradually en-
larges, and, near its termination, is about a.i eighth or tenth of
an inch over.
   In the Thorax, it receives the Lymphatics of the Spatia In-
tercoftalia,  one or two of which accompanies  each of ihe Inter-
coftal Arteries, and the whole go through fmall Glands placed 
16 J
 near thefe Arteries, but moft numerous about the fides of the Dor-
 fal Vertebrae, wheie they form a fort of chain.
   Hue, likewife,  it receives Branches fiom the  Efophagus and
 Lungs, the former of which is furrounded with a number  of
 Glands, and with  a remarkable and  intricate Plexus of Lym-
 phatic Veffels.
   The Superficial  Lymphatics of the Lungs form large Areola-,
 which have fmaller Areolae within them, the larger running chief-
 ly between the Lobules, and the firialler pafling over them in fuch
 a manner as to cover almoft the whole  Surface of the Lungs.
   From the furface they go to the root of the Lungs, where they
 pafs through the Bronchial  Glands,  which have already been ta-
 ken notice of in the defcription of the  Lungs.
  At this piace  they are joined by the deep-feated  Lymphatics
 which creep along the Branches of the Tiachea and  of  the Pul-
 monary Blood-veffels.
  Through  the medium of  the Bronchial Glands, the Lympha-
 tics of the two fides of the  Lungs communicate freely with each
 other.
  Having left the Glands,  thepiincipil  part of  thofe from the
 Left Lung form a Tiunk of conlideiable fize,  which terminates
 in the Thoiacic Dua, behind the bifurcation of the  Tiachea.
 • The  reft  of the Abforbents  of the left Lung pafs  through
 Glands behind the Aich of the Aorta, which are likewife com-
mon to thofe of the Heait.  They jun at laft by a princpal Trunk
 into the Thoracic Dua near its termination.
  After leaving the  Bronchial Glrnds, the Abforbents of the
 right Lung form a  few principal Trunks one of which common-
 ly afcends on the fore-part of the Vena Cava Superior, and, tun-
 ning in a convoluted mrmner, opens into the Trunk which termi-
 nates  in the Veins in the right fide of  the neck.              ,
  The reft of thefe Trunks go into the Thoracic  Dua, near the
 bifurcation  >f  the  I rachea.
  The Abforbents of the Heart are fmall, but numerous, and form
 principal Tumks which acctrnpiny the Coronary Arteries, and,
 like them, the  large ft btlong to the left Ventricle.
  •From the fide of the right  Coronary Artery, an Abforbei.t
 Trunk which conefponds with it, paffes over the Arch of the
 Aorta to a Gland commonly found behind the origin of the Ca-
 rotid Aiteries.
  From this Gland it goes afterwards to the general  termination
in the ride fide of the Neck.
  The Lymphatic Tiunk accompanying the left Coronary Arte-
 ry is formed of  two pr'ncipal Branches, one of which runs in the
 Groove between  the Ventricles on  the fuperior Surf ice of the ,
 Heart:  The other runs i   a fimdar Groove on  the under fide'
 of the Heart, and having reached the fpace  between the Auricles 
165
and Ventricles, turns  round to join the foimer Branch near its
correfponding Artery.
  The Trunk runs next to a Gland placed behind the Pulmona-
ry Arteiy, between the Arch of the Aorta and Root of the Tra-
chea,  which, with the others here fituated, is common to the Ab-
forbents of  the Heart and Lungs.
  This Trunk terminates at length in the upper end of the Tho-
racic  Dua.
  The Thoracic Dua, after receiving numerous Lymphatics
within the Thorax, and having reached  as high as the third or
fourth Dorfal  Vertebra, paffes obliqfcely over to the  left fide of
the Spine, behind  the Efophagus and end" of the Arch  of the
Aorta, or beginning of the Aorta Defceiidens, till it reaches the
left Carotid Artery.
  After this, it emerges from the Thorax, and runs between the
Longus Colli Mufcle and Internal Jugular Vein, to about the
fixth Veitebra of the Neck.
  It now makes a turn downwards,  and, after defcending near
an inch, terminates in the upper and back part cf the angle form-
ed by the left Internal Jugular and Subclavian Vein.
  Throughout its  whole courfe, it  has a waving Appearance, and
this becomes more confpicuous in proportion as it is diftended by
injeaion.   Near the middle of the  Thorax, it,.not unfreqnently
fplits into two or more branches, and fometimes forms  a Plexus,
the Branches of which again unite into a common Trunk  a little
higher up.
  After emerging from the Thorax, it commonly divides into two
parts, which unite again previous to the termination of the Dua
in the red Veins ; and where there  is no  divifion, there is gene-
rally a Dilatation or Sac at the termination.
  Sometimes there is one termination in the angle formed by the
red Veins, and one or two in  the Subclavian Vein, and now and
then,  though more f'ddom, in  the Internal Jugular, near the an-
gle.
  In a few inftances, it has been found double through its whole
length, one Dua going to the common  place of termination in
the left fide of the  Neck,  and the other in the  coiiefponding part
in the right.
  It has alfo,  in a few rare inftances,  been found terminati^ in
the Veins  in the right fide of the Neck, while a fhort Trunk, fi-
milar to that commonly found there,  has terminated in the left
fide.
  The Superior, in a fimilar manner with the Inferior Extremi-
ties, have two fets of Lymphatics, one l)ing  immediately under
the Integuments, and  belonging to the Skin ami Leilular Sub-
ftance  under it,  the other accompanying the principal Blood-vef-
fels, and  belonging to the parts deep-fetittd.
  The Superficial Lymphatics are numerous, and aie readily feen
in emaciaied Subjeas. 
16b'
   They arife from the fore and back-parts of the Fingers  and
 hand,  by a confiderable number of Branches, and form an ex-
 tenfive Plexus upon the correfponding fides of the Fore Arm.
   Thofe upon the anterior part of the Fore-arm run diiea.y up-
 wards  to the Arm, wh le the Lymphatics on  its  back-part,  fepa-
 rate into twofeis, one of which paffes obliquely over the- Muf-
 cles on the Radius, and the other over thofe on the Ulna, to join
 the Lymphatics on the anterior part of the Fore-Arm.
   The Lymphatics of the Fore-Arm mn  over  the  bending of
 the Elbow, and afterw ards^afcend upon the fore and  inner part
 of the Arm, the grea-ter number of t,;cm running near the Balilic
 Vein.
   Some of them  frequently pafs  through fmall Glands placed
 along the  Humeral Arteiy,  one of wh.ch is commonly found a
 little above the inner Condyle of the Os Humeri, o.hei s do not
 appear to enter any Glands till they reach  thofe ot the Axilla.  ■
   A few Lymphatics accompany the Cephalic Vei ', and receive
 Branches frun the outer part of the Aim, and.  after pafling be-
 tween the Pectoral and Deltoid  Mufcles,  penetrate  Glands «t
 the under fide ofrthe Clavicle.
   Of the deep-feated Lymphatics, two  commonly  accompany    <
 each principal Artery in the Fore-Arm, and thefe uniting at the    j
 Elbow, form  twb principal  Lymphatics, which  accompany the
 Trunk of the Humeral Artery.
   Having reached the upper part of the Arm, they enter  the Ax-   1
 illary Glands, where they are joined by Lymphatics which come   J
 from the Mamma and lateral parts of the Thoiax, after pafling   I
 through fmall Glands placed  upon the under ed^e of the former   1
 and of the large Peaoral Mufcle.
  The Axillary Glands vary in number and fize indifferent per-
 fons.   Thejj  arc fomewhat fmaller, and  fewer  in number than
 thole of the Groin.  They are generally furrounded by a confi-
 derable quantity of Fat, and are fituated in the  hollow  between
 the large Peaoral and Latiflimus Dorfi Mufcles,  adhering clofely
 to the Trunks of the Axillary Blood-veffels and Nerves.          J
  From the Axillary Glands large  Blanche* go under the Cla-
vicle, and form a Trunk, which, in the left fide, commonly joins
 .ll33§r,horacic Duft n-ear its termination.   In  the r'ghr fide, they
jojTrtiie fhort  Trunk which forms the fecond genera] termination
of the Abforbent  Syftem.  Sometimes this Trunk,  proceeding   f
 from the  Superior Extremity, terminates in the Subclavian Vein,   '
 at a little d fiance from the general termination.
  The  Axillary Glands  receive alfo  the Subcutaneous Lym-
phatics  from  the back-part of the Thorax, and likewife the
Lymphatics from  the Integuments and Mufcles  of the Scapula.
  The Lvmphatics on the outfide of the  Head  accompany the
Blood-veffels,  and  pafi  through  Glands  in their way to the
 Neck.                                             J 
167,
  Thofe pafling down with the Temporal Artery  go through
fmall Glands conneaed with the Parotid Gland, and alfothrough
others fituated immediately under the rdot of the Zygoma.
  The Lymphatics which accompany the Occipital Blood-veffels
penetrate one or two  minute Glands  placed a little behind the
root  of the Ear, over the Maftoid  Procefs  of  the Temporal
Bone.
  The Lymphatics proceeding from the different parts of the Face
accompany the Branches and Trunk of the Facial Artery.
  Some of them  pafs through Glands fituated upon the outfide
of the Buccinator Mufcle, while the principal Trunks go through
a number of large Glands  placed upon the outer,  and alfo at the
under part of the Lower Jaw, at the anterior edge of the Maffe-
ter Mufcle, and about the Inferior Maxillary Gland.
  The Lymphatics from the inner part of the Nofe run principal-
ly with the internal Maxillary Arteiy, and pafs through Glands
fituated behind  the Angle  of the  Lower Jaw,  where  they are
joined by thofe which belong to the  inner parts of the Mouth.
  The Lymphatics of the Tongue,  and  likewife of the Mufcles
and other parts obout the  Os Hyoides,  enter the Glands placed
behind  the angle of the Lower Jaw.
   Lymphatics  have been  frequently  fearched for in the Brain,
but  their exiftence in that  Organ  is not yet fully afcertained,
though rendeied highly probable,—from  an appearance of Lym-
phatics having been now and then obferved upon the Suiface of
the Dura  Mater, and between the Tunica  Arachnoides  and Pia
Mater,;—from Lymphatics and Glands being occafionally found
 ia^'or'  immediately on the outfide of the Paflages of the Blood-
 veflels of  the  Brain,—from fwellings in the Lymphatic Glands
 of  the  Neck,  following difeafes of the Brain,—from the Ab-
 sorption of Water, which  has fometimes happened  in Hydroce-
 phalus cafes, and—from their having been found on the Brain
 of  Fifties.
   From the Superficial and deep parts of the Head  in general,
 the  Lymphatics  accompany the External  and Internal  Jugular
 Veins and the Carotid Arteries, receiving at the fame time Branch-
 es from the Mufcles and other parts of the Neck.
   The principal part of thefe Lymphatics go along  with the In-
 ternal Jugular Vein  and Carotid Artery,  and  in  their paffage
 form a  remarkable Plexus, which goes through the numerous
 Glands feated  near the Blood-veflels, compofing a  chain, from
 which  they are termed Concatenata.
   The Glandula Concatenata are more numerous than any other
 fet of Glands in the Body,  excepting thofe which belong to the
 Mefentery.
   The Cervical Plexus of Lymphatics having paffed through the
 Glandulse Concatenata, unite  at the bottom of  the Neck into a
 Trunk, which,  in the  left fide, enters  the Thoracic Dua near 
i'$ termination, and in the right,  goes into the Trunk,  which
forms the general termination of that fide.
  The Trunk  which forms this general termination is only from
a quarter to half an  inch in length, but its fize not much lefs than
that of the  thoracic Dua.
  It is  formed by Lymphatics from the right fide of the  Liver,
Diaphragm, Heart, and  the right  Lobe of the Lungs, by thofe
of the right Aim, right  fide of the Head,  Neck, and Thyroid
Gland; the Lymphatcs of the left  fide  of the Thyroid  Gland
forming a trunk which ends in the  Thoracic Dua.
  Befides this common Termination, fome of thefe Lymphatics
occafionally open^into the Internal Jugular, or  into the Subcla-
vian Vein,  at a little diftance from the angle formed by thtfe tvo
Veins. 
16!*
                 PART    VI.



                       OF  THE

BLOOD-VESSELS  IN GENERAL.
  The  Blood-Vessels are divided into Arteries and Veins.
                       Arteries.
  The Arteries are elaftic Canals, which convey the Blood from
 the Heart to the different parts of the Body, and are diltinguifh-
 t-d from the Veins by their Pulfation.              ,. ,
 • They have obtained their name from the Ancients, fup^pfing
 that they carried the finer parts of the Blood mixed with Air,—
 forming what they confidered the Animal Spirits.
  The Original  Trunks of the Arteries, or thofe which arife
 from the Heart, are two in number, viz. the  Pulmonary Artery
 and Aorta,—all the others being derived from thefe.
  They are dilperfed over the whole Body, and are every where
furrounded with Cellular Subftance.
  The principal Trunks run in the Centre of the Body, or of the
 Extremities, where they are  leaft expofed to danger,—Jerivliur
 fupport or defence from the Bones along which they pafs.
  The Urged Arteries goto the Vifcera, within the great Cavi-
ties, the  fin tiler  ones to  the  Skin and Mufcles, and  thofe ftiU
fmaller to the Bones,—and, in a few places, they become fo ex-
tremely minute as altogether to  exclude the red Blood, carrying
a colourlefs Find only.                                    °
  The Arteries are diftinguifhed, in  the Subjea, from the Veins
by the lubitenefs of their Colour and thicknefs of their Coats.
  They are compofed of different Layers or Coats, which are rea-
dily feparated by Diffeaion.
   Vol.  II.           P 
170
  In feveral parts of the Body, as in  the Pofterior Mediaftinum,
thc|| are furrounded  by a Membrane,  common  to  them and to
the neighbouring Vifcera.
  In other parts cf the  Bodv,  efpecially in young Subjeas, they
aie furrounded with fo  much Cellular Subftance, as to give them
the appeal ance vf bcin.  inclofed in Sheaths.
  The firft of the proper Coats is the External  Membranous, or
Cellulr.r,  called alio by fome Authors the Nervous Coat.
  In the large Arteries, this Coat is frequently furnifhed with
Fat, and is of a very elaftic nature.   Owing to  this elafticity,
the Arteries, in receiving the Blood from the Heart, become di-
lated and elongated,  and ft art from  their place, in confequence
of w!i ch they form the Pulfe, called alio the Diaftole of  the Ar-
tcrie-.
  The Second, or Middle Coat, is  compofed  of Fibres  running
in a tranfveife direaion,—of  a pale red colour,—each Fibre ap-
pearing to  form  only  the  Segment  of a Circle, although the
whole conftilute a Cylinder round the Artery.
  By the Contiaadity of this, and  the elaftic nature of the for-
mer  Coat,  the Arteries are enabled to drive the Blood to the
Veins, in proportion as they receive it from the Heart ;—and this
Contraaion is called the Syftole of the Arteries.
  The Third, or Inner  Coat, is foimed of a tranfparent Mem-
brane, rcmarkab'y  thin, fmooth,  and denf'e, by which the Blood
is pi evented from tranftiding.
  The different Co?ts of the Aiteries are conneaed  to each other
hv fine Cellular Subftances, which fome Authors have confider-
ed as fo many Lamellae.
   The ArteYies are  lY-ppIied with  their own Blood veffels, teimed
VafaVaforum, which come from the neareft fmall Blanches, and
are every wh-:re difperled upon their external Surface.
  They have alfo their Lymphatics, which,  on the large Arte-
ries,  as the Aoita,  aiefo numerous as fometimes to cover them.
   They are  likewife furnifhed with fmall Nerves, forming,  in
fame parts  of the Body, a Plexus, which vanifties in  their ex-
ternal Coat.
   There are no Valves  belonging  to the Arteries, excepting
thofe which are placed at the mouihs of the Pulmonary Artery and
Aorta.
  *Where  the  Arteries run  a certain  way  without fending off
 Branches, they are obferved  to be of a Cylindrical form ; but
 where Branches come off, their Capacity is diminifhed,  and this
 in proportion to the number of then Rt.m.ficatior.s.
   Whenever an Artery divides into  two Branches,  the  Arese of
 thefe two Branches, tak'Jb conjunaiy, are  found  to be nearly
 one half larger than that of  ihe Trunk from which they iffue.
   When the Tiunk and Branches of an  Anery aie regarded col-
 lectively,  they appear evidently of a Conical figure, tne poirt of 
171
the  Cone  being formed by the Trunk,  and the  Ba'is by the
Branches of tne Artery.
  The Siaion of the Arteries  is circular;—when empty,  tbiey
become flat, but recover their round form  upon being diftended
by injeaion.
   The angles at which the Branches go off from  their Trunks
are in general in proportion to  their vicinity to the Hitut, and are
fuch as are moft favourable to the parts they have to i'i.pply.
   In the Trunk of the Body, or where they belong to tender and
delicate Vifcera, iheangel« are  more btufe;—in the Extremities,
they are m^re acute, the former circumftance tending to dimih.fh,
and  the la.tcr to increafe tiie force of the Bmod.
  The Arteries  for.n  miny  Diviii ms  and Subdivifions before
they reach the.r Ter.ninJiti ms,  a.ii.  at 1 i.l become inviiibie to the
naked eye.
   The Divifions fornved be any particular  Artery have been va-
rioufly  enumerated "By difi rent Authors,—one  reckoning  them
at forty, and another,  of equal refpeaabtlity, at twenty only ;—
the number of them,  however,  is fuch as to allow  them to fup-
ply  the moft minute parts of the Body.
   The ftrength of the Aiteries depends  upon the  thicknefs of
their Coats, which is found to  v.ny in different Aneries.—In the
Aorta, the  Coats  are thick  and ftrong;—In the Arteries of the
Brain '.Hid  Spleen,' they" aie thin and tcndei ;—but  the  thic'.nefs
and  confequent ftrength are proportionably greater in the fmall
Branches than in the lar e Tiunks.
   The Arteries run  more or  lefs in a wa\ ing direaion, which
breaks the force of the blood  in them, and p events them  from
being ftrained by the  motions of the paits  to which th.y belong.
   The, Flexions  are  moft frequent  in Arteries  belonging to
parts the fize and fituation of which are changeable.
   The windings of many of the Ar eries are in proportion to the
degree in wheh they are dillende.i,  thofe which are nc.rly ft, aight
in the r natural ftate,  frequently becoming terpentine .vhen their
diftenfion increafes.
  Several of the large Arteries form communications  with  eaah
other, term id by Anatomifts Anaftomofes ; but the  Anrulomofes
are more fiequent among the fmall Blanches,  whcie li.ey foun  a
Plexus which leifens the dancer of  obftruaion.
  The Analtomole-t are moft frequent in the Skin and Membra-
nous Parrs.  In  tin" fol id Vifcera, «he Arteries run in a  diti'.r. nt
manner, being in lomeciowdcd together in the form  of  Tr.--s or
Bufhes,  in otheis hiving ;\ ferpentiic appearance, and in feverd
forming Penicilli,  or little Brufhes, according  to the difpclition
of the part.
  The Arteries obtain their particular  names  from their fifci-
tions, place of  deftination, Sec. and tl.j term Capillary, as  ex-
prefllve of  their  fmallnefs, is apjlietd to  their ininuceft Branched. 
     The  Diameters of the different Trunks and  Branches of thr
 .  Arteries,  vary much in diffeient parts of the Body ;  but thole
   of the Capillaries are more nearly equal to each other.
     The Aiteries teiminate in the following manner,  viz.
     In red Veins, as is obferved by  the affiftance of the Microfcope
   and  by  Injeaions :
     In Glands or Follicles by Secretory Duas, which feparate a
   Fluid frcm the general Mafs of Blood. r      - ,
     In Exli3lcntVtffels, which difcharge their contents into the
  internal Cavities, or upon the external Surface of the Body.
     In colourlcfs or Lymphatic  Branches,  which are afterwards
   continued to the ciiculating Veins, as in  the Cartilages and
   Cornea.
     'I  he Ufe of the Arteries is :           «
     To convey Blood  fiom the Heart  to the different  parts of the
   Body :
     To affift in converting the Chyle  into Blood :
     To nounfh the Body, and promote its growth :
     To affift in preferving the fluidity of the Blood, and  the heat
  and  life of the Body :
*»■   To form the different Secretions : and
     To renew the growth of parts deftroyed by accident or difeafe.

                             Veins.
     The  Veins are elaftic flexible Tubes, returning the Blood from
   the different parts of the Body to the Heart,—and have no Pul-
  fation.
     The Coats of  the Veins are the fame in number with thofe of
  the Arteries-, but are thinner, denfer,  and lefs elaftic.
     In the large Veins, as the Vena Cava, the Coats can be fepa-
  rated fiom each other;—but in the  fmall Branches  their fepara-
  tion  is difficult.
     The Mufeular Coat of the Veins being much thinner, loofe
  like  Cellular Subftance, and more indiflir.a than that of the Ar-
  teries, has cccaficned  its exiftence to be denied by many  Au-
  thors.
  -  'The Veins are  alfo  furnifhed with their Vafa Vaforum,  fimi-
  lar to and from  the f.ime fource with thofe of the Ai terics.
    The Colour of  the Veins  is fomewhat blue, and when full  of
  Blood they appear  ot  a purple tinge,  in confequence of their
   hinnefs.
     Their Size is more than  double that of  the Arteries to which
  theybelonrr,  excepting the Pulmonary Veins, the fize of  which
  fcarcely furpi fl'es  that < f their Correfponding Aiteries.
     In the fiefhv pa ts of the Body,  part cularly in the Extremities,
  they   con I'11 of  Tvjo  Sets, one deep-feated  accompanying the
  Aiteries, the other  running immediately under  the Skin, and
  termed Subcutaneous. 
I To
  The Veins of the Thoracic and Abdominal Vifcera in general,
accompany  their Arteries;  and the fame  is obfervable in  the
fmall Branches belonging to Membranous parts.
  The Figure of the Veins is fimilar to that of the Arteries; and,
upon comparing the Area of their  Trunks with  the colh-cuve
Areae of their  Branches,  like them too, they are perceived to be
Conical, the Bafe of the Cone  being formed  by the Branches,
and the Ape» by the Trunks.
  The fize and number of the Veins is fo much greater than that
of their correfponding Arteries, that when the Veffels of  a Mem-
branous part are diftended by  an  Injeaion of different  colours,
the Veins are obferved in a great meafure to conceal the Arteries :
—In the  Inteftines  however, the number of the Arteries  and
Veins is nearly equal.
  There is  much  greater variety among  the Trunks of Veins,
with refpea to fituation and divilion into Blanches, than is  oL>-
fervable among the Arteries.
  The  variety in Nature is fuch, that the Veins  of every Sub-
jea differ a little from thofe of another.
  The Veins are  capable  of fuffering greater iLTrenfion  than the
Arteries, yet  aie more frequently ruptured.  .
  The Anaftomofes are greater and more fiequent in Veins thin
in Arteries,  thofe  of  the former  being  frequently by laige
Tiunks, whereas thofe of the latter, excepting  in a few plates,
are by fmall Branches only.
  Where the  Veins  are expofed  to  Mufeular iiaion,  they are
furnifhed wiih Valves, which are fern lunar Folds continued, from
the  inner fide of the Veffls, and  placed  in  pairs at iuegul.ir
distances, their nature being fimilar to thofe of the Abforbents.
  The  Valves are concave towards the Hetut, mid when  doled or
applied to each other, reprefent a figure fomewhat like  lhat of
the  fliut end of  a thimble.
  Between  the Valves and Sides of the.Vcins next the Heart, the
Blood infinuates, and Cavities ure forme I,  termed $i<;ufes of the
Valves,  which appear externally  in the form of Varicef.
  The Valves are found in  the flefhy parts of  the Body  in gene-
ral, but are chiefly fituated in the Veins of the Extiermtic*.
   Tiie-y arc awantingin the Ve.ns of the deep-feated Vifcera,  v'z.
in  thofe of the  Cranium,  Thorax,  and  Abdomci, excepting
the  Spermatic Veins,  and fometimes  the Internal M-unmary
Veins,  and the Branches  of the Vena Azvgot.
  ■ The Valves dnea the  Bloo.l towards tiic Heart, and  prevent
 R eguigitaiion.
   Tlve Ufe  of the Veins is :—
   To  convey  the Blood  from  the  extrem't'es of the Arteries,
with the Chyle and Lymph, from the A'tdbcbents  to the  lieait.
V<a.  II.
P  2 
i: *
        DISTRIBUTION OF THE BLOOD-VESSELS.

         Of the Pulmonary  Artery and Veins.

   The  Pulmonary  Artery arifes from the right Ventricle of the
 Heart,  and afcends  behind the Sttrnum, and wrffin the Pericar-
 dium, inclining a li'tle to the left.           ■*P&"
   Having run as  high as the concave fide  of the 'Arch of the
 Aorta,  it diyides  into richt and  left  lateral Branches, which
 terminate in the correfponding fides of the Lungs.
   "The riiht Branch pyfles behind the curvature of the Aorta and *
 ihe fuperior Vena  Cava, and is of courfe the longer of the  two.
   The  two Branches are difperled  throughout the fubftance of
 the Lung-., by ramifications which accompany  thofe of the
 Bronchi.
   From  the extreme  Branches  of the  Pulmonary Artery, the
 Bid d is returned  by coirefponclng Veins.
   The Pulmonary Veins run contiguous to the Aiteries, and un-
 lika the other Veilns in general,^are  nearly of the fame fize with
 thrtr Aneries.
   In  their  courfe,  they unite  into larger  Branches,  which at
 length form four  principal Trunks,—two from  the  right,  and
 two from the left  Lung,—which after perforating the Pericardi-
 um, terminate in the left Auricle of the  Heart.

       General Courfe of the Aorta and Vena Cava.
   'The  Aorta arifes from  the left  Ventricle of the Heart, and
 feeds  off, at its Origin, the Coronary Arteries formerly defcri-
 bed.
   Where it takes  its origin, it turns a little to the right, and is
 afterwards  diieaed  upwaids,1 backwaids, and towards the left
 iidc.                   - X *■»•;.
   Ir*afcends as far as  the top of the Thorax,  under the name of
 Aorta Afcendens,  and  is afterwards refleaed obliquely back-
 waids over the root  of the left Branches of the Trachea,  forming
 what is teimed Curvature, or Arch of the Aoita.
   It then-commences Aorta Dcfcendens,  which runs  down  clofe
 upon  the Spine, t.il  it  reaches ihe fourth Vertebra of the Loins,
 wheie it divides into the two Iliac Arteiies.
  TheThoiacic portion of  the Aorta Defccndens .is fituated on
the fore and left pait of the Spine, between the Ltiyers of the  Pof-
 terior Mveliallinum.
  Where it paffes fiom the Thorax to the Abdomen, it goes be-
 tween he long Crura of the Diaphragm, after which it defcends
 more L.medi -i.y upon  the fore-part of the Vertebrae. 
175
   The Aorta fends off Arteries which cany Blood to the differ-
 ent parts of ihe Body, from whence it is returned by Veins to the
 Inferior and Superior Vena Cava,—excepting what paffes to the
 Coronary Veffels.
  ' The Inferior Cava is formed by the union of the two Venae Ili-
 icx, upon the laft Vertebra of the Loins,  a little below the  Ter-
 mination of the 'defcending Aorta.
   It is fituated upon the fore-part of the Spne, and at the  right
 fide of the Aoita, which it accompanies for  a  confiderable way
 through the Abdomen.
   Near the upper end of the Abdomen, it recedes from the Aor-
 ta, and paffes behind the large Lobe of the Liver.
   It perforates the Diaphragm  in its Tendinous part, and  hav-
 ing entered the Perrtllrdium, it goes immediately into the right
 Auricle of the Heart^u
   The Inferior Cava  receives the Blood from  the Inferior Extre-
 mities, from  the Pelvis  and Abdomen, and carries  it  to the
 Heart.  *
   The Superior Cava,—formed by the  union of the  two great
 Vena? Subclaviae, with the  addition of the Vena Azygos,—is f\-
 tuated in the upper part of the Thorax, upon  the right fide of,
 and a little more anteriorly than the afcending Aorta.
   It  begins behind the  Cartilage  of  the firft  Rib,  fomewhat
 higher than the Arch  of the Aorta,' and has at firft a fmall incli-
 nation towards the  right fide.
   After defcending about an inch, it perforates the Pericardium,
 and having run down nearly twice this fpace, it enters  the Right
 Auricle, oppofite to the termination of the Inferior Cava.
   The Superior Cava receives  the Blood from the Head, Neck,
 Arms, and containing parts of the Thorax, and alfo carries  it to
 the Heart.




   BLOOD-VESSELS of the HEAD,   and  PART of
                  THOSE OF  THE NECK.

