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1853
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SYLLABUS fif
THE LECTURES
PHYSIOLOGY AND HISTOLOGY;
INCLUDING TH
OUTLINES OF COMPAKATIVE ANATOMY,
DELIVEKBD AT THE
Inihrsitg si Virginia,
B Y
J. L. CABELL, M.D.
I. V I
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PMSTED FOR THE USE OP THE MEMBERS OF THE CLASS.
UNIVERSITY OF VIRGINIA:—McKENNIE & SON.
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ERRATA.
The attthor*s Want of practice in correcting proof caused him to overlook many errors
of the press, in the first impression, and the distance between his residence and the city
where these pages were printed precluded the possibility of a second correction. Accord-
ingly the existing errors are very numerous, but to avoid making the list too long, ho
omits such of them as the intelligent reader will readily correct for himself, as where a
singlejetter is omitted, or where the singular number is Used instead of the plural, and
vice versa., of both classes of which there are many examples.
Page 6, line 11, for "blood, plasma" read "blood-plasma.'*
15, line 6, for "secretive" read " secreted."
16, line 14, for " tenacity" read " tonicity."
17,line 37, for " Chloride''read "Hydro-chlorate.'*
19, XII class, for " membrane. fiArOus" read "membrano-fibrous."
22, line 18, for"contractible" read "contractile."
22, last line, for " Physical" read "Physiological."
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PREFACE.
A Syllabus of Lectures, consisting of the mere heads of the
topics which are to be fully expounded in the oral discourses of
the teacher, can have no value except to the students who listen
to these discourses. It can, therefore, scarcely be necessary that
I should disclaim all intention of publishing these pages, which
are printed for the exclusive use of the members of my class. It
had long been my custom to write upon a blackboard the heads of
the topics discussed in each lecture, which served the two-fold
purpose of lessening the difficulty of taking notes, and of facili-
tating references to the text-books and other authorities that might
be occasionally quoted. The task of copying these notes from a
blackboard, which from the arrangement of the room was unavoid-
ably placed in an unfavorable position as regards the light, was
found to be so onerous, that I have felt myself constrained, by the
urgent solicitation of many members of the class, to have them
printed.
In view of the single use for which they are designed, I have
not regarded it as necessary or important to mark off the subjects
by any formal arrangement of Sections and Chapters, contenting
myself with merely numbering the paragraphs consecutively from
the beginning to the end. For the same reason I have deemed it
unnecessary to prepare a "Table of Contents." Those "who attend
iv
PREFACE.
the lectures will readily understand the principle governing the
arrangement of the subjects, and will therefore easily know where
tofind the appropriate place for each topic.
It will be observed, that Histology and the Outlines of Com-
parative Anatomy are taught with direct reference to their appli-
cations to Human Physiology, and, indeed, as a necessary part
of a complete exposition of the latter subject. Accordingly, the
consideration of these topics is introduced into the body of the
work, after a preliminary exposition of certain generalities on the
nature and objects of Physiological Science, and before the dis-
cussion of the Special Physiology of the several functions.
In several instances I have deemed it expedient to abandon, for
one or more paragraphs, the form and style of a syllabus, and to
substitute a more continuous statement of matter in hand, espe-
cially when this embraced abstract generalities not fully expounded
in the text-books, my experience as a teacher having satisfied me
that most youthful minds find much difficulty in apprehending
such generalities on a single hearing, or with only a compendious
statement of them in the form of a syllabus for revisal. But in
the main I have conformed to the principle of a syllabus, and
have presented only short summaries of the subjects which are
amplified and illustrated in the lectures. The almost exclusive
reference to Carpenter's Elements of Physiology, and Kirkes &
Paget's Human Physiology, is explained by the fact that these
works are both used as text-books.
SYLLABUS OF LECTURES
OF COMPAEATIVE ANATOMY AND PHYSIOLOGY.
OF PHYSICAL SCIENCE IN GENERAL.
1. Definition of Science in its most enlarged sense, as com-
prising all attainable knowledge of natural bodies and phenomena,
when such knowledge is " orderly and methodically arranged."
Distinction between mental and physical science.
2. Two-fold subdivision of physical science into natural his-
tory and natural philosophy. Natural history views objects
as they exist in space, and simply observes and narrates phenomena
as they are directly addressed to the senses. It should, indeed,
arrange and classify objects according to their relations of form,
colour, structure, and other similar qualities, but it does not specu-
late upon their active phenomena viewed as causes and effects, which
is the appropriate province of natural philosophy. Illustrative ex-
amples : zoology, botany, and anatomy, are branches of natural
history, while mechanical philosophy, chemistry, and physiology,
are branches of natural philosophy.
3. But inasmuch as the aim of natural history is to describe
and classify objects, it may take cognizance of the actions and
changes of bodies so far as they characterize the latter, provided it
does not seek to explain such actions, but only adopts them as facts
that may be of use in furnishing the basis of a natural classification.
An acquaintance, to a certain extent, with natural history, must
precede the study of natural philosophy, since we must collect,
verify, and classify facts, before we can interpret or explain them.
In natural history we do not go beyond the observation and clas-
sification of phenomena. In philosophy we begin with natural
history, (collection of facts,) and regarding phenomena as effects,
aim to explain them by the discovery of causes and laws.
Exposition of the special object and methods of the study of
physiology.
4. Physiology.—That branch of natural philosophy which seeks
to discover the laws under which the actions of living beings
are performed. Animal physiology may be studied with reference
exclusively to the actions of the human frame, (human physi-
ology,) or with reference to the whole animal series, (comparative
physiology.) Brief statement of the importance of the study of
comparative animal and vegetable physiology.
o syllabus, etc.
5. Two classes of facts embraced in the narrative division of
physiology, namely, (1) the characters of the ORGANS or material
instruments by which the actions of life are manifested, and (I) the
functions or special operations of the several organs. The inves-
tigation of the first of these two classes of facts is the special object
of anatomy. Thus one branch of the physiological problem con-
sists in seeking to establish the connexion between organs and their
functions, and may be thus stated: an organ being given, to dis-
cover its action or function, or conversely, a vital act^ being recog-
nised, to discover the organ or organs concerned in its execution.
Examples:
6. Evidence on which functions are assigned to given
organs, (a) Evidence derived from direct observation, (b) From
experiments'—sources of fallacy in deriving positive conclusions
from experiments on living animals of a high grade. Nega-
tive information from this source more reliable, (c) From pa-
thological observation—why more reliable than that derived from
the effects of sudden and artificial changes, (d) From compara-
tive anatomy. The contemplation of the anatomical structure of
a single species throws little light on the investigation of func-
tions, except where these are purely mechanical, in which case we
note the adaptation of the organ on mechanical principles for a
special use. The comparison of extensively varied types of ani-
mal forms, all executing substantially the same fundamental phe-
nomena of life, enables us to ascertain what are the essential con-
stituents of each organ, and what are the other essential conditions
of its action. Comparative anatomy thus furnishes " so many
kinds of experiments ready prepared by nature-"
7. After assigning to an organ its appropriate function, or after
having traced an observed action to the organs concerned in its
manifestation, it remains to explain or interpret it, which consti-
tutes the second branch of the problem. Only legitimate sense in
which a natural phenomenon can be said to be explained—elucida-
tion of the conditions under which it is exhibited. Systematic
arrangement of those conditions under the following heads—
(a) Proximate cause, or that inherent property of matter to which
the phenomenon in ^ question may be traced as an ultimate fact.
Examples—The action of muscles in displacing parts, traced to a
peculiar property inherent in muscular fibre, by virtue of which
the fibre, under certain circumstances, becomes suddenly and ac-
tively shortened. The ascent of the piston in a steam-engine,
traced to the expansive power of steam, a property inherent in that
material, and exhibited under certain circumstances.
(b) Exciting causes, or stimuli—The power of contracting,
which is inherent in muscular fibre, vet requires to be excited or
stimulated as a condition of its manifestation. As the ao-encies
which fulfil this office, may be said in a certain sense to cause or
occasion the resulting action, they are indifferently termed ex-
citing, occasional or determining causes, or STIMULI.
SYLLABUS, ETC.
3
(c) Laws.— Apart from the foregoing, there are other conditions
which indicate the mode and especially some limitation of the effects
resulting from the assigned causes, and these are termed laws, as
being expressions of the will of the Author of Nature. Ultimate
properties identified by their laws. Thus, to prove that apparently
diverse phenomena are really due to the same proximate cause, it
must be shown that they are governed by the same laws. Ex-
amples :—
(d) Final causes. As in attempting to explain the construction
and operation of a complicated machine, we have not only to in-
dicate the use or function of each separate part, and to show how
such action depends on the properties inherent in its material, but
must also point out the connexion between the independent actions
of the separate parts and the workings of the machine as a whole, so
in the study of Physiology we must show how the operation of the
separate organs contribute to the general welfare of the organism by
subserving special uses subordinate to that common end, and such
uses are termed final causes. The contemplation of final causes
presents to the rightly constituted mind incontestable evidence
of intelligent foresight and contriving skill, and hence forms the
basis of the science of natural theology. Final causes not to
be substituted for physical causes. The former indicate the bene-
ficent designs of Providence, the latter disclose the instrumental
methods employed, under certain determinate conditions or limi-
tations, by Infinite Wisdom to work out these designs.
8. Method of arriving at positive results in the research
for causes and laws. Observation does not directly and imme-
diately indicate causes and laws, but supplies the data which the
mind spontaneously and intuitively groups in appropriate order
according to natural relations, so as to infer from this comparison
general facts or laws. Such act of inference is the main element in
the inductive process of thought, by which we discover the laws
of nature. Illustration—Laws of human enactment made known
by proclamation, oral or printed; laws of nature discovered only
by observing facts, and from the uniformity of their sequence in
the past, inferring a like uniformity in the future. Brief statement
of some of the rules of procedure for facilitating the research
by induction for the laws which govern complex phenomena, (a)
Particular observations must be sufficiently numerous and extend-
ed, to eliminate sources of error. Illustration, (b) In assigning
causes we may often avoid error by inquiring whether a suggested
cause be appropriate, that is, whether on the ground of analogy
it be likely to have such a relation with the effects to be explained.
The assigned cause must be a vera causa, (c) Again it must not
only be a vera causa, but it must be adequate in degree.
9. Of the employment of the deductive process in the investiga-
tion of general truths. Our inductions are often accompanied and
aided by the deductive process, as when we make a provisional as-
sumption, and having deduced the consequences involved in such
Special Anatomy
or
Organography.
4 / syllabus, etc. ,7 /.
assumption, proceed to compare them with the observed phenomena,
so as to verify or refute the hypothesis, thus anticipating the slower
process of simple induction. Used in this way, the process of de-
duction may be made strictly subordinate to the most rigorous in-
duction. But this logical artifice needs to be used with caution in
the sciences that treat of vital phenomena, since in them the ma-
thematics cannot be employed to verify or refute the assumption.
general view of the chemical and structural composition
of the human body.
10. The distinct subjects of inquiry in the two leading divisions
of Human Anatomy, are exhibited in the following scheme, re-
presenting the successive stages of the anatomical analysis of the
fabric.
(a) The body is resolved into a number ofs
Organs of which the form, weight, co-
lour, situation, local connexions and struc-
ture are to be determined.
(b) In investigating the structure of organs,)
these are resolved into their constituent
tissues, a limited number of which are
combined in various ways, so as to form
all the different organs of the body.
(c) In taking note of the anatomical char-\
acters of the several tissues, we observe
that they too are compound structures,
and resolve them into a small number
of STRUCTURAL ELEMENTS Or PRIMARY
forms of organization, such as homo-
geneous membrane, fibres, cells, nuclei
and granules.
(d) Thus far the analysis is exclusively ana-
tomical, and the properties of the ma- )
terial concerned are unchanged. By a
different method of analysis, as the re- Histology.
suit of which the properties of tissues
are wholly transformed, we reveal their
chemical composition, exhibiting at the
first stage certain proximate animal
principles, such as albumen, fibrin,
gelatine, fatty principles, &c, and by a
further process reducing these to the
ultimate elements of matter. /
N B. Histology (a description of tissues) is not strictly sy-
nonymous with general anatomy, which comprises, in addition
to the anatomy of the simple tissues, all the generalities which
may be predicated of classes of organs, such as bones, muscles,
glands, &c.
General Anatomy
77'// /" '■''iiyr /
I44tt ?
syllabus, etc. 5 / ^
11. Definition of chemical or ultimate elements of matter, which
by their various combinations make up all known material objects,
such as gases, liquids, earths, stones, and the bodies of animals,
and plants. Example : limestone may be separated into two proxi-
mate ingredients, namely, a gaseous body, which is driven off by
a high temperature, called carbonic acid, and a white caustic solid,
known as quick lime ; but each of these ingredients is a compound,
the former consisting of carbon and oxygen, and the latter of cal-
cium and oxygen. These last named substances cannot be reduced
any further, and are presumed to be elementary.
12. Sixty-one or two such elements, are found in the mineral
kingdom, and only about seventeen ever enter into the composition
of animal structures, namely, oxygen, hydrogen, nitrogen, carbon,
sulphur, phosphorus, chlorine, potassium, sodium, calcium, magne-
sium, iron, fluorine, and occasionally manganesium, silicon, alumi-
nium and copper. The first four are named essential elements, the
others incidental elements.
13. Proximate organic principles of determinate characters,
are the products of chemical decomposition of organised structures,
short of their ultimate analysis. Example: a substance known, as
animal jelly or gelatine is separated from certain animal tissues
by protracted boiling. It is, therefore, one of the constituents of
animal flesh, but being itself a compound of carbon, oxygen, hy-
drogen and nitrogen, it is termed a proximate principle. The
various proximate principles entering into the composition of the
human tissues may be classified either according to their chemical
or their physiological relations. See Kirkes and Paget's Human
Physiology, chapter I. for the chemical classification. An arrange-
ment founded on physiological relations is thus stated by Carpen-
ter (Human Physiology, Ed. 1853).
(a) The Histogenetic substances destined to become part of the
organised fabric by progressive metamorphosis.
(b) The calorific substances, which are either introduced into
the body as components of the food, or which are formed within it,
by the metamorphosis of the histogenetic substances, or of the com-
ponents of the tissues themselves. These substances are destined
to undergo oxidation, and thereby to generate heat, and are all of
the saccharine, or of the oleaginous class, or are derivable from
them by very simple transformations.
(c) The components of the actual living tissues.
(d) The excrementitious substances which are formed within the
body as the products of the disintegration, and retrograde meta-
morphosis of its tissues, and which are on their way from these to
the outlets of the excretory apparatus. They constitute a group
of substances, which are intermediate in their chemical character
between the foregoing and inorganic matter.