              1J^^       Arteries.                   .;"
  From the upper fide of the Arch  of  the  Aorta, three large
Arteries arife, which fupply the Head,  Neck, and Superior Ex-
tremities.
  Of thefe  three Arteries, one on the right  fide,  termed Innomi-
nata, foon divides into the Right  Carotid, and  Right Subcla-
vian A, tery. 
176
  The other two are the Left Carotid, and Left Subclavian,
which come-off in feparate Trunks.
  Carotid Arteries : The C motid Arteries, after emerging
from  the Thorax, run up on each fide of the Neck, between the
Trachea and Internal Jugular  Veins,  and behind the Sterno-
maftoid Mufcles, graually receding from each other.
  In the Neck, they do not fend off any Blanches till  they reach
the top of the Larynx,  where each, oppofite to the Os Hyoides,
divides into External and Internal Carotid Arteries ;  the former
fupplying the outer parts ot  the Head, the other the Brain.
  The External Carotid  is placed more  anteriorly, and
nearer the Larynx, than the  Internal, which lies deeper, and  is,
at its Root, the larger of the two.
  The External, though fmaller than fhe#Other,  appears as a
continuation of ihe common Trunk.
  It runs up  behind the angle of the Lower Jaw, and in its paf-
fage befoie the Ear towards the Temple, is funk deep in the lub-
ftance of the Parotid Gland,  which it fupplies with Bldod, and is
divided into the following principal Branches, viz.
  The Arturia Laryngea Superior, Gutturalis Su-
perior, or Thyroidea Superior, which comes off from the
Root of the External Carotid, and fometimes from the top of the
common Carotid.
  It paffes downwards and forwards in a winding  direaion, and
fends
  Branches to the Mufcles about the Os Hyoides ;—
  To the Mufcles, Jugular Glands, and Skin near the Larynx;—
and
  To the different parts of the Larynx itfelf, the  continuation
and principal  part ot the Artery terminating  in  the  Thyroid
Gland.
  The Arteria Lingualis, which is  fent off immediately
above the former.—It eoes forwards and upwards  over the cor-
refponding Cornu of the Os  Hyoides, and under the Hyo-gloflus
Mufcle, in a direaion towards the under and fore-part cf ihe
Tongue.—It gives
  A fmall Branch to the Pharynx ;—
  A Branch, termed Ramus  Hyoideus, to the Mufcles placed be-
tween the Tongue and Larynx ;—           #
  The Dorfalis Lingua  to the  Fauces, Amygdala,  Epiglottis,
&c—
  The Ramus Sublingualis, which comes off under  the middle of
the Tongue, and is difperfed upon the Sublingual Gland and ad-
jacent Mufcles ;—and
  The Ramus  Raninus, which  is  the pi incipal Branch cf the
Lingual Aitery,  running at  the under and lateral part of  the
Tongue, and terminating near its point. 
m
  The Arteria Facialis, Maxillaris Externa, Labia-
LJ^s, or Angularis, which alfo runs forwards, and goes under
the Stylohyoid, and Tendon of the Digaftric Mufcles.  It per-
foiates the Submaxillary Gland? mounts fuddenly over the angle
of the Lower  Jaw, at the under and fore-part of the Maffeter
Mufcle, from whence it proceeds in a tortuous manner towards
the inner corner of the Eye.
  In this courfe, it fends the following Branches to the adjacent
parts.
   The Palatina Inferior, which runs upwards  upon the fide of
the Pharynx.-—
  A Branch to the Ton fil. Sec.—
  Branches to the Inferior Maxillary Gland ;—
   Small Branches to the root of the Tongue, to the Skin,Muf-
cles4 ice. near the angle of the Jaw ;—
  The A. Submentalis, which runs forwards under the Bafe of
the Lower Jaw, furnifhing Branches to the parts ne*r it, and ter-
 minating on the middle of the Chin ;—
   Upon the outfide of the Jaw,—a Branch to the Maffeter Muf-
cle ;—
   While upon the Buccinator Mufcle,—Branches  to the Cheek
and to the lower part of the Under Lip ;—
   Near the corner  of the Mouth,—the A. Coronaria Inferior to
the Under Lip ; and a little higher,—
   The Coronaria Superior to  the Upper Lip, from whence
Branches  run to the  under part of the Partition  and Point of
the Nofe.
   The Coronary Arteries run near the edge of the Lips, where
meeting with their fellows of the oppofite fide, they farm an A>
Coronaria Labiorum.
   Frequently one or both Coronary Arteries are larger than or-
dinary, in which cafe thofe on the oppofite fide are proportionally
fmal ice.
   After fending off the Coronary Branches, the Facial Artery
runs near the wing and lide of the Nofe.
   From this  part of the Artery Branches are fent inwards to the
Nofe, and outwards to the Cheek.
   The Facial Artery is at laft loll upon the parts about the inner
 coiner ot  the Eye, and middle of the Foie-head.
   'The Pharyncea Inferior, wlvch is a fmall Artery arifmg
 ne.u the Lingual Aitery, and frequently from the root of the Oc-
 cipitalis.
   After afcending fome way, it divides into Branches, which
 are d fper fed upon the Pharynx,  Fttuces, and Bafe  of  the Skull,
 where fi/me of them enter the large Foramina,  and fupply part
of the Dura Mater.
   The A. Occipitalis, which arifes from the back-part of the
External Carotid, and  at its oiigin is concealed by the  other ori-
 ginal Branches fent off from that Artery. 
Hi
   It runs over the beginning of the Internal Jugular Vein, and
 afterwards paffes under the Maftoid Procefs, and pofterior Belly
 of the Digaftric Mufcle.                                  -.
   It goes likewife under the upper ends of the Trachelo-maftoi-
 deus,  Splenitis, and  Complexus  Muf les ;  after which, it be-
 comes more fuperficial, where it runs near the middle of the Oc-
 ciput.
   In its courfe, it  is very tortuous, and  gives off different Bran-
 ches to the fuirounding Mufcles :  viz.
   One which defcends" along  the  Sterno-maftoid  Mufcle, and
 communicates with the Thyroid, Cervical, and  Vertebral Arte-
 ries s
   Another which  paffes, with the Jugular Vein, to the under and
 back-part of the Dura Mater ••
   A Twig, through the Foramen Stylo-mafloideum, to different
 parts of the  Internal Eat :
   A Branch which proceeds to the back-part of the  E-r, under
 the  name of  Auricularis Pofterior ;—and
   Another, of connderable fize, which defcends between the Tra-
 chelo-maftoideus and Complexus Mufcles, and, after bellowing
 Twigs upon feveral Mufcles of the Neck,  communicates with
 the  Cervical and Vertrebral  Arteries.
   The Artery is at laft dfperfed upon the beginning of  the Oc-
' cipito-frontalis Mufcle, and Skin  of the Occiput, where it com-
 municates with its fellow, and  with the  Temporal Artery.
   Sometimes, a Twig of  this Artery paffes to the  Dura Mater,
 through i\\m\. s'.V.'iU Hole  orrajignally found ne*r  the Maftoid
 Procefs of the Temporal Bone.
   The A. Maxillaris  Interna, which  goes off from that
 part of the Trunk which is covered by the Par.itid Gland, and at
 its origin lies behind, the middle of the  upright Plate which di-
 vides  into the  Condyloid and  Coronoid Proceffes  of the Lower
 Jaw.
   It paffes  firft between the Jaw and Externa! Pterygoid Muf-
 cle, and afteiwards runs,  in a very winding manner, towards the
 back-part of the Antrum  Maxillare, fending numerous Branches
 to the Parts belonging to  both Jaws.
   At its origin, it furnifhes Twigs to the fore-fide  and  adjacent
 parts of the outer  Ear.
   It then fends off the A.  Dura Matris  Media Maxima, Menin-
 gea, or Spheno-fpinalis, which runs between the External and In-
 ternal  Ctiro ids,  pafl'es thiough  the Foramen Spinale of the
 Spheno-d Bone, and fprcads over the furface of the Dura Mater
 and infide of the Par etal Bone, like the Branching of a Tree.
   The Inferior Maxillary  Branch, which  runs in  the Inferior
 Maxillaiy Canal, fending Branches to the fubftance of the Bone,
 and to the Teeth  ;—the remainder of it pafling out at the Ante- 
179
rior Maxillary Foramen, and communicating upon the Chin with
Branches of the Facial Artery.
  Branches  to the Pterygoid,  Maffeter, and  inner part of the
Temporal Mufcle, under the  names of A.  Pterygoidea, Maffe-
terica, and lemporales Profunda -.
  The A. Buccales to the Buccinator Mufcle and other foft parts
of the Cheek.
  The A. jtlveolares, which run behind the Antrum, and fend
Branches  to the foft  parts  fuirounding the  Upper Jaw.—The
Maxillary Artery  fends  other  Branches  which enter by fmall
Holes to.the Antium, and to the Subftance and  back-teeth of
the Jaw ;  one of which is larger than the reft, and is  the Proper
Alveolaris.
  The Inj'ra-orbitar, which paffes in the Canal under the Orbit,
giving, at its entrance, Twigs to the foft parts  in the bottom of
the Orbit, a.d in its  progiefs, other Twigs to the Antrum,  Sub-
ftance of the Jaw, and  Fore-Teeth ;  after which it goes out at
the Foramen Infra-oibitarium, and terminates on the Cheek by
fmall Branches which communicate with thofe of the Facial Ar-
tery.
  The Palato-maxillary Branch, which  paffes through the Fo-
ramen Palatinum  PoileTus, and runs between the Offeous and
Flefhy parts of the  Palate, fupplying thefe with Branches, and
frequently proceeding through the Foramen  Incifivum to the in-
ner part of the Nofe.
  The Superior Pharyngeal, which is a fmallBranch terminating
in and about the upper part of the Phaiynx.
   The Largs Lateral Nafal, which enters the Foramen  Spheno-
palatinum,  and divides into  many Branches which  fupply the
greater part ef the infide of the Nofe.
   A. Temporalis.—The  Trunk  of the External Carotid,
having given off the Arteries already mentioned, paffes up be-
tween the Meatus Auditorius and root of the Zygoma, and forms
the Temporal Artery, named alfo Temporalis Externa, or Super-
ficialis ;—from the icotof  wh'ch are fent off,
  The 1 ranfverfalis Faciei, which proceeds  forwards under the
Zygoma,  fupplying a large  portion of the,Cheek, and communi-
cating i-irh  the Facial and infra-orbitar Arteries :
   Some fmall Branches to the Articulation of the Jaw :
   Several fmail Branches  to  the  root of the Ear, part of which
are difperled upon the External Meatus and  Membrana Tym-
pani,—tome Twigs penetrating as far as the inner Ear.
  A little above the root of the Zygoma, where  the Puliation
of the  Temporal Artery can be feit, and frequently even feen, it
divides  into two large  Branches, an  Anterior,  and Pofterior,
which  are placed  fuperficially between the  Integuments of the
Head and Aponeurofis of the  Temporal Mufcle. 
180
  The Anterior Branch proceeds forwards, in a terpentine
direaion, to the fide and upper part of the Forehead, fupplying
the Skin and Mufcles near it, and communicating with  Branches
of the Facial and Occubr Arteries, and with thofe of its Fellow
on the oppofite fideot  the Head.
  The Postlrior afcends obliquely backwards, giving a few
Branches to the upper  put of the Ear, but is  chiefly dtfberfed on
the Integuments and Mufcles upon the lateral part anoTiown of
the Head, communicating with  t is fellow of  the fame and of the
oppofite fide, and alfo w,th the Occipitalis, by numerous Ramifi-
cations.
              Internal  Carotid  Artery.
  The Internal Carotid,—fometimes  termed A. Cerebra-
lis,—-is arched back tit its origin, and  then afcends in a waving
direaion on the fore-part of the  Reaus Capitis  Anterior Major
Mufcle, as far as the Foramen  Caroticum,  without  giving off
any Branches.                         .
  At the Bafe of the Cranium, it makes a fudden turn forwards,
and enters the Carotic Canal of  the Temporal Bone :  While in
the Canal,  it  paffes upwards and forwards, like the Canal itfelf,
and is furrounded by a confiderable quantity of  Cellular Sub-
ftance, and, by the Dura Mater, which form a  Cufhion between it
and the Bone.                    t
  After leaving the Canal, it again bends upwards and then  for-
wards, by the fide of the Sella Turcica; and  perforating theDu.
ra Mater, at the root of the Anterior Clinoid Procefs, it is fud-
denly refleaed obliquely backwards and upwards, after which it
divides into Branches.
   Through the whole of its courfe, it runs in a ferpentine mnn-
ner,  which  prevents the Blood in it from rufhing too quickly
and forcibly upon the tender Subftance of the Brain, and,—con-
trary to the nature  of other  Aiteries,—it is  of  a Conical form,
though it does not fend off any Branches, till it enters the Cra-
nium
   While at  the Side of the Sella Turcica, it turnifhes fmall
Twigs to the Dura  Mater and parts adjacent, one of which paffts
through the Foramen Lacerum to the Oi bit, and another, accom-
panied by a fimilar Twig from the Meningeal  Artery, through
the Pars Petrol":;, to the Tympanum.
   As focn as the Carotid perforates the Dura Mater, at the loot
of the Clinoid Procefs, it tranfmits
   The Arteria Ophthalmica, which  is the principal Ar-
tery  belonging to the  Eye and its Appendages.
   The Ophthalmic, orOcular Artery, immediately after it comes
off from the Carotid, enters the Foramen Opticum, and creeps
under the Optic Nerve, included in the Dura Mater, towards
the outer part of the Orbit. 
ISl
   After proceeding  fome way through the Orbit, it traverfes it«
Cavity, taking a Spiial direaion towards the 'J ie,  between the
Optic Nerve and Mufcles in the upper part of tie Orbit.
   In this courfe, it firft tranfmits  Filaments to the Dura Mater
.and Subftance of the Optic Nerve, and to  the  beginning  of the
Mufcles in the bottom of the  Orbit, after  which  it gives off the
following Branches, v z.
   The Arteria Lacrymalis, which runs at the outfide of the Or-
bit, and is chiefly  difperled  upon  the  Lacrymal Gland, fome
Threads advancing to  he Eye-lids :
   The A. Centralis  Retina, which penetrates the Optic Nerve a
little behind the  Ball  ot the  Eye,—runs  in the centre  of the
Nerve, and fpreads out into many fmall Branches  upon the inlidc
of the Retina.
   When the Nerve is cut acrofs, the orifice of the divided Ai tery
is obfervable,  wh.ch, before  its  nature  was underftood,  was
long known  by the name of Porus Opticus.
   In the Adult, the Central Artery appears to terminate entirely
upon  the Retina ;  but in  the Fcetus,  after furnifliing, at the bot-
tom of the Orb.t, the Blanches proper to the Retina, the Trunk
is continued  forwards  througfi  the axis of the Vitreous Humour,
fupplying its Cells  and Meii'ibrane with delicate Filaments, and
afterward* Ipreadiiig out  upon the back-part of the Capfule of the
 Lens.
   Its Branches aredifperfed upon the Lens in a radiated manner,
and after lurrounding it, fome of them are fent  forwaids to the
 Membrana Pupill uis.
   The Arteria Ciliares,—two or fometimes more in number,—-
 which divi.ie into Branches running in a ferpentine direaion a-
 long the oppofite fides of  the Opt c Nerve, and d viding into the
 Ciliares Breves, and Ciliares Longae.
    The Ciliares  Bievd, or  Pd-riores,—formed   not only of
 Branch.s from the original  Ciliary Trunk, but alfo of Twigs
 from  the Mufeular  Branches,—are numerous.   They perforate
 the Sclerotica, near  the infertion of the Optic Nerve, give Twigs
 to that Co.it, and dividin;, into ftill fmaller Branches, creep for-
 wards upon the Tunica Choruid-s,—foiming many Communica-
 tions  with each other as they advance, and retiring gradually  from
 the convex to the concave furfaCj of this Coat to  fupply the Iris
 and Ciliary Procefles.
   The Ciliares Longa,—which feldom confift of  mare than two
 Trunks,—perforate the Sclerotica a  little  farther forwards  than
 the former, pafs alon., the Choroid Coat  to its anterior part, and
 then feparate into Branches.
    Befides the  Ciliares Breves  et  Longa;,  there is another Set,
 termed Ciliares Anteriores, which are a few Arterious Filaments
 from the Mufeular Branches, enteiing the Eye where the Straight
 Mufcles are infeited.
    Vol. If.          Q 
1S2
  At the root of the Iris, the different fets  cf  Ciliary Arteries
unite into Aiches, which form an iiie,gular Circle, ct.lied Circulus
Iridis.
  From this Circle, many Arteries inn upon the Iris, in a radia-
ted  feipentine mannn, towards the Pupil, near  which feveral of
them alfo unite  into  Arches ; and  from thefe, Twigs are fent,
along with the reft of the radiated Branches, to the inner edge cf
the  Iris.—In the Fcetus,  they are continued to the Membrana
Pupillaris.
  The Mufcularis Superior, and  Inferior, which are  difpeifed
upon the Mufcles and Fat of the Eye.
  The OEthmoidalis Anterior, and Pofterior, two extremely fmall
Twigs, efpecially the latter, which  pafs through the Foramina
Oibitaria Interna,—Anterius, et Pofterius,—to the Bones and
Membranes of the Nofe.
  The Supra-orbitalis, or  Frontalis, which, emerging from the
Socket, paffes  through the Foramen  Supra-orbitarium, and is
divided into two parts ;—one  difperfed  upon  the Periofteum of
the  Fore-head,  the other running to the Skin and Mufcles on the
Fore-head and upper Eye-lid,  and communicating with  the an-
terior Branch of the Temporal Arteiy.
  The remains  of the Occular  Artery are continued to the inner
angle of the Eye, and are difpeifed upon the Eye-lids,  Lacrymal
Sac, fide of the Nofe, and  Frontal Mufcle,  communicating with
the upper end of the Facial Artery.
                Arteries of  the Brain.
  The Arteries of the Brain confift of the two Internal Carotids,
and the two Verlebrals.
  Each Internal Carotid, after fending forwards the Ocular Ar-
tery, gives a Branch  backwards to the Vertebral, termed  A. Corn-
municans, and  then divides into the A.  Anterior, and  A. Media  ■'}
Cerebri.
  The A.  Anterior Cerebri,  turns  towards its fellow of
the oppofite fide, and commonly (ends Filaments to the Firft and
Second Pair of Nerves.
  A little before the union of the  Optic Nerves, the  right and
left anteiior Cerebral  Arteries become almoft  contiguous, and
 anaftomofe by  means  of a fhort,  but laqe  tianfvtife  Branch,
 which forms part of that Communication of Veffels termed Cir-
 cus Arteriofus Willisii.                                       .
    From this tranfverie Branch, but  more frequently  from the
 Anterior Cerebral Artery ne?- it, a  Branch is fent off, which paf-
 fes into the Third Vtntiicle, and turn.fhes  Twi0s to the Septum
 Lucidum,  and  fore-part of the Fornix.
    The Anterior Cert-Mai Artery afcends upon  the inner fide  of   j
 the anterior Lobe of the Brain, and fends off a principal Branch,   1 
183
and commonly another foon after, both of which arch backwards
upon the inner flat furface of the Hemifphere.
  The continuation of the Anterior Cerebral Artery is  termed
A. Corporis  Callofi,  and is refilled back upon the union of the
Corpus Callofum and  Hemifphere, as  far as  the pofterior Lobe
of the Brain.
  The Branches of the Anterior Cerebral Artery are divided in-
to minute Ramifications, which are firtl fpread out upon the flat
furface ot the Jlemn'phere, and afterwards upon its upper part.
   The Ramifications  form numberlefs  Anaftomofes  with  each
other upon the furface ot the Brain, and afterwards pal's, by mi-
nute Filaments, into its Cortical and Medullary Subftance.
   Befides the Anaftomofes of the different Branches  of this  Ar-
tery on the furface of  tue Hemifphere, fmall Branches run acrofs
the Corpus Callofum,  and inofculate with thofe of the oppofite
fide.
   The Arteria Media Cerebri,—which is larger th; n the
former,—runs outwards in a lateral direaion through the Foffa
of Sylvius, to the outer  part of the Brain.
   It gives firft Filaments  to ihe Glandula Pituitaria and parts
adjacent to it, and then divides  into principal Branches, of which
one fet go to the Anterior, and  the other to the Lateral and part
of the Pofterior Lobe  of the Brain.
   From this Artery,  one  or two Twigs run up into the anterior
Cornu of the Lateral  Ventricle, and affitt  in forming the Choroid
Plexus cf that Cavity.
   Upon the outer furface of the Brain, the Branches of this Ar-
tery inofculate with each other, and with thofe of the Anterior
 Cerebral  Artery, and then plun;e  into the fubftance  of the Brain,
 where they meet  with the deep  Branches  of that Artery.
                   Vertebral Arteries.
   The two Vertebral Arteries,—which  are only a  little fmaller
than the  Intern d Carotids,—arife  from  the Subclavian Arteries
 at the bottom of the Neck.
   Each of them, at a fmail  diftance from its origin, enters the
 Canal formed for its reception by the fix uppermoft Cervical Ver-
 tebrae.
   It afcends  through  the Neck,  nearly in  a ftraight direaion,
 fending Twigs otuwards  between  the Vertebias to the deep Muf-
 cles of the Neck, and others which  pafs inw.uds  to  the Spinal
 Marrow and its Membranes, by the Holes which tranfmit the Spi-
 nal Nerves.
    Immediately below the Head, it gives out more  confiderable
 Branches to the deep Mufcles at the back-part of the Neck, which
 inofculate with the Occipital Artery.
   At the upper part of the Neck, it forms Contortions fomewhat
 finrlar to, and anfwering the fame purpofe with thofe of the In-
 ternal Carotid  Artery. 
184
  One turn is formed upwards and outwards, in paffing from the
third to the fecond  Vertebra ; and another  outwards and for*
wards, in .going between the fecond Vertebra and Atlas.
  After pei (o.ating the Atlas, it bends fudden.y back, and runs
in an horizontal direaion in a Notch upon that Bore.
  Having reached the Foiamen M  gntim Occipiti<, it turns  up-
wards, perforates ihe Dura Mater,  and enters the Cavity of the
Cranium.
  After entering  the Cranium, it  paffes  with the Medulla Ob-
longata, upon the  Cuneiform Procefs of the Occipital Bone, in-
clining towards its fellow on the other fide, and at the beginning
of ^he Medulla, the  two Vertebrals unite into the Trunk called
Bafilar Artery.                                        >
  Up. n entering the Skull, each Vertebral Artery fends a fmall
Branch, termed A. Meningea  Pofterior,—to the pofterior  part of
the Dura Mater.
  It then difperfes Twigs to the Medulla Oblongata, and  fre-
quently gives off the fmall Branch which forms the Pofterior Ar-
tery ot the Spinal Mariow.
  Near the part where ii unites with its fellow, it fends down the
Anterior Art. ry e f the Spinal Marrow.
  From the Vertebral, or from the  Bafilar, or f< metimes from
each, a principal Branch is fent off, named A. Cerebelli Pofterior,
or Inferior, which paffes  between  the Cerebellum and Medulla
Oblongata,  and furnifhes Branches  to  the  under  part of the
Cerebellum, to the   back-part of  the Medulla Oblongata  and
Tuber Annulare, and forms  the  Choroid  Plexus  of the Fourth
Ventricle.
  The Basilar Artery  runs along the middle of the Tuber
Annulare, which  it flightly impreffes, and lies upon the Cunei-
form Procefs of the  Occ pttal Bone.
   From tie fides of  this  Artery, numerous Filaments run tranf-
verfely, to be difperfed upon the Tuber and adjacent  parts
   One Branch, larger than the reft, called Auditoria Interna, paf-
fes between the  two poitions of  the  Seventh Paii of Neives  to
the Internal Organ of Hearing.
   At the extremty  of the Cuneiform or Bafilar Piocefs of the
Occipital  Bone, and at the upper and fore-part of the Tubar An-
nulare, the Bafilar Artery divides into four principal Branches,
two to  each lide,  and thefe go off almoft at light angles from the
Trunk, viz.
    The  A. Superior, or Superior Cerebelli, which turns round the
 Crura Cerebri, expands its Branches  upon the upper part of the
 Cerebellum, ar.d  finks  into its  fubftance, fupplying ailo the
Nates,  Teftes, and  Parts near them.
   The Arteria Pofterior Profunda Cerebri, which fends Twigs  to
the Tuber and to the Cru a Ceiebri, und unites  with the Internal
Carotid by the Aiteria Conimunicans. 
Vi5
  It fupplies alfo Parts lying near the Third Ventricle,  and af-
terwards turning round the Crura Cerebri, paffes back  between
the Cerebrum and Cerebellum.
  It diftributes its  numerous Branches chiefly to the Pofterior
Lobe of the Brain,  one Branch in particular penetrating into the
pofterior Cornu of  the Lateral  Ventricle, and with Branches of
the Internal Carotid, forming the Arterious part of the Choroid
Plexus.
   The Branches of this Artery anaftomofe with thofe of the an-
terior part of the Internal Carotid, at the infide of the Hemif-
phere,—and with thofe of the lateral part of that Artery,  at the
outfide of the Hemifphere, in the manner thefe do with each other
in the other parts of the Brain.
" The Arteria Communicans, wh'ch unites the pofterior Cerebral
Branch of  the  Vertebral Arteiy to the  Trunk of the  Internal
Carotid, and is nearly of  the fame diameter, but longer than that
tranfverfe  Artery  which conneas the anterior Branches  of the
Internal Carotid.
   It fends  minute Threads to the Crura  Ceiebri, &c. and con-
tributes to  the formation of the Circle of Willis,—or that kind
of Communicatio.i  by  which the  blood  or Injeaed Matter can
pafs  readily acrofs  from one  Internal Caiotid to  the  other,—or
from thefe  backwards to  the Bafilar Artery.

   Veins  of the  Head and of Part of the Neck.
   The  Veins which return the Blood  from the Arteries  of the
Head and Neck, unite into the following Trunks, viz.
   The  Facial  Vein, which is formed by  the  Frontal Vein, and.
by an intricate Plexus of Branches upon the Face.
   It winds obliquely  downwards and  outwards, at  a diftance
from the Aitery ;  but in crofting  the Jaw,  it goes clofe  by the
ourfideof it,  and terminates in the External Jugular Ye''i.
   The  Temporal Vein,  formed  by fuperficial and deep Branches
from  the fides and upper pait  of the Head,  and running down
upon the Temple at fome diftance fiom the Aitery.  •
   The Branches of the Temporal Vein form Urge Anaftomofes,
before,  with thofe  of the  Frontal Vein ;  above, with  their fel-
lows on the other  fide;  and behind, with the Branches  of the
Occipital Vein.
   The  Trunk defcends at the fore-part of the Ear, and,  along
with the Artery, is funk in the fubllance  of the Paiotid Gland.
   In its defcent before the Meatus Auditorius Externus,  it re-
ceives Branches from the Ear,  Parotid Gland, and Cheek, cor-
icfpondin-; with the Arteries fent to thefe  Parts from the Carotid
or Temporal Artery.
   At the under part of the Lower  Jaw, the Facial and Tempo
ral Veins commonly unite and form the External Jugular.
Vol.  II.
Q2 
186
  The External Jugular Vein receives the following branches at
the uppei part of the Neck,  viz.
  Branches  of  the Internal Maxillary Vein, the  principal  part
terminating in the Internal Jugular.
  The Lingual Vein,  one Branch of which, teimed Ranina from
its complexion,  is  feen  under the Tongue, and is  that" Vein
which  i; opened in the Venefeaion ot this Organ.
  Branches of the Occipital Vein, the reft pafling to the Internal
Jugular, and Vertebral Vein-, and fometimes alfo communica-
ting by a F..r;.nien Maftoideum with the Lateral Sinus.
  The Trunk of the External  Jugular  Ve:n  defcends in  the
Neck,  between  the Platyfma Myo.dcs and Sterno-maftoid Muf-
cles,  receives in its courfe Branches from the adjacent parts, and
terminates in the Subclavian Vein.
  In the formation and termination of this Vein, there  is  great
variety  in different Subjeas.
  It  frequently  happens that  moft of the  Ramifications,  which
Commonly run from the  Face  and Throat into this  Vein,  go  to
the Internal Jugular.
  Often the Facial Vein goesinto the Internal Jugular, and the
Temporal continued forms  the External Jugular.
  Sometimes one  of-the External Jugulars terminates in  the
ufual way,  and  the other in the Internal Jugular.
  In fome  rare  cafes,  the  External  Jugulars  have  both  been
found  tti minuting in one fide of the Neck.
  Anterior  External Jugular Vein.  Bi fides the Vein  commonly
called  External  Jugular,  a fmall Subcutaneous  Vein, termed
Anterior External Jugular,  defcends  in  the  fore-part of  the
Neck,  re eiving Branches from the adjacent parts, and  termina-
ting in the Subclavian Vein.
       Veins of the Eye  and  us Appendages.
  The Blood fent to the Contents of the O.bit is returned part-
ly to tin Facial  Vein  at the  inner corner of the Eye, but chiefly
to the  proper Ocular Vein,  which terminates in the  Cavernous
Sims by the following Veins, viz.
  The Vma Centralis Retina,  which is formed by many fmall
Branches expanded upon the inner furface of  the  Retina  alcng
with thofe cf the correfponding Artery.
  The Vet a Centralis enters the Optic Nerve, where  the Artery
leaves it ; and <• 1,  'ie behind the Ball of the Eye, ittmer esfioin
the Neive,  and  runs  between it and the Sheath  which covers it,
rtce vinf many Twigs from the Nerve and its Membranes.
  Ir raffs afteiwards under the Fafciculus ot Nerves which be-
lo"j*s to theEe,  and teminates, fometimes in the Ocular  Vein,
bu ,  ;n g.iui I, direaiy in th- Cavernous Sinus.
  Fiom tlit Iris 'nd C  oro  c'. Coat, the Blood is returned by the
Short  or j.i.h.. wi  Ciliary  Veins,  and by the Long or  Pofterior 
187
Ciliary Veins, and alfo by a principal fet of Ciliary Veins, termed
Vafa Vorticofa.
  Small Veins return from the Iris,  winch go under the Arteri-
ous Circle to the Veins of the Chuoid Coat, and communicate
with each other ;—but without  forming any Circle, fuch as is
found in the Eyes of Oxen, and which correfponds, in them, with
the Arterious Circle.
  The Anterior Ciliary Veins pafs from the Iris through the Scle-
rotic Coat,  near thefitme part where the Anterior Ciliary Arte-
ries enter.
.  The long Ciliary Veins are commonly two in number, like the
Arteries, and of a fmaller fize than the Vorticofe Veins.
  They  run from the Iris backwards along  the  Choroid Coat
Communicate in their paffage by minute Branches with the Vorti-
cofe Veins,  and afterwards perforate the  Tunica  Sclerotica be-
hind.
  The Vena Vorticofa, are numerous, and  obtain  their name
from the Whirls compofed by their Branches,  the courfe of which
lias been compared to a Jet d^eau,  or to the Spiral Ridges upon
the points of the Fingers, &c.
   Ot thefe Veins, four, or fomet mes five,  are by much the moft
confpicuous, the reft being fmaller, and having lefs of the Vor-
ticofe appearance.
  The Branches of  each  of the four principal Venae Vorticofae
run in a clofe congeries, unite at acute .nwles into lar er Branch-
es which have a curved  direaion,  and thefe proceeding from all
fides,  meet  in a poin>, and form the  Trunk of the Vein.
  The Trunks of thefe Venae Vort-cofae,  thus placed n the cen-
ter of their ref'peaive Whirls aie  fituated  at the oppofits  fides of
the Eye, and perforate the Sclerotic Coat obliquely near its mid-
dle.
  The reft of the Vena Vorticofa, or fmaller Ciliary Veins, com-
municate with  the adjacent larger Vorticofe Veins upon the fur-
face of the  Choroid Coat, and  alfo perforate the Sclerotica near
its  middle.
  After piercing the Sclerotica,  the different Vorticofe Veins
unite into four or five fmall CM ary Tru-.ks, receiving a number
of  minute Twi. s, which paint  the Cellular Subftance covering
the furface of the Sclerotica.
   The C  iiry  Veins run in a ferpentine dii  .'lion at the oppo-
fite files  of the  Eye, and pafs  either feparutly or united  with
othe. fmall  Veins in  ti.e  O.bit,  into the tiunk of the  Ocuiai
Vein.
  The other Venous Branches within the Orbit, ecu refpond  in
great meaf  re with their icf eaive Aiteiies ;  inch as,
  Branches fiom the Palpebral and inner corner of  the Eye.
  The La"-ymal Branch :  .
  The 0Ethmoidal Branches: 
IS*
   Mufeular Branches,--'and Branches from the Fat in the Orbit,
 a«d from the Membranes lining it.
   The different Branches from the Eye and its Appendages form,
 by th< ir union, the  Ocular Vein, which greatly exceeds the fize
 of the correfponding Artery.
   The Ocular  Vein  forms large Anaftomofes,  at the inner cor-
 ner of the Eye, with the Facial Vein, and afterwards paffes back
 at the inner fide of the Orbit.
   From the inner, it goes acrofs to the outer fide of the Orbit, un-
 der the Attoll ns Mufcle; and after running back under the An-
 terior Clinoid P.ocefs,  covered by the Third and Sixth  Pair of
 Nerves,  it terminates,  under the Carotid  Artery,  in  the Ca-
 vernous Sinus.
 Veins  of the Dura Mater Corresponding with its
                        Arteries.
   The Veins of the Dura Mater accompany their Arteries, and
 go partly through Perforations  in the Bafe of  the Cranium, to
 terminate in Branches of the External or Internal Jugular Veins ;
 —the reft go into the neareft Sinufes of the Brain.
                  Veins of the  Brain.
   The fmaller Veins  of the  Brain  accompany the Arteries.
 Their Trunks  run chiefly between the Ciicumvolutions of the
 Brain,  at a diftance  from the Trunks of the Arteries.
   They terminate in  the differerent Sinufes of  the Dura Mater,
 and generally in an oblique direaion,  which prevents the Blood
 from retuining  into them.
   The Sinufes moft commonly found are the following.
   The Superior Longitudinal Sinus,  which begins at the under
 part of the Spine of the Fiontal Bone,  runs along the upper edge
 of the  Falx,—and becoming gradually wider,  terminates upon
 the middle of  the Occipital Bone,  in the two Lateral Sinufes.
   It receives the Blood from the upper part of the Bra n, by feve-
 ral large Venous Trunks, which enter it obliquely foiwards.
  The Torcular Herophili, or Fourth Sinus of the Ancients,
chiefly f rmed  by  tue Vena Galen , which returns the  Blood
 from the Choioid Plexus, G rpora  Striata, Septum Lucidum,
 and other Inte.nai paits  of the Btain.
  The Torcular paffes back in the joining of ihe Falx and Ten-
torium,  and teiininates,  along  with  the Superior Longitudinal
 Sinus,  in the beginning of the Lateral  Smufes.
  The Inferior  Longitudinal Sinus, a lemarkably fmall one, fitu-
ated in the under edge of ihe Falx.— It receives  Branches  from
that Membrane, and from the C  us  Callofum and  parts of
the Brain near it, and terminates in me beginning of  the Torcu-
lar Herophili.
  The tvjo Lateral Sinufes, or Second and Third Sinufes of the
 *- -ents, formed by  the Longitudinal  and Torcular  Sinus.
s 
189
  'They run  at  the pofterior edge of the Tentorium, along th-
I.iteral ridges of the Os Occipitis,  as  far as the Bafe of the Pe-
tiofal Procefl'es of the Temporal Bones, from whence they wii d
downwards,  pafs through the Foramina Lacera common to  the
Occipital  and Temporal Bones,  and terminate in  the Internal
Jugular Veins.
  Frequently one of  the   Lateral  Sinufes is formed  by  the
Longitudinal, and the other  by the Torcular  Sinus ; in which
cafe,  the one is found larger  than the other.
  The Lateral  Sinufes  receive Veins from the Cerebellum and
from the under and  back-part  of the Cerebrum; they like-
wife receive the Blood from the following finali Sinufes,  fituated
under the Brain, viz.
  The Circular Sinus  of Ridley,  which  is  placed about the
Glandula Pituitaria, and frequently furrounds it completely, re-
ceiving the  Blood fiom it   and  from  the  adjacent Bones  and
Membranes, and terminating in the Cavernous Sitiufes :
  The Cavernous Sinufes, which are fituated at ihe fides cf the
Sella Turcica, and receive Blood from Veins lying near the lateral
B.anches of  the Internal Carotid Arteries, from the Ocular Veins,
and from the Circular Sinus of Ridley :
  The Cavernous Sinufes furiound  the  Carotid  Arteries  and
Sixth pair of Nerves,  and  have  a Cavernous flruaure  within,
fomewhat refembling that of the Penis :
  The Superior Petiofal Sinufes,  fituated upon the Ridges of the
Partes Petrofse.
  They  receive fome fmall Veins from the Dura Mater and Bafe
of  the Brain, and communicate backwaids  with the Lateral, and
forwaids with the Cavernous Sinufes:
  The Inferior Pctrofal Sinufes, placed at the roots of the Partes
Petrolae.—They receive the  blood from the Cavernous,  and dif-
charge it into the ends of the Lateral Sinufes.
   Befides the Smufcs mentioned above, the following others are
frequently met with, viz.
   A Perpendicular Occipital Sinus, fituated in th .  Falx Cerebelli,
wh'ch is fometimes  fingle, fometimes double, and  terminates in
the Lateral Sinufes.—It receives  Veins from the Dura Mater,
 ami communicates with the  Vertebral Veins.
   Anterior Supe ior, and Anterior Inferior Occipital Sinufes,  pla-
 ced over the Cuneiform Pro  efs of the Occipital Bone, and com-
 municating with  the Inferior Petiofal and Lateral Sinufes, and
 with the Vertebral Veins.
                 I\ i'ernal Jugular Veins.
   The  Lateral Sinufes,  having received  the Blood  fent to the
 Biain from  the Carotid and Vertebral  Arteries,  p<fs out of the
 Cranium, and form the Internal Jugular Veins ; each of which,
 at  its origin is bulge J back  in form of a Varix,  which is termed 
190
Diverticulum; and this is lodged in a Foffa at the root of the Pars
Petrofa of the Temporal Bone.
  The Internal Jugular Vein defcends behind the Sterno-
malloid MufJe, upon the ftre and  cuter part of  the Common
Carotid Arteiy, with which it is included in  a Sheath of Cellular
Subftance; and is frequently a good deal dilated towards its un-
der Extremity, efpecially in advanced life.
  In its courfe in the Neck, it receives
  Branches from the Pharynx and Mufcles adjacent to its
  The Internal Maxillary Vein :
  One cr more Branches from the Occiput:
  The Lingual Vein, which fometimes terminates in the External
Jugular:
  The Superior Laryngeal,  and now and then the Inferior La-
ryngeal, which more frequently goes into the Subclavian, or to
the top of the Cava.
  The Internal Jugular alfo receives Branches from the Mufcles
of the Neck,  and  at length terminates in the Subclavian  Vein.

The  remaining Blood-Vessels of the Neck, with   thofe of
           the Superior Extremity in General.
                       Arteries.
  Subclavian   Artery.  The  Subclavian Artery has been
already  obferved  to  arife on the right  fide,  in  common with
the  Carotid ;  and on the left,  to come  off direaiy  from  the
Aorta.                                          '
  After the Artery leaves the Thorax, it paffes tranfverfely out-
wards at the under part of the iNeck,  behind the  under end of
the Sterno-maltoid Mufcle, and continues its courle outwards  be-
tween the  Anterior  and  Middle Scaleni Mufcle--, and between
the Subclavian Mufcle and firft Rib.
   After cioffing the firft Rib, it goes under the Peaoral Muf-
cles  to the Axilla, whe.e it obtains the name of Axillary Artery.
—In this courfe,  it fends off the  following Branches, viz.
   The Vertebral;—The  Internal Mammary;  and—The Supe-
rior Intercoftal Artery.—The firft of thefe has been Already  de-
fcribed ;  the two others belong to the inner  part of the Thorax.
   The Thyroidea, orGuTTURALis Inferior, which  ari-
fes at the outer fide of the Vertebral, and, afcending obliquely
inwards  behind the Carotid Arteiy, gives Branches to  the Tra-
chea and Efophagus, and Mufcles neai them ; but is chiefly  dif-
perfed upon the Thyroid Giaid, communicating by large Ana-
ftomofes with the Laryn  ea Superior.
   The  Cervicalis Anterior, wnich frequently comes off
from the  root of the Inferior Thyroid,  and afcends  in  the
 Neck,  furnifhing fuperficial Branches  to the Mufcles  which 
191
go from the Trunk of the Body to the Neck, and deep Branch-
es to the Glands,  Neives, &c.  lying on the fore and lateral
parts  of the Cervical Vertebrae.
  The Deep Branches anaftomofe with  the Vertebral and Oc-
cipital Arteiies ; and fome pafling  through the Inteivertebral
Holes where the Nerves come  out, communicate with the Spinal
Arteries.
  The Cervicalis Posterior, which arifes in common with
the Anterior Cervical,  or  with the  Inferior Thyroid.—This is
larger than the foimer, lies farther  out, and runs in a winding
direaion outwards and upwards.
  It fupplies the Skin and Mufcles at the lateral and  back-part
of the Neck, communicates with Branches  of the  Occipital and
Vertebral  Arteries, and  fends a principal Branch downwards to
the parts about the top of the  Shoulder.
  The  Dorsalis  Superior Scapulae, which comes fre-
quently from the root of the  Thyroid, and running tranfverfely
behind the  origin  of the Sterno-maftoid Mufcle, near the Clavi-
cle,—perforates the Notch in  the fuperior Cofta  of the Scapula,
and expanding its  Branches upon the Dorfum of that Bone, fup-
plies the Spinati and other Mufcles  fituated there, and  likewife
furnifhes Branches to the joint of the Shoulder.
   The Axillary Artery, lying in the Axilla, and furround-
ed  by the Lymphatic Glands and Fat, and by the large Nerves
 which form the Brachial Plexus.  The Axillary Artery, gives
 fome fmall  Branches to the  parts adjacent;—but its principal
 Branches arc,
   The Thoracic*:, or  Mammarije Externa,—three or
 four in number,—which, by fome Authors, are defcribed by par-
 ticular names ; as,
   The Thoracica  Superior, which  gives Branches to the Peao-
 rales and Serratus, and fome  to the Intercoftal Mufcles :
   The Thoracica  Longa,  which fends  Twigs to the Axillary
 Glands ; but  goes chiefly to the large Peaoral Mufcles, Mam-
 ma, and Integuments, and inofculates with the Branches of the
 Thoracica Superior.
   The Ihoracica  Humeralis,  or Thoracic Artery  of the Shoulder,
 which  goes off oppofite  the Thoracica Superior, and divides fud-
 denly into Branches which run to the upper parts of the Thorax
 near it, and to the Mufcles and  Integuments fuirounding the Ar-
 ticulation :
   The Thoracica Axillaris, which, when  prefent, goes  off from
 or near to the Thoracica Humeralis, and  is  bellowed upon the
 Glands, Fat, &c.  frequently difperfing Branches upon the under
 edge of the Subfcapularis Mufcle.
    The Scapularis  Interna, which foon divides  into the
 Proper Scapularis Interna ami  the Dorfalis Scapula Inferior. 
192
  The Scapularis Interna runs near the inferior cdye of the Sca-
pula, fends off many large Branches, the principal part of which
are difpeifed upon ihe Latiffimus Dorfi, Teres Major, and Sub-
fcapubris Mufcles, and have large Analtomofes with each other,
and with the Superior D rfal Artery of  the Scapula.
  The Dorsalis Scapula: Inferior, immediately after lea-
ving the Internal Scapulary Artery, turns round the inner edge
of the Scapula, a little  below its Ceivix.
  Upon ihePofleri.r Surface of  the Scapula, it fpreads out into
Branches ot conli.lerabie fize, which are difpeifed upon the Muf-
cles covering the under and back-part  of the  Bone ; while the
Tru,nk,  afcendmg, inoi'culates with that of the Superior Dorfal
Artery of the  Scapula, whereby an Arch common to the two Ar-
teries is formed at the root of the  Acromion.                  '
  The Circumflexa An terior, or Articularis, which
paffes  in a tranfveife d  reition between the Heads of the Coraco-
brachialis and Biceps Mufcles, and  Body of  the Os Hunieii,
immediately below the Joint of the Humeius.
  The Circumflexa, or Articularis Posterior, which
arifes  direaiy oppofite to the former, and is  by much the  larger
of the two.
  It paffes firft between the Subfcapularis Mufcle and Teres Ma-
jor, and then  turns round between the back-pait  of the Os Hu-
meri, and long Head of the Triceps, and the Deltoid Mufcle, and
is difpeifed upon the Deltoides and  parts about the Joint  ;—its
extreme Branches anailomofing with thofe of the Anterior Cii-
cumflex Aitery, fo as  completely to encompais the Body of the
Bone.
  After giving off thefe different Branches, the Axillary Artery
emerges from behind the edge of the  great Pectoral Mufcle,  and
runs along the Os Humeri, where it is termed Humeral cr Bra-
chial Artery.
  The  Humeral Artery defcends behind the inner edge of
the Biceps Mufcle, covered by  the  Tendinous  Aponeurofis of
the Arm, and having  the Triceps Extenfor  Cubiti behind.  In
this couife, it bellows  Branches  to the Mufcles and Integuments,
and to the Periofteum  and Bone, viz.
  The Profunda Humeri, or Spiralis, which  arifes  near
the upper pait of the Arm, at the inl'ei lion of the Latiffimus
Dorfi and Teies Major Mufcles, taking a Spiral direaion down-
wards and outwards, between the Triceps Mufcle and Bone, and
terminating at  the outer Condyle cf the Os Humeri.
   The  Arteria Profunda fends  Branches chiefly to  the Coraco-
brachial and Triceps Mu.cie>, and  to thofe at the outer part
of the Elbow ;— nd one of them, defcending at the  inner fide of
the Arm, i fjincr.mes fo confiderable as to form—
   The Profunda InflRior or Minor.  I his Artery is fre-
quently a Branch of the Profunda Supciior, but mcie commonly 
193
»n original Branch fent off from the Trunk of the Aitery, near
the middle of the Arm.
  It gives Branches to the Mufcles and other parts it  the infide
of the Arm, and terminates about the inner part of the Os Hu-
meri.
  The Ramus Anastomoticus Magnus, which comes off
a little above the Eli'ow, and bellows Branches to the  Brachials
Interims, to  the  under end of the Triceps, and to the Parts in
general about the Elbow-Joint.
  Befides thefe, there are feveral other Branches fent in fucceftion
from the Trunk of the Humeral Artery into the Mufcles and o-
ther parts adjacent.—Thefe  are  fhorter than the  reft, and run
more in a tranfverfe  direaion, efpecially thofe to the Biceps Muf-
cle.—One fmall Branch, termed Nutritia,  or Medullaris,  pene-
trates the  fubftance of the Bone by the paffage near its middle,
and  fupplies the Marrow and Parts which contain it.
  The Trunk of the Humeral Artery having fent of  the differ-
ent  Branches which belong to the Arm, paffes to the  middle  of
the  bending of the  Elbow, between the Aponeurofis  and round
Tendon  of the'B  ceps Mufcle.
  About an in. h  below the Elbow, it commonly divides into two
principal Arteries, the Radial and  Ulnar.  It happens, however,
now and then, that this Divifion takes  place about the middle of
the Arm ;  and in certain inftances, as hgh as the Axilla.
  The Radialis paffes  over  the Pronator Teres Mufcle, and
follows the courfe of the Radm* through the whole length of that
Bone
   At the  upper part of the Fore-arm,  it is covered by the  Supi-
nator Longus :  In its defcent, it becomes  more fuperficial, and,
at the under part of the Fore-arm,  it liesclofe upon the Radius,
and immediately  under the  Skin,  in confequence  of which, the
Pulfe is  commonly felt in this place.
  The Recurrens Radialis, which is  refleaed to the  Muf-
cles and  Parts of the  Joint near it, and anaftomofes freely with
the Arteria Profunda Humeri at the outer part of the Elbow.
  Numerous Lateral  Branches, in the defcent of  the  Artery, to
the Mufcles and Integuments, and parts in  general  fituated about
the Radius.
  A Branch  at the Wrift,  which goes over the root of  the
Thumb, and fometimes a principal Branch along one fide of it;__
at other times, it is difperfed upon the Palm of the  Hand.
  Small Branches to the Ligaments, Bones and other parts about
the Wrift.
  One, or fometimes two Branches, termed Dorfal, to  the back-
part of the Metacarpus and Fingers.
  At the under end of the Fore-arm,   the Radial Artery turns
back under the Tendons  of the Extenfors of the Thuiab, and
   Vol.  II.             R                        ^ 
i
194
 gets  between  the  roots of the Metres pal Bones of the Thumb
 and Foie-finger, where it divides into three principal Blanches,
 viz.
   The A. Magna Pollicis, which runs along the fide of the
 Tumb next the Fingeis, and Jometimes divides at its root,  into
 two Branches, which fupply both fides of it.
   The Radialis  Indicis,  which runs  along  the file  of the
 Fore-finger nexi the Thumb.
   The Palmaris Profunda, which croftcs the Hand between
 the roots of the Metacaipal hones and Flexures  of the Fingers,
 and foims an Arcus Profundus, from  which  Branches  go off to
 the Interoffei Mufcles and other deep  parts of the Palm.
   TheULNARis   appears  at  firft  as the Continuation  of the
 Trunk of the Humeral Artery.
   At its upper part, it finks deep  behind the Flexor Mufcles of
 the Hand,  and paffes afterwards.for fome way between the Flex*
 or Sublimis and Profundus Digiiorum.
   Near the Wrift, it becomes more fuperficial, and runs between
 the  1 endons of the Flexor Carpi Ulnaris and Flexor Digitorum
 Profundus, to the  Hand.
   In this  courfe,  it fends off many Branches to the Fore-arm,
 among which the following are the moft confiderable.
   The Recurrens Ulnaris, which runs deep among the Flex-
 or Mufcles, and foon  divides  into Branches which nfcend  and
 fupply the Parts about the under and inner  fide of the Elbow.—
 In the Gioove behind the inner Condyle of the Os  Humeri, it
 communicates by diftina  Anaftomofes with  the Profunda Infe-
 rior, or with the R  mus Anaftomoticus, fent down from the Hu-
 meral Artery.'
   The Interossea Posterior, which comes off at the  upper
 end of the Interofl'eous  Ligament,  perforating it  immediately at
 its origin, and going to the back-part of the Fore-arm.
   From this place, it fends upward.-< a Recurrent  Branch,  which
 communicates, upon the back-part of the Elbow,  with ihe other
 Recurrent  Arteries, and with the  Branches fent down  fiom  the
 Humeral Artery, and  foims along with thefe a Plexus of Veffels
 upon the, hick part  ot the Joint.
  The Intcroffea  is afterwards continued  downwards,  and is
clvefly difperled upon the Bellies of the External Mufcles  of  the
 Hand and Fingers, being commonly exhaulted before it  leach the
 Wrift.
  The Interossea  Anterior,  which comes off fi metimes
 immediately btlow  the foimer, and  ai  other times in common
with it.  It is confiderably the larger of the two ; but only a-
bout half the fize of the Ulnar Artery  irom which it fprings.
  It runs  clofe upon the Interofl'eous  Ligament, and  fuiiiihes
 Tranches to the Mufcles and  deep Parts upon the  anterior  f.'le
of the I wi.-arm. 
                            IV-

  Near the Wrift, it perforates the Ligament, and goes to the Pof-
terior fide of the Carpus and back of the  Hand, dividing into
Branches Which inofculate with others of the Pofterior Interoffe-
ous and Radial Arteries.
  The Ulnary Aitery, having given  off its Recurrent Branch,
and the Arteriae Interofllae, with  many  Lateral  Branches to the
inner fide of the Fore-arm, paries by the fide of the Os Pififorme,
and then over the  Annular  Ligament into the Palm, where it
forms the Arcus Volaris Superficialis.
  At the under end of the Fore-arm, it fends offa Dorfal Branch,
which paffes under the Tendon of the Flexor Crpi Ulnaris to
the back of the Hand, where joining with Branches of the An-
terior Interoffeous and  Ulnar Aiteries,  it  affifts  in forming a
Plexus which  fupplies  the back-part  of the  Wiift and of the
Hand and Fingers with  a number of Branches, which  are fmall
when compared with thofe in the Palm.
  The Arcus Voj.aris Sublimis,  or  Superficialis, is
placed with  its convex fide downwards,  and exten.l =  obliquely
from  the root of the Me i arpal  Bone of the  Little Finger to-
w irds that of the Firft Bone cf the "I humb,  being coveied by the
expanfun termed Jp-aieurfis Pahiurii.
  From the  Arcus Volaris,  Branches ..re fent off in the follow-
ing order, viz.
  Several Small Branches  to the Integuments and other Superfi-
cial parts of the Palm :
  A confiderable Branch which finks near the root  of the Meta-
carpal Bone of the Little Finger, and inofculating with the Pal-
mar Branch of the Radial Aitery, affi.ls in forming the Arcus
Profundus :
  A Branch to the inner fide of the Little Finger :
  Three  large Digital Branches which run  oppofite to the  Inter-
faces of the  Mcacarpal  Bodes, to the Roots of or Clefts between
the Fingers.
  At thefe  Clefts, each of the Three Digital Arteries  is divided
into two Branches, one of which Branches  of each divifion runs
along the Anterior Radial margin of one Finger, and the other
along the Anterior Ulnar margin of the  Finger next it ;—the
Three Digital Arteries  thus  fupplying the margins of  all the
Fingers, excepting the inner margin of  the Little  Finger,  and
the outer margin of the Index.
  At the Roots  of the Fingers, each of  the Digital Arteries re-
ceives a fmall  Branch from the Arcus Profundus.
■  At the Roots and Joints, but more particularly at the Points
of the Fingers, the Arteries  communicate by crofs  Arches,  and
fend Branches to the parts adjacent.
  The Supeificiai Arch of the Palm  commonly fends off one of
the  Arteries of the Thumb, and ultimately communicates by a
large Antiftoinofc* with the Root of the Arteria Magna Pollicis. 
I 9o
   VEINS  of the SUPERIOR EXTREMITY and of
                  PART of the NECK.

   The Veins of the Superior Extremities have numerous Valves,
 and are divided into a  Superficial and a Deep Set ;  the former
 lying immediately under the  Integuments, the  latter accompany-
 ing the Arteries, and taking  their names from  them.
   The Subcutaneous Veins have many large  Anaftomofes with
 each other, particularly  on  the Fore-arm, where they unite,  fe-
 parate, and re-unite feveral times, thus forming a Plexus by which
 it is furrot nded.
   The Supeificiai  Veins from the back of the Hand (one  of
 whick, belonging  to the Little Finger, was teimed  Salvatella
 by the Ancients) go chiefly  to the Superficial Radial,  and partly
 alio to the Ulnar Veins.
   The Superficial Radial Veins  form the Vena Cephalica, and
 the Superficial Ulnar Veins the Vena Bafilica, at the Joint of the
 Elbow.
   The Superficial Veins on the Anterior part  of ihe Fore-arm
 communicate laterally with the Radial and Ulnar Veins, and, in
 the'r afcent, from a Trunk termed Mediana Longa.
   The Mediana  Longa, a little below the bending  of the El-
 bow, is divided into Mediana  Cephalica and Mediana Bafilica,
 which running obliquely  upwards, terminate a little above the
 Elbow, the former in the Cephalic,  and the latter, crofling over
 the Humeral  Aitery, in  the Bafilic Vein.
   Though this defcription correfponds with the general diftribu-
 tion of the Veins of the Fore-arm ; yet, fo great is the variety
 among them,  that they are fcarcely found to agree exaaiy  in any
 two Subjeas.
   The Basilica, in its afcent, forms the princ:pal Humeial
 Vein, which  paffos alorg the fide of the Os Humeri, a little to
 the infide of the Humeral Aitery, and  receiving Branches from
 the correfponding fide of the Arm, it luns into the Aim-pit, and
 forms the Vena Axillaris.
   The Cephalica afcends at  the outfide of the Biceps Mufcle,
 receives Branches  from the adjacent parts of the Arm, and com-
 municates''in feveral places with the Bafilic,  and paffing in the
 Groove between the Large Pectoral and the Deltoid Mufcle, ter-
 minates in the Axillary Vein.
   The Deep Veins, termed alfo Vena Satellites, or Concomites run
clofe by the fide of  their refpeaive Arteries, one lying commonly
on each fide of the Artery, and receiving the Blood from the ad-
 acent parts.
   In various  places they anaftomofe with  each other  by fhort
Branches, which crofs over the  Arteries. 
107
  Near the Joint of the Elbow, the Deep  Radial,  Ulnar,  and
Interoffeous Veins, form a Plexus over the Bifurcation of the Hu-
meral  Artery.
  From this  Plexus, a fhort but large Branch paffes  outwards,
and forms a Communication with one of the Subcutaneous Veins,
and, in general,  the  Communication is with one of the Median
Veins.                                               „,.
  The Vena Axillaris,  formed by the Trunks of the Superficial
and Deep Humeral Veins, receives the Veins correfponding with
the Circumflex  Arteries, and the Internal, and the Inferior Dor-
fal Veins of the Scapula.
  A little higher, it  is joined by the Vena Thoracica Externa,
and about this  place, changes its  name for that of Subclavian
Vein.
  TheVEKA Subclavia  paffes betwen  the  Clavicle and firft
Rib, at the inner fide of the trunk of the Artery, and afterwards
goes over the fore-part of the Anterior Scalenus Mufcle,  at the
under  end of the Neck.
  After crofling  the firft Rib,  it receives  the Vein correfponding
with the Superior Dorfal Artery  of the Scapula, others wh.ch  fee-
long to the Cervical Arteries, and alfo fmall Veins from the Skin
and Mufcles on the back part of the Neck.
  While  fituated in the Neck, it likewife  receives the External,
and then the Internal Jugular Veins ; and near this laft a Vein of
confiderable fize, which correfponds  with  the Trunk of the Ver-
tebral  Artery.
  The Vertebral Vein communicates within  the Cranium, by
fmall branches, with the Inferior Petiofal Sinufes, or  with Oc-
cipital Sinufes  ;  but is  chiefly formed by branches arifing from
the Spinal Marrow and its Membrane:,  and from the Bones and
deep-feated Mufcles of the Neck.
  Behind the top of the Sternum, the Subclavian Vein frequent-
ly receives the Inferior Laryngeal Vein,  the Anterior External
Jugular,  and   the Internal Mammary Vein.—Be fides thefe,  the
Left Subclavian receives alfo the Left Superior  Litercoftal  Vein;
after which, it  goes acrofs the Root of the Great Aiteries  fent up
from the Arch  of the Aorta, and joins its fellow on the oppofite
fide to form the Superior Ca\a.
:0«W»-----
       BLOOD-VESSELS withim the THORAX.

  Of the Blood Veffels within the Thorax, the Pulmonary Ar-
tery ^ and  Veins, the Aorta, the Coronary Veffels,  and the other
Veffels conneaed with the Heart have been uiready noticed.
   Vol.  If.           U 1 
195
   The following are thofe which remain to be defcribed.
   The Mammaria Interna,  whjch arifes from  the Subcla-
 vian, oppofite to the  Inferior Laryngeal, and defcends between
 the Pleura and Camiages of the True Ribs, at the  edge  of the
 Sternoin ;—fending off
   A Small Refieiled Branch to the Integuments and Mufcles ad-
 jacent to the Clavicle :
   One or two fmall Branches,  termed Thymicte, to the Thymus
 Gland;  and which, like the  Gland itfelf, are moft confiderable ia
 the Young Subjea :
   A mini:te Branch,  termed Comes  Nervi Phrenici, which ac-
 companies  the Phrenic Nerve, and after giving Twigs  to the
 neighbouring Membranes,  is diftributed upon the Diaphragm :
   Some fmall Branches,  called  Med.iajlime, and Pericardia, to
 the Mediaftinum and Pericardium :
   Several Branches outwards, to the Intercoftal  Mufcles ;  and
 ethers between the Cartilages of the True Ribs at the edge of the
 Sternum, to the Peaoral Mufcles,  Mamma  and  Integuments,
 which communicate with thofe of the Thoracica? Externa? :
   A Large Branch, at the   under end of the  Thorax, which is
 difpeifed upon the Diaphragm.
   The Mammary  Aitery afterwards emerges from the  Thorax,
 commonly under the Cartilage of the feventh True Rib, and  runs
 upon the back-part of the Reaus  Abdominis Mufcle, upon the
 upper end of which it is difperled, after fending a Branch to the
 Oblique Mufcles of the Abdomen.
   The Intercostalis Superior,  which comes off  a  little
 farther out than the Mammary,  and defcending near the  Spine,
 commonly divides  into two  or three Branches, which fupply an
 equal number of Intercoftal  Spaces.—It alfo fends a Branch up-
 wards to the Deep Mufcles at the under and fore-part of ,hc
 Neck.
   The Arteri^e BrONCHIales, one in the right and two or
 three  in the left fide of the Thoiax,  which  are difpeifed upon
 the conefponding fides of the Lungs.
   The Bronchialis Dextra, which  arifes moft frequently
 from  the  uppermoft Intercoftal Artery of the Aorta ; and the
 Bronchialf.s Sinistra, which  are of unequal  fize,  from
 the fore pait of the Aorta at a little diftance from each other.
   The Bronchial Arteries fend fmall Branches to the Efophagus,
 to the Pofterior Mediaftinum and Pericardium,  and afterwards
 accompany  thofe of the Trachea through the fubllance of the
 Lungs.
   The Arteri^;  EsophagE.S, which are  minute Branches
 arifing from the Aorta,  and dffperfed upon the Efophagus, alfo
 fending  Twigs to  the Pofterior Mediaftinum.
  The  Intercostales Inferiores, which are nine  or ten
pairs in number, arifing from the back-part of the Aorta,  and
« 
199
running in the Grooves at the under edges of the Ribs, between
the External and Internal Intercoftal Mufcles.
  They furnifh Branches to the  Spine and Spinal Marrow, to the
Intercoftal Mufcles, Pleura, &c.  alfo numerous Branches to the
Mufcles on the  back of the Thorax,  and communicate with
thofe of the Internal and External Mammary Arteries.

                         Veins.
  The Blood  fent to the Thorax by the Arteriae Mammiriae In-
terna?, Intercoftales, and Efophageae, is returned to the Heart by
the following Veins, viz.
  The Mammary Interna, which accompany their corre-
fponding Arteries, and terminate, the Left in the Subclavian, and
the Right in this, or in the top of the Vena Cava.
  Some fmall  Veins, as the  Pericardiaco-Diaphragmatic,  the
Thytnic and'Pericardiac, which, in place of joining the Mamma-
ry Trunk, commonly terminate, the Right in the Subclavian, or
top of  the Cava, and the Left in the  correfponding  Subclavian
Vein.
  The Ven^e  Intercostales, which are the fame in number
with their Arteries, and accompany them along the edges of the
Ribs.
   Several of   the Lower Left  Intercoftals unite into  a  trunk
termed Vena Azygos, which croffes over the Spine about the mid-
dle of the Thorax,—behind,  but fometimes before the Trunk of
the Aorta,—to the right fide.
   The Vesa Azygos, or Venafine Pari,  thus originally form-
ed by the Lower Left Intercoftals, afcends on the fore-part of
the Spine over the  Intercoftal  Arteries, at the right fide of the
Aorta.
   At its lower extremity, it generally communicates with one of
the Lumbar Veins,  or with the Vena Renalis ; and not unfre-
quently with the Trunk of the Inferior Cava.
   Upon the Spine, it receives the Right Intercoftals, and the Right
Bronchial Vein ; and turning forwards over the Root of the Great
Pulmonary Veflels of that fide,  it terminates in the Superior
Cava.
   The Upper Left  Intercostal Veins, or fuch as are not
received by the Vena A7\'£os,  terminate in a trunk on the left
fide, improperly called Lejt Vena A~yg;-.   t   f
   The Left  Vena Azygos, Ll V Bronchial,  or Left
Superior Intercostal Vein, befides  the Superior Intercof-
tal Branches,  receives  the Left Bronchial Veins and Branches
from the Efophagus and other parts near it, and terminates in the
Subclavian Vein.
   The Vena  Cava Superior,—formed by the union of the
Subclavian Veins,  with the addition  of the Vena Azygos,—paf-
fes down at the right fide of the afcending Aorta, perforates the
m 
200
Pericardium,  and terminates  in  the  upper part  of the Right
Auricle.                        *

           Blood-Vessels of the Diaphragm.
  The Diaphrrgm  is  fupplied  with Blood-veffels from  va-
rious fources, viz. thofe  entering its upper part  from the Inter-
nal Mammary, already defcribed ; alfo fmall Branches from the
Intercoftal and Lumbar Arteries.  Its  principal Branches, how-
ever,  are the  Phrenic, or Diaphragmatic.
  TheARTERi/E Diaphragmatic^:, are two in number, one
on each lide, which arife  from the fore part of the Aorta as foon
as it enters the Abdomen.
  In general, their originis diftina from each other, but fome-
times by a common  Trunk ;  and now and then, one or  both,
originate from the root of the Cceliaca.
  They afterwards go obl'quely upwards and outwards over the
Crura  of  the Diaphragm, fpread  out  into many  Branches
which are  chiefly difpeifed upon its Flefhy fides, and inofculate
with thofe which enter at its upper fuiftce.
  They likewife give fmall Branches to ihe Glandula? Renales, to
the  Cardia, and parts in  general which lie near ihem.
  The Ven^e  Diaphragmatic.*, like  their correfponding
Arteries, run  upon the under part of the Diaphragm, and ternii -'
nate in the Inferior Cava, behind  the Liver,—the right  being
commonly a little lower than the left.
•C'
    BLOOD-VESSELS of the CHYLOPOETIC, and
       ASSISTANT CHYLOPOETIC VISCERA.

                       Arteries.
  The Arteries of thefe Vifcera, confift of the Ccrliac, and the
Superior and Inferior Mefenterics; all of which are A"Zygous  or
fingle Arteries arifing from the  tore part of the Aorta.

                   Arteria  Coeliaca.
  The Arteria Coeliaca, ariies from the Aorta,  immedi-
ately after it emeiges from between the Ciura of the Diaphragm
into the Abdomen ;  and is fituated at the upper edge of the Pan-
creas.
  The Trunk of the Coeliac Artery is remaikably fhort, being
little more than half an inch in length, before it divides into its
three princ pal Branches, called from  their dcftination,  Superior
Gaftric, Hepatic, and Splenic. 
201
  The Gastrica Superior, or Coronaria Ventriculi
Superior, is the final left of the three.  It goes upwards,  and
a I ttle towards the left, to reach the right fide of the upper Ori-
fice of the Stomach.
  Here it fends Branches to the Cardia, which encircle it,  and
afcending fomeway upon the Efophagus, communicate with the
Arteria: Efophagese.
  The Trunk of" the Artery afterwards  divides upon the fmall
Curvature  of the  Stomach, into  principal Branches,  feme of
which run acrofs the upper and under Surfaces, and other*  ob-
liquely towards  the right fide;  fupplying a large portion  of the
Stomach,  and fending Twigs  to the Omentum  Minus,—while
the Trunk is frequently extended as far as the Pylorus.
  The Arteria Hepatica, the lai;geft  of the tlnee, paffes ob-
liquely upwards,  towards  the Pylorus,—before, and a litttle to
the right fide of the Lobulus Spigelii,—till it arrives at the  Ca-
vity of the Liver called Porta.
  Where it approaches the Porta, it divides into the Gaftroica-
Inferior Dextra, and the Proper Hepatic Artery.
  The Gastrica Dextra, or Gastrica  Inferior Dex-
tra,  or Gastro-Epiploica Dextra, fends out—
  The Arteria Pylorica, which, however, is frequently produced
immediately from the  Hepatic Artery.  It gives Branches to the
Pylorus and other parts about the fmall end of the Stomach, and
afterwards runs fome way along its  fmall Curvature, inofcula-
ting with the Superior Gaftric Artery.
  Befides this principal Branch, there are a few fmaller ones fent
from  the Gaftrica Inferior to the Pylorus.
  The Duodenalis, which is difperled upon the  beginning  and
right  portion of the Duodenum, along with other Branches com-
ing from the fame fource,  but of inferior  fize.
  Rami Pancreatici, diftributed to the right  end  of the Pan-
creas.
  After furnifhing the Branches already mentioned,  the  Inferi-
or Gaftric Artery paffes under the Pylorus to  the great Curva-
ture of the Stomach, along  which it  runs; being  included, to
near its large extremity, in the Layers of the Anterior Portion of
the Omentum.
  In this courfe, it fends oft—
  The Rami Epiploici, which are long and flender Branches dif-
peifed upon the Epiploon or Omentum.
  The Rami Gaftrici, which pluiu-ing fuddenly into both fides
of  the  Stomach, communicate with  the  Pyloric and  Sup rior
Gaftric Arteries.
  The Hepatic  Artery, having given out  the  Inferior Gaftric,
and frequently, the Pyloric Arteiy,  foon  divides into two prin-
cipal  Branches,  a right and left, of unequal  fize, which  run 
                           202

into the Porta;—the on-,—-nder  the Hepatic Du** — © fupply
the great, aad the other the liiall Lobe of the Liver.
  Frcm the Right  Branch, before it plunges into the Liver, is
fent off the drtericFCyjlica afterwards  divid ng into two lmalier
Branches, termed Gemella, which are difpeifed upon the Gall-
bladder.
  Frequently,  befides the Hepatic Artery fent of from the Coe-
liac, there  is  another,  coming fometimes  fr. m  the Superior
Gaftric, at other times from the Superior Mcunteric Aiteiy,  to
be lent into the  L'ver.   In fuch cafes, the i runk which gives
origin to this additional  Artery  is  greater than  ufual,  and t!,«
Hepatic Branch which it  accompanies is proportionally fmaller.
  The Arteria Splenica, nearly equal in fize to the Trunk
of the Hepatica, takes a long and ferpentine comfe acrofs the
left fide of the Body ;  running  firft  behind, then at  ihe  upper
part  of the  Pancreas  in its way to  the  Spleen.   Its Branches
arc.
   i he Rami Pancreatici, which are  few in number and  fma I.
They run from the Splenic .Artery  nearly at right angels, and
fupply the greater part of the Pancreas.
  The Gaftrica  Siniftra, Gaftrica Inferior  Siniftra, or Gaftro-
Epiploica Siniftra,  which  is confiderably inferior in  length and
fize te the Gaftrica Dcxt a.   It communicates by its Branches
with the Gaftrica Superior, and Inferior, while its Trunk runs a
little way towards the right fide along the great Curvature of the
Stomach.
  It fends feme Rami  Pancrea ../,  and Gaftro-Epiploici, am'
Mefo-colici Suiiftri, to  the Pancreas, left portions of the Omen-
tum  and Mefocolon;  while its Tiunk fiequently forms  a com-
mon Arch widi the Gaftrica Dcxtia.
  Thiee or four confiderub.e Branches, termed Vafa Brevia, or
Arteria Breves, which run to  the left part of the great  Curva-
ture of the Stomach,  to be diftributed upon its lat?.e  xtcnity  ;
their Ramifications anallomofn*^ vri.h thofe of the Superior and
of the Left Inferior Gaftric Arteries.
  The Rami Sp'enici, 1. vera I  in  number and  of confiderable
fize,  which go at the concave fide of  the Spleen, to be diftributed
throughout the whole of its fubftance.
                Mesf.nterica  Superior.
  The  Mesenterica  Superior  arifes  from the Aorta, im-
mediately below tie Cceliac Artery,  which  it equ ds in fize ; and
running under the  Pancreas, and  then over the  Duodenum, it
paffes between  the Layers of the  Mefentery towards the under
fide of the Abdomen.
  In its defcent, it is bent a little to the left fide,  its lower ex-
tremity turning towards the beginning of the Colon.
  From the convex fide of the Artery, many large Branches are
fent off to the fmall Inteftines; while others proceed in the oppo-
fite direaion to the right fide of the Colon. 
203
  The Firft Arteries fent off from the Trunk are very inconfHe-
rable, running to the Pancieas and to the left portion of the Du-
odenum, and commun.cuting therewith Branches  of the Cceliac
Artery.
  The  principal Branches from  the  left fide of the Trunk  re
difpeifed upon the Jejunum and Ilium, fupplying, in theircourfe,
the Layers of the Mef. ntery with the parts it contains.
  The firft of thefe Branches arc fhort and fmall,  thofe which
fucceed gradually incieafe in  length and fize to the middle of the
Arch, after which they diminifh again fomewhat in the fame pro-
portion  towaids the lower part of the Ilium.
  In  their courfe through the Mefentery, the principal  Branch-
es communicate,  firll by reciprocal Arches, then  by Areolae  of
diftcrent fi  ures, winch incrcafe in number, but dimin.fh in fize
as they  approach the Inteftines.
  Fiom thefe Areolae, many Branches  are detached, which take
a ftraight courfe to the Inteftines, and are afterwards ramified
through their fubftance, forming numberiefs  Anaftomofes with
each other.
  The  Branches produced from the right or concave fide of the
Trunk  are fituated between  the Layers of the Mefo  colon,—
their length being almoft equal to the breadth of that Membrane.
  Near the Inteftines,  ihey communicate by large and then by
fmaller  Arches : Thefe laft, however, are lefs frequent than thofe
which belong to the fmall Inteftines.
  The principal Branches are the following.—
  The Ileo-colica, which arifes near the under part of the Trunk,
fupplies the end of the Ilium and beginning of the Colon, and
communicates with the Branches fent from the extremity  of  the
Trunk  of the Artery.
   A  Short Trunk,  which divides into—
   The  Colica Dextra, for fupplying the right fide of the Colon,
—its Branches commun eating with thofe of the Ileo-colica : And
  The  Colica-Media, or Media  Anaftomotica, which proceeds to
the great Arch of  the Colon.
  Near the  Colon, the Colica  Media divides into two  large
Branches ; one formin.; an Arch with the Dextra, the other with
a Branch  of the Mel'enterica  Inferior.
   From the oppofite fide of the  Colon,  Branches  of this Artery
run to the Omentum, and communicate with the Gaftro-Epiploic
Aiteries.
  Befides the Colic Branches already defcribed, there is frequent-
ly an  additional one, which arifes from the beginning of the Su-
perior Mefenteric Aitery, and in  its Tifcent Fp I its into two others,
one of which, uniting wiih ehe  Colica Media,  forms  the  lane
Mefocolic Arch, and the other a  fimilar Arch with the afcending
Branch of the Inferior Mefenteric Artery. 
20 1-
                Mesenterica Inffrior,
  The Mesenterica Inferior  arifes from the Aorta fome-
what lowei than half way between the Superior Mefenteric  and
the Bifurcation of the Aorta.
  It defcends obliquely upon the left Pfoas Mufcle, and  foon
divides into pnncipal Branches.
  Thefe near the Inteftine join with each other, and form Arches,
from which others go off compofing Aieolae in fome meafure fi-
milar to thofe which belong to the right fide of the Colon.—The
principal Branches are :—
  The Ramus Afcendens, which  divides near the Inteftine, into
two Branches ; one  of which joins the  Colica Media, to form
the great Mefocolic  Arch,  the other is  refleaed upon  the  left
portion of  the Colon.
  The Colica Siniftra, which is frequently double from its ori-
gin, or at other times fplitting intwo two Branches, one joining
the Ramus Afcendens, the other pafling down by the  Sigiuo.d
Flexure of the Colon.
  The Hemorrhoidalis Interna,  which is the Trunk continued.
It anaftomofes with the Col ca Siniftra, and afteiwaids defcends
upon the back-part of the Reaum to near ills under extremity.
                         Veins.
  The Veins which return the Blood from the  Chylopoetic and
Affiftant Chylopoetic Vifcera, accompany their refpeaive Arte-
ries,.—the  Hepatic Branch excepted.—They have, like their Ar-
teries,  large and  fiequent  Communications with each other, aie
much  fuperior irt fize, and, as well as the other Veins of the Vil-
cera fituated in the great Cavities, are deltitute of Valves.
          The following are the Principal Trunks.
  The Mesenterica,  or Mesaraica Minor,  or  He-
morrhoidalis Interna.
  The Mesentlrica Minor, running up at the left fide of
the Spint, receives—
  The Proper Vena Hjemorrhoidalis  Interna, which
returns the Blood from the  Inteftinum Reaum;—the name  ob-
tained from  the Vein being fuppofed to  be conneaed  with the
Tumours  called  Hamorrhoids or Piles.
  The Vena Colica  Siniftra, which return the Blood from the
left portion or fide of the Colon.
  A Vena Duodenalis, which  leturns the Blood from  the  left
portion of  the Duodenum.
  The Mefenteiica Minor commonly terminates in the  Vena
Splenica,  though not unfrequently in the Mefenterica Superior.
  Vena  Splenica.—The Vena Splenica, fituated at the under
fide of its Artery and immediately behind  the Pancreas, re-
Cl'v; S--- 
L'05
  The Rami  Splenici, which return the Blood from the Spleen :
  The Rami  Pancrealici, which pafs from the under end  of the
Pancreas :
   The Vena Breves,  or Vafa Brevia, which come from the left
or great end of the Stomach :
  The Vena Gaftrica Siniftra,  or Epiploica Siniftra, which comes
from part of the great Arch of the Stomach, and correfponding
portion of the Omentum :
   The Gaftrica Superior, which comes  from the fmall  Curva-
ture of the Stomach and  Omentum  Minus,  and goes into the
Splenic near its termination, or into the beginning of the Vena
Porta?.
   The Splenic and  Inferior Mefenteric Veins,  after  receiving
their refpecbve Branches, form a fhort  Trunk which joins the
Superior Mefenteric.
   Vena Mesenterica Superior, or Major.  The Great
Mefenteric Vein, fituated at the under  fide  of the Artery, re-
ceives—
   The Rami  Mefenterici, which are very lar^e and numerous, re-
turning the Blood from the Jejunum and Ilium,—-the Branches
going  into the left fide of the general Trunk.
   The Ileo-Colica, which comes from the end of the Ilium and
beginning of the  Colon.
   The Colica Dextra, which belongs to the right fide of  the Co.
Ion, and terminates in the right or concave fide of the Mefenteric
Trunk.
   The Colica Media Anaftomotica, which  comes from the riq;ht
portion of the Great Arch  of the Colon, forming, with  the de-
fcending Branch of the Mefenterica Minor, a  largj Arch fimilar
to that of the cotrel'pondmg Artery,  and  terminating alfo in the
right fide of the Trunk.
   The Gafiro-Epiploica Dextra, which belongs to the right por-
tions of the Stomach and Omentum, and  frequently unites with
the Veins from the fide of the Colon, forming a fhort common
Trunk, which has the term of Gaftro-Colica applied to it.
   The Pylorica  and Duodenalis,  which  f. metimss terminate
in the Superior Mefenteric, at other times in the Gaftrica Dextra.
   The Great Meienteric Vein, formed by the Branches mention-
e 1 above, paffes over the beginning ot the correfponding Artery,
 and joins the Vena Splenica.
    The Trunk formed by  thefe Veins, runs  under the  head of
 the Pancreas, and here obtains the name  of Vena  Porta, or  V.
 Port arum.
                       Vena Porte.
   The Vena Port*., formed by the two Mefenteries, and  by
 the Splenic Vein, returns the  Blood from the Stomach  and Intef-
 tines, and from the Spleen, Pancreas, and Omenta.
    Vol.  If.            S 
  The under pirt cf the Venn Portar is termed by fome Authors
/ nn Porta Abdominalis, or Ventialis; while the upper  part,—
beiiiii of great fize, but without having any particular Dilatation
it  it,—-s cilled Sinus of the Vena Poriae.
   Tue Vena Potta?, at its beginning, frequently receives the Ve-
na Gaftrica Dextra, the Gaftrica Superior, the Pylorica, and the
Duodenali-;,  which at oilier times terminate in one of  the  great
Trunks which foim it.
  It p .lies upwards, inclining a little to the right in its courfe lo
the L'Ve-r, having  the  Tiunks of the Biliary  Duas before,  and
the Hepatic Aitery on the left fide of it,—and is  about tince or
four inches in length.
  When it reaches the Porta  of  the Liver, it receives the Ven»
Cyfticae into its Tiunk, or into its right chrifion, either by two
feparate Branches, or thefe united into a fingle Vein.
  In the Porta, it divides  into two great  Branches, a right and
left, l'v metimes termed Vena Porta Hepatica,  which go off nearly
at right angles, to be difperled, through the fubftance of the li-
ver, after trie manner of an Artery, the fubordinate Branches ac-
companying  thofe of the A. Hepatica.
  From the  extremities of the Vena Portarum, and likewife from
the extremities of the Hepatic Aitery,  a fet ot Veins arife, term-
ed Vena Hepatica, and fometimes Vena Cava Hepatica, which
accompany the Branches of the Hepatic Aite.y and Vena Por-
tarum.
  The Branches of  the Venae Hepatica?  afterwards unite into
lar^e  Tiunks, which iecede fiom the Hepatic Aitery and Vena
Porta?, and terminate in the Inferior  Cava.
  Their termination  in the Cava is  by  two,  and frequently by
three Trunks, at the place where it  perforates the  Diaphragm  ;
but commonly, below this, a few  fmall Hepatic Branches go into
the Cava whtie it is fituated behind ihe Liver.




 BLOOD-VESSELS of  the ORGANS of  URINE  and
                     GENERATION.