For a detailed account of the sensible character and chemical re-
actions of albumen, caseine, gelatine, chondrine and fibrine, and
their relations to proteine, see Carpenter's Elements of Physi-
SYLLABUS, ETC.
ology § 167 to § 187 inclusive. Other organic proximate com-
pounds will be noticed in connection with the description of the
tissues in which they exist.
B.—STRUCTURAL COMPOSITION OF THE HUMAN BODY.
14. The animal organism in its integrity as a living machine,
consists of fluids and solids. The fluids divided into (a) forma-
tive fluids, as lymph, chyle and blood and (b) secreted fluids,
such as bile, saliva, urinekc, &c. The solids constitute the dif-
ferent tissues. Both fluids and solids are composed of certain
structural elements, which may be classified thus:
(1) Liquid blastema, such as the fluid bloody
-plasma.
(2) Solid cytoblastema, as the intercellular ma-
trix of cartilage, &c.
(3) Primary membrane, forming walls of cells and
of the finest blood-vessels.
(a) Amorphous Elements,
which show no trace of
structure, being simple and"
homogeneous.
(b) Primary organic forms,
which are so arranged as to
constitute tissues of deter-
minate structure, some of
them being themselves com-
posed of definitely arranged
dissimilar parts.
(4) Granules
{Free, as in chyle, milk, or
inclosed, as in pigment cells,
or imbedded, as in bones and
teeth.
, Free nuclei, either floating
in a liquid, as those of gas-
tric juice, or loosely imbed-
ded in solid substance, as in
the vesicular matter of the
brain and spinal marrow.
Attached nuclei, either
closely imbedded in homo-
geneous substance, or fixed
to the surface of fibres or
membranes, or finally in-
closed in cells.
' Free and either floating as
those of lymph, chyle and
blood, or loosely imbedded
in solid or semisolid sub-
stance, as those of the grey
matter of the brain, epithe-
lium cells, &c.
Cells whose walls have
coalesced while their cavi-
ties remain distinct.
Cells whose cavities have
coalesced so as to form tu-
bules.
Fibre-cells, or cells trans-
formed into solid fibres.
Cells whose cavities are
more or less obliterated by
secondary endogenous de-
posit.
^(1) Primary fibres, formed directly without cell-agency.
See Human Physiology by Kirkes and Paget, Chap. II.
(5) Nuclei or cyto-
blasts, minute vesicles
with walls of simple
membrane and usually
inclosing, besides a pel-
lucid fluid, one or
more minute granules
of a peculiar appear-
ance, called nucleoli.
(6) Cells, which are
vesicles of larger ave-
rage size than nuclei.
In their perfect condi-
tion they generally con-
tain each a nucleus and
sometimes two nuclei.
A cell thus consists of
a nucleus inclosed to-
gether with liquid con- ,
tents in a secondary^
vesicle having homo-
geneous membranous
cell-walls.
syllabus, etc.
7
GENERAL ANATOMY OF THE HUMAN TISSUES.
A. Simple Fibrous Tissues.
15. Anatomical characters of the white elementary fibre. Its
occasional origin in the direct fibrillation of fibrinous plasma, inde-
pendently of cell-agency—its occasional origin from transformed
cells—its chemical composition and reactions—its uses. Car-
penter's Elements, §188-9, §180-183, §193.
16. Anatomical characters of the yellow fibrous element—micro-
scopic tests—chemical composition and reactions. lb. § 190-192.
17. General anatomy of the tissues and organs composed exclu-
sively of the white fibrous element, and hence termed the white
fibrous tissues.
Distribution. Tendons of muscles. Most ligaments. Investing
membranes of bones and many other organs. Conformation, funi-
cular, fascicular, membraniform; naked eye characters, colour,
polish, fibrous arrangement; microscopic characters, physical 'pro-
perties, vital properties, chemical composition, uses.
18. General anatomy of the yellow fibrous tissues, found pure
and unmixed in the ligamenta sub-flava, ligamentum-nuchse, vocal
cords, and in a stratum of fibres constituting a part of the arterial
tunics. Found inseparably mixed with the white fibrous element in
areolar tissue, and with cartilage in the ear, nose, epiglottis, &c.
For other characters, see Carpenter's Elements, loc. cit.
19. Areolar tissue formerly called cellular tissue. Definition;
white fleecy body, composed of translucent and softish fibres, con-
necting the skin with the subjacent organs and these with one another.
Distribution; subcutaneous, sub-mucous, subserous, intermediate
and investing, interstitial, parenchymal or interlobular, &c. Confor-
mation ; arranged in masses whose outline is determined by the
shape of the space they are to fill, and susceptible of being flattened
into membranous fasciculi. Structure ; fibres and lamellae intersect-
ing in various directions. Microscopic characters. Mixture of white
and yellow elementary fibres; former predominating, latter of very
variable dimensions, some being excessively minute, and wound
spirally around the white band-like fibres. Other characters
are such as would result from its composition as a mixture of the
two fibrous elements.
20. Serous membranes, comprising also synovial membranes.—
Definition. Distribution. Conformation, a membrane arranged in
the form of a short sac, presenting a free surface, smooth and
polished, and an adherent surface»with a subserous areolar tissue.
Structure: next to the free surface a layer of tessellated epithelium
cells, resting upon a basement primary membrane itself supported
by an areolar derm very delicate, but condensed and nearly non-
8
syllabus, etc.
vascular, the vessels not extending beyond the subserous lax
areolar tissue; this last is generally lax and contains fat, but is
sometimes dense and close. Physical and vital properties— Uses.
Peculiarities of synovial membranes and of their relations with
articular cartilages before and after birth.
21. Mucous membranes constituting the internal integument.
Distribution; (a) alimentary tract and its glandular appendages.
(b) Respiratory tract, (c) Lachrymal tract, (d) Genito-urinary
tract, (e) System of glands and follicles opening on the skin.
Conformation ; membranes with a free, and an attached surface of
variable thickness—free surface more or less villous except in the
more delicate specimens, which approximate to serous membranes ;
attached surface areolar; body spongy; colour more or less reddish
according to the different degrees of vascularity of different speci-
mens ; redness uniform, ramiform, or punctiform. Structure: next
to free surface there is a layer of epithelium cells which may be
tessellated, cylindrical, or spheroidal. This layer rests on a base-
ment membrane supported by an areolar derm, which is commonly
thicker than that of serous membranes and is generally very vas-
cular; arrangement of the vessels in the villi; arrangement of
vessels around the mouths of follicles; nerves of mucous mem-
brane. Physical and vital properties—uses. See Carpenter's
Elements, § 199 to § 205 inclusive.
(B.—BASEMENT OR PRIMARY MEMBRANE.
22. Definition—Three varieties: (1) simple amorphous mem-
brane seemingly formed directly from the nutritive fluid, by a
simple consolidation of a thin layer; (2) a membrane with minute
granules imbedded in its substance, as if the blastema from which
it was formed had included nuclear granules ; (3) a membrane with
distinct spots arranged at equal or variable distances, and having
a tendency to break up into portions of equal size, as if it had
been formed by the coalescence of cells whose cavities had been ob-
literated and their contents removed, but whose nuclei had con-
tinued to perforin their peculiar functions. Distribution : on all the
free surfaces of the body, beneath the epithelial or epidermic cells.