  Arteria Renalis.   The Arteria Renalis, called  alfo A.
Emulgens, arifes from the fide of the Aorta, a  little below the rout
•f the Superior Mefenteric Arteiy.
  It commonly comes off by one large Trunk, though frequent-
ly by two or moie, in which cafe, each of thefe is fmaller than
when the Aitery is fingle.
  It runs acrofs the Spine and  Pfoas Mufcle, nearly in a tranf-
verfe direaion.   The Arteiy of the  ri^ht  fide goes behind  the 
207
Vena Cava, an 1  is longer than the left,  in confequence of  the
Cava  being fituated  between the Aorta and the Right Kidney.
  At the concave edge of  the Kidney, the Ariery divides into
th ce or four Branches which fometimes  fend Tw,oS  to  the
Glandula Renalis and Tunica Adipofa of the  Kidney.
  Tttt Renal Branches then plunge into the fubftance of the Kid-
ney, furround its Pelvis, and afterwards ramify chiefly in its
Cortical Subftance ;—forming Arches' with eaeh other, but few
in number, at the i\;oN of the Pnpill*.
  The Vena Ren \Lis, or Emulgens, terminates  in the In-
ferior Cava; and is more fuperficial tiian its correfp-mdinrr Arte-
ry.  It is the 1 irgeft  Vein received  by the Cava  from  its  origin
to the part  where it reaches the Lever.
  The left Renal Vein is the longer of the two ;— the Aorta, be-
fore which it paffes,  being fi;uaiea  between  lite Cava and  Left
Kidney.
   AitTERra: Capsularfs.  The Arterire  Cipfubres, or Ar-
teries of the Renal Capfules or Clan.:*, are fmall but  numerous.
   They are derived from the Renal and Diaphragm.it..- A't-rics ;
and,  in  general,  the  left Renal  Gland  receives  aud.tLnai
Branches fiom the Trunk of the Aorta.
  The Ven^: Caisulares commonly unite in*) a large Trunk,
which, in the left lide, terminates in that of  the Kidney, while
in the right it frequently goes into  the Lava.
  Arterive Adipos^e.  The Arteries which fupply the Tu-
n'ca Adipofa of the  Kifney are  numerous  Twigs proceeding
from the  Diaphragmatic, Capfular, and Renal Arteries, or from
others near it.
   The Veins which return from the extremities of thefe Aiteries
pafs into the Trunks adjacent.
  Arteria Sperm atica.  The Spermatic Artery, the diame-
ter of which is fmall  when compared with its great length, arifes
oppofite to its fello v, from the foic-part  of  the  Aorta, a little
below the Renal Arteries.
  Sometimes it aides from the A. Renalis, at other times a little
higher from the Aorta, and in rarer inltances from the Diaphrag-
matic Aitery.
  It defcends, in a waving direaion, on the furface of  the Plba»
Mufcle, covered by the Peritoneum ; the rL'ht pafling obliquely
over the Cava, the left behind the Colic  Arteries  of the fame
fide, and both befoie the Uieters to the un.ier part of the Abdo-
men.
  After this, it perforates the R ng  of the Obliquus Externus,
and runs in the Spermatic Coni,  where it divides into  Blanches
which are difi.erfed in a very convoluted manner upon the Tellicl?
and Epididymis. ■
  In the defcent of the A-tery it imparts—
  7ve-igs to the Tunica Adipofa of the iv'dn y.
  To the Pc/iio.-.euin and Cellular SublLniec- near it;—and 
                           208

  To the Ureters,—wheh are alfo  fupplied with other Arteries
from the adjacent Veflels, viz. from  the Renal and Capfular Ar-
te: les, from the Aorta, the Iliacre and Veficales.
  The Vlna Spermatica is much larger than its correfpon-
ding Aite.y, and is furnifhed with Valves within, but more par-
ticularly without the Abdomen.
  It forms a Plexus  which accompanies the Artery, and about
the place where it recedes from it,  which is nearly  oppofite the
under end of the Kidney, it forms a fingle Trunk,  which in tho
rirjht fide goes into the Cava a little below the Emulgent Vein,
and in the left into the correfponding Vena Renalis.
  Befides the Arteiy commonly termed  Speimatic,  the Tefticle
generally receives a Minute Branch, which arifes from the Hypo-
gaftric, and accompanies  the Vas Deferens to the Body of the
Tefticle upon  which it is difperftd,—communicating theie with
the Branches of the Spermatic Arteiy.
  The Vein proper to this Arteiy, terminates in the Vena Hypo-
gaftrica.
  The Spermatic Artery, in the Female,  has the fame kind of
Origin, and  the fame courfe through  the  Abdomen  as in the
Male ;—but in place of perforating the Abdominal Rinr, as  it
does in the latter, it defcends into the Pelvis, between the Lamina
of the Ligamentum Latum, to be  difpeifed firft upon  the Ova-
rium and Uterine Tube, and then upon  the  Body of tiie Uterus
itfelf,—paffing in at  its corner, and  communicating with the Ar-
tery of the oppofite  fide.
  The Spermatic Vein has the fame termination in the Female as
in the Male,—but is confiderably larger.
   ARTERltft  iLiACffi.   The Iliac Arteries confift of the Tivo
Common lliacs, which are formed by the Bifurcation of  the Aor-
ta ;  and of the External  and Internal lliacs of each fide, which
are formed by the Bifurcation  of the Iliacx- Communes.
   The External Iliac paffes out of the  Abdomen behind the Li-
gament &/POUPART ; the Internal, termed alfo A. Hypogafti ica,
defcends obliquely into the Pelvis.
   At  the  fide  of the Pelvis, the Internal di'.ides into many
Blanches, feme of wh;ch  belong to the Organs of Urine and Ge-
neiation, the reft to other pai'ts  of  the Pelvis and adjacent p..its
of the Thigh.
   The following are the Branches fent from the Hypogaftric Ar-
tery to the Organs of Urine and Geneiat'on.
   Arteria UmbiL'CALIS.  The Arteria Umbilicalis appcais
in the Foetus as the continued 'Trunk of the Interna!  Iliac ; but
in the Adult, is fhrivelled in the form  of a Ligament, excepting
at its beginning or under part.
   The beginning of the Umbilical  Artery gives off-
   One or more  Arteria Vejicoles, which run to the m der pa> t of
the  Bladder,  and  extend itlos c, its  fides as far as the fundus Vc- 
                           2':r'

fir ae.  At their origin, they furnifh Twigs to the Veficuli: Semi-
i. ales, Proftate Gland, and Redlum.
  In the Female, the Umbilical Artery fends minute Branches to
the Uterus and Vagina.
  Arteria Uterina.   The Arteria Uterina, termed alfo Ute-
rina Hypogaftrica, is much larger than the Spermatic  Artery.
  It arifes from the Hypogaftric, near the origin of the A. Pu-
dica, and runs into the Uterus at its under extremity.
  It is afterwards refleaed upwards along the edge of" the Uterus,
towards its Fundus or upper part, where it  meets with the Sper-
matic Artery,  with  which it forms frequent Anaftomofes, and
afterwards many Communications  with the Uterine Artery of
the opp-.fife- fide.
  The (J  erine Artery fends  Branches downwards to the fub-
ftance of the Vagina, and  others forwards to be difpeifed upon
the Bladder.
   Artkria Vaginalis.  The Arteria Vaginalis is frequently
awanting.—When prefent, it arifes  from fome of the Branches
of the Hypogaftric,—as  that common to the hchiadic  and Pu-
dic,—or from  the  Haemorrhoidalis Med.a ; and  is diilributed
upon the under part of the Vagina.
  B.-fides  this, there are  other Vaginal Branches from the neigh-
bouring Arteries ;  a; from the Veficales, Uterina, and  Pudica,
which communicate with each other, and with the proper Vagina-
lis, upon the fubftance of  the Vagina.
  Arteria Pudica, or Pudenda Communis.—The> Arte-
ria  Pudica,  named  from its belonging to the Parts of Generation
in  both fexes, comes  off  either immediately from the  Trunk of
the Hypo.^afti  ic, or from the A. Kchiatica.
   It paffes  our of  the Pelvis, ihrough  the under  part of the
Notch of  the  Os Ilium, at the lower ed^e ef the Pyriform Muf-
cle.
   It then  turns between the Sacro-fciatic Ligament*,  to get to
the inner fide of the Tuber llchii, where it  is lodged deep in the
C:!lular Subftance.
   From the Tuner,  it proceeds along the inn jr fide of the Cms
of th ■ Os  li'chium and of  the Os Pubis,  and behind  the Crus of
the Penis, tdl  it approaches the Symp'iyiri of the Pubis.
   In it. counc, it fiends off many Brancues,  of which the follow-
ing are the principal, viz.—
  Branibes to the Veficulje Seminales, Prolt te  Gland, Neck of
the Bladder, and Reectutn.
  Branches to the Mufcles and parts adjacent to the Sncro-fcia-
tic  Ligaments ; fome of  them extending ai far as the Joint of
the Thiyh-bone.
  Branehesto  the Mufcles, Membranes, and Fat about the Tu-
ber of the Os Ifciuum.
    Vol. 11.           S2 
21t>
   The Arteria Hamorrhoidalis Externa, which foon divides into
 Branches, to fupply the Mufcles  and Integuments about  the
 verge of the Anus.
   The A. Perinei,  which paffes under the Tranfverfilis Perlnei
 Mufcle, in the fpace between the Cms of the Penis  and Bulb  f
 the Urethra, and gives Branches to the Skin and Mufcles at the
 fore-part of the Anus and root of the Penis,  and to the Scro-
 tum ; while the Artery itfelf terminates on the under fide of the
 Penis.
   After difperfing the Branches already  mentioned, the Pudic
 Artery divides, at the root of the  Penis,  into three  principal
 Branches, viz.—
   The Firft Branch, which pafl'es into the  Bulb of the  Urethra,
 and is continued forwards  in the Corpus Spongiofum Urethrse,
 into ihe Cells of which many of its Branches open.
   The Second Bianch, termed Proj'unda Penis,  which gees  into
 the  Crus Penis, anddireas its courfe in the Corpus Cavernofum ;
 its Branches  communicating with the  Aitery of the oppofite fide,
 and with the Cells of the Penis.
   ■The Third Branch, called  Dorfalis Penis,  which turns be-
 tween the Symphyfis of the Pubis and  root of the Pen's, and  pro-
 ceeds along'the Dorfum, as  far as the Glans,  adhering clofely
 to the L'gamentous Subftance which indoles the Corpora Caver-
 nofa, and fending Branches to it and to the Integument9.
   In the Female, the Pudic Artery has the fame general courfe as
 in the Male.
   After reaching the  inner fide of the  Tuber of the Os Ifchium,
 it is extended forwaids, and fends Branches to  the Anus, Peri-
 neum, end of the Vagina, and Labia Externa, and terminates in
 the Clitoris, fomewhat in a fimilar manner as in the Penis.
   The  Blood is returned from the  Branches of the Hypogaftric
 Aitery difpeifed upon the  Organs  of Urine and Geneiation, by
 the following Veins, viz.—
   The Vena Veficalis, which returns the Blood from the Bladder.
   The Vena Uterina Hypogaftrica, which comes  from the Uterus.
   The Vena Magna  Ipfius  Penis, which runs along the middle
 cf the Dorfum, and is often double to near the root ot the Pe-
 nis ; after which it paffes between  this and the  Arch ot the  Pu-
 bes, forming a Piexus which  furrounds the Neck of the Bladder,
 and  fending out Branches which terminate in others at the lides
 of this Vifcus.
   The Vena  Pudica,  which  communicates anteriorly  with the
 Branches of the Vena Magna at the root of the Penis, and after-
 wards paffes  back with the  correfponding Artery.
   The Vena Tegmentorum Penis, which is  formed by fmall Sub-
 cutaneous Branches, and ends in the top of the Femoral Vein.
   The Veins above-mentioned, the laft excepted, terminate in the
 Hypogaftrica, along with other  Veins belonging to the Pelvis, to
be afterwards defcribed. 
211
 BLOOD-VESSELS  of  the CONTAINING  PARTS  o»
       the ABDOMEN, and of  the PELVIS and
                INFERIOR EXTREMITY.

   Arteri*  Lumbares.—The  Lumbar Arteries, which are
 commonly four  in number on each fide, arife in pairs from  the
 back-part of the Abdominal Aorta, in the fame manner as the In-
 tercoftals do from the Aorta in the  Thorax.
   They  run firll over the fore-part of the Bodies of the four up-
 permoft Lumbar Vertebraae, and afterwards go between them and
 the  Pfoae Mufcles,  in their way towards the fides of the Abdo-
 men.                                                 .»
   They  give Branches to the  Spine,  to the Spinal Marrow and
 its  Membtanes  ; are particularly  difpeifed  upon  the Lumbar
 Mufcles, and upon  the  Tranfverfus and Obliqui Abdominis;
 and perforating  thefe,  they alfo furnifh  Branches  to  the  large
 ITnfcles and the Integuments in the back-part of the Loins.
   Superiorly, they communicate with the lower Intercoftal and
 Diaphragmatic Arteries.
   Sacra Media.   The Sacra Media is a  fmall Azygos Ar-
 tery, which arifes  from  the under  and back-part of the Aorta,
 immediately at its Bifurcation.
   It generally fends  offa Branch over each  fide of the laft Ver-
 tebra of  the Loins,  which takes nearly the fame courfe back-
 wards with the Arteria? Lumbares.
   The Sacral  Artery afterwards defcends  along the middle  of
 t^e  Sacrum,  as  far as the Os Coccygis, fending Branches to the
 Membranes and Subftance of thefe Bones, and to  the back-part
 of the Reaum.
   Iliac* Communes.   After  giving  off  the  Arteries of  the
 Contents and of the containing  parts  of  the  Abdomen,  the
 Aorta, upon  the und-r part of the Fourth  Lumbar Vertebra,
 divides into the Two Common Iliac Arteries, which are of equal
 fize.
   They pafs obliquely downwards and outwards ; and at  the un-
 der au*l lateral  pans of the laft Vertebra of the Loins, i. e. oppo-
 fite to the pofterior  Symphyfis of the Pelvis, each divides into
 two  others, an Anterior, termed Iliac a Externa,  and a Pofterior,
 termed Iliaca Interna, or Hypogaftrica.
   Iliaca  Externa.  The  Iliaca Externa,  which appears in
 the Adult as the continuation  of the common Trunk, defcends
 along the Brim of the Pelvis, taking a curved direaion by the
 fide of the Pfoas  Mufcle, and afterwards paffes behind the Liga-
ment o/Poupart, to form the Femoral  Artery.
   In this courfe, it does not fend off any Branches, excepting
fometime; a Twig or  two to the Peritoneum,  Pfoas Mufcle, &j. 
21'2
 till it is about to leave the Abdomen,  where it gives rife to two
 principal  Arteries,—the Epigaftrica, and Circumflexa Offis  Ilii.
   The Arteria Epigastrica, obtaining its  name  from its
 fituation in  the  fore-parr  of the Belly, goes off from the  inner
 fide of the Femoral  Artery,  immediately before  that Veffelgets
 behind the Ligament o/Poupart.
   At its origin,  it is a little bent downwards, and about half an
 inch from the place where it  firft comes off, it croffes obliquely
 upwards and inwards,  behii d the Spermatic Cord in the Male,
 and round Ligament  in the Female.
   It proceeds in this oblique manner behind the  Tendon of the
 Tranfverfuf, till it reaches as high ns the point of the Pyramida-
 Iis, after which it takes a perpendicular direaion along the back-
 part cf the Reaus Abdominis Mufcle.
   It furnifhes Branches to the Mufcles, Integuments, and Mem-
 branes of the fore-part of the  Abdomen, communicates  in  feve-
 ral places with the Lumbar Arteries, and terminates a little above
 the Umbilicus,  where  it  foims feveral dillina  though  fmall
 Anaftomofes  with the under end of theMammaiia Interna.
   Circumflexa Ossis Ilii.—The Circumflex  Artery of the
 Ilium, almoft as large as the Epigaftric Artery, arifes nearly op-
pofite  to it, though frequently a little lower,—immediately be-
hind the under end < f the Fallopian Ligament.
 Tt runs at the under edge of the Os Ilium,  till it arrives  near
the Vertebra* of the Loins.
   It gives Branches to the  Pfoas and Iliac Mufcle?, to the under
end of theObliqui and  Tianfverfus Abdominis, and at length
communicUes with the Epigaftric, and wilh the  Inferior Aite-
ries of the Loins.
   Iliaca Inti rsa.  The  Iliaca Interna,  or Hypogaftrica
pafl'-s downwa.ds and backwards in the pofterior and lateral part
of  the Cavity of the Pelvis, for  about a  couple  of Fingers-
breadth, afte. which it generally divides into a Pofterior and*An-
 terior Set of Branches ;  the former fupplying the parts neaieft the
 Sacrum and  Ilium, the latter belonging more immediately to the
paito about the Anterior region of the Pelvis.
                  1'i  terior  Branches?
  Ileo-lvmbarts, or Iliaca  Interna  Minor.   The  Ileo-
 lumbar is a  fmall Arteiy,  arifing fometimes from the e<-d ot the
 i.ypogaftric,  at'other times from the beginning ot the Giutea.
   It paffes outwards under the Pfoas Mulcle,"and div des  fud-
 denly into Branches,  one of which frequently fotms a kind  of
 Lumbalis lma.
   T'u other  Blanches  go to the Pfoas  and  Iliacus Internus
MutJo, communicating  there  with the Lumbar Arteries  and
C  rcumflex Brant lies  of the Ilium;—a  particular  Twig cot. lt.tu-
ing an A. Nutritia, or  Medullaris ot the Os Ilium. 
213
   Sacr/e Laterales.   Thefe are generally two or  three in
number, arifing from the common Tiunk, or frequently front
th.-Gluteal Aitery ;—though fometimes, there is only a fingle
Artery, which defcends by the fides of the Sacral Holes, giving
Branches, which fupply the place of the  Sacrae Laterales,  ar.d
fometimes alfo of the Sacra Media.
   They furnifh Branches to the Membranes on the furface of the
Os Sacrum, and inofculate by crofs Twigs with  the Sacra Me-
dia.
   Their principal  Trunks enter  the Anterior Sacral Holes, to
be diftributed upon the  Cauda Equina  and the Membranes  and
Bones inclofing it.
   Arteria Gi.utea.—This is fometimes teimed Iliaca Po-
fterior,  and is the  largeft Branch of the Hypogaftric Artery.
   Soon after it arifes, it paffes through  the  upper part of the
great Notch of the Os Ilium,  and is refleaed over the edge of the
Bone, in  the manner of the Inferior Scapubry Artery.
   At the under edge of the Gluteus Medius,  it is divided  into
two fc-ti of Branches,  one of which runs in a rad ated  direaion
clofe upon the Bone, and is chiefly difpeifed upon the two fmaller
Glutei, while Branches of inferior fize run fome of them down-
wards  to the  Mufcles  and Ligaments about the Joint  of the
 Thigh, and  others backwards  to the parts  about the  Sacrum,
communicating with the Lateral Sacral  Arteries through the Po-
 fterior Foramina of the  Os Sacrum.
   The other fet of Branches of the Gluteal Artery creeps in be-
 tween ihe Gluteous  Medius- and Maxmus Mufcles, upon the
 latter of  which it is chiefly difpeifed.
                   Anterior Branches.
   Arttria Obturatoria,  or Oeturatrix.—The Obturator
 Arteiy has  its origin  from  the  Trunk cf the Hypogallric,  or
 from the Ileo-lumbar or from the Ilchiatic,  and fometimes  from
 the end of ihe Iliaca Externa.
   It defcends in the Pelvis by the fide of the Pfoas Mufcle, and
 afterwards paffes through the Hole at  the upper part of the Ob-
 turat r Ligament.
    While in the Pelvis,  it frequently gives Twigs to the Bladder
  and ether pni ts near it.
   After perforating the Ligament,  it divides into Branches, one
 fet of which  are difperled upon  the parts about the  Hip-joint,
 while another briong to the Obtmator  Mclcle, and to  the Muf-
 cles which are fituated at the upper and inner part of the Thigh,
 .—the  two fets of Branches inefculatin; with each oiher.
    Art7ria Umbilicalis.—The Umbilical Arteiy fends  < ft
 Rami Veficales fiom its under part or beginning ;  the reft of it, in
 the Aduli, being Ihrivelled into Lirjainent, as alicady obTer.'cd. 
2\4
  VEsrcALis  Ima of  Haller.—This  is a  Ion* and  (lender
Branch which frequently comes off from  the root of the Pudica,
and runs to the under part of the  Bladder, ;md  to the Piollate
Gland.
  Arteria Uterina.  The Uterine  or Uterine-Hypogaftiic
Artery,  is difperf-d upon the Uterus, as has  been  already de-
fcribed.
  H/emorrhoidalis   Media.   The middle Hemorrhoidal
Artery is fometimes fent -off from the original Tiunk, and at
other times from fome of its Branches, jh the Pudic in the Male,
or Umbilical in  the Female.
  It is  chiefly  diftributed upon the lower end of the Reaum,
where it  anaftomofes with the Ha.-morrlioidalis Interna.  It fre-
quently  fends Branches  to the under part of the Bladder, to the
Veficula: Seminales  and Piotfate in the  Male;  and to  the Va-
gina and Bladder in ihe Female.
  Pudica Communis.—The Pudica Communis,  termed by
fome Authors FLemorrboidalis Externa, belongs to the p..its of
Generation and  Anus,  as was tormeily liken  notice ef.
  Arteria Sciatica.  The Sciatic, or Ifchiatic Aitery is the
largeft of the Uinc Branches, the Glutea excepted.
  It goes through  the under part uf the Sciatic Notch, accom-
panied by the Nerve of  that nan-e having the Pyriform Mufcle
between it and the Glut -A Artery.
  It afterwards  defcends fonieway down the Thigh,  in compa-
ny with  the Sciatic  Nerve, in the hollow between the great Tro-
chanter ct the Thi^h bone and Tuber of the llchium,—coveied
by the Gluteus Masimus Mufcle.
  It fends  an  Artery backward?,  termed A. Coccygea, which
creeps along the Sacro-Sciatic Ligaments, fumifhing Branches to
the parts about the Os  Coccy  is,  and others which alcend  from
it,  and  anaftomofe with fome of the lateral  Sacral  Arteries
through  the Holes in the back-part of the Os Sacrum.
  The principal Branches  of the Sciatic Arteiy, however, aie
difperfed upon the under part of the  Gluteus  Maximus Mufck,
and upon thofe at th» upper and bacR-part of the Thigh, where
they communicate with  the Ooturator and Pudic Arteries.

                  Arteria Femoralis.
  The  Femoral or Crural Artery,*—the  continuation of
the External Iliac,—pafl'es out of "the Abdomen between the Li-
gament of I'ouPAR't and Brim or the Pelvis.
  "At its firft exit,  it is fituated fuperficially over the  Ball of .the
Os Fcmoris, having the Fiexois of the Thigh between it and the
Joint.
  Farther down, it is lodged deep in a  hollow at the upper and
inner, pait of the Thigh, having the Reclus  and Sartorius upon
th? outer, and the Adduaoies ietnoris upon the inner fide ot it. 
•15
  Here, it is coveied  by the  Glands of the Groin, and by the
general Aponeurofis and Fat ; and from this pait it defcends" at
the inade ot  the Thigh turning gradually backwards till it reach-
es the Ham.
  From the top cf the Femoral Artery, a few fmall  Branches are
fent off to the Superficial Mufcles and Inguinal Glands,  and to
the common Integuments at the upper part of the  Thigh ; alfo
one or two others termed Pudica Externa,  to the External Parts
of Generation and Integuments of the infide of the Thigh.
  About two Fingers-breadth below the Ligament of Poupart,
the Femoral Arteiy divides,  fomewhat like the Common Iliac,
into Anterior and Pofterior parts :—The former is,the Femoral
Artery ftriaiy fo called,  the latter is termed Profunda Femoris.
                   Profunda Femoris.
  The Arteria Profunda, alfo  called Vast a, Posterior, or
Muscularis Femoris, immediately at its origin from the Fe-
moral Artery, gives  off two large Blanches,—the Circumflexa In-
terna, and Cicumflexa Externa,—which run in oppofite direaions
at the upper part of the Thigh.
   The Circumflexa Interna, though moft frequently com-
ing off from the beginning of the  Profunda,  often arifes higher
than it, fiom the top of  the  Femoral ; and  there, are now and
then two of  them, one a little  lower than the other.
   It paffes between the under end of the Pfoas, and the Peaina-
lis Mufcle,  and .afterwards turns  round the inner part of the
Joint of the Thigh.
   It fends off—
   Large  Branches  to  that portion  of the Adduaor Mufcles
which belongs to the upper part of the Thigh.
   Small Branches to the Mufcles in the vicinity of  the Trochan-
ters.
   A Branch, termed Articularis Ace tabula  to the Capfular Liga-
ment of the Joint.
   A  Tvjig, which enters the breach at the uflderand fore part of
tlie Acetabulum, to be difpeifed upon the Ligamentum  Rotun-
dum and the fubftance called Gland of the Joint.
   A confiderable Branch, which-anaftoinoles  with  the Trunk of
the Obturator Artery :—And
   Smaller Branches which  communicate with the  Aiteria  Sci-
atica,                                    f.
   Circumflexa Externa.—The Circumflexa Externa arifes
for the moft part nearly oppofite  the former, but  frequently a
little  lower.—Now and then this artery has a double Origin, one
of the Tiunks coining off higher than the other.
   It paffes outwards between the upper ends of the Reaus, Ten-
for Vu;inx Ferrioris, and Vaftus Externus Mufcles, and over the
Great Trochanter of the Os Fenaoirs. 
21 fi
  It fends Branches upwards to the under part of the Glutei and
lo other Mufcles placed at the inferior and back part of the Pel-
vis,-which anaftomofe with  thofe running down from the Aite-
ria Sciatica.
  Others which have more of a  lateral direaion, and are diftri-
buted upon the Mufcles at the upper and back part of the Thigh,
and upon thofe more immediately about the Joint,—communica-
ting with the Branches of the Circumflexa Interna.
  The largeft Branches defcend between the Reaus Femoris and
Vaftus Externus ;  one,  longer than the reft, reaching almoft as
far as the outer part of the Knee.
  The Profunda Femoris,  having detached the Circumflex  Ar-
teries,  finks deep behind the Trunk of the A.  Femoralis, and is
fituated upon the Adduaor  Mufcles of the Thigh.
  In its defcent it is divided into principal  Branches, termed
Rami Perjbrantes,  which, after fending off fmall Branches to the
Triceps Mufcle,  perforate it to be difpeifed  upon the Flexors on
the back part of the Thigh.
  The Pcrforantes come off in the following fucceflion,  viz.
  The Perforans Prima,  which arifes  rear the  Small Trochan-
ter, perforates the Triceps a little farther  down, and furniflies
Blanches  to the  Mufcles  in the upper and  back  part of the
Thigh.
  It forms numerous Communications with the Circumflex Ar-
teries,  about the root of the Great Trochanter, and anaftomofes
in particular with the under end of the Sciatica.-
  The Perforans Secunda or Magna, which  comes off fome-way
below the former,  and is  the largeft of the perforating Aiteries.
  It gives Branches to the Mufcles  in general about the middle of
the back-part of the Thigh,  particularly to the Flexors of  the
Leg;  and communicates above  with Arteries  ot the Perforans
Prima, and with the Circumflex Arteries.
  Befides thefe, there is one,  and  fometimes two other perfora-
ting Branches, which are gic-atly inferior in fize to the  two for-
mer, and are loft upon the Flexors  at the under and back part of
the Thi 4I1; one Twig fent off from thefe fometimes forming a
Nutritta or Me dull arts of the Os Femoris.
  The Femoral Artery,  after giving oft' the Profunda Femoris,
paffes down  between  the Vaftus Internus and infertion of  the
Triceps, giving only fmall  Blanches to the adjacent Mufcles and
Integuments.  ♦*
  About the middle of the  infide of the Thigh, it is fituated be-
hind the Sartorius Mufcle;  and  nearly two-third* down upon
the Os Femoris, it perforates the 'Triceps,  pafling between lhat
Mufcle and the Bone, in its way to the Leg.
  Having pafled through the Triceps, it is  found  in the back-
part ot the Thigh, wheie it fends  Blanches,  fometmie-.  teimed 
2H
Perforantes, to the Flexors  and Integuments, one Branch,  the
principal Medullaris, to the fubftance of the Bone,  and others to
each of the Vafti Mufcles, the  Mufeular Branches communica-
ting above with Branches defcending  from the fuperior parts of
the Thigh.  In this part of the Thigh it lies clofe upon the Bone,
and adheres  firmiy to it,  till it reaches  the  Ham, where it is
termed A. Poplitea.

                    Arteria Poplitea.
  The Arteria Poplitea is lodged deep in the hollow be-
tween the Ham-firings, and between the Condyles of  the Os  Fe-
moris, covered by  its affociate Vein and Nerve, and generally by a
great deal of Fat.
  It gives off feveral Brtnches, termed Articulares Superiores and
Inferiores, to the Joint of the Knee.
  Four of thefe,  fituated, two  above and two below the Joint,
are more regular and  conftant  than the reft, viz.
  The Articularis Superior Interna, which turns  round the Os
Femoris, above the Inner Condyle, paffes  under the Semimem-
branofus and Semitendinofus ; and, after perforating the Ten-
don of the Triceps Mufcle, is difperfed upon the upper and inner
part of the Knee,  anaftomofing above with  Branches fent down
from the  Femoral Artery.
  The Articularis Superior Externa, which arifes nearly oppofite
to the former, paffes  outwards between the Tendon  of the  Bi-
ceps and Body of the Os Femoris,  immediately above  its outer
Condyle, and is loll  upon the upper and outer part of the Knee 5
its  Branches anaftomofing with thofe of its fellow, and particu-
larly with the long defcending Branch of  the Circumflexa Ex-
terna.
   The Articularis Inferior Interna, which  arifes  oppofite  the
bending of the Joint, paffes  downwards, and then turns round
the Tibia, immediately below its  Inner Condyle.
  It fends Branches firft to the back-part, then  to  the inner fide
of the Knee;  fome of them  infinuating by  the Semilunar Car-
tilages into the inner part of the  Joint.
  Ii communicates above with the Branches  of the Articularis
Superior Interna.
  Ths Articularis Inferior  Externa,  which comes off near  the
former, and paffes firft downwards, then outwards,  between  the
External Lateral and  the Capfuiar Ligament, to be  difperfed  up-
on  the under and outer part of the Knee arid inner part of the
Joint ; communicating with its fellow of the oppofite fide, and a-
bove, with the Branches of the Articularis Superior Externa.
  The other lefs conftant Articular Branches are difperfed uoOn
the Mufcles a little above the Joint.
   Vol. II.              T 
SI*
   The Arteria Pophu ., having  furnifhed Branches to the Joint
 of the Knee, gives others to the  Mufcles at the upper  and  back
 part cf ihe Leg, two of wh.ch,  termed Surales, more confidera-
 ble than  the reft, pafs into  the heads of theGaftrocnemius Ex-
 tern us.\
   The Trunk < f the Arterv paffes afterwards  between the heads
 of the external Galwoi mmius, and commonly from two to three
 inches below the bending  of the  Knee, and  at the  under and
 outer edge of the Popliteus dvides into  two large Arteries, the
 Tibialis Antica, and Tibialis Poftica.
   'Tibialis Antica.— The  Tibialis Antica  pafffts direaiy
 through the upper end of  the  Interofl'eous Ligament to the fore-
 part ot the Leg.
   In its defcent in  the  Leg, it  adheres clofely  to the anterior
 furface of the Interofl'eous Ligament ;  and has the Tibialis An-
 ticus on  the inner fide, and the  Long  Extenfors of the Toes on
 the outer.
   A little above the Ankle, it paffes upon the outer and fore-part
of the Tibia, and getting under  the Annular Ligament and Ex-
 tenfor Pollici.-,  it  goes along the convex furface of the Foot.
   It fupplies, in general, the Mufcles  and  Integuments,  which
 belong to the outer and fore-part of the Foot, and ultimately paf-
 fes into the Deep Mufcles of the  Sole.
   Its Branches come off in the following order, viz.—
   A. Small Branch fent off  before  the Tiunk  perforates the In.
teroffeous L'gament,  to be difpei fed upon the parts near the  Joint;
the fuperior Twigs running in a  retro, rade direction.
   The Recurrens Anterior, which ariies from the  Artery after it
lias perforated the Ligament, and is  diftributed  upon  the  Muf-
cles at the upper part  of the Leg, and upon the Ligaments at ihe
under part of the Knee, anaftomofing therewith the Inferior Ar-
 ticular Arteries.
  Numerous Branches fent off in a lateral direaion to the Mufcles
and Integuments on the outer and fore-part of  the Leg.
  The Malleoli Interna, which comes off near the lower end of
 the Tib;a, and is difperfed on the parts about, the inner Ankle.
  The Malleoli Externa,  which  arifes  a  little  lower than the
former, and is d ftrihuted to the parts near the  outer Ankle.
   The Arteria Tarfea, which  takes  its origin a little anterioil?
to the bending of the Ankle-joint, and  is  more confiderable in
 f.zc than the Malleolar Branches.
   it paffes obliquely outwards and forwards under the Extenfor
 Brevis Digitorum, and fends Branches to the Joint of the Ankle,
 where it communicates with the Malleolar Arteries.
   It fupplies the greater part  of  the Mufcles,  Integuments, &c.
on the upper and outer part of  the  Foot,  and  fends Branches
 strned Interoffei, to the Mufcles  between the Metatarfal Bones of 
lv19
the* mall Toes,—vluch, however, are frequently derived from the
Metatarfal Artery.
  The Arterin- Mctatarfea, which  goes off about the middle of
the Dorfum Pedis, aad pafl'es  obliquely towaids the root of the
Little  Toe, aflilltng the former Artery in furnifliing Branches to
the upper part of the Foot and Toes,  and fometime.;,  in part 01*
entirely, fupplying the place of that Artery.
  The  remaining put of the Anterior Tibial Artery afterwards
advances between the Extenfor of the gieat, and long Extenfor
of the  fmall Toes, fending Twigs to the adjacent pam, and di-
vidiisg, be.ween the Metatarfal Bones of the Great Toe and that
next k, into a Large Pojlerior and a Small Anterior Branch.
^  The Pofte-■ ior Branch,  which may  be  confidered  as the  con-
tinuation of the Trunk,  finks between the Metatarfal  Bones
of  the two firft Toes, and anaitoinofes with a deep Aitery in the
 Sole.
   The Anterior Branch  runs forwards, under the name of Dor-
Jalis Pollicis, to  fee difperfed upon the Great and Second Toes.
   Tibiai  is Postica—The  Tibialis   Poftica  divides about a
fingu-'i.  breadth under the origin of the Tibialis Antica, into the
Fibulans,  and Tibialis Poftica itriclly fo called.
  The Fibularis, termed alfo Peronea, which is fmaller  than
either of the Tibial Arteries, runs down at the inner fide of the
Fibula, for a confiderable way along the Leg,  and  is fituated,
firft under  the  Soleus, and then under the Flexor Longus  Pol-
licis.
   Its Branches are diftributed to the Mufcles at the outer part of
the Leg  in the neighbourhood of the Fibula,—a (hull Medullary
Branch alfo penetrating the fubftance of that Bone.
   A little above the inferior Articulation of the Tibia and  Fi-
bula,  it fends a  Branch forwards,  termed Peronea  Anterior,
which perf.rates the Interoffeous Ligament, and is difperfed up-
on  the fore-part of the Ankle, where it anaftomofes wtth the Ex-
ternal  Branch of the Tibialis Antica.
  The continuation of the  Trunk,  fometimes  termed Peronea
Pofterior, defcends behind  the Malleolus Externum, to the outer
and back-part of the  Foot, anaftomofing with the External Mal-
leolar and  Tarfal Branches  of the Tibialis  Antica.
  The Tibialis Postica, properly fo ca.led, paffes down at
the back-part of the Tibia, and runs over the  Tibialis Poflicus
and Flexor Digitorum,  and  under the Gaftrocnemius  Internus,
in its defcent through the  Le^.
  Behind  the inner Ankle, it becomes more fuperficial, and has
the Tibialis Pofticus  and Flexor Digitorum Longus on the inner,
and the Flexor Loir-us Pollicis  on the outer fide of it.
  From  the Ankle, it runs in the Hollow of the Os Calcis, and
behind the Abduftor Pollicis, to the Sole of the Foot. 
120
  Its  Brandies fupply the Mufcles at the back and inner part
of the  Leg, and the different parts of the  Sole; forming many
Inofculatioiis with the Branches of the anterior Tibial and the
Fibular Artery.
  In its courfe along theLej, it gives off—
  Numerous Branches, fimilar to thofe of the Tibialis Antica, to
the funounding Mufcles :
  The Arteria Nutritia Tibia,  which begins a little below the
upper end of the Trunk, defcends for fome way in the Leg, and
gives Blanches  to the deep Mufcles and Membranes near it, and
one Branch ttrmed A. Medullaris,  which enters the HAe neai the
middle of the Bone.
  Several Branches  to the parts behind, and  at the inner fide of
the Ar.kle and Htel, which communicate with others of ihe An-
terior Tih:al Ai tery.
  The Trunk of the Arteiy divides in the Hollow of the Os Cal-
c's, at  the place where it is about to go behind the Abduaor
Pollicis,  into two princ pal Plantar Branches,—ihe Interna  and
Externa.
  The Plantar Arteries run  forwards under  the  Aponeurofis
Piantari'-, having  the Flexors of ihe Toes between them.
  The Plantar is Interna pafl'es near the  inner fide of the  Sole,
between the Aponeurofis Plantaiis and Abduaor Pollicis.
  It gives Branches  which run in  a retrogiade direaion  to the
back-part of ihe Ankle and adjacent parts of the Heel  :
  Several Branches fiom each fide, which go forwards to the
Mufcles  and Integuments, and other parts at the concave edge of
the Sole.
  At the root  of the Great Toe, it fends a principal  Branch to
its  inner fide; it then  paffes under the Flexor  Longus Pollicis,
and after anaftomofing  with the Arcus  Plantaiis, gives  off a
laree Branch which fplits into two,—one to the outer fide of
the Great Toe, and the other  to the adjacent fide of  the Toe
next it.
   The Plantaris Externa,—which  may be confidered as
the continuation of the Trunk, being in general much larger than
the Interna,—paffes obliquely outwards between the Flexor Bre-
 vis Digitorum, and  Flexor Accefforius, till  it reaches the  Bafe
 of the Metatarfal Bone of the Little Toe.
   It is afteiwaids  arched forwards between the Flexors of the
 Toes and  Matataifal bones, the Trunk being continued  to the
 root of the Great Toe, under the name 6f  Arcus Plantaris.
   The External Plantar Aneiy fevids off—
   A Confiderable Branch, firft to  the under, then to the outer part
 of the Heel, which communicates  externally with Branches of ihe
 anterior Tibial and the Fibular Arteries :
   Several Branches to the Flexors of the Toes, and to other parts
  n he outer portion of the Sole, which communicate, on  the '.n- 
221
ner fide, with the Branches of the Plantaris Interna, and at the
outer with thofe of the anterior Tibial Artery.
  The Arcus Plantaris gives out—
  Several Branches to the deep Mufcles of the Sole, particu-
larly,
  Rami Interoffei to the Mufcles between the Metatarfal Bones :
  A Branch to the outer fide of the Little Toe :
  Three Large Digital Arteries, which are forked at the roots of
the Toes, and run along the edges of thefe, in the manner the Di-
gital Arteries do along the Fingers.
  Between the Metatarfal  Bones of the Great  Toe and the one
next it, the Plantar Arch  anaftomofes with the  pofterior or per-
forating Branch of the anterior  Tibial  Artery, forming a free
communication between the Arteries of the upper and under fide
of the  Foot.  Frequently  it  fends  off here a Digital  Artery,.
which forks and runs  along the outer fide of" the  (Treat Toe, acd
inner fide of the Toe next it, fo  as to fupply the  place of one of
the Branches of the Internal Plantar Artery.
  At the roots of the Toes,  the Interofl'eous Arteries of the up-
per part of the  Foot, alfo form diftina anaftomofes with  the an-
terior extremities of the Trunks of the Digital Arteries.




                        VEINS.

  The Veins of the  Inferior Extremities,  like  thofe of
the Superior, confift of a Subcutaneous and Deep  fet, and like
them alfo, are furnifhed with numerous Valves.
   Subcutaneous Veins.—The Subcutaneous Veins .re fitu-
ated between the  Common Integuments and General Aponeuro-
fis, and, in many pa.ts, are entirely concealed by  the Fat.   They
a.iaftomol'e frequently with each other by  lar^e Branches, and
have feveral communications alfo with the deep Tea ted Ve-ns.
1 They form two pr nc pal Trunks,  called  Sapbana Major and
Saphana Minor ;— the term Saphaana  applied,  from  u»e  Vun
being fuppofed to be always vifible.
  The SapHj-ena Major begins upon the upper fide  of the
Foot, runs  over 'he fore-part of the inner Ankie, and  afcends in
the Leg at the inner edge of the Tibia.
  From the Leg, it pafl'es up uy the  mfide of the Knee, and af-
terwards, from  tlu inner  to the 'u, per  and toio-udit of  ihe
Thigh.
  It is at firft compofed of Veins, derived from the upper and in-
ner pait of the Doiluin Pedis, wnich have  frequent anaftomofes
with each other, and are  of confidtiable fize.
   Vol. II.           T  1 
I'l'l
  In  its afcent  it is joined by Branches  from  the  fuperficial
paits of the Leg, and is frequently fplit into a Plexus, fome way
below  the  Knee.
  It receives Branches from the fuperficial parts  of the Thigh,
and fmall Twigs from the Inguinal Glands.
  It terminates in the top of the Femoral Vein, nearly oppofite to,
©r a little higher than, the origin of the Arteria Profunda.
  The Saph^ina Minor arifes upon the outer fide of the Foot,
and afterwards paffes behind the Malleolus Externus.
  From this,  it afieids  in the back-part of the Leg,  upon  the
furface of the Gaftrocnemius Externus, and goes  imo the  Ham.
  If is  formed by the Veins of the upper  and outer part of the
Foot, and is joined  to the Saphaena Major, over the MetArtarfal
B nes, by one or more Arches, which receive a Plexus of Blan-
ches into their lower or convex part.
  It is joined by the fuperficial Veins of the outer and back-part
of ihe  Leg, which  have frequent anaftomofes with each other,
and wiih the Branches of the Saphaena Major.
  It  terminates  in the  Vena Poplitea, and communicates con-
ftantly  by a  fmall Branch with  the Saphxna Major, a little
above the Knee.
  Deep Veins.  The Deep Veins of the Leg, like thofe of the
Fore-arm, run clofe at each fide of  their Arteries, and are dou-
ble the.r number,  but differ a little  from the Radial and Ulnar
Veins, in being proportionally larger.
  The Tibial and Fibular  Veins anaftomofe in fome places
with  each other, and alfo communicate with the Subcutaneous   (
Veins.
  At the upper part of the Leg, they are united together, to form
the We\\2k  Poplitea, and the union is  nearly  at  the fame place
where the coiiefponding arteries come off
  The Vena  Poplitea adheres clofely to the upper furface of
the Artery, which it in  a  great meafure conceals, and  is com-
monly fingle,  excepting a  fmall Vein which  fometimes accom-
panies and communicates with it.
  The Popliteal Vein receive-, the Venae Surales and Articulares,
and th^r Sajjhaena Minor;  after which it forms the Femoral Vein.
  The VttiA Fr.MORALis receives the Veins which correfpond
with the perforating Brunches of 'he Femoral Arteiy, and paff.-s
in through the Triceps, whe<e the Arteiy comes out.
  In  the  middle of the Thigh, it lies deeper than the  Arteiy,
afterwards turning  gradually to its inner lide ; and at the upper
part of the Tnigh, it is joined by the Vena Profunda.
  The Vena  Pround.v receives  the  Veins correfponding with
the Branches of the Artery ot that name,  and is  fbtnetimes of a
large fize,  being then  in a great meafure the  continuation  of the
Vena Poplitea, a In all Vein only  in  fuch cafes  accompanying
the Trunk of  the Femoral Aitery. 
2-2Z
  Befides the Vena Profunda, the  Femoral Vein takes in fmall
Veins  from the External parts of Generation, from the Ingui-
nal Glands, and from the other fuperficial parts of the Groin i
—and, in particular,  it receives  a  Branch of confiderable  fize,
which defcends from the Integuments of the fore-fide of the Ab-
domen.
  The Trunk of the Femoralis, having received the different
Veins of the Inferior Extremity, paffes into the Abdomen, be-
hind Poupart's Ligament,  bein?  ftill fituated at the inner fide
of the Arteiy,—after which n forms the Iliaca Externa.
  The Iliaca Externa  receives  into  its beginning the Epi-
gaftric, and Ciicumflcx Vein of ihe Os Ilium,  and fometimes the
V.  Obturatrix.
  Ii is fituated at the infide of the  External  Iliac Artery,  and
afterwards  ctoffes behind it on the right, and behind the Inter-
nal Iliac Aitery on the left fide of the pelvis,  to  join the Trunk
of the Hypogaftric Vein.
  The  Vena Hypogastrics, or  Iliaca Interna, is fitu-
ated at the outer fide of the Artery and receives the  different
Veins  which correfpond with thtf Branches of the Hypogaftric
Artery,  and which are furniihed with Valves  where they are
fituated  among the Flefhy parts of the Pelvis.
  The External and Internal lliacs unite and form the Common
lliacs, a little below  the divifion  of the  correfponding Arte-
ries.
   The Iliaca Communes afcend by the right fide of their
refpaaive  Arteries, and a little below the the Bifurcation of the
Aorta,—or upon the fore part of the Fifth Lumbar  Vertebra,—
unite to form the Inferior Cava, fituated,  as formerly mentioned,
 at the nglit fide of  the Aorta.
  The Vena Cava Inferior,—which is  much  larger than
the Ca.a Superior,  and  greatly exceeds in fize the defcending
Aorta,—re eives, at its beginning, the Vena Sacra,  and higher,
the Venae  Lumbares, which, in the  left fide,  pafs behind the
Trunk of the  Aorta.
   It likewife leceives the Vena? Renales,  and the Spermatica of
 the right fide.
   At length it takes in the  Venae  Hepaticae  and Diaphragma-
ticae, and  perforating the Diaphragm at the root of the Liver, it
 terminates in the Right Auricle of the  Heart. 
2'-'1
PART   VII.
               OF THE

NERVES IN GENERAL.
|Q|
     THE Nerves are firm, white Cords  which  are generally
     confidered'as being direaiy continued from the Medullary
Sutiftance of the Brain and Spinal Manow ;—although inftan-
ees have been  frequently met  with, where the Brain,  and even
the Spinal Marrow, have been found nculy obi  ter.ited  in the
Fcetus,  and yet the Nerves retained then  ui'ual appearance.
  They are compofed of Funiculi clofely  conneaed,  and each of
thefe again of fmaller Fibrilla which may  be fubdivided into parts
fo extremely minute, as almoft  to  elude  the  naked Eye, but
which  may be readily feen by the tifliflance of the M crofcope :
—No Cavi'y,  however, has been  yet obferved in them.
  The  Medullary Part of the F brillie appears  to be  furnifhed
with  Cineritious  Subftance derived  from their Pia Mater;  in
proof of which,  they are obfeived to be  in general of a browner
colour  than the Meilullary Subft. nee of the Biain, and larg'.r
in their coutfe than at their fuppofed origin.—Monro's Obr. on
Nerv. Syft.
  Tue Medullary Subftance of the Fibrillar is pulpy and tender,
but rendered thicker and ftronger by  ihe coverings they receive
from the Tunca Arachnoidea, and Pia Mater, while within the
Bones,  and more particularly  bv the a  ditional  covering given
them by the D-.ra Mater upon their exit.
   The Dura Mater, in its  paffage through the  Bafe  of the Cra-.
nium,  and between  the diffr-en.  Vertebiae,  s  conneaed by its
External Surface to the  Peii ianium  ar.d  Periofteum;   while
the inner part of it,  together w.tn tiie Tunica Arachnoidea and
Pia Mater, is continued along tut Neives. 
225
  The Involucra,  or Coverings, inclofe each  of the  Neives in
general, and likewife the feveral Fibiiliae of which they are com-
pofed, whereby  their fize, as well a3 ftrength,  is  greatly  in-
creafed.
  The  Nerves,  foon after leaving the Bones, have the  Dura
Mater fo intimately  con:>e&ed with them, that it  has been con-
fidered by fome Authors, as degenerating into condenfed Cellul. r
Subftance,  notwithllanding it lt.il retains the general  appearance
of the Dura Miter.
  Upon  examining  the Nerves, efpecially  the fmall ones, in  a
living or recently  deal  animal,  they are obferved to have nu.e-
rous White Lines placed tranfverfely,  or in a ferpentine dirtaion.
—Obf. on Nerv. Syft. Tab. XIII.
  When the Nerves  are  moderately  ftretched,  this  appearance
becomes lefs evident; and when extended confiderably,  or when
macerated in water,  it vanifhes entirely.
  Prochaska  'De Carne Mufeulari) fuppofes  thefe   Serpen-
tine Lines to  be owing  to  a decuffation ot Vcffeis and Fibres of
 Cellular Subftance ftraitening the Nerves.
   Dr. Monro contiders  them  as Folds or Joints allowing the
 Neives to  accommodate themfelves to the various ftates  of Flex-
ion and Extenfion.
  The Nerves are fupplied with Arteries from the neighbouring
Blood-veffels, to  which they fend correfponding Veins.
   Thefe, however,  are fmall, and difficult of injeaion, except-
 ing in the large Nerves, where the Veffels are more confiderable,
 and where, after a minute injeaion, the Nerve receives the colour
 of  the matter injeaed.
   Upon dividing the Nerves,  they are not found to poffefs much
 contractility ;  while  the Arteries,  upon being cut are obferved to
 retraa very confiderably.
   They are generally lodged  in  the common Cellular Subftance
 and Fat,  and in the Interftices of the  Vifceia and Mufcles, where
 they are prevented from being compreffed ; though in feveral parts
 they ate expofed to  the hardnefs of Bones,  or  to  the aaion of
 Mufcles, over or through which they pafs.
   In their courfe  bhrough the  different parts of the  Body, they
 generally run as ftiaight as  is confiftent with the nature of the
 particular part over which  they pafs,  and their own fafety.
   In their progrefs, they  divide  into Branches,  which become
 gradually fmaller, and wh ch, though taken colleaively, are in-
 ferior in fize to  the  Trunks from which they iffue.
   The Branches generally run off at  acute angles ; but in feveral
 places th-ry have a retrograde  direaion.
   Th; y have commonly the fame kind diftiibntion in the oppofite
 fides of  the fame  Subjc-a, and vary little in this refpea in diffe-
 rent Subjeas. 
                           22G

  In fome parts of the Body, feveral Nerves unite together,  and
form a Plexus or Net -work ;  in other?, they unite into a Common
Trunk;  and in many, by fuch  an  union,  a hard  knot,  termed
Ganglion,  is formed.
  When the PUxvfts, 01 the Common Trunks,  are  minutely ex-
amined by  flitting open their coverings,  it is found, that  their
Fibrillae are intermixed  in  fuch  a manner,   thai  each  of ihe
Nerves pafling out from the p.cxus, or from the Commcn Tiunk,
is  compofed of  Fibrillar from  feveral, or from all  the Nerves
which entered it,  in confequence of which, the Organs in gene-
ral  are turn flud with  Nerves fiom  various fources. Obf. on
Nerv.  Syft.
  The Ganglia differ  from each other  in fize aid figuie : They
have thicker Coats and are more Vafcular ihan the N  i ves ;  and
are larger than the whole of the Nerve:., taken conjunaiy, which
enter into or go out from them.— 1 hey  are fuppofed  to feive as
frefh four, es of Nervous  Influence.
  They a e compofed of Neivous Fibrillar, env.-red by foinething
like a  Cineritious Mattei, and are f.■ divii.J, multiplied, and
inteimixed, that  each of die Nerves puffin, out from a Ganglu n
is found to be compofed of Fibrilise deiived from the gieater part
of the Neives which enter it.—Obf. on \erv. Syft.
  Where Neives  pafs out  from  the  fide of  a Ganglion,  they
are compofed of Fibrillae which come offin contra.y  direaions;
—tne  one  fet  from  ihe beginning, the other  frun the oppo-
fite extremity of ihe Ganglion.
  The  Nerves  which go  out from the different Ganglia have the
fame flruaure with thofe which enter them, but are found,  with
only a few exception-, to be rather latger.
  In the Trunk of a Nerve, the Curds  appear to run parallel to
each other ; but when macerated in water,  fo as  to  diflolve the
Celluiar Subftance, or when otherwife accurately examined, they
are feen evidently to intermix fomewhat after the  manner of the
Fibrillae in the  Plexus,  or in the Ganglia.—Obf. on Nerv.
Syft em.
  The Termination of the Nerves is foft, pulpy,  and pellucid,
as is diftinftly feen  in the Retina of the  Eye or Ear ; the exter-
nal Covering bein:-. entirely laid  afide,  while  the Pia  Mater,  in
particular, accompanies them throughout.
  The Nerves preferve the motion of the Mufeular Fibres.
   They conftitute the immediate Organs of  Senfation,  and con-
vey Impreflions made upon them to the Mind.
   The manner in which thefe Impreflions are produced,—whe-
ther by a Vibration communicated to the Nerves; or by a Liquid
called Nervous Fluid, contained and moving in them  ;—or by an
elearic N\a\\tr common to them and many other fubflances ;  or
in  what   manner that power  aas, termed  Animal Electricity, 
227
which has been la'ely difcovered to take place  in  the Animal
Kingdom,  upon the appli:ation of certain Metals; is not yet
underftood.
            DISTRIBUTION OF THE NERVES.

  THE Nerves are diftinguifhed into  two Claffes ;  one arifing
from the Biain, termed Cerebral; the other from the Spinal Mar-
row, teimed Spinal Ner vets.
  The Cerebral Nerves are generally reckoned Nine or Ten Pairs
in number, befides  a  particular Pair,  which hafs  the  name of
Sympathetic.                           '
  They pafs through the Holes in the Bafe of the Cranium,-and
receive their refpeaive Names according to  their order ; or from
their Functions; or from the Parts on which ihey are difpeifed, &c.
  The Spinal Nerves confift  of Twenty-Nine or Thirty  Pairs,
which  pafs out between the different Vertebise, befides a Pair
called Acceffory,  which enter the  Cranium  from the  top of  the
Spinal  Marrow, and afterwards pafs out with one of the Cei\bral
Nerves.

   Nerves which pass  through  the  Base of the
                        Cranium.
  The First  Pair,  or  Olfactory  Nerves,—arife,  on
each fide of the Brain,  by  three feparate  Striae,  from the Cor-
pora Striata,  at the under and back-part of the Anterior Lobes,
near where the Carotid  Arteries enter the Fiffures ©/'Sylvius.
  They are more tender than  the other Nerves, and alfo differ
from them  in not being compofed of Fafciculi.
  They run each in a  Furrow, upon the  under Surface  of  the
Anterior Lobes of the Brain, converging a little and becoming
fomewhat  larger, till  thej reach the Cribriform Plate of  the
OEthmoid  Bone.
  Upon th s Plate, each forms an Oblong Bulb,  which, in colour
and  confillence,  ref'embles the Cortical part of the Brain,  but is
mixed  with ftreaks of Medullary Matter.
  From this Bulb, numerous Nervous Filaments are fent off,
which  pafs through the Holes of the Cribriform Plate,  and now
become firm and ftrong like the other Neives, by receiving a co-
vering  from the Dura Mater.
  After entering the  Nofe, they divide into two Portions or
Planes,—one pafling on the Septum, the other  upon the Offa Tur-
binaia, and othei pans oppofite to the Septum, and both running
at firft  in Grooves of the Bones. 
226
  They form a beautiful Plexus,  which is fpread  out upon that
fide of the Membrane of the Nofe which is  contiguous to the
Bones, and may be traced a confiderable  way upon ir in diftina
Threads, which becoming gradually fmaller, fink into the Mem-
brane, and are fuppofed to terminate on the hit face next the Ca-
vity of the Nofe, theie conftituting the Organ of Smell.
  The Second Pair,  or Optic Nekvks,—which are of great
fize, arife from  the Thalami Optici,  and are conneaed in  their
paffage to Tubercles at the root of  the Infundibulum, which
furnifh them with an addition of  Medullary Subftance.
  They are of a purer white than other Nerves, having lefs Ci-
neritious Matter entering their compofition, and  differ alfo in
the Pia Mater furn fhmg thtm with a geneial Covering, before
it invefts the feveral Fafciculi of which they are formed.
  At the  fore part of  the  Sella  Turcica, they unite,  and  have
their Medullary Parts intimately  intermixed.
  From this union, they go obliquely outwards  and forwards
through the Foramina Optica into the Orbits ; and advancing in
the  OrbTs in a  waving  dirtaion,—to prevent them from  bring
over-ftretched in  the motions  of the  Eye,—they  perforate the
Balls, to be expanded into the Retinae, which have been already
defcribed.
  The Third Pair, or Motor f.s Oculorum,—fmaller than
the Optic  Nerves,—arife at the under, inner, and  back-part  of
the Crura Cerebri, or between the Corpora  Albicantia and  Tu-
ber Annulare, by numerous Threads  which  are  foon  colleaed
into their refpeaive Trunks.
  They pafs outwards, peiforate the Dura  Mater at the fides of
the Pofterior Clinoid Procefs, and running  along the upper part
of the Cavernous Sinus, at the outfide of the Carotid Arterie>,
they get thiough the Foramina Lacera into the Oibits.
  Upon entering the Oibits, they divide into feveral Branches,
which fupply the greater number of the Mufcles of the Eye, in
confequence of  which the Neives have obtained their  particular
name.
  A Bianch  runs to each of the  Mufcles within the Orbit, ex-
cepting the Trochlearis and Abduaor ;  and the  Nerve likewife
affifts in  forming a fmall Ganglion, termed Opthalmic, from
which Twigs are  fent off to fupply the Ball of the Eye.
  The Fourth Pair, or Pathetic—have their origin  the
higheft of the Cerebral Nerves, and aie the moft (lender of  the
Body, being generally formed of one Fafciculus only on  each
fide.
  They arife by a fingle, and fometimes by a double root, behind
the Teftes,  from  the Medullary Expanfion which lies over  the
paffage to the Fourth Ventricle, and  which unites the Pioceffui
ad Titles to each other. 
$29
  .They afterwards turn round the Crura Cerebri, and perforate
the Dura Mater at ihe edges of the Tentorium, fome way behind
the entrance of the Third Pair.
  They run afterwards along the Cavernous Sinufes, at the outer
fide of the I hud Pair, then crofs  over that Pair, and pafling
out of the Cranium through  the Foramina Lacera, they  go  ob-
liquely over the Mufcles at he upper part of  the  Orbits, to be
entirely difperfed upon  the Pathetic or Trochlearis Mufcles.
  The  Fifth  Pair,  or Par Frigeminum,—.vhich  aie the
largeft Nerves of the Brain, arife, each by an anterior fmall, and
a poller or large Portion,  from the fide of the Tuber Annulare,
where the Crura Cerebelli join it.
  They enter the Dura Mater a little below the Tentorium, over
the points of the  Partes  Petrofas of the  Temporal Bones,  and
form a Plexus on each  fide,  in which upwaids of fifty Fafcicu-
li have frequently  been enumerated.
  The Plexus finks clofe by the outfide of the Cavernous Sinus,
concealed by a doubling of the Dura Mater,  and foims a Gang-
lion fometimes  called Gafferion,  after Gasslr, who, if not the
Difcovcrer, was the firft who illuftrated it.  :
  The Ganglion is of a femdunar fotm, and placed tranfveifely
with refpea to  the Trunk of the Nerve.
  From the oppofite and curved edge of the Ganglion, three large
Blanches come out; the fii ft and Anterim ,  termed Ophthalmic,
■—the fecond and Middle, the Superior Maxillary, and the third
 nd Pofterior, the Inferior Maxillary.
  The Firs r Branch of the Fifth Pair,—at the fide of the
Sella  Turcica,  is fituated lower than the "Third Pair, and after-
wards  croffes over it,  being previoufly conneaed by Nervous
Matter to the Trunk of the Fourth Pair.
  It goes through the Foramen Tacerum into the Orbit,  and is
there divided  into the following Branches, viz.
   Fhe  Supra-Orbitar, which is  the largeft of the whole, being
a continuation of  the Onhthulmic.
  It pafl'es immediately ender the Membrane which lines the  up-
per part of the Orbit,  and fplits into two branches of unequal
fize.
  The fmaller  Branch  termed Supratrochlearis, runs under the
Superciliary Ridge to the Upper Eye-lid and  Fore-head.
  The larger paffes through the Foramen Supri-Obitarium,—or
over the Superciliary Ridge when the  Foramen is  awantiug,—
fends  Branches  to the Upper  Eye-lid, and divides into  feveral
others, which run back partly above, but chiefly under the Fron-
tal  Mufcle, to fupply the fore ai d upper part of the Head in ge-
neral,  while minute Fibres appear to penetrate the Bones.
  The Nafal  Branch,  which runs obliquely over the Optic
Nerve,  where it detaches a Filament or two  to the Eye, then
under  the Levator Mufcles of the Eye-lid and Eye; and getting
    Vol,  II.            U 
330
between the Abduclor Oculi and Trochlear!*, paffes to the infide
of the Oib.t.
  It fends a Branch, which after'entering the Foramen Orbitai i-
vni Internum Anterius, re-enters the cav.ty of the Cranium, and
gets upon the Cribiifoim Plate of the OEihmoid Bone.
  From thenoe it paffes down throut h one of the anterior Holes of
this Plate,  and fends Twigs to the membrane at the anterior part
of the Noilril, while the Nerve defcending at the foie part of :he
Septum Narium, is difperfed upon the  point and Wing of the
Nofe.
  The continuation of the Nafal Branch, now called Infratroch-
learis, paffes forwards to  the inner Corner of  the Eye, and is
diftributed upon  the Laciymal S*c and parts adjacent.
  The Lacrymal Branch, which runs along the Abduaor Oculi
Mufcle, fends Twigs to the Membranes  and Fat near it,  likewife
one or two  thiough the Subftance of the  Cheek-bone, and one in
particular to the Subftance of the Lacrymal  Gland,  while ano-
ther paffes  over the Gland, and vaniflies in the neighbouring
parts.
  A Branch to the Ophthalmic Ganglion, which is fometimes fint
off fiom the Nafal, at other times from the Ophthalmic Trunk.
  The Ophthalmic Ganglion,—termed alfo Lenticular, from  its
Ihape, is foimed by this Branch from the Fifth,  and by  another
from  the Third Pair, and is commonly the  fmalleft in the Body,
  It is of an oblong form and compreffed, is fituated at the out-
fide of th«  Optic Nerve a little before its entrance into the Orbit,
and is concealed in  Fat.   Sometimes, though rarely, the Fila-
jnents which form it take their origin  entirely from the Third
Pair.
  From the Ganglion, about a dozen of Filaments arife, termed
Ciliary Nerves,  colle6led into two  Portions, which creep along
the oppofite fides of the Optic Nerve, feparated a little from  each
other and running in company with the Ciliary Arteries.
  Befides the Ciliary Nerves from the Ga./glion,  one and fome-
times two  Filaments arife from the E/amus Wafalis, and pafs
along with the other Ciliary Branches.
  The Ciliary Neives, running with fcaicely any  divifion, reach
the back-part of the Eye ; and a little before the Infertion of the
Optic Nerve, enter the Sclerotic Coat, pafs obliquely through it,
and about the middle of the Ball, appear upon the Suiface of the
Tunica Choroides.
  Upon  this  Coat,  they run  flat,  and  in  a parallel  direaion,
fending very few evident Branches,  either to it or to each other,
till they reach the Ciliary Circle,  where they divide into nume-
rous  minute Filaments.
  Upon the Choroides, five or fix  ate larger than the reft, fome
bun-To minute as almoft toefcape the naked Eye. 
231
  At the Ciliary Circle, each commonly divides into two Bran-
ches, which arc covered by the Cellular Subftance of the Circle ;
and thefe, at the root of the Ins, are fubdiv ded into ft 11 fmaller
Branche;, which run in a radiated and waving direaion, the Ci-
liai , Vefiris being  interpof'ed.
  Near the inner edge of ihe Pupil, they are united into Arches,
from wh.ch very minute Twigs run to the interio r margin of the
Ins.
  The Slcond Branch, or Superior Maxillary Nerve,
—is larger  thai  the  Ophthalmic, and is principally  difperfed
upon the Parts belonging to the  Upper Jaw, from which it  has
its  name.
  It goes throu.h the Foramen Rotundum of the Sphenoid Bone,
and at  its exit divides into numerous Branches,  viz.
  The Spheno- Palatine,  or Lateral Nafal Nerve, which fends a
reflea.-d Bianck through the Foramen Pttrvgoic.eum of the Sphe-
noid B-j.ic, to join  the Sympathetic Nerve in the Canalis Caroti-
cus, and a Branch which enteis the Foramen Innominatum of the
Pars Petrofa, to join the Portio Dura of the Seventh Pair.
  The Lateral Nafal  Nerve goes afterwards into the  Spheno-
palatine Hole, to be difperfed upon the under and back-part of the
Sepium,  and oppofite fide of the  Nofe, and upon  the Membrane
of the Sphenoidal  Sinus and Eultachian Tuhe : One  Branch in
particular, after pafling along the Septus*, goes through the Fo-
ramen Incifivum to the Roof of  the Mouth.
   The Palato Maxillary,  or  Palatine Branch, which  defcends
through the Canal  leading to the Foramen Palatinum Pofterius ;
and  running near the Alveoli  with correfpondmc;  Blood-veffels,
fends Branches to the Velum Palati and Roof of the Mouth, and
Minute Filaments  which penetrate  into the P.dt.tt-piate of the
Superior Maxillary Bone.
  Small Branches,  which '.al's round  the Upper Jaw, and vanifli
in the Chrek.
  A Tvjig,  which  goes through the lisle  in the Os Malse, along
with a Branch if the Ocu'ar Artery,  to the Face.
  Small Filaments, which run down into the back  part of the Su-
perior  Maxillary Bone,  and fupply the fubftance  of the Upper-
Jaw, the large De  ites Molares,  and Membrane  lining the An-
trum M.ixillare.
   The Second Part of the Fifth Par after fending off thefe dif-
ferent  Branches, goes into the Canal under the O.bit,  and forms
the Infraorbital- Neive, which,  while in the Canal, gives off
Filaments pafling through minute Conduits in the Upper Jaw, to
the Antrum, to the Subftance of the Bone, to the  fmall Mo! ies,
Caninus,  Incifores, and Fore-Teeth ; and  fometimes ;i Tw'g,
the companion of a fmall Branch of  the Interned  Maxillary Ar-
tery, to the Membrane lining the Orbit. 
   The Infra-Orbitar Nerve paffes aftei wards out of the Foramea
Infra-Orbitarium, and divides into many large  branches, to be
diftributed upon the Cheek,  Under Eyc-iid,  Upper Lip, and fide
of the Nofe.
   The Third Branch, or Inferior Maxillary Nerve,
goes though ihe Foram n Ovale of the Sphenoid Bene, and  fup-
plies the parts belonging to the Under Jaw, and the Mufcles  fitu-
ste.i between it and tlieOs Hyoides,  by the following Branches,
viz.
   One,  or fometimes two Deep Temporal Branches,  to the inner
part of  the Tcmioial Mufcle.
   Branches,  to  the Maffeter, Pterygoideus,  and  Buccinator
Mufcles.
   A Branch wlvch paff:s  behind the Cervix  of  the  Lower Jaw,
and i.ives  oft' Filaments to the fore-part of  the Ear, and after-
wards accompan.es  the Temporal Artery up^n the  lide of the
Head, where it terminates.
   A Branch, to the  Buccinator  Mufcle and other parts of the
Cheek.
   A Nerve of confiderable  fize,  termed  Lingual or Guftatorius,
which paffes  between  the  Ptery>:o'd  Mufc es, to the inner of
which it gives  feme Filaments.  It then fends off, from its  un-
der fide, a Gangl.oB which tranfmits Nerves to the  Interior Max-
illary Gland.
   The Lingual Nerve alfo tranfmits feveral Branches to die Sub-
lingual Gland, and to the Mufcles of the Tongue.
   It terminates, at length,  near the Point of the Tongue, by
many Branches which belong chiefly to the  Papillae ;  in  confe-
quence  of which this Bi anch is  confidered  as the  principal
Nerve of the Organ of Tafte.
   The Trunk of the Inferior Maxillary Nerve,  having parted
with the Lingual Nerve, direas its courfe between the  Pterygoid
Mufcles to the Pofterior  Foramen of the Inferior Maxillary
Canal.
   Before entering  the Canal, it  fends off a long  and  fltnder
Branch, which is lodged at  firft  in a Fum.w of the  Bone,  and
gees afterwards to  be  difpeifed chiefly upon the Mylo-hyoideus
Mufcle  and Sublingual Gland.
   The Trunk of ihe N  rve is afterwards conduaed alonej the
Canal of the Jaw under the Alveoli, where it  diftributes Fila-
ments to the different Teeth of  the correfponding fide,  and to
the Subftance of ihe Bone :  and  coming out of  the Canal by the
Anterior Max.ilary Foiamen, fomewhat  diminifhed in fize,  it
fcatters  its remaining Branches upon the Chin and under Lip.
   The Sixth Pair,  or Abducentls, arife from the begin-
ning of  the Medulla Oblongata,  at the part common to the  Tu-
ber Annulare and Corpora Pyram dalia, and are the fmalleft of
the Ceiebral Nerves,  the  Fourth Pair excepted. 
23 3
  They peiforate the Dura Mater at the  inner  fide of the,en-
trance  of the Fifth Pa;r, and run forwards within the Cells of
the Cavernous Sinus ; but fo furrounded by Cellular  S .lutance,
as to feem to be proteaed from the Blood of that Receptacle.
  While in the Sinus  Cavernofi, they are fituated between the
Ophthalmic Nerves and Carotid Arteries,  upon the furface of
the latter of which  they fend  off two or thiee  Filaments  on
each fide of the Head, to affift in forming the Great Sympathetic
Nerves.
   The  Trunks of the Sixth Pair afterwards go through the Fo-
ramina Lacera, to be difperfed entirely upon the Abduaor Muf-
cles of the Eyes.
   The  Seventh Pair is compofed, on each fide, of two porti-
ons,—the Nervus Auditorius, Nervus  Acufticus, or Portio Mollis;
and the Communicans Faciei, or Portio  Dura.
   The Portio Mollis, is the fofteft of the Nerves, excepting
theOlfaaory.
   It  arifes by  tranfverfe Medullary Striae from the anterior
part of the Fourth Ventricle, and is feparated from its fellow of
the oppofi e fide only by the Crena of the Calamus Scriptorius.
   The  Striae, tinning  round  the Medulla Oblongata, apply
themfelves to  the Tuber Annulare,  from  which  they  receive an
addition  of fubftance,  and  then get to the fide of  the  Portia
 Dura.
   The Portio  Dura, fometimes alfo called Sympatheticus Mi-
nor, arifes f.oin  that part of the Braui which is  common  to ine
Pons Varolii,  Crura Cerebelli, and Medulla Oblongata ; and
at its origin, is fituated upon the inner  ildo of  the Poi tio M 1-
 lis.
   Between the origin of the  Portio Dura and Trunk  of the Por-
tio Mollis, a fmall Nerve arife", termed  by Wrisberg,  Portio
Media  inter P. Duram et P. Mullein.
   It comes off by minute Fibrillae,  which foon urite  into  a
 Trunk, from the pofterior part of the Pons Varolii, or  from
 the adjoining  part of the Medulla Oblongata, and ri an Acceflory
 Neive  of the  Portio Dura.
    The Portio Dura, confiderably fmaller than  the  P. M>'li%
 gets  into the  Meatus Aud tonus Internus and is there lod. e 1
 in a kind of half-flieath, formed by  that Nerve, to  which it  is
 conneaed by  fine Cellular Subftance  ; the.Dura Mater,  which
 lines the Paffage, giving here a general Covering to both Me. ves.
    Portio Mollis.—The Puitiu Moths is famed  of two Faf-
 ciculi, nearly of  eqial fize, o e of which belongs to the Coc.ilc.i,
 the other to the Veftible and Sem.circular Canals.
    Each of thefe Fjfciculi paffes by numberlefs Fi'nHlx through
 the Cribriform Plate in the b ttom of the Meatus Auditoriu* In-
 ternus, to the inner parts of the Labyrinth.
    Vol. II.          U  J 
L'34
   The Fib: iliac deftined for the Cochlea go throii"': the T'uri<- in
the fiLs of the Mod o.us.
  Some pari between ihe Plates which for in the Septa of the Gy-
ri ; G ncrsgo ihinu^h.Holes ' etween ihe Off hi*  i\ ,.c> vf the
LanTin.: t->,)iialis ; bu. bv much the ^.'lertteft ri in n:r uutorati the
files -<1 ih. M >d,oius, between the Septum ot  the  Gyri and the
Limma Spiralis.
  The larger F biillae run  upon the Mem'ram' c vring tht  La-
mm.t >puaiis ;  while the ima.ltr go from theMod.olus, between
the Ofleou> S ,a i anil  on the inner fides  of the  Gyri, to be  dif-
pcrf'd  up.n the Membrane lining them.
  The lem.imtng Fibrillx peiforate the PI vc common to the Mo-
di Jus  an i  Infundibulum,  and  vamfli upon the laft half-turn of
the Lamina Spirali  and the Cupola of the  Cochlea.
  Upon the Olleaus part of the Lamina  Spii. lis, the Nerves have
the common appearance ; but upon the  Membranous  Portion,
they are of ihe colour of the R> tina of the Eye.
  In the whole of iheir courfe upon the Lam na  Spiralis, they
form a red  Retina;  though  the  leticulated flruaure becomes
much lefs appaient npon the outer part of this Lamina, and upon
the loTitiiiuation of the Membrane lming the Gyri,—the Ner\ts
feeinin^ to  terminate  in a  fcmipellucid  Pulpy Membrane relem-
Liing the Retina of the Eye.
  The Membiane  upon which  the Nerves are expanded, is but
fli;>htiy coin tcteu to  the Periofteum  which lines the   nner  fide
of the  Cochlea, a:;d which, though thin, may be readily  percei-
ved, being  painted with Blooil-vefferi ,—nor does it differ  lorn
tl-.c Periofteum lining the Tympanum.—See Dr. Monro's Trea-
ty e »nyfhe Ear.
  The Fafciculus which belongs to the Veftible and Semicircular
Canals, forms at fiift a Plexus, then a Gangltform Enlargement,
previous to  ts entrance into ihe Labyrinth.
  The Nerves whi  h belon:: *.o the Veftible and Semiciicular Ca-
nals p Ts thiough tht Macula Ciibrofa, 01  Holes fubdivided  into
fmaller Holes by Ciibnfcrm Plates in the  bottom  of the Meatus
Auditonus I ten us.
  Of thefe Bi  ne  es, fmall Filaments pafs thronph the Macula
Cribrofa in the  Inferior Foffula . f the Meatus Auduorius In tr-
nus, to the Alveus Communis or Sacculus Veitibuli.
   A fmall Branch  goes t1  rough  another Ciibiifonn Hole in  the
Inferior Foffula,   the Ampulla of  the Pofteiioi  Membranace-
ous Semiciicular Ctu.al.
  ABiancii, b.rg-r ihan any of  the farmer, enters the Pofterior
ITle in th; upp-r Fofula tf the Me  tus lnternus,  to be difperfed
upoi  the Ampullx of the Supeiior and Exteriot Membranaceous
Canals.
   1 hr Neve.-., after reaching  the Sacculus  Veftibuli and  the
different Ampullae, are fpread out upon  them, as in the Cochlea, 
£',&
in the form of a Net-woik, the Fibres of which, by degrees be-
coming pellucid, difappear upon the beginning  of the Membra-
naceous Canal i.
   P 'R i i -■ jJ'URA.— Th  Por io Dura feparites from the Portio
M./Iij, a.  ne b..tiom ! f  the M-u us Auditorius Into nus, .nd
eru.i ^ th.  L.niatts or Aquaduilus FaLLOPII, by  the anterioi Hole
in the- uppci Foffula at  the bottom of the Meatus.
   Aher t.eting into the C mal, it  receives the  retrograde Nerve
from ihe  Second Ban  h of the Fifth Pair, which enters by the
Foramen  Innominatum  on the fore-fide of the Pars Petrofa.
   It lends Twigs through Foramina in the fides  of the Aquedua,
t... the Maftoid Cells and to the Muf.-le of the Stapes.
   A liltle befoie its ex'u from the  Aquedua in tne Adult, but
at the outer end  of it in the Fcetus, it gives offa  refleaed Branch,
termed  Chorda  Tympani, which  pafl'es  between the long Pro-
ceffes of  the Mallews and Incus, and over the Membrana Tym-
pani.
   The  Chorda  Tympani goes afterwards in  a Fiffure at the
outfide  of the Euftachian Tube, and joins  the Lingual  Branch
of the Fifth Pair, foon after that Nerve has got out of the Cra-
nium.
   lx\ its paffage, it  fupplies the Mufcles of the Malleus, and the
Membranes, &c. of the Tympanum.
   The  Portio Dura afterwards pafl'es out of the Aquedua by
the Foramen Stylo-maftoideum, and is at firfl lodged deep, being
fituated in a hollow behind the Parotid Gland.
   Here it  gives a fmall Occipital Branch,  which ft nds Twigs  to
the back part of the Ear, and terminates in the  Oblique Mufcles
of the .lead.
   It  fends a Branch to the Digaftric, and another to  the Stylo-
hyoid Mufcle ;  jcicts off a Filament which  joins the Auricular
Branch of the inferior Maxillary  Nerve, and  goes to the fore-
part of the Ear; and  is.conneaed by another fmall Filament at
the under  part of the Ear, with  Branches  of  the  Sympathetic
Nerve  which run along  the External Carotid Aitery.
   It alfo furnifhes Filaments to the Parotid Gland, and then per-
fora es it, dividing into Jarge Branches, which join, feparate, and
rejoin, different  times, oh  ihe  fide of the Face.
   This Plexus is expanded in fuch a manner as to conftitute what
has  been  called by fome the Pes Anferinus, and is  divided into
the  following fets of Branches, viz.
   The Temporal Branches, which afcen.i  upon  the  fide  of the
Head, to  be diftributed  upon  the I'emple ;  iome running over,
others under the Branches of the Temporal Artery,  and forming
feveral joinings with the Frontal Branches  of the firft part of the
Fifth Pair of Nerves :
   The  Superior Facial Branches, which are difperfed upon the
Orbicularis Oculi  Mufcle, and the parts  in general  about the 
236
outer angle of the Eye,  communicating in various places  above
and below the Orbit, with the firft and fecond Branches of the
Fifth Pair :
  T'he Middle Facial Branch, or the Great Facial Nerve,  which
runs  acivfs  the  Maffeter  Mufcle, and divides   into  many
Branches, to be difperfed upon the Cheek, and fide of the Nofe
and  Lips.
  They are conneaed with the Branches of the Superior Facial,
and iitM.i  the  corner  of the  Mouth, with others of the fecond
and third parts of the  Fifth  Pair.  They  have likewife  fome
communications  with deep Blanches of thelie two Nerves  which
pari ou.^rards between the M lilter and Buccinator  Mufcles.
  T'he Injerior Facial Branches, which proceed alung ihe fide of
the under Jaw, to be difpeifed upon the parts covering it, and up-
on the Under Lip ; and  connea  themfelves with  fome of the
Middle  Facial Branches, and with others belonging to the third
part of the Fifth Pair :
  The Defcending, or  Subcutaneous Cervical Branches, fome of
which run  forwards under  the Lower Jaw,  and others down-
wards, near  the External Jugular Vein, to the Supeificiai Muf-
cles, and to the Inte.  uments  at the fide and  upper part of the
N-^k, where they foim communications with the Infeiior Facial
Branches, and with different Branches of the upper Spinal Cer-
vical Nerves.
  The Eighth  Pair  arifes from  the Medulla Oblongata, at
the fides of the Bafes of the Corpora Olivaria, and confift in each
fide,  of the Nervus Gloffo-pharyngeus, and Fars V aga.
  The GlossoPharyngeus is the fmaller of the two,  being
only a little fuperior in fize  to one of the Neives of the Fourth
Pair.
  The Pars Vaga comes off immediately under the former, and
is compofed of feveral feparated Fafciculi, which arc foon col-
leaed into a fingle Cord.
  The two Nerves, pafling outwards, go through the Bafe of the
Cranium, immediately before the  end of  the  Lateral Sinus, by
the Hole common to the Occipital and Temporal Bone, and are
feparated from each other and from the Sinus by  fmall Proceffes
of the Dura Mater.
  The Gloffo  Pharyngeus, termed alfo Lingualis Lateralis,  upon
its  exit from the Cranium, fends a  Branch backwards,  which
joins the Digaftric Btanch of the Portio Dura.
  A little lower, it gives off  Branches, which,  with  others from
the Pharyngeal Branch of the Eighth  Pair, and from the Great
Sympathetic Nerve, form a Plexus which  embraces  the Internal
Carotid Aitery, and afteiwards fends Branches along the Caro-
tis Communis fo the Heart.
   Still lower, it gives  Branches which communicate with others
belonging to the Pharyngeal Nerve,  and  go to the upper part of
the Pharynx and to the Stylo-Pharyn^eus Mufcle. 
237
  The GloTTo-Pharyngeus,  after  fending  a Twig or two to the
Tonfi , to th.- upper part of the Pharyn:, an I Membrane of the
Ep riotti:,, divides int.; many Branches, which run partly to the
margin and partly to the middle of the root of ihe Tongue, fup-
plying, efpecially, thj Pap.Ha? Majores and  the parts in ih.h"
neighbourhood.
  The Pars Vaga,—upon emerging from the Cranium, frequent-
ly becomes a l.tt.c increafed in dameter f ,x about an inch down-
wards ; forming what fome authors  have  termed its GangliJ'orm
Enlargement.
  It defcends in the Neck  at the outer  and back-part of the
common  Carotid Arteiy, to which it  i; clofely unitec, being in-
cluded along with it in the fame common fh.-ath of Cellular Sub-
ftance.
  At the  upper part  of the Neck,  it tranfmits a Branch to the
Pharynx ;   and immediately  afterwards, a  large  one to the
Larynx ;  and near  the top  of the Thorax, it fends a Filament,
and fometimes two, to the Heart.
  The Pharyngeus,—chiefly formed by the Pus Vaga, but partly
alfo by a Branch  from the Accefforius, is afterwards joined by
Bi-indies from  the Gloflb-Pharyngeus, and defcends obliquely
over the Internal Carotid Artery.
  Near the origin of this Artery,  it  fends  Filaments which join
others from the upper part of the  Great  Sympathetic, and creep
along the Common Carotid, to be united  with the  Carotid Ar-
tery.
  Upon  the middle of the Pharynx, it expands into a Gangli-
form Plexus, from  which  many fmall  Btattches are fent oir,  to
be diftributed upon the  three Conflriaors of the correfponding
fide  of the Pharynx ;  one or two  Filaments uniting  ab-.ve with
the Gloft'o-Pharyn^ tui,and others below with the Laryngeus Su-
perior.
  The Laryngeus Superior,—defcends obliquely forwaids be-
tween the Carotid Arteiies and Pharynx ;  and behind the origin
of die Carotids, is divided  into a large Internal or Superior, and
a fmall External or Inferior Branch.
  The Internal Branch  paffes forwards between the Os Hyoides
and  Superior Cornu of the Thyroid Cartilage.
   I: divide into numerous  Branches, ion.c of which go  to the
Arytenoid Gland, and to  the Oblique and "Tranfverfe Arytenoid
Mufcles, and others to the  Glandular Membrane of the Epiglot-
tis ; while the greater numb.'r and the lar, eft of thel'e Benches
are difperfed upju the  Glandular M mbrane lining the  upper
portion of the Larynx and parts adjacent.
  The External Branch,—which  Scarpa confiders as more pro-
perly termed Pharyngo Laryngeus,—is originally compofed of a
Branch from the Internal Laryngeal, and another from the Great 
233
Sympathetic ; and is conneaed by a Filament to the Pharyngeal,
and fometimes alfo by one to the Internal Laryngeal Nerve.
  It imparts Twigs to th. Middle and Lower Conftririors of the
Pharynx, and afterwards terminates in the Thyroid Gland  and
inneV part of the Larynx.
  The Filament, fent  from the Pars Vaga at the bottom  of the
Neik, joins the  Great Caidiac Bianch of the Sympathetic Ni. ve
in ihe upper part of the Thorax, to be difperfed upon the Heait.
  Tne Ninth  Pair,—'ki; rently termed Linguales, and fome-
times Linguales Medii,—arife from the under and lateral parts of
the  Corpora Py.am dd a, on the foie fide of  the Medulla  Ob-
longata, by numerous Filaments  which aie colleacd into  Faf-
ciculi.
  They pafs out at the Superior CondToid Foramina of  the  Oc-
c'pital  Bone, after  which they adhere, for  fome way, to the
Eighth Pair, by Cellular Subftance.
  A little briow  the Cranium, each of the Tiunks of this  Pair
of Nerves is conjoined by a crofs  Bianch with the luhocciptal
Nerve, or with an  Arch which  conneas that Nerve and the  Firft
Cervical together.
  The Trunk then defends between the Internal  Jugular Vein
and Internal Carotid Artery, and at the i oof of the Occipital Ar-
tery crofies (Vu- bo.h Carotids to its place of deft nation.
  Where it be-ins to  crofs over the  Carotids, it fends downs
Bianch of confiderable fize, termed Defceiidens Nuni.
  The Dejcendens Noni panes down a certain length along  with
the  common  Carotid Artery,  and,  in  its  courfe,  turn  fhes
Branches to the upper ends of the Omo-hyoid and Sterno-thyroid
Mufoles, after which it unites  v/.ih Branches fr. m the Firft and
Second, and with fmall   Filaments  from the  Second and Third
Ceivical Neives, forming t.n Arch, from which lm;;  and llender
Twigs go to t.ie under per; 10113 of the Stcino-thyro.d, and to the
Omo-hyo'd and Sterno-hyoid Mufcles.
  The  Ninth  Pair paffss  afterwards behind the Facial Trunk
and Temporal Veins, or the Trunk formed by thefe, and over the
root of the  Facial  Artery,—.'ending a  Nervous'Twig to the Hyo-
thyioid Mufcle.
  Upon  the  Hyo-gloffus  Mufcle, the Trunk of the  Nerve is
fpread into  a great number of Branches, which go to the middle
of the 'Fongue, and terminate chiefly in its Flefliy parts ; a Twig
extend ng as far as the Genio-hyoid  Mufcie,  and two or fome-
times only one Filament  anaftomofing with the Lingual Branch
of the Fifth Pair.
  The Gxeat Sympathetic Nerve,—obtaining  its  name
from its numerous Conneaions with  moft of the other Nerves of
the Body,—;s either formed originally by  the refleaed Branch
from the fecond of the Fifth Pair, and by one or two and fome-
times three fmall  Filaments, fent down from the Sixth Pair while 
2*59
in the Cavernous Sinus ; or, according to the opinion of fome
Authors, the Sympathetic fends off thefe fmall  Nerves to join the
Fifth and Sixth Pairs.
  Upon the Surface of the Internal Carotid Aitery, while in the
Caiotic Canal,  the  Branches of  the  Fifth and Sixth Pairs and
Great Sympathetic making this conneaion, arepwlj.y and tender,
and foim a Plexus which furrounds the Carotid, and from which
the Trunk of  ihe Sympathetic is  moft frequently confidered as
bein_ ri.u out.
  After efcaping from the Carotic Canal, the Trunk  which is
of lmall fize,  is  clofely  conneaed,  for a fhort  fpace,  with the
Trunks of the Eighth and  Ninth  Pairs;  and, feparating from
thefe, it expands into a large  Ganglion,—termed Ganglion Cervi-
cale Superius,—of a long oval form, and fituated oppolite to the
Second Cervical Vertebra.
  From this Ganglion, the Nerve comes out very little  increafed
in fize,—and defcends on the anterior Vertebial Mufcles  of the
Neck,—behind  the  Eighth  Pair  of Nerves,  with which,  and
with the Carotid Artery, it  is conneaed by a Sheath of Cellular
Subftance.
  At the under part of the Neck, and nearly where the Inferior
Laryngeal Artery turns over towaids the Larynx, the Sympa-
thetic forms another Ganglion, termed by fome Authors Cervi-
cale Medium and by others Cervicale Inferius.
   The Ganglion Medium is fomewhat fimilar in fliape and fize to
the Ganglion Superius ;  though it varies confiderably in  thefe
refpeas in different  Subjeas.
  From this Ganglion, principal Branches are fent down, one of
which, larger than the reft, and confidered as the  continuation of
the Trunk,  turns outwards  between the Inferior Laryngeal and
Vertebral Arteries to another Ganglion.
   This third Ganglion,—is  placed at the head of the firft  Rib,
and is teimed  by fome Authors  Ganglion Cervicale Inferius,  or
Imum, while others coniider it as the firft of the  Thoracic Gan-
glia.
  The Cervical part of the Great Sympathetic is conneaed  with
other Nerves, and difperfed  upon different parts by the following
Branches, viz.
  One or two fhort, but thick Branches,  which connea the be-
ginning of the Superior Ganglion wiih the root of the  Subocci-
pital Nerve :
  One or two Pulpy Nerves, which run forwards behind the In
ternal Carotid Aitery, and divide into many others.  Thefe, to-
gether with Filaments  from  the  Gloflo-pharyngeus,  form a
Plexus which fends  Branches to the Gangliform Expanfion of the
Pharyngeus,  and  afterwards embraces  the external  Carotid
Artery,  fending Plexufts   of Filaments  along its   different
Branches : 
•40
  One or two other foft Nerves, going behind the Internal Caro-
tid, and with a Branch of the Laryngeus Interims of the Eighth
Pair,  forming the Laryngeus Externus :
  Thick flioi r Roots connecting the Firlt, or Conjugation of the
Firft and Second Cervicals,  with the fuperior  Ganglion of the
Spmpathetic Nerve.
  From the Siqierior Ganglion alfo,  are fent off fmall Branches,
which  uniting with  Fil nients  from  the Laryngeus Superior,
form the Rumus Cardiacus Supremus, or Superficialis Cordis.
  The Superficial  Cardiac  Nerve of  he Sympathetic, in the
Right Side,  d vides  into Blanches at the bottom of the Neck,
which fend a Filament or two  along the Inferior Laryngeal Ar-
tery to the Thyro d Gland and afterwards unite with the Supeifi-
ciai Caidiac Neive of the Eighth Par before the Subclavian Ar-
tery, and with  the Laryngeal Nerve behind it.—In the left fide,
it terminates in the Canliac Plexus of  Neives.
  From the Second, Third, and Fourth Cervical  Nerves, an
equal  number of Cords defcend behind  the Scaleni and Ream
Major Mufcle,  to the middle Ganglion of the Great Sympa-
thetic.
  From the oppofite fide of the Ganglion, Branches  are  fent
down, which join  and  foim  the .\ervous Magnus Projundus  ;
others aie fixed to the Superficial Cardiac and to the R current cf
the Eighth Pair ;—-the reft go partly over and partly behind  the
Subclavian  Arteiy, to  the  Inferior  Cetvical,  and  to  the  firft
Thoracic Ganglion.
  Nervi Accessorii ad Par Octavum.—The Acceffory
Nerves arife by fmall  Filaments from the lateral Parts ot the
Medulla Oblongata and upper portion of the Spinal Marrow.
  The Filaments from the Spinal Marrow come off between the
anterior and pofterior Bundles of the Cervical Nerves,—the firft
of them  frequently  extending as far as the fpace between the
Sixth  and Seventh Pairs.
  The different Filaments unite by degrees into their refpeaive
Trunks, and  often  have  conneaioHS  while  within the  Dura
Mater, with one or two  of the Bundles of the upppermoil Spinal
Nerves.
  The Trunk of the Nerve paffes out, on each fide of the  Cra-
nium, in company with the Nerve of the Eighth Pair; but forms
no part of that Nerve, being included in its own peculiar Sheath
received from the Dura Mater.
  After perforating the Cranium, it feparates from the Eighth,
and defcends  obliquely outwards  through ihe Sterno-maftoid
Mufcle to the Shoulder.
  At  its exit, it fends off a Branch, termed by  fome Ramus Mi-
nor,  (the Trunk itfelf being then called Ramus Major), which
affifts in forming the Pharyngeal  Nerve ; and gives another, 
241
fmaller than the former,  to be conneaed to the Pars Vaea of the
Eighth Pair.                                      6
  At the fore-part of the Sterno-maftoid Mufcle, it is joined by
an Arch  to the Suboccipital, and frequently by another to the
Firft Cervical Nerve.
  In  its  paffage through the Sterno-maftoideus, it fends feveral
Branches to the fubftance  of that Mufcle,  and terminates  at
length in the Trapezius.
OOOOOOOO-S'cOOOOOOOO'
       SPINAL  MARROW,