Uses &c. See Carpenter's Elements, § 206 to § 209 inclusive
Kj.—STRUCTURES COMPOSED IN PART OF SIMPLE ISOLATED CELLS.
23. Hhtory of an independent animal cell; its structure ; albu-
minous cell-wall; contents variable, but generally include a nu-
cleus which is itself vesicular and may contain a nucleolus. De-
velopment, in one of two modes; (1) from pre-existing cells 'either
by subdivision of parent cell, or by endogenous multiplication •
SYLLABUS, ETC.
9
(2) by a new production of cells in an organizable plasma, which
is then called cyto-blastema. Carpenter, loc. cit. § 210 to § 213"
inclusive. \
24. Formative fluids, chyle, lymph and blood. Definition ;
(a) notice of the anatomical characters of the cells, which are
common to all of these fluids and which are variously named, chyle
corpuscles, lymph corpuscles, and white or colourless corpuscles of the
blood; globular, with finely granulated surface, about 3^00 mchin
diameter; the addition of water causes a delicate cell-wall to rise up
from the granular nucleus with which it was previously in contact.
Uses ; they are now commonly regarded as embryo blood disks, and
are probably concerned in the assimilation of crude albumen into
vitalized fibrine.
(b) Red discoid cells of the blood, improperly called blood
globules.—Form—Biconcave disks having a circular outline in man
and the mammalia generally, except only the camel tribe, which
have elliptical disks; as have also all the oviparous vertebrates.
Average diameter in man ^Ve inch. Thickness, one-quarter the
diameter. Tendency to run together in piles when drawn from the
body. Effects of certain re-agents in altering their shape. When
exposed to a liquid denser than serum, they give out a part of
their fluid contents and become corrugated; if the liquid be less
dense they absorb water and swell out into the form of biconvex
lenses. Structure ; colourless cell-wall, tolerable thick and tough;
no nucleus in the blood disks of mammals. Other vertebrata have
a distinct granular nucleus, identical with that of their chyle cor-
puscles, the colouring matter being superadded around the latter.
Chemical composition, uses, vital properties, &c, to be noticed in
connexion with the special physiology of the blood.
25. Epidermis or Cuticle. Definition; naked eye characters;
physical properties. Microscopic structure. Next to the base-
ment membrane we have a semifluid cytoblastema; then a stratum
of nuclei or cytoblasts, then epidermic cells of primordial char-
acters ; then flattened cells, and lastly mere scales, the result of
the desiccation of cells. Uses; Carpenter, loc. cit. §224 to §228.-
26. Pigmentary body. Definition ; a group of cells sometimes
mingled with epidermic cells as in the skin of Africans; sometimes
forming a distinct body, as in the pigmentum nigrum of the eye,
which cells secrete colouring matter instead of horn. Anatomical
and chemical character of pigment granules. Development of pig-
'ment cells. Carpenter §§ 229 and 230. —
27. Epithelium. Definition. The epidermis of mucous and
serous membranes, whose constituent cells are never so completely
flattened as to destroy their organization. General characteristics,
those of nucleolo-nucleated cells. Varieties. (1) Tessellated, found
on all serous and synovial surfaces, and on the endangium of blood-
vessels and lymphatics, and on the smaller ramifications of gland
ducts, except in the very follicular ends. (2) Columnar or Cylin-
drical, found on all mucous membranes, except where other varieties
10
'SYLLABUS, ETC.
are specified. (3) Spheroidal, found on the urinary tract from mouth
of bladder up to the smaller uriniferous tubes, where it is displaced
by the tessellated, on the mammary ducts, and in the terminal fol-
licles of most glands. (4) Scaly, which is rather a soft cuticle
than a true epithelium, found on the mucous membrane of the
mouth, pharynx and oesophagus, terminating at the cardiac orifice
of the stomach in a. fringed border. Ciliated epithelium, is the
name applied to any of the foregoing varieties when they are beset
on their free side with Cilia (from " Cilium," an eyelash,) little
hair-like vibratile processes from T¥fo o to 5-57 mch long? and im-
measurably fine, found on the epithelium of respiratory tract, ven-
tricles of the brain, and in the uterus and Fallopian tubes. Chemi-
cal composition: Uses. All the vegetative functions executed
through the instrumentality of cells either epithelial or strictly
analogous to these in their origin, as chylosis, hsematosis, aeration
of the blood, nutrition, secretion and generation. Carpenter, loc.
cit. § 231 to § 247.
D.—Tissues, composed in part of cells that are connected
TOGETHER AS PERMANENT CONSTITUENTS.
28. Such cells are connected either by a general enveloping
membrane, or by an intercellular cement, the sacculi containing
cells of adipose tissue exemplifying the former, and the hyaline
matrix of cartilage the latter.
29. Adipose tissue. The structure containing the animal fat.
Distribution. Sub-cutaneous, except on eyelids, pinna, scrotum and
penis. Intermuscular; between the fasciculi of many muscles,
around certain organs, as the eye, kidneys, base of the heart, &c.
sub-serous, but never sub-mucous; in the medullary cavities and
cancelli of bones—never in the lungs or in the cavity of the cra-
nium. Fatty principles, but not adipose tissue, found in chyle and
blood, either mechanically suspended or chemically dissolved.
Found, likewise, intimately united with other ingredients, in many
solids, as muscular fibre, and especially nervous matter, which has
two peculiar fats; also excreted by sebaceous follicles of the skin.
Finally, is formed as a morbid product, indicating degeneration of
normal tissues, as fatty liver, &c, &c. For structure and develop-
ment of adipose tissue, and its relations with areolar tissue; for
chemical characters of oleine, margarine and stearine, physical pro-'
perties and uses of fat, see Carpenter, loc. cit., §257 to §203,-""
inclusive.
30. Simple, or cellular cartilage. Definition. The white
gristle which incrusts the articular heads of bones, &c. Distribu-
tion. (1) Articular or incrusting cartilage. (2) Framework of
larynx, trachea, bronchi, &c. (3) The unossified segments of the
skeleton. These three are ^permanent cartilages," although
number (3) is closely related to (4.) Temporary cartilage, or car-
syllabus, etc.
11
tilage of ossification. Form. Incrusting or articular cartilage of
variable thickness, and thinning off at the edges, has a free,
smooth surface, and another attached to the bone. Colour. Bluish-
white, or pearly; translucent in thin slices. Structure. Appa-
rently homogeneous to naked eye; non-articular varieties covered
by perichondrium; articular, covered on free surface by synovial
membrane, as proved before birth, by a layer of intervening vessels,
which disappear after birth; these never have a perichondrium.
Microscopic character. Nucleolo-nucleated cells, imbedded in an
apparently homogeneous hyaline matrix, with which the cell walls
coalesce; cells multiply by binary division; hence, often seen in
groups. By a very high power Dr. Leidy resolved the apparently
homogeneous matrix into an exceedingly close tuft of very fine
fibres. Chemical characters, physical properties and uses, see
Carpenter, loc. cit., § 264 to § 273, inclusive. —-
31. Fibro-cartilage. Definition. Cartilage, of which the pe-
culiar cells are imbedded in a net-work of white or yellow fibrous
tissue in place of the hyaline matrix. Distribution. (1) Yellow
fibro-cartilage found in the external ear, nose, epiglottis, tarsal
cartilage of eyelids, &c. (2) Interarticular disks. (3) Articular
marginal cartilages for deepening sockets. (4) Connecting or
interosseous cartilages. (5) Cartilages lining the bony grooves in
which tendons of muscles glide. For other characters, see Car-
penter, loc. cit., § 269. .___
32. Bone. Two varieties of structure, the spongy or cancel-
lated, and the compact or ivory. (1) Cancellated, how constructed;
medullary membrane and oil. (2) Compact structure, very con-
densed, system of Haversian canals, &c. Three classes of bone
distinguished by their form. (1) Thick or irregular, a mass of
cancellated structure, covered by a thin shell of compact matter.