                 AND

ORIGIN  OF THE SPINAL NERVES.
O'
  THE Spinal Marrow is the continuation of the Medulla
Oblongata,  and obtains its name from being  contained in the
Offeous Canal of the Spine.
  It is inverted by the fame Membranes which cover the Brain,
and has an additional partial Involucrum from the Ligamentous
Membrane which  lines the Bodies of  the Vertebrae,  and which
has been already taken notice of in the  defcription of the Liga-
ments.
  On the inner fide of the Ligamentous Lining, the Dura Mater
is fituated, which paffes out of the Cranium  by the Foramen
Magnum Occipitis, and forms a Cylindrical Sheath which lojfe-
ly envelopes  the Spinal Marrow, and  extends as  far as thj Os
Sacrum.
  It is more elaftic than the Dura Mater of the Brain, and there
by admits more readily of the different motions of the Spine.
  At its egrefs from the Cranium, it is intimately conneaed to
the  beginning of the above-mentioned common  Ligamentous
Lining, and is alfo united with the Pericranium at the edge of
the  Foramen Magnum of the Occipital Bone.
  Below the Firft Vertebra of the Neck this intimate conneaion
between the Dura Mater and inner Ligament of the Vertebras is
difcontinued ;  a Cellular Fatty, and Slimy Subftance, which fur-
VOL.  II.             X 
242
rounds the Dura Mater throughout the reft of the Canal,  being
interpofed between theMiinbrane and the Ligament.
  The Dura Mater is only in contaa w th the Tunic a Arachnoi-
dea, and this alfo onlv in contact with the Pia Mater,  and lying
fo loofely over it as to be feparated from  it with facility through
the whole length ot the Spine.
  The Spinal Marrow, I ke the Brain, confifts of a cortical and
Medullary Subftance, but d ffers in this refpea,  that the Cineri-
tious Mater is  placed within the other.
  Upon the Suiface  of  the Spinal Marrow, while lying  in  its
natural  fituation,  many tranfverfe Wrinkles or  Folds are ob-
ferved, which allow it to be extended in the motions of the Ver-
tebiae.
  It is a little flattened on its anterior and pofterior Surfaces, and
is larger near the under  part of the Neck, and at the top  ol  the
Loins where the great Nerves of the Extremities are fent off, than
in the other parts of  the Spine.
  It is divided into two lateral Portions or Cords, which are fepa-
rated from each  other externally by an anterior and pofterior Fif-
fure continued  from  the Medulla Oblongata ;  and each of  the
lateral Portions  is in  fome meafure fubdivided by a fuperficial
Furrow into a larger anterior and fmall pofterior Cord.
  The  lateral Portions  are firmly  united  together by fine Cellu-
lar  Subftance, but may be fepirated from each other  before at
well as behind,—without lacerating either,—to near their  mid-
dle, where they  are conneaed by a Layer of Cineritious Mat-
ter  which pafl'es  from the one Cord into the other.
  When the Medulla Spinalis is divided  tranfverfely,  the Cine-
ritious Subftance is obferved to have a Cruciform  appearance,
correfponding with the Cords of which it is compofed.
  The Bodyof the Spinal Marrow defcends as far as the Second
Vertebra of the  Loins,  and terminates there by a Conical  point,
which is concealed by Fafculi of Nerves.
  Each of the lateral portions  of  the Spinal  Marrow fends off
from its anterior and pofterior parts, flat Fafciculi of Nervous
Filaments, which are placed oppofite their fellows on  the  other
fide.
   Several of the Fafciculi of the  Cervical Nerves detach Fila-
ments to thofe immediately above  or below them ; and the fame
thin? is occafionally obferved of fome of the Bundles  of  Dorfal
Nerves.
   The anterior and pofterior Fafciculi peiforate the Dura  Mater,
from the inner part  of  which each Fafciculus is furnifhed with a
 proper Sheath,  and is continued within  it, the Sheaths conneaed
 by Cellular Subftance only,  till they get  between the Vertebrae.
    Between the anterior and pofterior Fafciculi or  Spinal Nerves,
 and between the  Tunica Arachnridea and Pia  Mater, a fmall
 Ligamentous Cord termed Ligamentum Denticulatum,  is fituated,
                            > 
213
which  is  attached to  the Dura Mater,  where that Membrane
comes out from the Cranium and accompanies the Spinal Mar-
row to its inferior exuemity.
  It adheres by  Cellulai Subftance to the Pia Mater,  and fends
oft from  its oppofite fide fmall  Cords, in the form of Denticuli,
which cirry the Tunica Arachnoidea along with them, and run-
ning more or lefs in  a tranfverfe diieaion, are  fixed, each by
minute Fibres  to the Dura Mater, in the  Interftices of the Fafci-
culi.
  The Ligamentum Dent'culatum of the oppofite fides incorpo-
rate with the Pia Mater at the inferior extremity, or Conical point
of the Spinal Marrow, and forma Ligamentous Filament which
perforates the under  end  of the Dura  Mater,  and is fixed by
fmall Fibres to the Membranes covering the  Os Coccygis,  in
the manner the Denticuli are  fixed to the  Dura Mater.
  It was termed by lome Authors Ligamentum Pia Matris.  It
was confidered by  the Ancients  as the Fortieth Pair of  Nerves,
and was  alfo called Nervus  Imparus Sacrus.
  It affifts in preventing the Spinal  Marrow and the tender origin
of the  Neives from being overftretced.
  Having got  between the Vertebiae, each of  the pofterior Bun-
dles forms a Ganglion,  from the oppofite end of which a Nerve
comes  out, and  is immediately joined by the anterior Bundle,
thus conftituting the  beginnings of the  Trunks of  the Spinal
Nerves.
  The Nervous Cords fent out from the Spinal  Marrow, after re-
ceiving their coverings from the Dura Mater,  become confidera-
bly larger than the  Fafciculi  which form  jltem ;  as  has been
already obferved in the general  defcription of the Nerves.
  As foon 3s the Spinal Nerves emerge from between the Verte-
brae, each fends Branches backwards to the Mufcles near the Spine,
and others forwards to join the  Great Sympathetic Nerve,  while
the Trunk is  continued outwards to its place of deftination.
  The Spinal  Nerves ai. diltingmfhed on eti h fide, by numbers,
accoi ding to the Bones under which they pafs  ; Thirty Pairs are
moft commonly enumerated.—One going under  the  iiead,  and
termed Suboccipital;—S .veil  pifling  under the Vertebrae of the
Neck ;—Twelve under the Doifid ;—F.ve under the Lumbar Ver-
tebrae ; and—Five undei the pieces  winch originally compofed
the O  Sacrum.
  The Fafciculi which form  the Cervical Nerves aie fiWr, run-
ning nearly in a ftraight d'reaion fr >m tlu-ir oiigin  to the Inter-
vertebral Holes.  1 hole which form the Dorfal Neives are long-
er than  the former, and run more obliquely  downwa.ds;  and
thofe which form the Lumbar and Sacral Nerves are veiy long and
run ftill  more  obliquely downwards, tiil  ai length the undcrmoft
•f them  become neaily longitudinal. 
244
  The fize of the Fafculi correfponds with that of the Nerves
which they go to form.—The Fafcicnli of the four loweft Cervi-
cal and firft Dorfal, are large and  broad,  giving origin to the
Great Nerves which fupply  the  Superior  Extremity.—Thofe of
the Back are much more (lender, while the Fafciculi of  the Loins
and the two upper Sacral  ones are of grea't fize,  to  form the
very large Nuves which run to the Lower Extremity.
  ThxLnmbar and  Sacral Fafciculi, while included in the Dura
Matei\  form a Bundle of Cords, termed Cauda Equina, from
the refemblance it has to the Tail  of a  Hoife;  efpeoally when
the Fibrillae of the Nerves are unravelled by feparating them from
each other.
  The Fafciculi perfeiate the Dura Mater, nearly oppofite  to the
parts  where  they  pafs  thiough the  Vertebrae,—of courfe the
Neives of the ir.feiior pnrts of the Spinal Manow  emerge from
the Spine, confiderably lower than their different origins.
  Blood-Vessels  of the  Spinal Marrow.— The Arte-
ries of the  Spinal Marrow confift of Anterior and Pofterior Spi-
nal Areries, and of many additional Branches  communicating
with o.hers from the adjacent Veffels.
  The Anterior Spinal Arteries arife,  one on each fide, from the
Vertebrals, near where thefeuom to form tht Bafilar Artery.
  Upon the beginning of the Spinal  Manow,  they  generally
unite into a common  Trunk, which defcends  in that  depitflion
on the  Anterior Suiface of  the Medulla, whereby it  is diftin-
guifhed into two Lateral  Portions,—and the  Arteiy  continues
nearly of the fame fize throu hout, in confequence  of  additions
it receives from the  neighbouring  Arteries.
  In the Neck, it communicates with the Vertebral Thyroid, and
Cervical Arteres, by Branches which  pafs through  the fame
Holes with the Nerves.
  In the Back, it receives Branches from the Intercoftal,  and in
the  Loins  from the  Lumbar  Arteries; all  of  which alfo go
through the Intervertebral Holes.
  It terminates at  the under end  of the  Spinal Marrow; the
Cauda Equina  being fuppl.ed  by Branches  from  the Internal
Uiai   Artery, which  enter through the  anterior and pofterior
Holes of the Os Sacrum.
  The Pofterior Spinal Arteries,—arife commonly from ihe infe-
rior Arteries of the Lercbclium, and frequently from the '1  runks
of the Vertebral Arteries within the Cranium.
  They are eqiia. in leng h to the rofmer Artery,  but confidera-
bly  r.fei ior to it in lize,  and continue feparate through  thtwhole
of the r courfe.                                •►
  They have conftantly a Serpentine appearance, and form fre-
quent  Inofcuh.tions  with  each other,  aid  with  Arteries,  the
Branches of which  communicate  with the anteirir S'pitta! Ar-
tery. 
245
  The Arteries of the Spinal Marrow are divided  into mi-iute
Branches, which are difperfed upon its fubftance, upon the Mem-
branes which inclofe it, and alfo upon the fubftance of the Verte-
brae and upon the origins of the Nerves.
  The Veins of  the Spinal Marrow accompany  their  Arteries,
and afterwards terminate in the Sinus Venofi of the Spine.
  The Sinus Venofi confift  of one on  each fide,  which runs exte-
rior to the Dura Mater, being  chiefly lodged  in the Ligamen-
tous Membrane which lines the  fore  and lateral parts of the Ver-
tebral Canal.
  They extend from  the  Foramen  Magnum  of the  Occipital
Bone, to the under end of the  Os Sacrum, and are fo  inegul.ir
on their furface, and fo much divided and fubdivided within by
the openings of Veins, as in many parts to  have the appearance
of Cells.
  At  the different Vertebrae, they are conjoined by crofs Branch-
es, which have a Semilunar form, like the furface of the Bones
which furround them.
   They communicate at their Superior extremity  with  the Occi-
pital  and Lateral Sinufes, and fend numberlefs Branches out-
wards, wh.ch open into the Veins  the  Arteries of which analto-
mofe  with thofe of the Spinal Marrow.
          Nerves  of the Neck  and Superior
                       Extremity.
   Nervus  Accessorius.—The  Acceffory Nerve belongs in
fome refpeas to  this  Clafs  of Nerves ;—but having part of its
origin within the Head, and from  its pafling out with one of the
Cerebral Nerves, it has been already defcribed along with thefe.
   Suboccipital  Nerves.—Thefe weteformerly called Tenth
Pair of the Head, and by many  at  prefent are termed Firft of the
Ntek.
   They  arife, on each fide, from the  beginning of  he Spinal
Marrow, by an Anterior and  Pofterior Fafc icul.is,  Ike  the reft
of the Spinal N'erves ;  and, like thefe aifi>, they have then Gan-
glia where they  pafs out between  the Bones.
   They  perforate the Dura  Mater immediately under the en-
trance of the Vertebral Arteries and pafs forwards under them,
and over the tranfverfe Proceffes of the A las.
   Tiiey afterwards appear in the fop-part of  the Neck, and are
each conneaed above by an Arch to the root of the Ninth Pair,
and below by a fimilar Arch to  .he Firft Cei vical Nerve.
   Anteriorly, they are joined  by  one  or two  Ihori  Branches to
the upper Gangl'a of the Great  Sympathetic Nerve.
   They afterwards divide into Branches, wh ch are diftributed
upon the Reai and Obliqui Capitis, and upon fome of the Deep
 Extenfor Mufcles of the Head.
    Vol.  11.           X 2 
21ti
  The First Cfrvical Nerve,—comes out, on each fide, be-
tween the Atlas and Second Vertebra cf the  Neck, and immedi-
ately fplits into two parts ; the firft of  which paffes forwaids un-
der the tranfverfe Procefs of the Atlas, and is joined by an Arch
with the Nervus Acccfforius, and by  Branches  with  the  Ninth
Pair:  It is alfo^cor.neaed by a foft Gangliform pellucid root with
the upper Garghon of the Sympathetic Nerve, fending a Branch
downwards,  to be fixed to the fecond Cervical  Nerve,  and alfo
fmall  Branches to the Mufcles conneaed with  the fore-part of
the Vertebias.
  The othei, which is the principal part,  goes backwards, and,
after fending Branches to the Extenfor Mufcles of the Head and
Neck, perforates thefe, and forms the Proper  Occipital Nerve.
  The Occipital Nerve afcends upon the Head with the Artery of
tint name, and terminates upon the Mufcles and Integuments on
the upper and back-part of ihe Head; fome of  its  Filaments
anallomoiing with  others belonging to the Firft Branch  ot the
Fifth, and Portio Dura of the Seventh Pair.
  The Second Cervical Nerve,—after  efcaping from be-
tween the Bones, gives off a Branch, which  perforates the Muf-
cles connt-aed to the fore and lateral parts of the Vertebiae, and
joins the middle Ganglion of the Sympathetic Nerve.
   It fends another Branch of confiderable fize downwards to the
Trunk of the Third Pair.
   It fends feveral Branches to the Sterno-maftoid Mufcle, behind
which it is conneaed by an Arch, and ftill farther out by a Fila-
ment, with the Nervus Accefforius.
   It  is afterwards divided  into feveral Branches, one of which
paffes downwards  fome  way  upon the External  Jugular Vein,
and,  together with a Branch from the  Firft Cervical, forms an
Arch with the Defceiidens of the Ninth Pair.
   It gives offa fmall root which is united  with others in  the for-
mation  cf the Diaphragmatic Nerve.
   A Large Branch comes out from it behind  the Sterno-Maftoi-
deus, which, turning over this Mufcle, fends off the following
Nerves, viz.
   The Injerior Cutaneous Nerve of the Neck, which paffes for-
wards to the parts under the Lower Jaw  :
  The Middle Cutaneous Nerve, which runs  towards the angle of
the Jaw.
   The  Great Pofterior Auricular Nerve, which furniflies an ante-
rior Branch  to the under part of the Ear, and a  pofterior . Branch
div.dmg into  many others which go to the back-part  of the Ear
and Temple.
   The  Cutaneous and Auricular Nerves are difperfed  upon the
Platyfma  Myoides, Integuments of the  fide of the Neck and
Head, the Parotid Gland, and External  In ;  and have feveral
Communications with the Portio Dura of the Seventh Pair. 
2+7
  The remainder of the Second Cervical is diftrbuted upon the
Levator Scapulas,  and the Extenfor Mufcles of  the Neck and
Head.
  The Third Cervical  Nerve,—after  emerging from be-
tween the Vet tebrae,  fends  down a Branch to the Trunk of the
Fourth Cervical, and another Branch which forms the principal
root of the Diaphragmatic Nerve.
  A Third Branch perforates the Mufcles on the  fide of the
Vertebrae, and joins  the  middle Ganglion of the  Sympathetic
Nerve.
  A Small Filament  conneas a Third Cervical wiih  the De-
fcendens of the Ninth Pair.
  The Nerve is afterwards divided into External and  Internal
Branches.
  The  External Branches form Anaftomofes with  the Nervus
Accefforius, near the upper part of the Scapula ;  wh le the In-
terior,  after furnifliing Twigs to  the Jugular Glands,  are dif-
peifed by feveral large  Branches upon the Mufcles and Integu-
ments at the under part  of the Neck,  and  upper part of the
Shoulder.
  The Fourth Cervical,—fendfc a  Branch behind the Muf-
cles fituated on the fore and  lateral parts of the Cervical Verte-
bras,  to the middle Ganglion  of the Sympathetic Nerve.
  It is conneaed by one, and fometimes by two Filaments to the
Diaphragmatic Nerve.
  It gives Twigs  to  the  Jugular Glands  and  deep Mufcles of
the Neck, and at the outer edge of the  anterior Scalenus,  joins
the Fifh Cervical  Nerve.
  The Fifth Cervical,—is  united  with  the  Fourth into a
Common  Trunk, which, after running a little farther out,  joins
the Sixth  Cervical Nerve.
  The Sixth Cervical,—joins the Seventh behind the Clavi-
cle ;  and  to the Seventh, the Firll Dorfal Nerve is added over the
Firft  Rib.
  The Four Inferior Cervical s and Firft Dorfal Nerve are of great
fize,—efpecially  the three n,termed ate#Nei ves.
  They pafs out between the Scrinus Amicus andMedius,—
and afterwards run between the Subclavian Mufcle and Firll Rib,
at the ou  er fide of the  Subclavian Arteiy, to the  Axilla.
  In  the  Axdla, they fepaiaie, unite, and  l'ep.  ate gain, form-
ing an  irre. ular Piexas,  termed Axillary  or Brachial,—which
furround* th  Axillary Arr-.y.
  The Axillary  Plexus feds Blanches to tht  Subfcapularis, Te-
res Major, and  L.iffiinus  Dv-ni,  and furmfhes  the "External
Thoracic Neives  wveh  accompanv  the  Biiod-v.ff Is ol that
name to tht Pea ral  'fun ie-  and  1  e*rum< -us.
  The PI. x-is-if'e w<  '- Jiv.'des in," Ne. »■■•, mi.t of wh ch are
of [.in fi.-?,  o ft.^iy-t. e-biij.eae'r Extremity — T..ey are  as
folio v-                        r 
248
   The Scapularis,—which commonly arifes from the  com-
bination of the Fourth and Fifth Pairs, and extending outwards,
runs through the Semilunar Arch in the upper edge of the Sca-
pula, afterwards defcending between  the root of the Spine and
Head of the Scapula.
   It fun.ifhes Blanches to the  Supra-Spinatus, and is afterwards
confumed upon the Infra-Spinatus Mufcle.
   The Articularis,—which arifes,  like the former Nerve,
from the Trunk common  to the Fourth and Fifth Cervicals.
   It finks deep in  the Axilla, and getting  between the under
edge of the Subfcapularis, and Infertions of the Teres Major and
Latiffunus Doifi, it follows the courfe of the Pofterior Articular
Artery round the Body of the Os Humeri, immediately below
the Articulation.
   It fends Branches to the Teres M:nor, and fome Twigs to the
Ligament of the Joint;  but is  chiefly difperfed upon the Deltoid
Mufcle.
   The Nervus Cutaneus,—which arifes  from the Trunk
common  to  the laft Cervical  and Fill  Doifal Nerve; but  is
chiefly farmed by Fibrillae from the latter.
   It runs down at the inner and  fore-part of the Arm,  near the
Radial Neive.
   It fometimes gives a finallBranch to the upper part of the Co-
raco-brachialis and Biceps ; and, farther down, it gives others
to the Integuments and  Coats of the Blood-veffels.
   About the middle ot the Aim, it fplits into two Branches, an
Internal and External.
   The Internal Branch, which is rather the  fmaller of the two,
paffes before the Bafilic Vein  to the  inner part of  the Elbow,
where it divides into Branches,  two ot which, larger than the
reft, turn obliquely over the Heads of the Flexor; of the Hand,
to be  difperled upon the inner and back-part of the fort-arm.
   The External Branch divides into  feveral others, behind the
Median Bafilic Vein, wh.ch defcend on the anterior and Ulnar
fide of the Fore-arm, as  far as the Wrift.
   They pafs partly over  and   partly  under the  Subcutaneous
Veffels ; furnifliing Twigs to  thefe, and vanifhing in the Integu-
ments.
   B Tides the Nervus Cutaneus, there is another termed Cutane-
us Minor Internus cf Wrisberg,  which, like  the reft of the
Nerves of the Superior Extremity, takes its origin from the Ax-
illaiy  Plexus ; but is more particularly conneaed w th the Ul-
nar Nerv .—It is confiderably inferior in  fize to the Nervus Cu-
taneus.'
   Ir foon fep rates from the Ulnar, lunning afterwards between
it  and the inner nde of the Arm.
   A little below the Axilla, it  fplits into two Branches : 
249
  The fmaller, turning to the pofterior part of the Arm, is divi-
ded into Filaments which are chiefly difpeifed upon the Triceps
and its Integuments.
  The larger Branch  defcends at the inner edge of the Triceps,
and vanifhes upon the  under end of that Mufcle and Skin of  the
Elbow.
  The Musculo-Cutaneus, called alio Perforans Caserii,
—which contifts of Fibrillae  from  almoft all the Nerves entering
the Plexus.
  The Cord formed bv thefe  perforates, obliquely,  the upper
part of the Coraco-brachialis, to wh'ch it gives  Branches.
  It afterwards paffes between   the Biceps and  Brachials Inter-
nusv furnifliing Branches to  both.
  At the Elbow, it gets to the outfide of the  Tendon cf the Bi-
ceps, and runs behind the Median Cephalic Vein.
  From thence it defcends in the Fore-aim, between the Supina-
tor Longus and  Integuments ; furnifliing Branches to the latter,
as far as the root of the Thumb and  back of ihe  Hand.
   The Spiral,  or  Spiral-Muscular Nerve,—which is
apparently fanned  by all the Nerves entering  into -he Axillary
Plexus, and  when the Sheaths of the Nerves are  flit  open, is found
to be compofed of Fibrillae from each of the Trunks,  excepting
from that of ihe Firft Dorfal.
   It is rather larger than any other Nerve of  the  Superior Ex-
tremity, and is diftingu.fhed  by  its Spiral direaion.
  Itis at firft fituated Detween  the Axilltuy Artery and the Ul-
nar Nerve, and  pafles obliquely  downwards  between the  two
Heads of the Triceps  Extenfor Cubiti, and afterwards behind
the Os Humeri, to the outfide of the Elbow.
   From thence it p.oceeds*among the Mufcles  of the Radial fide
of  the Fore-arm, as far as the Hand.
   While  pafling behind the  Os Humeri, it gives fevetal Branch-
es of confiderable fize to the  different  Heads  of the Triceps ;
fome of them  accompanying the Branches of the Arteria Spiralis,
and terminating on the Heads of the Extenfors  of the Hand.
   Immediately behind the body of theOs Humeri, it  tranfmits a
Subcutaneous  Branch, which  is  diftributed upon the Mufcles
and Integuments on the pofterior part of the Fore-aim, analtomo-
fin2; at laft with the Nerves on the  nack-part of  the Hand. ^
   The Tunnk of  the Nerve having arrived at the Elbow, is  lod-
ged in a F. flu re between the Brachialis Intemus and Radial  Ex-
tcnf.irs of the Carpus, and there gives off other Branches to the
Extenfors of the Hand, and to the Supinator Mufcles.
   At the  Head of the Radius,  the Trunk of the  Nerve divides
into  two nearly equal  Branches,—the Superficialis and Profun-
 dus.
   The Superficial:', continued  almoft ftraight  from the Trunk,
immediately tranfmits a Bianch to  the Exucrircs  Radiaies and 
250
Supinator Longus, and then defcends at the  ncer edge  of  this
Mufcle along with the Radial  Arteiy.
  A little below the middle of the Radius, it croffes between
the Tendon ef  the Supinator  and  Ex-.er.lores Radiales,  and is
fubdivided into  a Volar and Dorfal  Branch.
  The Volar Branch, after fe: ding Twigs to the Annular  Li-
gament,  is  diftributed to  the  Mufcles  and Integuments of the
Thumb.
  The Dorfal Branch  s again  fubdivided  into numerous other
Branches, fome of which go to the Mufcles in  the  in erval of
the M^etacaipal  Bines  of the Thumb and Fore finger,  a few Fi-
laments beinv, diftiibuted to the Annular Ligament,  while prin-
cipal Branches run one along each fide of the Foie and Mid-fin-
gcr, and lkewife along the Radial  fide  of th.- Rin^-finger.
  The Ramus Profundus, after fending feveial  Branches to ihe
Extenfuies Radiales and Supinator  Brevis, perforates the la ter,
and gets  to the back-part of the Fore-arm.
  After quitting the Supinator, it  defcends under the Extenfor
Primi Inteinodii Pollicis and  Extenfor  Digitoium to the back of
the Hand.
  In this courfe, it  fends Branches to the different Extenfors of
the Thumb and Fingers, and at length  degenerates into a (lender
Branch,  which,  at  the Wrift, adheres clofely to the Annular
Ligament,  where it  has a G inglifurui appearance, and is  difper-
fed partly upon this Ligament and partly upon the Membianes
on the  back  of  the  Mettcarpu .
  The Median  or Radial Nerve,—which comes from the
middle and  lower part  of the Plexus, is  formed by Fafciculi  from
all  the Nerves which enter the Plexus,  and is nearly of a fimilar
fize with the Spiral Nerve.
  It defcends in the Arm along the anter or furface of the Hu-
meral Artery, to which, and to the Deep Veins,  it adheres firm-
ly by Cellular Subft ince.
  In this courfe,  it does not give off any confiderable Branches ;
—Twi^s, however,  are fent from it to the Coats of the Adjacent
Veffels.
  At the bending of the Elbow, it flips over the Tendon of the
Brachialis Internus, and peiforites the back-part  of the Pronator
Teres  Mufcle.
  It afteiwards paflls d wn between the Flexor Radialis and
Mufculus Subbmis, and goes in the middle of  the  interval  of
the Radial and  Ulnar Artery in its way to the Hand.
  V/hen it approaches the Forearm,  it tranfmits Branches  to
the Pronator Teres  and Integuments near that Mufcle.
   In the Flexure of the Arm, it fuinifhcs Branches to the Pro-
nator,  Flexor Radialis, and Flexor  Sublimis, and an Interofl'e-
ous Branch  which,  in fome Subjcas, receives an addition from
ihe Spiral Nerve. 
f 51
  The Interoffeous Nerve gives Branches to  the Flexor Longus
Pollicis, and to the Flexor Profundus Digitorum, defcends upon
the Interoffeous Ligament with the Veffels of that name, and ter-
minates in the Pronator Quadratus.
  Near the Hand,  it fends a Branch dividing into others, which
fupply the  Mufcles  and  Integuments forming  the Ball of the
Thumb.
  The Trunk of the Nerve having given Branches to the  Fore-
arm,  paffes under  the Annular Ligament of the Wnft,  where it
divides into Brandies which are fituated behind the Aponeurofis
Palmaris,  and Supeificiai Arch of the Arteries.
  The principal Branches in the Palm come off in three divifions,
from which feven Nerves  of confiderable fize are diftributed to
the Thumb and  Fingers.   Of thefe, two go to the Thumb,  and
one to the Radial fide of the Foie-fin.,er; the reft come  off from
two-forked Trunks, near the Heads of the Metacarpal-Bones,
and fupply the adjacent fides of the  Fore and  Middle, and of
the Middle and Ring-finszer.
  Thefe Branches fend Twigs through  the Aponeurofis to the
Integuments  of  the Palm, and  others  to the  Mufculi Lumbri-
cales ; after which  they accompany the Arteries lent out from the
Supeificiai Palmar Arch, bellowing Twigs  to the adjacent parts
of  the Fingers,  at the points  of which they terminate by nume-
rous Fibres.
  The Ulnar  Nerve,—which,  like  the  former,  is  of great
fize, comes off chiefly fiom the laft  Cervical  and  Firft Dorfal
Nerve.
   It extends along the infide of the Triceps, frequently perfora-
ting fome of its Flefliy Fibres, and, near the Elbow, flants a lit-
tle backwards, to get into a Groove between the inner  Condyle
of  the Os Humen and Olecranon of the Ulna.
   From thence it paffes to the Fore-Arm, where, after perfora-
ting the Heads of  the Flexor Mulcles,  it joins the Ulnar Artery
a little below its origin, and  accompanies that veffel,—mnning
behind it ajj the way'to the Hand.
   Under the  Axilla,  it fometimes receives  a Branch from the
Spiral Nerve; and from this conneaion, or font the Trunk of
the Ulnar Nerve itfelf, a Subcutaneous  Branch is fent off,  which
runs  between  the Triceps and Integuments, furnifliing Branches
to the latter for  a confiderable way along the Fore-arm.
   Near the under end of the Os Humeri, a  Twig or two com-
monly go to the inner edge of the Triceps.
   Under the  bending of the Elbow, a  Branch is given out to be
diilributed upon the Belly of the Fiexc r Ulnaris.
   Immediately  below the former,  another  Branch  is produced,
which is difperfed upon the Flexor Profundus Digitorum.
   About  the middle of the Fore arm,  a Filament is traBfmitted
which adheres to the  Ulnar Artery, furnifliing fmall Twigs to 
2J2
the Coats and  Sheath of the Artery, and terminating in the
correfponding parts of the Wrift, and  Integuments of the Palm.
   Near the end of the Ulna, a confiderable Branch,  termed  Dor-
falis, is fent out, which turning between  the Flexor Ulnaris and
Ulna,  is direaed to the back part of  the Hand.
   The Dorfal Nerve  fends  Branches to  the Integuments of the
Wnft  audi Metacarpus, which have various  anaftomofes  with
others  of the Spiral Nerve.
   It lends off a Branch  which proceeds along the  Ulnar fide of
the Little Finger;—and at the Heads ot  the Metacarpal Bones,
another fplitting into two Branches which run along the adjacent
fides of the Auricular and Rinz-fingers.
   The Trunk of the Nerve paffes with the correfponding Artery
over the Annular Ligament into the Palm,  where,  like the Ra-
dial Nerve, it is coveied with the Aponeurofis Palmai is.
   In the Palm,   it  divides into Supeificiai and Deep  Branches ;
the former deftined chiefly for the Fingers, the latter for the deep
region  of the Hand.
   The Superficial Palmar Nerves fends—
   Tiai dies to the  fhort Mufcles of the Little Finger :
   A Branch  to the Volar-umar fide of the Little Finger: and—
   Another, which,is foon fplit into two fmaller Branches ; one to
the Radial fide of the  Little Finger, the other to  the  Ulnar fide
of the Ring-finger.
   The Deep Palmar Nerve finks in between the  Abduaor  and
Flexor Parvus Digiti Minimi, or perforates the head of the latter,
and f-rms an Arch which accompanies the Deep  Arch of the
Aiterie , under  the tendon of ihe  Flexors, and the  Lumbricales
Mufcles.
   The Deep Nerve gives—
   A Branch to the Abduaor Minimi Digity, and one to each of
the Intei c.fi'ei :
   A Twig to each  of the Lumbricales,  which enters from be-
hind :
   Branches to the Flexor Brevisand Adductor Pollicis.
   The  Nerve terminates at  length by feveral fhort Branches
upon the Abduaor Indicis Mufcle.
   The Nerves on the Palm  and correfponding parts of the Fin-
gers, like the Arteries, are much larger than thofe of the oppo-
fite fide of the Hand.
   The Digital Neives fends off many lateral Branches to the In-
teguments and othtr parts of  the Fingers, and terminate,  each,
by a Brufli of Fibres, at the Apices of the Fingers.
   Bttween the Branches of the Radial and Ulnar Nerve, differ-
ent Anaftomofes are frequently found  ; and the fame may be ob-
ferved  between the Neives of  the Palmar and Dorfal fide of the
Fingers. 
25 S
  Inteixosto-Humerales.—Befides the Nerves of the Supe-
rior Extremity fent fron the Brachial Plexus, there are others be-
longing to it, which take their origin from the Intercoftal Nerves,
and which may therefore be termed Intercofio-Humerales.
  The Intercofio-Humeral Nerves,-— confift of a Branch from the
Second, and of another from the Thiid Intercoftal Nerves, both
of which pafs out at the fore and lateral parts of the Thorax,
the one under the Second, and the other under the Third Rib.
  The firft Nerve is joined by a fmall Branch with the Cutaneous
Nerve, or with the Cutaneous Internus of Wrisberg, and is af-
terwards  difperfed by numerous  Filaments upon the Axillary
Glands,  and upon the Integuments of the Axilla and of the in-
ner part of the Arm.
  The Second Nerve is conneaed by one or more Branches with
the Firft,  and fends fome Twigs to the Axillary Glands ; but is
chiefly diftributed upon the Integuments of  the back-part of the
Ann, which it fupplies with many Branches, fome of them ex-
tending as far as the Elbow.
>oooooooo<doooooooo
     NERVES

       WITHIN

THE  THORAX.
,0'
  THE Nerves, in each fide  of  the  Thorax, confift of the
Phrenic, the Pars Vaga of the Eighth Pair, the Great Sympa-
thetic, and the Intercoftals ; all of which are covered and conceal-
ed by the Pleura, till they are expofed by diffeaion.
  The Phrenic or Diaphragmatic  Nerve, has  a fmall
Filament from the Second Cervical ; but is chiefly formed by a
Bianch from the Thiid,  and  by one, and fometimes by  two,
from the Fourth Cervical Nerve.
  It defcends in the  Neck, along the outer and  fore-part of the
Scalenus Anticus Mufcle, and enters the Thorax behind the an-
terior extremity  of the Firft Rib, between the Subclavian Artery
and correfponding Vein.

   Vol. If.            Y 
254
   In the Thorax it runs down  over the root of the Lungs,  at d
 then pafles along the  Pericardium, to which it adheres clofely in
 its way to the Diaphiagm.
   The Right Phrenic has nearly a ftraight direaion oppofite to
 the Superior Cava and Right Auricle ; while the left makes a
 confiderable Curve near its under end, correfponding with that
 part of the Pericardium which covers the point of the Heait.
   Upon the Suiface of the Diaphragm, the Trunk is divided in-
 to feveral Branches, which are diftributed in a radiated form upon
 the Flefhy fides of that Mufcle.
   Pars Vaga.—The Pars Vaga, upon approaching the Thorax,
 fer.ds a Filament, and fometimes two,  termed Cardiac Nerves,
 which join the Cardiac Bianch of the Great Sympathetic, as al-
 ready obferved.
   It enters the Thoiax between the-Subclavian Vein and Artery,
 and after giving off the Recurrent Nerve,  paffes behind the  loot
 of the Lungs.
   Recurrent  Nerve.—The Recurrent,—is  refleaed  up-
 waids, behind the Subclavian Aitery in the  right,  and behind
 the Arch of the Aorta in the  left fide of the Thorax*; in confe-
 quence of which,  the left  nerve is the longer of the two.   It af-
 teiwards afcends in the Neck, adhering to the pofterior and late-
 ral part of the Trachea,  in its way  to  the Laiynx.
   It is conneaed, near its origin, by one or two Branches of con-
fiderable fize, with the adjacent  Ganglia of the Great Sympathe-
 tic Nerve, and from the oppofite fide of its root,  fends other con-
 fiderable Branches to join thofe of the Eighth Pair,  in the  for-
 mation of the Anterior Pulmonary  Plexus of Nerves.
   Near the Subclavian Artery,  it is conneaed by different Fila-
ments to the Superficial and deep Cardiac Branches of the Sym-
 pathetic Nerve.
   In its afcent in the Neck, it  tranfmits Pencils of Filaments
 which penetrate the Trachea,  and are difpeifed upon its Internal
 Membrane.
   Behind the Thyroid Gland, it fends  off minute Fibres to the
beginning of the  Efophagus  and  bottom  of the Ph.irynx  and
fmall Twigs to the Gland itfelf.
   Upon the  inner fide of the Thyroid Cartilage, it  furniflies a
 Bianch which conftituies a remarkable Anaftomofis with another
from  the Internal Laryngeal Nerve.
   At the back part of the Larynx,  it is divided into many Fi-
bril.ae, which are diftributed to the  different Mufcles fixed to ihe
Arytenoid Cartilage of the correfponding fide.
   It  has alio  fome  conneaions, fmaller  than  the one already
mentioned, with Branches of the Internal Laryngeal Nerve  and
fends minute Fibrillae to the Internal Membrane of the Larynx •
from which  circumftance the Recurrent Nerves are confidered as
tire principal Inftruments of the Organ of Voice. 
255
  The Pars Vaga, having tranfmitted the recurrent Nerve, gives
•ff  Fn unents wh.ch form conneaions with Branches arifing from
the  mt or the Recurrent of the fame and of the oppofite fide.
  Tuy  an illoinoie  alfo  by fmall  Fibrillae with  the  Cardiac
B;  nth  f  i ne Sympathetic,  and then pafs to the fore-part of the
B. ,r.ch:,  v iere they conftitute what is termed the Anterior Pul-
monary Plexus of Nerves.
   The Anterior Pulmonary Plexus, thus formed by Branches from
the Eightn Pair, with the affiftance of  others from  the Recurrent
and Sympathetic Nerves,—extends  acrofs the Great Branches of
the Pulmonary Artery, and after tranfmitting fmall Filaments to
the Pericardium and to the Great Cardiac Nerve, furniflies many
minute Fibrillae,   which  accompany the Ramifications of  the
Bronchi  and Pulmonary Blood-veflels  in the fubftance  of  the
Lungs.
  From the Pars Vaga, a little below the  origin of the Recurrent,
and likewife from the root of the Recurrent itfelf, Nerves are fent
off, which form a Plexus, to be difperfed  partly upon the Flefhy-
glandular Subftance of the Trachea, and partly embracing  the
OEfophagus,  and  forming   upon it  the  fmall  OEfophageal
Plexus.
  Behind the root of the  Lungs,  about fix  or feven Nerves  of
different fizes are  fent off in  a  tranfverfe direaion,  which are
termed Pofterior Pulmonary Plexus,  although they have few con-
neaions with each other.
  The Pofterior Pulmonary Nerves, like the Anterior, follow
the Branches of" the Bronchi and Blood-veffels in the fubftance of
the Lungs, and becoming gradually fmaller,  fend  off minute
Twigs, which penetrate the Air-Veffels,  and are ultimately dif-
perfed upon their Internal Membrane.
  After giving out the Pulmonary Nerves, the Pars Vaga is fplit
into Cords termed  Great  OEfophageal Plexus,  which furrounds
the OEfophagus,  fends Filaments  into  its  Subftance,  and is
joined by Funiculi of the Pars Vaga of the oppofite fide.—Tt goes
afterwards through the Diaphragm, to be diftributed  upon the
Vifcera of the Abdomen.
  From the Ganglia of the   Great Sympathetic  Nerve, at  the
bo'tom of the Neck and top of the Thorax, the principal Cardiac
Nerves are produced, which are difperfed upon the Heart; while
the continuation of the Ti unk of the Sympathetic defcends in the
Thorax at the lide of the Vertebra?.
  The Cardiac Nerves of the  Right Side  confift of the
Cardiacus Magnus Profundus,  and Cardiacus Minor, the latter cf
which is termed by Scarpa Cardiacus Aorta Superficialis.
  The Cardiacus  Magnus  Profundus,—is  principally
formed by Branches from  the Second  Cervical Ganglion of the
Sympathetic, and afterwards  receives one or  two Filaments from 
556
the Card;acus Supremus, together with the Superficial  Cardiac
and oiher Branches of the Eighth Pair, as f rmerly defciibed.
  The Trunk, arifing in  this manner fiom d ftereit  fources,
paffes between the Superior Cava and afcending Aorta to the Poi-
re.ior Suiface of the latter, and joins the Caidiac Blanches of
the Left Side.
  By the additionof the Left Cardiac Nerves, a Plexus is formed,
termed Plexus Cardiacus Magnus of Haller, firm  which is
fent out  a long Ganglicn  of a  foft confidence, defer.bed by
Wrisberg under the name of Ganglion Cardiacum.
  From The Cardiac Ganglion, the following Branches are gi-
ven off, viz.
  A Branch which, after tranfmitting Filaments to the Anterior
Pulmonary Plexus of the Eighth Pair,  paffes  behind  the Right
Divifion of ihe Pulmonary Aitery to the Left Coronary Plexus
of the Heart :
  One or two Filaments, which unite with others fent from the
Anterior Pulmonary Plexus ot the Eighth  Pair, and go before
the Right Branch of the Pulmonary Artery to  the Bafe of the
Heart:
  Branches of confiderable fize, pafling partly over the right fide
of the Aorta, and partly between it and the Pulmonary Artery
to the Anterior Coronary Plexus :
  Small  Branches which unite with  others coming  from  the
Trunk of the Great Card'ac Nerve, and pafs  over the Aorta to
the Anterior Coronary Plexus.
  The Nfrvus Cardiacus  Minor arifes from the undermoft
Cervical Ganglion, creeps over the Arteria Innominata and Aor-
ta, and terminates in a Plexus formed by the Cardiac  Nerves on
the left fide of the Aorta Afcerdens.
  The Left  Cardiac Nerves  are,  the Cardiacus Superfici-
alis, and the Cardiacus Magnus Profundus.
  The Cardiacus Superficialis arifes from the  upper part
of the Sympathetic Nerve, as  formerly noticed, and paffes be-
hind the Arch of  the Aorta to the Plexus Cardiacus Magnus.
  The Cardiacus  Magnus Profundus Sinister, the up
per portion ( f which is  fmaller than that of the  right  fide, arifes
by numerous roots from  the middle, and from the loweft Gan-
glion of the Sympathetic Nerve.
  It paffes acrofs the Arch of the Aorta, and, after receiving the
Caidiac Bianch of the Eight h Pair, joins the Great Cardiac of the
right fide,  to affift in forming the Cardiac Plexus.
  From the Caidiac  Plexus, a Reticulum of Nerves extends up-
on the left fide of  the afcending Aorta,  which receives the Car-
diacut Minor, and a F lament or two from  the Cardiacus Mag-
nus of the right fide,  paffing over the Aorta.
  From this Reticulum, the Anterior or Right Coronary PIcxui
is produced,  which  paffes between  the  Pulmonary Arteiy anJ 
2bl
Aorta,  and  afterwards  follows the courfe of the  Trunk and
Branches of the Right Coronary Artery,  along with which it is
difperfed upon the correfponding fide of the Heart.
  The Great Cardiac Plexus, after fending a Filament or two
to the Lungs,  gives off Nerves which unite,  and form the Trunk
of the Great Deep Cardiac Nerve of the left fide, which has a foft
Gangliform appearance,  and pafles along the correfponding fide
of the Pulmonary Artery.
  Upon the Surface of this  Artery, the Trunk foon divides  in-
to Branches, which, after fending Filaments acrofs it to the right
Coronary Plexus, give origin to the Coronary Plexus of the  left
fide, which attends the Trunk and  Branches of the Left Corona-
ry Artery.
  In the Left or Pofterior Coronary Plexus, the Nerves are lar-
ger than in the Right, correfponding  with the Parts  they have
to fupply;  and,  in both, they  have  repeated conneaions with
each other on the furface of  the Heart.
  In general, the Neives run clofe  to the  Arteries ; fome of them
being continued as far as the' Apex, while others  penetrate  the
fubftance of the Heart.
  The Great Sympathetic, having  fent Nerves to the Heart, con-
fifts of an anterior and pofterior part,—the former going over, and
the latter under the Subclavian Artery.
  Behind this Artery, the two parts unite into a Tiunk, which
defcends in the Thorax over the Heads of the Ribs.
  At the Head of each Rib,  it foims a fmall Ganglion of an ir-
regular fliape, which unites behind  with  each of the  Interi-oftal
Nerves, generally by two, and fometimes by three fhort Bran-
ches.
  From feveral of the Dorfal Ganglia of this Nerve,  Filaments
are  detached  obliquely over the Vertebiae  to the Coats  of  the
Aorta-.
  From  the Sixth,  Seventh,  an I E: hth Dorfal Gar.glia,—and
frequently  from a Ganglion  above  or below thefe,—Blanches a-
rif'e, which defcend obliquely upon the  fides of the  Vertebra;,
and unite into  a  Trunk, te med Nervus Splanchnicus,—which
pei forates the Appendix  of the Diaph agm, and goes to the Vif-
cera of the Abdomen, from which circumftance the Nerve obtains
its  name.
  Befides the Nervus  Splanchnicus, another, termed Splanchni-
cus Secundarius,  or Accefj'orius, is generally  obferved, whi.h  a-
rif'co from one or two  of  the Dorfal Ganglia,  below the origins
of the Splanchnicus,—near  its  terminal.on,—or  runs feparate
from it into the Abdomen.
  The  Intercostal, or  Costal, or Dorsal Nerves,—
afrer efcaping from the Vertebrae,—run  in the  Furrows  at  the
lower edges of the Ribs,  in company with the Intercoftal Blood-
    VOL. II.           Y2 
25 *
veffels, and proceed to the anterior part of the Thoiax, between
the tw» Laye.s of Intercoftal Mufcles.
  Immediately after  getting out from between  the Vertebra;,
each is conneaed,  as already noticed, by fhort  Branches to the
Sympathetic Nerve.
  Oppofite  to this conneaion, they give principal Branches,
backwa'ds, to the Mufcles lying near the Spine, and ferving for
the ereaion of the Trunk of the Body.
  Through the reft of their courfe, they give Branches to the In-
tercoftal Mufcles,  to the Mufcles and Integuments of the Tho-
rax,  anil alfo to thofe of the Abdomen,  and becoming gradually
fmaller, they at lalt vanifli in the fore-part of the Body.
  The Six upper Intercoftals  fends  Branches  to the numerous
Mufcles, and to the Integuments covering the back-part of the
Thoiax,  to the Serratus Magnus, and to the upper part of the
Abdominal Muf  les ; while the remains of them, pafling out
between the Ribs at the edge of the Sternum, are refleaed along
with Branches of the Internal Mammary  Blood-veffels, to be dif-
perfed by fmall Filaments upon the Mamma, and likewife upon
the Mufcles and Integuments next the edge of the Sternum.
   The Trunk of the Firft Intercoftal enters the compofition  of
the Axillaiy  Plexus;—a Branch ot  it, however,  runs along the
edge of the firft Rib, in  the manner  the other Intercoftals run a-
long  their refpeaive Ribs.
   Two principal Branches,—one from the Second, and the other
from the Third Intercoftal,—are occupied  in forming the Inter-
cofto-humeral Nerves, already defcribed ;  while a confiderable
Branch from the Fourth is lefleaed  over the edge of the Latiffi-
mus Dorfi to, the Integuments of the back-part of the Thorax.
   The Six lower Interct.ftals, after fupplying the adjacent Muf-
cles and Integuments ot the Thorax, continue their courfe ob-
 liquely forwards,  and are difperfed  upon the  different Mufcles
 and  Integuments of the Abdomen ;—the Twelfth, running from
 the laft Rib  along the under end of ihe Abdomen, fends  Fila-
 ments which extend as far as the Skin of the Pelvis and Thigh.

                    ----™»o«»—---

                       NERVES

                          OP  THE

   CHYLOPOIETIC AND  ASSISTANT CHYLOPOIETIC
                         VISCERA.

   THE Nep ves of the Chyloooietic and Affiftant Chylopoietic
 Vif era, are  foimed by  Branches, of the Par Vagum, and the Ra-
 mi  Splancbnici of the Great Sympathetic Pair. 
253
  The Pars Vaga of the Left Side,—defcending from the Great
OEfophageal Plexus of the E ghth Pair, creeps along the  fore-
part of the Cardia, detaches Filaments to the Left Hematic Plex-
us,  and divides into many Branches which are diftributed to the
upper and left portion of the Stomach.
 ^ The Right Pars Vaga  paffes upon the pofterior part of the
Cardia, and fplits into two Fafciculi, one of which goes to the
root of the Hepatic Plexus and  to the Ceeliac Ganglion, while
the  other, which is the principal one, is  difperfed by numerous
Branches upon the under and left portion of the Stomach.
  The Nerves of the two Fafciculi have feveral conneaions with
each other, about the Cardia and along the fmall Curvature of
the  Stomach, and form a Plexus, by fome Authors termed  Coro-
nary, from which Branches extend along the fmall Curvature as
far as the Pylorus.
  The Ramus Splanchnicus and Splanchnicus  Secun-
darius  have their origins from the Sympathetics,  and  perforate
the upper and lateral part of the inferior Mufcle of the Diaphragm,
—as already mentioned  in the Defcription of the Nerves of the
Thorax.
  After entering  the  Abdomen, they expand  their Fibres, and
unite  with  the lateral part  of the Great Semilunar Ganglion.
   The  Semilunar Ganglion,—is  formed by the  Rami
Splanchnici of the Right and Left Sympathetics, with  the addi-
tion of the Branches from the Eighth Pair.
  It is of a long  curved fhape,  with the convex edge nndermoft,
and is compofed of many fmaller Ganglia,  teimed Coeliac, which
are ot  different fize and oi irregular forms.
  The Coeliac Ganglia are placed over the Aorta, about
the roots of the Coeliac  and  Superior Mefenteric Arteries, and
extend fome way upon the Flefhy Pillars of the Diaphragm.
  From the Coeliac Ganglia innumerable Nerves  ifl'ue on all fides
forming a Plexus, termed by fome Authors Solar, which extends
along the Trunks and Branches of the Ceeliac and Superior Me-
fenteric Arteries.
  The Nerves upon thefe Arteries are fo intermixed with each o-
tber and with Cellular Subftance, as to form confufed Webs;
the name of Plexus,  however,  is ftill retained,  and the particu-
lar name of each Plexus is derived from the Artery which it fur-
rounds, or the Vifcus to which  it belongs.
   The Hepatic Plexus,—after giving Twigs  to the Renal
Glands, fends Filaments to the Dhphra^m, which accompany
the Diaphiagmatic Arteries, and anaftomole with  Branches of
the Phrenic Nerves.
   It afterwards divides into R'^ht and Left Plcxufes, correfpond-
 ing with the Right and Lett Branches of the Hepatic Aitery, or
 with the Right and Left Trunks, when fuch are prefent. 
260
  The Left Hepatic Plexus  furnifhes feveral Branches to the Sto-
mach, which intermix with thofe of the Eighth Pair,  upon the
fmall Curvature.
   The Right Hepatic P.exui imparts Branches to the correfpond-
ing part of the Pancreas, to the fmall end of the Stomach and
beginning of the Duodenum, and gives origin to the Right Gaf-
tro-ep ploic Plexus,  which attends the Artery of the fame name,
diftributing its Filaments to the great Curvature of the  Stomach,
and to th  Omentum Mains.
  The Hepatic Plexnfes furround the Hepatic Artery and Vena
Portae, and, after fending feveial Filaments to the Biliary Duas
and  Gall-Bla.filer,  follow the Branches  of the Blood-veffels
through the fubftance of" the Liver.
  The Splen'C Plexus, compofed of feveral fmall Filaments,
furrounds the Splenic Aitery, gives Twigs to the Pancreas,  and
then accompanies the Veflels into the Spleen.
  The Superior  Mesenteric  Plexus, forms a Vagina,
which furrounds, and in a great pait conceals the Trunk of the
conclponding Artery.
  From this Plexus, numberlefs Filaments are ptoduced,—many
of them extremely minute,—which run thiough the Mefentery,
partly with the Blood-veffels, and partly at a diftance from them ;
ar.d which, after fupplying  the Coa.s of the Veffels and Mefen-
teric Glands,  are diftributed to the fmall Inteftines in general,
and to the right portion of the  Colon.
  The Nerves of the Colon are, in proportion to the part  they
have to fupt ly, laigcr than thofe of  the  Small Inteftines,  and in
feveral places form Arches,  which are fituated at the fides of the
Arteries.
  The Ceeliac  GanrTa fend down, along the Aorta, a Vagina
fimilar to that  furroiinding the  Superior Mefenteric Aitery,
which is joined by other Neives from the Trunk of the Sympa-
thetic continued along the Lumbar Vertebiae.
  From the Aortic Vagin : or Plexus, a  Procefs is fent off, term-
ed Inferior Mese .tery  Plexus,  which  furrounds  the
Trunk of the Inferior Mefenteric Artery, and follows  it  to  the
left portion of the Colon, and to the Reaum;—the Nervous Fi-
laments forming Arches in  feveral places, as in the Superior Me-
fenteric Plexus.
  The Aortic Plexus receiving frefh fupplies from the Trunks
ot the Sympathetics,  fends down  a Plexus,-commonly termed
Hypogaftiic,  which  paffes  over the end  of the  Aorta,  and,
upon the  laft Lumbar Vertebra, fplits  into right and left  por.
tions, whiji defcend to the  Vifcera contained  in the Pelvis. 
in' I
                      NT E R V  E S

                         OP  THE

        ORGANS OF URINE AND GENERATION.

  THE Nerves of the Organs of Urine and Generation confift
ef the  Renal and Hypogaftric Plexus,  and of the Spermatic and
Pudic Branches.
  The Renal Plexus  is compofed of Nerves  fent from the
Ceeliac Ganglia, joined by fome others derived from one or  two
of the  Ganglia, of the Sympathetic Nerve in the bottom of the
Thorax.
  It is interfperfed, at its beginning, with fmall Ganglia, termed
Renal,  and is afterwards divided into Anterior and Pofterior
Plexufes, which extend along the correfponding  Surfaces of the
Renal Artery to the Subftance of the Kidney.
  From the Renal Plexus, fmall nervous Twigs  afcend to the
Renal Gland,  which is furnifhed  with others from the Ceeliac
Ganglia and root of the Hepatic Plexus.
  The Renal Plexus alfo fends down Filaments to fupply the'up-
per portion  of the Ureter ;—the  under receiving Nerves  from
the Hypogaftric Plexus.
  The Hypogastric Plexus, the origin and courfe of which
have been already mentioned, is conneaed by different Nerves to
the adjacent Trunks of the Great Sympathetic and Sacral Nerves,
and fends many Filaments 10 the RecTum, Bladder,  and  Sper-
matic Veffels in the Male ; and to the Reaum Bladder,  Uterus,
and Vagina  in the Female.—The  Nerves of the Uterus  are pro-
portionally fmall.  They pafs  into its fubftance at the Cervix,
and follow the courfe of the Blood-veflels.
  Spermatic Nerves.—The Spermatic Nerves are very mi-
nute—They confift of a Superior or Internal, and of an Inferi-
or or External fet of Capillary Branches.
  The former  are derived from the Renal and Aortic  Plexus,
and  accompany  the  Spelmatic Blood veffels  in their courfe
through the Abdomen, and afterwards to the Tefticle.
  The litter are lent off from  a Branch of the Second  Lumbar
Nerve,  which running behind the  Tendon of the External  Ob-
lique Mufcle,  near Poupart's Ligament, detaches a Filament,
which, in the Male, goes to the Spetmalic Cord,  and more par-
ticularly to the Cremafter Mufcle;  and in the Female, is reflec-
ted along the Ligamentum Rotundum to  the Uterus.
   Nervi Pudici.—The Nervi Pudici arife in two Fafciculi,—-a
Superior and Inferior—which are formed by Fibrillae from all the
Cords entering the compofition of the Sciatic  Nerve, 
1262
  The Superior  Fafciculus is formed,  more particularly,  by
Threads from the two  under Lumbar  and two upper  t'     1
Neives ;—the Inferior is compofed of a fmall Cord from the be-
cond, and a large one from the Third Sacra..
  The Fafciculi pafs  through the under pait of the Notch of the
Os Ilii.in, and afierwards between the Sacio lciatic Lii amri :«,
and  follow the Pudic Blood-veffels, anaftomofing in fome pcices
With each other by Oblique Branch.-s.
  T.tey fend many Branches to the Mufcles and other parts a'.oi  t
the Anus  and Perineum, and then pafs  forwaids  to fupply the
different parts of the Penis.
  On the Penis, the Neves follow the courfe  of the Arteries, the
Superior Fafciculus conftituting the Nervus Dorf.Ji , and the In-
ferior L;ving Branches to the under part of the Penis.
  The Nervus Dor falls  which is  the  moll  con. dei able of the
Penis, runs forwards between the correfponding Aitery and Vena
Magna,  expanding into many Blanches  which aftd fupplving
the Corpus  Cavernofum and  Teguments of  the  corrciponding
fide, terminate in the Subftance of the Glands.
iQi
                     NERVES

                         OF THE

    LOINS, PELVIS,  AND INFERIOR  EXTREMITY.