(2) Flat bones, having two tables of a compact bone and an inter-
mediate cancellated structure, presenting certain peculiarities, and
called diploe. (3) Long bones, consisting of a shaft and two arti-
cular ends or epiphyses ; medullary canal in the shaft; medullary
membrane and fat; arrangement of blood-vessels. Microscopic
characters. Elementary bony lamellae, covered by delicate medul-
lary membrane, whose vessels never enter the substance of the
lamella. Osseous corpuscles or lacunas, with radiating canaliculi.
Interlacunar matrix of close fibres, with calcareous granules im-
bedded. Dimensions and other characters of lacunae and canali-
culi in different classes of vertebrates.
33. Mode in which the two varieties of bony structure are built
up of the elementary lamellae. (1) Spongy or cancellated struc-
ture. Compound lamellae, formed of several layers of the elemen-
tary forms in close union, and covered with a highly vascular
medullary membrane intersect to form cancelli, which are filled
with reddish oil. (2) Compact structure formed of fasciculi of
ossicles, closely packed together and arranged around the medul-
12
SYLLABUS, ETC.
lary canal. An ossicle, a cylindrical rod of bone, pierced longi-
tudinally by the canal of Havers, from ^Vo to sh of an inch' or
about gfa as an average. The bony walls of this canal formed of
several concentric cylinders of elementary lamellae, fitting within
each other with exceeding closeness, and each containing an im-
mense number of lacunae and canaliculi. Arrangement of these
"plasmatic tubes," with reference to the Haversian canal, the ex-
terior of the ossicle, and the intervening substance. Very minute
dimensions of the canaliculi. A few lamellae concentric with the
medullary canal. Lateral communications between contiguous
Haversian canals, so as to constitute a coarse net-work. Chemical
composition, physical properties, uses, see Carpenter, § 288 to § 299r-
34. Development of bone. Three stages of osteo-genesis.
(1) Gelatinous stage, consisting of primordial cells in a semi-fluid
blastema. (2) Cartilaginous, representing the different temporary
cartilages. A few flat bones are fibro-membranous in place of
being cartilaginous. (3) Ossific stage, which may succeed either
the membranous or the cartilaginous condition.
(a) Intra-membranous ossification. The flat bones forming the
roof of the cranium, prior to ossification, exhibit "only a mem-
branous layer, made up of white fibres and granular corpuscles,
with a soft, amorphous or faintly granular uniting matter." The
corpuscles are true cells, with an envelope and granular contents,
most being two or three times larger than blood corpuscles. The
fibres are calcified by impregnation with calcareous granules—a
very vascular spot, (punctum ossific at ionis,) near the centre of the
surface, indicating the point at which the process commences.
Blood vessels, at first superficial, soon become inclosed by pro-
gressive deposits around them, and thus determine the formation
of Haversian canals. The progressive extension of the ossific
deposit in radiating spjcula, with oblique connections, making a
loose net-work, that afterwards becomes compact. The original
granular corpuscles, it is probable, shoot out tortuous lines, and
those organs resisting the deposit of calcareous matter, form the
lacunas and their radiating canaliculi.
(b) Intra-cartilaginous ossification. Arrangement of the carti-
lage cells near the punctum ossificationis. Penetration of blood-
vessels to such point. First appearance of provisional bone (with-
out lacunse, $c.,) in form of a net-work, occupying the spaces be-
tween the columnar groups of cells. Subsequent enlargement of
the areolae of this temporary bone, from which the cartilage cells
seem to disappear, and are replaced by a blastema, derived from
the neighbouring vessels, and giving rise, by development, to a
fibrous membrane and a new set of cells. These new structures
then undergo ossification, in concentric layers, within the spaces
bounded by the coarse temporary bone first formed. Formation
of lacunae and canaliculi from the cells of this ossifying fibrous
membrane. Formation of Haversian canals. Bone, first spongy
SYLLABUS, ETC.
13
and very vascular, may become very compact and almost non-
vascular. Relation of the temporary cartilage to the permanent
elements of bone. Growth and regeneration of bone. See Car-
penter, § 300 to § 309, inclusive. ---"
35. Teeth. General conformation ; crown or body, neck, and
root or fangs, alveolus, alveolo-dental periosteum. Varieties of
forms. Incisors, canine, bicuspids, molars. Dental formula of
man. Structure. Cavity of the pulp, canal extending through
the fangs, dentine, enamel, crusta petrosa or cement. Microsco-
pic characters. (1) Of the pulp. (2) Of dentine, which consists of '
microscopic tubules, opening by their large end into the cavity of
the pulp, and radiating in lines perpendicular to the walls of this
cavity towards the periphery of the tooth. The diameter of these
tubular rods, at their large end, 4$Vo? Avith a bore of twott inch;
at the peripheral end, which exhibits numerous branches, they
are immeasurably fine. Intertubular substance faintly granular.
(3) Enamel. Prismatic, solid fibres, so closely packed that there is
no intervening material; prisms four or six sided, adhering by
one end to dentine, and free by the other; -5-^ inch in diameter.
(4) Cementum has characters of true bone. Chemical characters
of dentine and enamel, Carpenter, § 310 to § 319. —
36. Development of teeth. Embracing, (1) an account of the
formation of a tooth as a whole; (2) the formation of each of its
structural constituents ; and (8) the successive evolution of the
different teeth in two sets—namely, the deciduous and the per-
manent set.
(a) Development of the individual teeth as distinct and entire
organs. (1) Papillary stage. Papillae, consisting of a mass of
cells, inclosed by structureless membrane, and lodged in the pri-
mitive dental groove. Commences in seventh, and completed in
tenth week of embryonic life, to be immediately succeeded by
(2) the follicular stage, which is completed at the thirteenth week.
(3) Saccular stage. Follicles closed by opercula, and become sacs.
Structure of dental sac. External fibro-cellular layer; and internal
highly vascular layer, lined with epithelium. Cavity of reserve be-
tween the operculum and the point at which the lips of the sac
approach to cohere together. Development of future permanent
teeth in these cavities, which are thus offsets from the sacs of the
deciduous teeth. (4) Eruptive stage. Shortly before the closure
of the follicles, the papillae begin to assume forms more character-
istic of teeth, and soon exhibit the exact shape of the crown of the
coming teeth; henceforward called pulps. After a time, vary-
ing with the different teeth, the outer layer of the pulp becomes _
transformed and calcified into dentine, the process commencing on
the cusps as an exceedingly thin shell, looking like an excretion
moulded on the cusps. Successive enlargement in surface and
thickness, the pulp becoming proportionally smaller in breadth^
and thickness, but being elongated towards the bottom of the
14 SYLLABUS, ETC.
cavity. The incorporation of calcareous matter with this elon-
gated fang, causes the tooth to be lifted towards the gum, which
opposes less resistance than the bony surface at the bottom of the
alveolus, until ultimately the crown of the tooth is said to cut its
way through the sac and the gum, those tissues giving way, how-
ever, by progressive absorption and not by laceration.
(b) Formation of each of the structural constituents of a tooth.
(1) The pulp. See Carpenter, § 310. (2) Dentine. lb., § 313 and
§314. (3) Enamel and cementum. lb., § 320.
(c) Successive evolution of the different teeth in two sets. (1) De-
ciduous set, twenty in number. Dental formula. Incisors, § -§;
canine, y T; molars, f -§. Order of eruption. Middle incisors, lateral
incisors, first molars, canine, second molars. Eruption commences
at about seventh month after birth, and completed from eighteenth
to thirty-sixth month. Order in which they are shed to be re-
placed by permanent teeth. The process of shedding is usually
preceded by the eruption of the first permanent molar, behind the
last deciduous molar, in the seventh year. Then the deciduous
teeth drop in the following order, to be replaced in each case by a
permanent tooth: Middle incisors, lateral incisors; first molar to
be followed by first bicuspid of permanent set; second molar to be
followed by second bicuspid ; canine, which is the last of the deci-
duous set to fall out, occurring in the thirteenth year. Then appear
second permanent molars, and finally, from sixteenth to thirtieth
year, the third molars or wisdom teeth.
Development of permanent teeth in cavities of reserve, between
the closed mouths of the sacs of deciduous teeth and their oper-
cula. The permanent molars, however, lying beyond the range of
deciduous teeth, form an exception. The first permanent molar,
appearing before the shedding of any deciduous tooth, is developed
at the back part of the primitive dental groove. Second molar de-
veloped in a cavity of reserve, an offshoot from the sac of the first,
and the third from the second. Shifting of the position of the
second, and especially of the third permanent molar, in the progress
of the growth of the deciduous teeth and of the jaw bone. Possible
consequences of the confinement of the wisdom teeth in the ramus
of the jaw. Carpenter, § 321 to § 325, inclusive.
37. Hair.—In many respects analogous to teeth. Hair follicle—
hair bulb and pulp. Cortical substance of a fibrous, horny texture.
Medullary substance of a more distinctly cellular character. Mi-
croscopic characters of human hair—cortical layer, "a thin trans-
parent horny film, composed of flattened cells or scales, arranged
in an imbricated manner, their edges forming delicate lines upon
the surface of the hair—within this a cylinder of fibrous texture,
forming the principal part of the shaft, and only in the centre is
there a distinctly cellular structure." Pigmentary matter between
the fibres and in the cells, or sometimes equally diffused. Develop-
ment of the several structures. Carpenter, §§ 329, 330. -___- •
syllabus, etc. 15
E. Tissues composed of cells coalesced into tubes.
38. Dentine would be placed in this category by some histolo-
gists, but others deny the cellular origin of the dentinal tubules.
Two classes of tubes having such origin, (1) those without any sec-
ondary deposit and serving as channels for the circulation of the
nutritive juices, or else for conveying off the secretive fluids ;,£<.£,-,-*,
and (2) those with secondary deposit, such deposit being organized
elements executing vital acts, as muscular and nervous fibres.
Only the minute capillary vessels which are intermediate be-
tween the arteries and veins, and the smaller portion of glandular
ducts, have their origin in the coalescence of cells laid end to end,
the larger vascular and glandular tubes being formed of several
layers of fibrous tissue, lined in the case of blood-vessels with a
peculiar kind of serous membrane called endangium, and in the
case of gland ducts with mucous membrane.
39. Arteries—Definition. General form of a limited portion of
an artery—of the whole arterial tree—of the trunk divested of its
branches. Relation of the collective areas of the trunk and all its
branches at any given distance from the heart, with those nearer to or
farther from it. Structure. (1) External fibro-areolar tunic, pene-
trated by the nutrient vasa vasorum. (2) Middle tunic formed ofyel-
loiv elastic and pale unstriped muscular fibres, most of which are
circular but some longitudinal. They are arranged in layers, of which
as many as forty have been counted in the aorta. The elastic fibres
predominate in large arteries—the pale muscular in the small. (3) In-
ternal tunic, or arterial endangium, consists of a layer of tessella-
ted epithelium cells, resting on a peculiar, brittle, perforated or
fenestrated membrane, which curls up when torn in shreds. The
artery thus constructed is inclosed, with or without satellite veins,
in a fibro-areolar sheath, to which it is united by a somewhat lax
areolar tissue. Appearances of a living artery, color, pulsations.
Patulous state of a dead artery emptied of its blood, provided it
be of medium size or over. Anatomical relations—Satellite veins
and nerves enclosed in a common sheath, arterial anastomoses.
Physical properties.—Extensible, dilatable and elastic, owing these
qualities mainly to the characters of the middle coat. Internal
coat very brittle under the pressure of a sharp edge, such as a nar-
row thread. Vital endowments—power of tonic contractions.
40. Veins.—Definition—general form and distribution. Veins
are similar to arteries in these respects, but are larger or more nu-
merous, and less apt to retain their cylindrical form when emptied.
Anastomoses more frequent. Structure, analogous to that of arte-
ries; (1) external coat thin but tough; (2) middle coat has few if
any yellow elastic fibres, the pale muscular fibres which also are
sparse, being mixed with white fibrous tissue. Internal coat more
16 syllabus, etc.
seroid, and less fragile than the arterial endangium, and is thrown
into semi-lunar folds strengthened by included fibro-areolar tissue,
so as to constitute valves which yield to the column of blood moving
towards the heart, but prevents its reflux towards the capillaries.
Sensible appearances of a living vein; bluish cylinder when filled
with blood; no pulsations ; easily compressible, collapsed when
emptied. Anatomical relations.—Generally each artery lies be-
tween two satellite veins, except the larger arterial trunks which
are accompanied by a single vein each. Sub cutaneous or super-
ficial veins without accompanying arteries. Veins and arteries run
apart from each other in the cranial cavity, vertebral canal, and
some bones; vasa vasorum penetrate to the inner tunic. Physical
properties—flexible, extensible and dilatable: less elastic and less
brittle than arteries. Vital endowments: veins have less tenacity
than arteries, but a superior plastic force. A-n-v rV >'■
41. Capillaries.—Definition. Test of their distinctive charac-
ter: calibre not diminished by division, nor increased by union. Small
arteries recognized in observations on the circulation of a living
animal, by noting that the corpuscles move from trunks in diver-
gent branches of a smaller size. In veins the currents converge
from small tubes into larger ones. Form of capillary system in
different tissues, a net-work of anastomosing tubes, the meshes
being arranged conformably to the disposition of the component
structural elements of the tissue or organ. Examples. Average
diameter of a capillary blood-vessel joW inch, but some are much
smaller and others greatly larger. Automatic variations of calibre
in the same vessels in a living animal. Structure—Capillaries
under ^iirs inch have a simple homogeneous membrane, resulting
from the coalescence of the walls of a number of cells. On each
side they gradually assume additional elements, so as to pass into
arteriesand veins respectively. Around articular cartilages and
in erectile tissues the minute arteries pour their blood into dilated
pouches whence the veins arise. The same arrangement exists in
the placental portion of the uterine walls in pregnancy. Develop-
ment of blood-vessels, from nucleated cells sending out ray-like pro-
longations which coalesce and form a network of channels, &c, &c.