  THE Nerves of the Loins, Pc'.v s, and Inferior Extremity,
conlill of the continuation or inferior portion cf the Sympathetic,
and of the Trunks and  Blanches of the Lumba and  Sacral
Nerves.
  The Sympathetic Nerve, after reaching the Abdomen,
m ikes a fweep forwards upon the anterior and lateral part of the
Lumbar Vertebrae, between  the  Tendinous  Crura of  the  Dia-
phragm and ihe Pfoas Mufcle.
  It afterwards defcends  into the Pelvis, nearly of the fame fize
as in the fuperior parts of the Body,  and paffes  over the anteiior
Surf.ce of the Os Sacrum, at the  inner fide of the Great Sacral
Foramina.
  'Towards the lower part of the  Pelvis, it becomes confiderably
fmaller, and at laft nnfhes its courfe upon the furface  of the Os
Coccj'lms, where it unites into an Aich with its fellow of the op-
pofite fide. 
263
  In the Loins, it forms Ganglia fimilar to thofe in the  Thoiax,
each of which is conneaed  behind, by two or three long flender
Branches, to the roots of the  Lumbar Nerves, and before,  by
other flender Neives to the Aortic Plexus.
  In the Pelvis  alfo, it forms Ganglia  which are conneaed to the
Sacral Neives on one fide, and to the Great Sympathetic on the
other,  by crofs  Branches.
  Filaments are fent off in  the Pelvis, from  the  Sympathetic to
the Mufcles and Membranes about the Os Coccygis, and to the
Intellinum Rectum.
                    Lumbar Nerves.
  The  Five Lumbar Nerve1-, immediately  after emerging
from the Bones, communicate with each other and with the Sym-
pathetic Nerve, and fend large Blanches backwards to the Muf-
cles "and Integuments on the pofterior part of the Loins.
   By their conneaions with each other, they compofe a Plexus
termed  Lumbar, which is fituated behind the Pfoa; Mufcle, and
fends Branches outwards to  the Quadratus  Lumborum,  and  to
the Flexors of  the Thigh.
   The First Lumbar Nerve is conneaed by a fmall Branch
to the Twelfth  Dorfal, and by its Trunk  to  the Second Lum-
bar.
   It gives Twigs to the Quadratus, and a principal Branch which
paffes  over that  Mufcle towards  the  Spine  of the Os Ilium,
where  it fends Nerves to the Integuments of the Pelvis, to the up-
per and outer part of the Thigh, to the under end of the  Abdo-
minal Mufcles, and to the Integuments of the Pubes.
   The Second Lumbar  perforates  the Pfoas, to which it gives
Branches; and afteiwards runs into the Third.
   From the Second Lumbar, the Spermaticus Externus  is fent
off, which perforates the under part of the Tranfverfe and Inter-
nal Oblique Mufcles, near the anterior end of the Spine, or Creft
of the  Ilium.
   It goes next under the  Tendon of the External Oblique, at
the inner fide of Poupart's  Ligament,  and pafling  thiough the
Abdominal Ring, is diftributed to the Scrotum and  to the Sper-
matic Cord in  the Male.
   In the Female,  it fends  a  Branch  to the  Labia, and another,
refkae'd along the Ligamentum Rotundum, to the Uterus ;  and
in both Sexes,  it gives Branches alfo to the  Integuments  and
Glands of the Groin.
   Another Branch, fmaller than the  former, arifes alfo from the
Second Lumbar,  and pafling between  the Pfoas Mufcle  and Ver-
 tebras,  conftitntes the Cutaneous Medius of  the Thigh.
   The Cutaneous Medius defcends in  the foie part of the Thigh,
oppofite to the inner edge of the Reaus Mufcle,  and  fupplies the
Integuments near it as far  as  the Knee,—one  Branch of it anaf-
 tomofing with another of the  Cutaneus Anterior. 
264
  Branches  of the Second, Third, and Fourth Lumbars, form
a Nerve of confiderable fize, called Obturator, which  paffes be-
tween the External and Internal Iliac Blood-veffels, and along the
fide of the Pelvis.
  The Obturator Nerve accompanies the Blood-veffels, of
the fame name,  through the upper part of the Obturator Muf-
cles and Ligament,  and having  fnrnifhed Branches to the Ob-
tutator and Peaineus Mufcles, it divides into an Anterior and
Pofterior Fafciculus ;  the former difperfed upon the  two  fmall
Adduaors aud Gracilis, the latter upon  the Great Adduaor of
the Thigh.
  The principal parts of the Trunks of the four upper Lumbar
Nerves, efpecially of the Third and  Fourth,  unite and form
a Nerve of great fize, termed Crural, or Anterior Crural.
  The Crural Nerve, after beftowing  Branches  upon the
Iliacus Internus, paffes behind,  then  at the outfide of  the Pfoas
Mufcle, to get to the Thigh.
  In its courfe from the Abdomen,  and at the upper part of the
Thigh, it is  fituated at the outfide of the Femoral Artery, which
lies between it and the correfponding Vein.
  Behind Poupart's Ligament, it is  divided into many Branch-
es, which are diftributed to the Mufcles and Integuments on the
fore and lateral parts of the Thigh,.—one Branch in particular de-
fcending upon the Leg.
  The Branches are as follow :
  The Cutaneus Anterior,—more internal  than  the Cutaneous
Medius, which crofl'es over the  middle of the Sartorius Mufcle,
and after fupplying the adjacent Integuments, terminates in the
Skin and Cellular Subftance, at the fore and  inner part ef the
Knee.
  The Cutaneus Internus,—ftill  more   internal than the former,
—which pafles between  the  Sartorius and Triceps, and, after
giving Filaments to the Integuments at the infide of the  Thigh,
terminates in thofe at the under and fore part of the Knee.
   The Deep Blanches of the Crural Nerve, which  are confide-
rably larger  than the Supeificiai, go to the Peaineus  and Tri-
ceps,  to the Sartorius  and Gracilis, and  to the  four  Extenfors
of the Leg, and  furnifh  Twigs to  the Femoral  Blood-veffels
alfo.
   The Branch to  the Leg,  termed Saphenus, defcends between
the Sartorius and Triceps, and afterwards behind the Tendon of
the former,  to the inner fide of the Tibia.
   Under the Knee, it gives off a Branch,  named  by Fischer,
Saphenus Minor, which goes down a little behind the  Saphenus,
and,  furnifhine-Filaments to  the Integuments of  the inner and
back-part of the Leg,  terminates behind  the Malleolus Internus,
on the Integuments of the Foot. 
2G5
  The Trunk of the Saphenus attends the Vena Saphena Major,
fending many Nervous Threads obliquely forwards to the Lnie-
guments on the inner and fore-part of the Leg, and is at length
confumed upon the Skin and Cellular Subftance of the upper and
inner part of the Foot.
  The remaining part of the Fourth Lumbar Nerve unites with
•he Fifth into a Trunk which defcends into the Pelvis.
                    Sacral  Nerves.
  The Sacral  Nerves confift of fmall Pofterior, and large
Anterior Trunks.
  The Posterior  Sacral Nerves  pafs out  by the Holes in
the back-part of the  Os Sacrum,  and anaftomofe  with each other,
and with fome of the Branches of the Gluteal Nerves.
  They fend out a few tender Fibrillae, which are difperfed upon
the Mufcles  covering the back-part of the Os Sacrum, and upon
the Glutei Mufcles and their Integuments.
  Anterior Sacral Nerves.—Of the Anterior Sacrals,—*
the two  uppermoft are the largeft: The reft fuddenly diminifh in
fize,  the laft  being the fmalleft of the Spinal Nerves.
  They go through the Holes in the fore-part of the Os Sacrum,
and, foon  after their exit, are united with each other, and  with
Branches of  the Sympathetic Nerve.
  The First,  Second,  and  Third  Sacrals, join into a
Trunk, which receives the common one fent down from the Fourth
and Fifth Lumbars, and forms a Plexus which fends out the Sci-
atic, the largeft Nerve of the Body.
  The roots of the Sciatic Nerve give  origin  to  the Fafciculi
which compofe the Pudic Nerve, formerly defcribed, and alfo to
the Gluteal  Nerves which are difperfed upon the Mufcles of the
Hips.
  The Gluteal Nerves run in two Fafciculi,—a Superior,
arifing immediately from the Trunk formed by the two laft Lum-
bars, and—an Inferior, coming off from the two  laft Lumbars
and firft Sacrals.
  The Superior Fafciculus  goes through the upper part of the
Notch of the Os Ilium, to be difperfed upon  the two fmaller
Glutei Mufcles.
   The Inferior Fafciculus paffes through the under part of the
lame  Notch, and below the Pyritoim Mufcle, to  be diftributed
upon  the Gluteus Maximus and Integuments.
  The Fourth Sacral fends  Filaments to the Hypogaftric
Plexus, others to the Mufcles and Ligaments of the Os Coccy-
gis;  the reft  pafs outwards to the Mufcles and Integuments about
the Anus.
   The Fifth,  which is fcarcely above the  fize of a Filament,
after giving Twigs  to the Coccygeus Mufcle, perforates the Sa-

   Vol.  II.             Z 
266
cro-fciatic Ligaments, and terminates in the Mufcles and Integu-
ments of the Anus.
  Sciatic Nerve.—The Sciatic or Ifchiatic Nerve.—paffes ob-
li niely through the Notch of the Ilium, under the Pyritorm Muf-
cb.  It goes afterwards  over  the other  fhort Rotator Mufc'.e*,
and is placed between the Tuber  If hii an I Trochanter  Major,
where it is covered by the Gluteus Maximus.
  After leaving the Pelvis, it  defcends in the  back-part of the
Thigh, firft between  the Long Flexors and Adduaor Magnus,
and then between the latter and Os Femoris to  the Ham,  where
it obtains the name of Popliteus.
  In this courfe, it gives out the following Branches, which fup-
ply the Mufcles and Integuments on the back-part of the Thigh,
viz.
  Tvjigs to the Rotators of the Thigh, which  come off from it
after its paffage through the Sciatic Notch.
  The Cutaneous Pofterior Superior, which arifes within the Pel-
vis, and pafling out with the Sciatic,  is  divided into  Branches,
fome of which are refleaed to the Scrotum  in the Male,  and to
the pofterior parts of the Labia in the Female, and, in both,  to
the Skin abont the Anus and Peiineum.—The principal Branches
of this Nerve pafs downwards,  fupplying the Integuments of the
back-part of the Thigh,  as far as the bending of the Knee.
  A Branch to the long Head of  the Biceps.
  Two fmall Nerves, the  one termed Cutaneus Internus Superior,
which comes off near the upper part of the Thigh, and vaniflies
in the Skin, a little farther down ; the other termed Cutaneus In-
ternus Inferior, which arifes near  the former, goes down the pof-
terior part of the Thigh, and then  defcending upon the inner
Head of the Gaftrocnemius Externus, terminates in the Integu-
ments of the Calf of the Leg.
  A Large Common Trunk,  and fometimes, inftead  of it, fepa-
rate Branches, which arife near  the middle of the  Thigh,  and
aie diftributed to the Adduaor  Magnus, Seinimembranofus, Bi-
ceps,land Semitendinofus.
  Nervus Popliteus.—The Popliteal  Nerve is  fituated be-
tween  the Ham-ftrings,  and  between the  Skin and Popliteal
Blood-veffels.
  A little above fhelsending of the Knee,  it is divided  into a
Small External, and a Large Internal  Bianch; the former named
Fibular,  and the  latter Tibial Nerve.
   The Tibial and Fibular Nerves adhere,  for fome way, by Cel-
lular Subftance, and even the Trunk  of the Sciatic may be fplit
into thefe two Nerv»s for a confiderable way up the Thigh.
   The Fibular,—termed alfo Peroneal Nerve,—fends off,
3t its beginning,  the Cutaneus Externus,  which is  a  fmall
Bianch giving TwLs to the under end of  the Biceps, and which, 
267
after running down on the Outer Head of the Gaftrocnemius,
difappears  in the Integuments of the fame fide of the Leg.
  Over the outer C< n iyle of the Os Femoris, it gives off another
Cutaneous Branch, winch  goes over the Gaftrocnemius Mufcle,
and, after anaftomoilm.; with a Branch of the Tibialis, :;oes along
the outer part of the Leg, and terminates in the Integuments of
fide of the  foot.
  The Fibular  Nerve afterwards paffes  over the Head of the Fi-
bula,  and divides into Superficial and Deep Branches, which fup-
ply die Mufcles and  Integuments of the outer and fore-part of
the Leg.
  The Superficial Fibular croffes over  the Fibula,  immediately
under its articula ion, and perforating the Peioneus Longus, and
going  over the   Brtvis, it gives Blanches to  both,  and after-
wards becomes  Subcutaneous, about the middle of the outerparta
of the Leg.
  It fend* Branches to the Mctatarfus, to the Extenfor Digitorum
Brevis, and others,  winch, after ana ft tmofing upon the upper
part of the Foot,  hi.nifh Dorfal Branches to the larger Toes.
  The Deep Fibular Nerve croffes over the Fibula   immediately
above the former,  and divides into feveral Branches, viz.
  A RefleiledBranch to the foft parts of the joint :
  A Branch to the Peioneus Longus :
  A Branch to  the Tibialis Amicus .-
  Branches to  the Extenfor Pollicis,  and Extenfor Digitorum
Longus :
  Filaments which creep along the Periofteum of the Tibia, and
others which adhere to the Coats of the Tibial Artery.
  The longeft Bianch of the  Nerve accompanies the Anterior
Tibial Artery,  and div'des upon the Foot into Branches,  which
have  fome  conneaions with each other, and  fupply the Exten-
for  Digitorum  Brevis.—Some Filaments continued  from thefe
Branches run to the Mufculi  Interoffei, while  others of more
confiderable fize go to fome of the innermofl Toes,  one  Twig
finking with a Bianch of  the Anteiior Tibial Artery to the Deep
Mufcles of the Sole.
  The Tibial Nerve paffes between  the Heads of the Gaftroc-
nemius Mufcle, and, after perforating  the origin of the  SoIeuS,
defcends between tt and the Flexor Digitorum Longus, upon'the
P.-lienor Tibial Artery,  to the under part ot the Leg ; in which
courfe it fends  off the following Nerves, viz.
  The Communicans Tibia,— vl.ich accompanies the Vena Saphe-
na Minor in the back part of the Leg,  and to  the outer  part of
the Foot.
  Behind  the. Belly of  the Gaftrocnemius,  the Communicans
fends a Branch  to be confumed  in the Fat;  and a little lower, it
anaftomofes  with the communicating  Branch of  the  Fibular
Nerve. 
♦ciS
   The under part of this Nci ve is difperfed upon the Integuments
of the outei Ankle and adjacent fide of the Foot, fome Branches
pafling as far  as the Dorfal fide of two or three of the  fmaller
Toes.
  Branches to  both Heads of the Gaftrocnemius,  to the Planta-
ris, and to the Soleus.
   Near the middle of the Leg, it fends Branches to the Tibialis
Pofticus, to the Flexor Digitorum and Flexor Pollicis.
   One or two Cutaneous Branches, difpeifed upon the Skin at the
under and inner part of the Leg.
  Near the Ankle a Branch which paffes behind the Tendo Achil-
lis, principally to the Integuments of the outer and back-part of
the Foot.
  The Tibial  Nerve paffes afterwards between the Aiteries and
Os Calcis into the Sole.
  In the hollow of the Os Calcis,  after  detaching  Branches to
the parts adjacent, it divides into Internal and External Plantar
Nerves,  which aie nearly of equal fize.
  The Internal Plantar Nerve runs near the inner fide of
the Sole, fends F laments to the Abduaor Pollicis, Flexor Digi-
torum Brevis,  and Flexor Digitorum Accefforius,  and Twigs to
the Lumbricales.
  It afterwards gives out four large Branches fplitting into others,
which run with the Arteries along  the Plantar fides of the three
firft Toes, and inner lide of the fourth Toe,—in the manner the
Radial Nerve runs along the correfponding Fingers.
  The External Plantar  Nerve, fends  branches to the
Heel, and paffes with  the Artery of the-fame name to near the
outer edge of the Sole,  where it fplits into three principal Bran-
ches.
  The two fii.1  run to the  adjacent fides of the fourth and fifth
Toes,  and outer fide of the Little Toe,  the inner one often an-
aftomofing with a correfponding Branch of the Internal Plantar.
   The third forms an  Arch correfponding  with that of the-  Ex-
ternal Plantar  Arteiy,  furnifties Branches to  the fhort Mufcles
of the Little Toe, to the Interoffei, Lumbricales, and Tranfver-
falis, and terminates in the fhort Mufcles of the Great Toe.
   The  Plantar  Digital Nerves  fend Filaments to the Integu-
ments, and upon the Toes anallomofe with each other, and with
the Dorfal-digital Nerves,—as the Palmar Digital Nerves do iu
the Hand.
FINIS. 
INDEX  TO FYFE'S ANATOMY.

              VOLUME  SECOND.

                     — o^—---
A
Page.		1	yage.
Abdomen, Ofthe	91	Appendices vermiformes of the	
		cerebellum	
			zo
phatics of the under part		Appendix vernaiformis of the	
of the,	158	caecum	98
		Aqua labyrinthi, Aquadu&us Fallopii,	
the containing parts of the	ZII		55 53
Abducentes, or fixth pair of			18
nerves,	232	Aqueous humour	32
Absorbent System,ofthe	J53	Arachnoidea tunica,	12
Acceflbry nerves to the eighth		Arbor vitse,	20
pair,	240	Arch of the aorta,	1-4
Acervulvs cerebri,	19	Arches of the palate	62
Acuflicus nervus,	233	Arcus plantaris arteri Tus,	221
Adductor oculi,	37	——- volaris piofundus,	i'4
AdepsJ	8	————— fuperficiaiis,	195
Adipofe arteries and veins,	207	Arteries, of the,	169
Alae vefpenilnnis,	*34	Articular nerve of the fhoulder	248
Albuginea tunica,	124	Arytenoid cartilages,	65
Almonds of the Ears,	63	Auditorius nervus,	233
Alveolar arteries,	179	Auricles of the heart,	7&
Amnir.s,	146	Auris tranfverfus,	45
Amygdalae,	63	—— internus,	5°
Anthelix,	44	Axillary artery,	191
Antitragicus, ? Antitragus, J	45	———-- plexus,	166 247
Aorta, general courfe of the	i74	Azygos vena,	199
Appendages of the fkin	.6	■j	
                             B
Ball of the Eye,      -      26  Bladder of urine, blood-veffels
------:-------, coats of the,  ib.                 of the,    208
.-------------, humours of the 32                , lymphatics
-------------, mufeles of the, 36                 ofthe,    158
■ ■ ■         , yefl'els of the,  38  Blood-Vessels in general,
                      181.186                 of the,    169
. 1           , nerves of the  38 • Brachial artery,      -      192
                         228        - plexus of nerves,     247
Bafilar Art rv,      -      184  Brain, of the,      -       9
Bafilic vein,    -      -    196        , arteri s of the,      182
Bladder of  urine,      -    120  ——, veins of the,   -    1**

    Vol.  II.          Z  2 
iMfliX.
Brain, nerves which  arife
  from the,
Bronchi,
page.
227
 86
                           p«gt.
Bronchial arteries and veins, S8.198
Buccales arteriae,     -       1-9
Bulb of the urethra,    -     129
CcEcam inteftinum,      -      98
1      -----, abforbents of the  160
Calamus fcriptorius,      -     20
Canals of the cochlea,     -     51
Capfulae renales,       -      119
            —, blood-veffels
of the
                         117.207
11   "-     ■  , lymphatics
  of the       -       -     163
Cardia,       -                94
Cardiac Nerves,    -     -    255
Carotid arteri.s,       -      176
'        artery,  external,       ib.
         »     ,  internal,      180
Caruncula lacrymalis,     -     26
Cauda Equina,       -       244
Cava, geneial courfe ofthe,    174
—, fuperior,       -       223
—, inferior,      -  "'      199
Cawl,       -       -        101
Cellular fubftance,      -       7
Centralis retinae arteiia,   -    181
»      -■        vena,     -    186
Centrum cvale of Vkujfens,     15
         femicirculare geminum 16
                             196
                              *9
                             184
                             182
                              !3
                             246
                             190
                              57
                           55-*35
                             146
                              29
                              16
Cephalic vein,
Cerebellum,
 ■        -, arteries of the,
Cerebral arteries,
Cerebrum
Cervical nerves,
Cervical arteries,
Chre-kt,
Chorda tympani,
Chorion,
Choioid coat,
       ■  plexus,
Chylopoietic andAssisTANT
Chylopoietic Viscera,
   of the,       -       -     91
■         blood-veffels of the 200
—-----—. abforbems of the,   158
         ■ nerves of the,
Ciliary  circle,
     1 '  glands,
        proceffes,
Cilia,
Ciliary  arteries,
       1 veins,
29
»4
30
Cineritious fubftance ofthe brain 14
Circulus iridis arteriofus,
Circumflexa fe- f interna, 7
  moris arteria, { externa, 3
         1  hu- C anterior,  J
  meris. arteria, \ pofterior, J
182

214

192
212
 '3
           -offis ilii arteria,
Circumvolutions of the brain,
                of the cerebel
  lum    -       -           20
Circus arteriofus of Willis,     185
Clitoris,      -,-       -      138
Coats of the  eye,     -     -   26
Cochlea,     -     -     -    51
Coeliac artery,        -       aoo
Colic arteries,       -        203
■       veins,     -      -   204
Colon,       -                98
1     -, abforbents  of the, '   160
Columnae valvulae Vieuffenii,    20
     1     carneae of the heart, 77
Commiffurae  eerebri,       -    18
Commiffura mollis of the optic
   thalami,     -      -       16
Communicans faciei, nervus, 233
Cord, umbilical,       -      144
Cornea,                      27
Cornua ammonis,       -      17
Cornua of the ventricles of the
   btain,                      15
 Coronary veffels of thefheart,   82
 ---------artery of the lips,    177
 ■               of the ftumach 200
                              21
                              128

                               17
                              22
                              ib.
                                8
                               13
                              30
                                4
258   Co
 25   —
181   —
J87   -
Corpora albieantia,
—— cavernofa penis,
1        fimbriata, or Tcenii
  Hippocampi,       -   * ■
Corp ra olivaria,     -    -
        pyraniidalia,
 us adip<>lum,
---callofum,
—  iliare,
—• mucofum, 
INDEX.
                            page.
Corpus fpongiofum urethrae,    129  Cryftalline lens,
portical fubftance of the brain,  14  Cutaneous nerve of the fupe
Coftal neives,        -        257    rior extremity,
Cranium, nerves which pafs         Cuticle,
                              227
                               65
  through the bafe of the,
Cricoid cartilage,
        f cerebri,  >
        \ cerebelli, J
Crura
Cutis vera,
Cyftic artery,
Cyftis fellis,
 pap.

   3*

  248
     3
     5
  202
* no
Dartos,       -       -        123
Depreffor oculi,        -        37
Diaphragm, blood-veffels ofthe 200
nerves of the
Dorfal nerves,
Drum of the ear,
Duel,  cyftic,
*53
257
 47
in
Duct, hepatic,
■     , pancreatre,
Duftus communis cholidochus
Duodenum,
Dura mater,   ■»
           , blood-veffels of the
                          11.189
       '   ■, proceffes of the,   10
no
"5
112
 97
  9
Ear,  ofthe,
——,  fmall bones of the,
     ,  mufcles proper to the,
Ear, external
—, mufcles of the,  vol. I.
Ear, internal,
----, qjufcles of the,
Eighth pair of nerves,
           f olivares,      ~i
Eminentiae< mammillares, >:
           {_ pyramidales,  J
Emulgent artery and vein,
Epidermis,
Epididymis,        -*
Epigaftric artery,
44   Epiglottis,                     65.
49   Ergot, or Hippocampus minor,  15
45   Euftachian tribe,       -       ^.55
44   Extre 5 fuperior ,  fuperior 7 extre-
60   Tnity, l inferior •>" interior \ mity.
 47
 5°
236
207
  3
124
212
Face,  lymphatics of the,      167
----,  blood-veffels of the,     185
----,  nerves of the,     -     235
Falx, or Sc turn cerebri,       10
    ■ minor, or fepcum cerbelli, n
Fat,       ...     8
Femoral artery,
——  vein,
       , or 1:rural nerve
Fibular artery,
v.1.1,
nerve,
214
222
264
219
222
266
       of the,
----,  cdats of the,    -       26
——,  humours of the,     -   32
——,  veffels of the,     -     38
——,  nerves of the,   -   38.228
Eye  and its appendages, arte-
  ries  of  the,        .       igc
              "Veins ofthe,  186
                mufcles of the, 36
                See alfo vol. I. 58

Fifth pair of nerves, or par
  tri^eminum,    -    -    229
Firft pair  ot" nerves, or olfactory 227
Follicles,  febaceous
Fornix,       -         -       f
Foffa, or rima magna,     -  13
FofTU nav cularis,       -     1-
—— Syl<vii,     .             1
Fourth pair of nerves, or pathetic 27
r x <um lingu.*,       -     <
       - lrbioram pudendi,    i"
——— - preputii,     -       r
Gall-bVaci.i
Gratia,
11-
226
Ganglion femilunare magnum, 2
Ga'iric auciies,        -      2 
INDE X.
-, nerves of the,
                             page.
Gaftric vein9,     -       -   205
Generation #nd urine,, Or-
  gans of",       -      116.159
——, lymphatics ofthe   157
         , blood-veffels of the  206
                             261
                              *5
                              61
                              J9
                              18
                             126
                              61
                              lb.
                              66
                             166
                              «7


                             156
                              ib.
                             160
                                7
                             160
Gland,  lacrymal,
——-,  parotid,
     -,  pineal,
-----,  pituitary,
——,  proftate,
-----,  fublingual,
——-,  fubmaxillary,     *
Glands,  aryien-.id.
——, axillary,
———, bronchial,
     ' , congobate,
■       ', iliac,
       , inguinal,
■     -■, lumbar,
———, mefenteric,
——, miliary,
— ..    , popliteal,


Haemorrhoidalis  C media,  7
  arteria,      J. externa, }
                           page.
                          -   119
                          -   60
                              *4
                           -   »7
                          -    46
                             167
                          -    24
                         130.139
                             129

                             236
                              66
                             213
                             265
Gravid Uterus,  ofthe,   140
Great fympathetic nerve, 238 et seq.
Gula,  or gullet,     -,     -    89
Gums,                       57
Guftatorius,  nervus,     -     232
Gutturalis,  arteria ,\ f»P«»°r. V*
                   I inferior,  190
                              51
Glands,  renal,
       ,  falivary,
11      ,  febaceous,
       ,  tracheal,
Glandulae ceruminofa;,
---------concatenitae,
---------Meibomiana,
———« odoriferae,
Glans penis.
-----clitoridis,
Gloffo-pharyngeus, nervus,
Glottis,
Gluteal artery,
       nerves,
Gyri of the cochlea,
H
                             214
               vena,     -    204
Hairs,                         7
Head, lym|.haticson the outfide 166
——, blood-veffels of the,     175
Heart,  ofthe,      -       74
       -,  abforbents of the,   164
Hellicis,  W'r'J      -    45
       '  I minor, 3           T->
Helix,                        44
Hemifpheres  of the brain,     13
Hepatic arteries,       -      201
Jejunum,
, ladleals of the,      160
Iliac aiteries and veins, 208.212.223
Ilium, ihteftinum,     -       80
Impregnation, changes produ-
  ced in the uterine fyftem by, 142
Incus,        -                49
Infi rior cava,       -         223
Inferior extremity, lymphatics
  of the,
■        , blood-vt ffels ofthe
.--------, nerves ofthe
     Hepatic veins,
     Hippocampus major,    -
     Hole between the right auricle
       and \entriele of the heart,
     — between the lateral ven-
       tricles of the brain,
     Humeral  Attery,
     ■         vein,
     Hymen,
     Hypogaftric  artery,
                 vein, .
     ———— lymphatics,
                nerves,

I & J
79   Infundibulum of the brain
                 of th- cochlea,
                - of the kidneys,
206
 17

 76

 17
192
196
140
212
223
*59
261
 52
118
  3
120
257
 79
infra-OJ'itar artery,
156
211
262
179
Integuments, common,
Intercoftal arteries and veins,
———— nerses,
Intestines,
———— -, abforbents of the 159
Iris,        -        -        27
Ifthmus hepati;,        -     108
——— faucium,    -        63
......  Vitufftnii,      -      76 
11» D *. y..
Iter ad tertium ventriculum,
       ■quartum —
Kid
NEYS,
page.                              page.
   18  Jugular vein, external,        18;
   18          '  ■  ,  internal,     -   189
     K.
  116
Labia pudendi,
Labial artery,
Labyrinth of the ear,
Lacrymal artery,
Lacteals,
Lactiferous  ducts,
Lamina fpiralis,
Larynx,
Laryngea fuperior, artciia,
Laxaior tym;>ani,
Leg,—fee Inferior extremity.
Levator oculi,
t •          Clata.    7
Ligamenta,  J rotu'nda>C uteri,

Ligaments of the liver,
Ligamentum fufpenforium
   penis,
Lingual artery and vein,   176,
——— nerve,
177
 51
181
'53
 70
 53
 64
176
 5°

 37
134
107

128
186
23a
Lips,    -  _    -      -       57
Liquor a:nnii,       -     -    146
■       pericardii,        -      73
Liver.       -          -     106
—-—,  lymphatics of  the,    161
     ■  1,  blood-veflels of the,   108
                             201
——,  nerves cf the,    -   2C.9
Lobes of the brain,      -       13
— of the liver,     -       107
—— of the lungs,       -     84
Locus niger crurum cerebri,     21
Lumbar arteries,        -     211
   ■     plexus of nerves,     263
Lungs,       -        -       84
——,  lymphatics of the,     164
------,  blood-veffels of the 88.174
nerves of the,
M
Malleus,
Mammae,
Mammary arteries and veins,
49
68
M.iffeteric  arteries,

Mater, <  ."
      ' *P':
    Dura
fee ...
J   Pia
198 199
     lb.
    179
Medulla fpinalis,
Medullary fubftance of the
  brain,
Membrana cellularis,
           pupillaris,
254
-  241
                               7
                          27.147
Membrana tympani,           47
                 -, fecundarii, 54
M.^t.ix,
Maxillary artery, external,
                , internal,
 vein,
• nerve
  C fuperior,
'  \ inferior,
Meatus auditorius externus,
,_______1,          internn*,
Median vein,
i.       nerve,
Mediaftinum,
M:Julia oblongata,
133
'77
178
186
231
231
 46
 5'
196
250
 72
 21
Meningeal artery,
P.lefcnteric blood-veffels
N
Nails,                          6
Neck, blood-veffels ofthe 175.189
     ,  neives of the     -    245
------1---nerves,
Mefentery,
Mefocolon,
MeforeCtum,
Metatarfal artery,
Modiolus,
Motores oculoruin, or third
   pair of nerves,
Mouth,  of the,
Mufculo-cutaneous nerve of
   the fuperior extre.nity,


Nerves, of the,
       -,  cerebral,
■    1   -,  fpinal,
178
202
260
100
 ib.
 ib.
219
 53

228
 57

249

224
227
245 
IXDEX.
Ninth pair of nerves,
Nipple, or papilla,
Noni defcendens nervus,
page.

 238
  69
 2*8
Noss, of the,
Nymphae,
/-"i1 ■
   40
  139
nir        i.    C fuperior, 7
Obliquus oculi,   -J .  I .  ' >
    1        '   (_ inferior,  }
Obturator artery,
O
Occ pital artery,
11         vein,
213
264
177
186
OLf pha^eal arteries and vcins^ ic,S
————— nerves,     -     255
Ofcior-hagus,       -          89
OEthmoidalis  C anterior, 7     «
  arteri.i,     "l pofterior, J
Olfadt'.iry, or firft pair of nerves 227
Orr:"ntum, or cawl,     -     ici
Opthalmic artery,         -  180
'lroic vein,
—— new-,
Ootic, or 2.1 p.ir of nerves 31
Ora!culare, os,
Organs ofthe fen.' p,
         of uiine and general
         in the male,
         in the female,   -
         lymphatics of the
         bl K;d-vettlls of  the,
         nerves of the,
Os tincae,
Ova
Ovana,
>,s
 iK3
 2-9
.228
  49
   3
ion
 116
 '3-
 »57
 206
 261
 J34
 "35
Palate,
     -, arches of the,
Palatina inferior a-teria,
Palmaris profunda arteria,
Palmar arch, dee;>,
1            , fuperficial,
—— nerve,
P.'lpebrr,
Pancreas,
Panniculus carnofus,
P.sp of the throat,
Papilla,
Pap llae of the tongue,
Pai trigeminum, or fifth pai'
  of nerves,
Parotid
duct,  I
gland, S
 58
 62
177
194
 ib.
'95
252
 *4
114
  9
 58
 69
 59

229
 61
Pars vaga of the ei..  tii pair
  of nerves,    -    236.254.259
Pathetic, or fourth pair of nerves 228
Pedes hippocampi,       -      17
Pedunculi ofthe brain and
  cerebellum,        -         21
Pelvis, lymphatics cf the      158
•-----, blood-veffels of the     211
-----, nerves of the          262
Penis,     ;  -        -      128
-------,  lymphatics of the     157
       ,  blood-veffels of the   208
———,  nerves ofthe        261
Pericardium,           -       73
Perineum,
Peritoneum,
Peroneal artery,
■         nerve,
Pharyngeal artery,
Pharynx,       .
Phrenic nerve,
Pia mater,
Pinguedo,
Placenta,
Plantar artery and arch,
Pljura,
Pumum Adami,
Pons ) Tanni> l
^°nS ) Varolii, i
Popliteal attcry,
1-ortse, vena,
Portio \ °">1"».J
                 ofthe 7th
                    pair,   ;
Prepuce of the penis,
■        of the clitoris,
Profun :a femoris, arteria,
               ■, vena,
— .umeri arteria,
—i enis arteria,
Pfalterium fornicis,
Pterygoideae arteriae,
Pudendum,
Pudic artery,
-----vein,
138
 92
219
266

 63
a53
 12
   8
J45
220
 7»
 64
 21

223
205

233
139
215
222
I92
210
 17
179
I38
209
210 
INDEX.
Pudic nerves,
Pulmonary artery and veins,

Radial aitery,
       nerve,
Ran.na aneria,
•■       vena,
Recoptaculum chyli,
Rectum,
■       ',  lymphatics of the,

Sacral artery,
■     lateral arteries,
     -  nerves,
Salivary glands,
c   i             C major,
Saphaena, vena,  <  .J   '
   r          '  I minor,
Saphaenns, nervus,


Scaoular arteries,
  ■       nerve,
Sciatic artery,
Sciatic nerve,
Sclerotic coat,
Scrotum,
 Sebaceous ducts,
page.

 261  Pupil of the eye,
 174  Pylorus,

    R
 193  Recurrent nerve ofthe eighth
         pair,
        -------radial artery,
        ——— ulnar artery.
page.
   27
   95
194
176
186
 90
 98
x59
254.
J93
194
207
261
  3i
      Renal artery and vein,
      —— nerves,
      Retina,

    S   *
211   Spermatic artery and vein, 125.207
                                  I2S
213
265
 60
221

264

 52

192
248
214
266
 28
122

  7
Second pair of nerves, or optic, 201
Secundines,         -        144
Semicircular canals of the coch-
  lea,
Semilunar ganglion,
Seminal  veffels,
Senses, Organs ofthe,
Septum cerebri, or falx,
Septum cerebelli,
'       lucidum,
■       penis,          -      129
—— fcioti,      -         122
Seventh pair of nerves,    -    233
Sinufes of the dura mater, 12.188
 5*
259
126
16
Sixth pair of nerves,
Skarf-fkin,
Skin,
262
cord,
nerves.
Sphincter veficae,
Spinal Marrow, ofthe,
  ■       nerves, origin of the,
Spinalis dorfi, fee vol.  I.
Spiral nerve,
Splanchnicus nervus,
Spleen,
-------,  lymphatic* of the,
Splenic artery,
Splenic vein,
1    '  ' nerves,
Spongiofum, corpus, urethrae,
Stapedius,
Stapes,
Stomach,       -  »
——,  abforbents ofthe  96.161
———,  blood-veffels of the 95.200
       ,  nerves of the      96.259
                             176
                             177
                         -   245
                              37
                              23
                             199
    261
    121
    241
     ib.
     86
    249
257.259
    112
    i6t
    202
    204
    260
    129
     5a
     49
     93
Sublingual artery,
Submental artery,
Suboccipital nerves,
Superbus,
Supercilia,
Superior cava,
Siirrmon Extremity,
       , lymphatics of the,
———, blood -veffels of the,
      ., nerves of the,
Supra-orbitar artery,
Sympathetic nerve,
      165
      190
      245
      182
238 etfcq.
Taenia hippocampi,      -      17
       femicircularis of Haller, 16
Tarfea arteria,       -       218
Tarli:.-! of the eye-lids,     -   24
Tela clioroidca,        -       17
Temporal artery,
——— vein,    -
Tenlor tymrani,
Tentorium cerebelli,
Teftes,
T79
185
 5°
 11
122 
IXDE.X.
                           page.
 Teftes, lymphatics of the   -   158
 ■     , blood-veffels of the 125.206
 —-, nerves ofthe          261
 Thalami nervorum opticorum   15
 Third pair of nerves, or mo-
   tores oculorum,      -      228
 Thoracic duel,       -     90.163
 Thorax,  of the,        -      68
 1    ,  blood-veflels within the  197
     ,  nerves within the       253
 Throat,  ofthe,       -      62
 Thyroidea arteria Hnferi.or'    r9°
   J            £ fuperior,   176
 Tibial arteries,        -       218
 ■■      veins,     -      -      221
— - nerve,       -          266
 Tomentum cerebri,     -      13
 Tongue,  ofthe,        -     59
~.......,  lymphatics of the   167
■      ■  ,  blood-veflels of the  176
—       ,  nerves of the,
Tonfils,
Torcular Herophili,
Traftus optici,
Tragicus,       -      -
Tragus,
Tricufpid valve,
Trochlearis,
Tuber annulare,
Tubercula  quadrigemina,
Tuberculum, Loiveri,
Tubes, Euftachian,
——— , Fallopian,
Tunica albuginea,
——— arachnoidea,
■       aranea, or vitrea,
'       choroides,
■      ■ fclerotica,
       vaginalis,
Vagina,
Vaginal artery,     -    -     209
Valves of the abforbents,      154
       of the veins,           173
1       of the heart and arteries  76
Valvula coli,        -        104
V.fa brcvia,     -       202.201;
■ '   efferentia of the teftes,    126
     C efferentia, 7 of the  ab-
     l inferentia, J forbents,   155
____laftea  5Prirn!»  ?gene-
          '  I fecundi, 3 ris,    160
Vafa vaforum,         -      170
Veins,  ofthe,        -      172
Velum Vieuftenii,       -      20
Vena cava, general courfe of the  174
      Tympani laxator,
      Tympanum,       -     -
232
 U & V
136   Vermiform appendix of the
        ccecum,
      Vermiform appendages of the
        cerebellum,
      Vefica urinaria^
      Veficalis  ima aitcria,
      Veficula fellis,
      Veftible of the labyrinth,
             ofthe pudendum
  page.
    63
12.188
    16
    45
  -  44
    77
    37
    21
    19
    76
    48
-  135
   123
    12
    35
    29
    28
   123
    5°
    47
104
  lupenor,
-, inferior,
Vena magna ipfius penis,
Vena portae,
Ventricles of the brain,
■          of the heart,
199
223
210
205
 *5
 76
Viscera, of the,
Vitreous humour,
Ulnar arteries,
■      nerve,
Umbilical cord,
--------- artery,
Volar arches,
Vorticofe veins,
Urelers,
Urethia,
Uterus, of the,
——--, appendages of the,
Uvula,
120-133
    214
    110
     51
    139
      3
     34
 -   194
    Zjl
    144
    208
    >9 5
    186
119.133
130139
    133
    134
     5»
Zonula ciliaris,
43 
 
 
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