^ 42. Muscular Tissues, Definition; the tissues endowed 'with
vital contractility, and which, thereby, become the active instru-
ments of the automatic movements of animals, are termed mus-
cular. Two varieties ; (a) those muscles which are subservient to
the functions peculiar to animals, are characterized by a striped
appearance of their ultimate fibres : (b) most of the muscles con-
cerned in effecting those movements which are subservient to the
functions of organic life, are characterized by pale, unstriped
43. Striated variety of muscular tissue. Distribution; all the
voluntary muscles, those of respiration and expression, the heart
upper part of the gullet, and the muscles of the urethra. General
form and structure. Body or venter, head, origin and insertion
syllabus, etc.
17
both of which are often tendinous.. Fasciculi of red, soft fibres,
mostly parallel to each other, though some may intersect as in the
heart; areolar or fibrous sheath, interfascicular areolar matter,
blood vessels and nerves and their relations to the proper muscular
elements. Microscopic characters. Primitive or ultimate fibre
striated with alternate light and dark spaces in a transverse
direction; structure of fibre tubular, with delicate homogeneous
wall, called myolemma or sarcolemma, with closely packed fibrillse
deposited in the tube, and from being originally cylindrical, becom-
ing prismatic by mutual pressure in a fasciculus. Structure of a
fibril; a chain of quadrangular bodies separated by pellucid
spaces, in the middle of which a faint line can be perceived. The
pellucid space also extends around the sides of the dark bodies.
These appearances probably due to quadrangular cells, whose
walls are pellucid, and whose cavities are filled with a highly
refractive material. Explanation of the cross striae. Lateral
adhesion of the cells sometimes greater than longitudinal cohesion,
and then the contents of a tubule separate by transverse cleavage
into disks; average diameter of a tubule 3^> inch in male, and
4rb- in female. Average diameter of fibril To£oo inch. Carpenter,
§ 332 to § 336 inclusive. ----
44. Unstriped variety of muscular tissue. Distribution;
found in all the muscles of organic life, except the heart and
upper part of the gullet. For its peculiar characters see Carpen-
ter, §§ 337 and 338, from which it will be seen that the striated----
fibre is the perfect condition of the tissue, the contractile cells
of Kolliker and the pale unstriped nodose fibre representing early
stages of its development. The contractile cells with long staff-
like nuclei are often found unmixed in the smaller arteries, veins,
and lymphatics, &c, &c.
45. Chemical characters of muscular tissue. The albumen and
gelatine found in muscles probably belong exclusively to their
nerves, vessels and interfascicular areolar tissue. Fibrine, the
chief solid ingredient, is probably the sole solid organic ingredient
in pure muscular fibre. The juice of muscle contains kreatine,
kreatinine, inosinic acid, lactic acid, and certain salts, especially //';
those of potash, (chloride and phosphate.) Physical properties
of muscular tissue when relaxed ; when vitally contracted. Vital
endowments: plastic force, tonicity and rythmical contractility.
general anatomy of the nervous system.
46. Definition.—Varieties of nervous structure, (1) ganglionic
or vesicular; (2) fibrous or white substance : fundamental office of
each.
47. Fibrous or white nervous substance. Distribution;
forms the trunk and branches of all nerves and also the white
matter of the brain and spinal cord, where it comes into relation
2
18
syllabus, etc.
with the ganglionic or vesicular substance. Structure of nerves.
Neurilemma—fasciculi—ultimate nerve fibres, of which there are
two kinds; (a) tubular or nerves of animal life, diameter jVoo to
j^j inch in nerves, but very minute, (rdro-cr inch) in some parts of
the brain; external homogeneous envelope, white matter of
Schwann, and axis cylinder; more delicate tubes apt to become vari-
cose under the least inequality of pressure, (b) Gelatinous, or nerves
of organic life: flattened, soft and homogeneous, resembling un-
striped muscular fibres ; nucleated nodosities ; diameter between
BoVo and 40V0 inch. See Carpenter, § 373 to § 375 inclusive. —~-
48. Ganglionic, vesicular, or cineritious substance.—
Distribution: found on the surface of brain and cerebellum, and
in circumscribed masses in the substance of these organs; as a
continuous longitudinal mass in the centre of each half of the
spinal cord ; in the knotty enlargements called ganglia found on
the posterior roots of spinal nerves, and on some other nerves ; and
finally at the peripheral expansion of some of the nerves of special
sense. Naked eye characters as found (1) in brain and spinal
cord; (2) in ganglionic knots on nerves. Microscopic characters.
Ganglion vesicles of various shape and dimensions, disseminated
through a granular matrix, and lying somewhat loosely in the
midst of a minute plexus of blood-vessels. Carpenter, § 378 to -~
§ 380.
49. Anatomical relations of the two varieties of nerve structure,
(a) In the brain and spinal cord. (1) Continuity of fibres with ray
like prolongations of the cells. (2) cells included in a follicular
dilatation of nerve tube. (3) Fibres merely passing among and
around, possibly adhering to, but having no organic continuity with
the ganglion cells.
(b) Relations of the peripheral ends of nerves with the structural
elements of the tissue to which they are distributed, (1) in muscles :
loops of nerve tubes around ultimate muscular fibres, or else a
net work of the ultimate nerve tubes. (2) Of sensory nerves. In
some cases, as in the retina, we find an expansion of vesicular
matter, which by analogy is presumed to exist for all sensory
nerves.
(c) Relation of nerve fibres within the trunk and branches of
nerves. Mere juxtaposition and no anastomosis. Nervous plexuses,
their structure and uses. Carpenter, §§ 376 and 377.
50. Chemical characters of nervous substance. Waste—devel-
opment—regeneration-^wtaZ properties, $c. lb. § 384 to § 390.__
51. CLASSIFICATION OF THE HUMAN TISSUES FOUN-
DED ON THE CHARACTERS OF THEIR STRUCTURAL
ELEMENTS.
I. Molecules or Granules.
(1) Molecular base of chyle.
(2) Granular blastema.
(3) Granular contents of pigmentary
and other cells.
syllabus, etc.
19
II. Nuclei, or Cytoblasts.
III. Simple, homogeneous membrane.
IV. Simple fibres.
V. Nucleated cells, free and floating.
(4) The assimilating corpuscles of the
" so-called vascular glands," such as
the thymus, thyroid, spleen, &c.
(5) The free nuclei in the gastric glands
and juice.
(6) Nucleated blastema, as on the sur-
face of open wounds, &c.
(7) Mammalian blood disk(?) accord-
J ing to T. W. Jones.
(8) Basement or primary membrane.
(9) White fibrous tissue, as in tendons
and ligaments.
(10) Yellow fibrous tissue, as in the
vocal cords, &c.
(11) Areolar tissue, and the derms
formed of it.
(12) The corpuscles of chyle and lymph,
and the white cells of blood.
(13) Red blood-disks of oviparous ver-
tebrates.
(14) Absorbent cells imbedded in the
substance of the intestinal villi, and
engaged in chylosis.
(15) Adipose cells.
(16) Vesicular nervous structure.
(17) Epithelium and cuticle.
VI. Cells imbedded in a vascular net-
work, with or without a soft granu-
lar blastema.
VII. Independent cells, slightly held
together by a mucous cement, and so
arranged as to form membranous
expansions.
VIII. Cells with cavities distinct, but '
with walls coalesced by means of
intercellular matter.
IX. Sclerous elements, in which both
THE CELL WALLS AND THE INTERCELLULAR
MATRIX HAVE BEEN HARDENED BY
HORNY OR BONY DEPOSIT.
X. Cells transformed into tubes with- 1 (24) Capillary blood and lymph ves-
out secondary deposit. / sels.
XI. Cells converted into tubes with "t (25) Muscular tissue.
secondary deposit./i.i^u^^,^,., v, <«, J (26) Fibrous nervous structure.
XII. Compound membran# — Fibrous "
structures, consisting of basement
membrane and a layer of cells, with
or without a derm beneath the mem-
brane.
(18) Cartilage.
(19) Fibro-cartilage.
(20) Hair and nails, consolidated with
horny matter.
(21) Bone.
22) Dentine,
23) Ename
LilOiULCi .
e: ]
tine, >■
mel, J
with calcareous mat-
ter.
(27) Serous "] (a) Common serous m.
membrane, j- (b) Synovial " "
embracing, J (c) Endangium.
(28) Mucous membranes.
OUTLINES OF COMPARATIVE ANATOMY.
ON THE VALUE OF COMPARATIVE ANATOMY, AS SUPPLYING MOST OF THE
DATA ON WHICH THE INDUCTIONS OF PHYSIOLOGY ARE BASED.
52. Complexity of the mechanism of man and other animals high
in the zoological scale. Mutual dependence of the organs and cor-
relation of functions. Action of each organ thus dependent on
two sets of conditions; (1) those which immediately and directly in-
fluence it, and which may, therefore, be called essential; and (2)
20
syllabus, etc.
those which primarily concern other organs, and only exert an in-
direct and reflected influence upon a given organ, for the reason
that there must be a harmony of action throughout the system ;
these last conditions, though important, or even necessary are
not essential in the sense employed, and may be called conco-
mitant or incidental conditions. Examples: essential conditions
of muscular contraction, contrasted with certain conditions which
are incidental to the peculiar organization of man, in respect to the
relation between muscular action and the functions of the heart
and lungs. Simple observation of the vital acts in one species
will not enable us to discriminate between the essential and inci-
dental conditions, since both are necessary to the^ continuance of
the acts, and, for the same reason, artificial experiments are pre-
cluded. But nature presents us with experiments already pre-
pared, by exhibiting a chain of beings of continually decreasing
complexity of organization, until we arrive at some in which any-
given function is executed in its simplest and most essential condi-
tions. Ascending from this point, we notice the successive super-
additions to each organ or apparatus of organs, and comparing
these with the habits, sphere of life, and other peculiarities of the
beings which exhibit them, we learn, by an easy induction, the
uses or functions of the numerous superadditions which we find in
most of the human organs, as compared with the simplest and most
elementary state of the same organs in the lowest animals.
ON THE CHARACTERISTICS OF ORGANIZED STRUCTURES IN GENERAL.
53. Division of natural bodies into animals, vegetables, and
minerals, the last comprising all bodies, whether solid, liquid, or
gaseous, that do not belong to one or the other kingdom of living
beings. Peculiarities of animals and vegetables, as contrasted
with mineral matter. (1). Peculiar structure, called organization.
An organism, a union of dissimilar organs, i. e. parts differing in
structure and office, and yet all working towards some common end.
So each organ is composed of different tissues, and each tissue of
certain structural elements, most of which exhibit, under the
microscope, a peculiar structure, and all of which are unlike mine-
ral particles. Minerals are mere aggregations of similar particles,
each having all the properties of all the rest. See Carpenter, loc.
cit. §§ 4, 5, and 6, for apparent exceptions, &c. (2). Form.'"
Organic forms contrasted with crystals, both as to appearance and
as to the forces under which they are respectively developed. (3).
Size. (4) Intimate structure and consistence. Carpenter, § 2 to-—'
§ 10 inclusive. (5) Chemical composition. See Kirke and Paget's
Human Physiology, chap. I. Notice especially the following "~"
points, (a) Small number of elements found in the organized
kingdoms, not more than 16 or 17 out of the 62 found in the
mineral-kingdom, and the relatively large number (4, 5, or even
SYLLABUS, ETC.
21
more) in most of the organic proximate compounds, (b) Their
complex mode of union in forming these compounds, contrasted
with the binary mode of union of the elements in inorganic com-
pounds, (c) The large number of organic compounds formed out
of a few ultimate elements, (d) Proneness to spontaneous decom-
position dependent in part upon the complexity of composition, and
favoured by the presence of nitrogen and water. (6) The posses-
sion of peculiar forces, which only exist while the organization is
perfect. Mutilation of the organism not only arrests the action of
the machine as a, whole, but destroys the capacity for action in each
part; whereas, in inorganic machines, the properties of the material
are unaffected by the disturbance of its action from mutilation or
other influences. Hence, our notion of organization implies not
merely a mutual adaptation of dissimilar parts, but also the pos-
session by each part of peculiar forces, which only exist while the
entire organism is perfect.
ON THE DISTINCTIONS BETWEEN ANIMALS AND VEGETABLES.
54. Amplification and explanation of the aphorism of Linnaeus,
that " minerals grow; plants grow and live; animals grow, live,
and feel." Thus the "vital powers of a plant are directed solely
to the performance of the formative operations," and whatever
movements it may exhibit, have reference to the same end, and
originate in physico-vital forces that are entirely independent of
consciousness. An animal possessing these same powers has also
others that " are subservient to the operations of the conscious
mind, so that consciousness and spontaneity are involved in many of
its movements which thus originate in psychical causes." (Carpenter.)
But signs of consciousness in lower animals are often equivocal.
Adaptive movements following a received stimulation, do not re-
quire that the stimulus be felt, or that the movement be voluntary.
Brief notice of physico-reflex acts. Besides there are certain
organisms (Protozoa) admitted to be destitute of consciousness,
and yet having more points of analogy in their structure and com-
position with animals than with plants, resembling the embryonic
or transitional forms of higher animals. Hence, other grounds of
distinction than the possession of consciousness are needed. (1)
Chemical characters. Though vegetables have a proteinaceous
compound entering into the composition of the primordial utricle,
and form and store up other proteine compounds, yet they have
their tissues mostly composed of cellulose, a ternary compound.
All true animal tissues, on the other hand, are composed of azo-
tized compounds, having four or more elements. (2) Mode of ali-
mentation. Animals feed only on matter already organized. Plants
alone have the power of generating organic compounds, by the
union of their elements obtained from ammonia, carbonic acid, and
water. Difficulty occasionally experienced in applying this as a
22
SYLLABUS, ETC.
test. (3) The antagonistic influences of animals and plant on the
purity of the atmosphere. Vegetables thus abstract from the at-
mosphere carbonic acid and ammonia, the chief sources of its im-
purity, and convert them into organized compounds, which are
stored up in its tissues. These are taken in by animals, to be assimi-
lated to their own structure; and, after fulfilling a temporary
use as the instruments of vital actions, are, in those very acts,
again disintegrated and returned to the atmosphere as carbonic
acid, ammonia, and water, the identical impurities which the plant
had originally removed, and which will be again removed by other
plants. Thus, under the reciprocal actions of plants and animals,
the " chemical and physiological balance of organic nature" is
constantly maintained. (4) Structure, (a) Most animals require
a digestive sac, in which to receive and melt down the organic
compounds on which alone they feed. But this is an adaptive
rather than an essential character, and may be wanting in low ani-
mal organisms, (b) Nervo-muscular apparatus. Some plants
appear to possess a conjrajptible tissue, which may be considered
as the lowest form of a muscular apparatus; but where there are
both nerves and contractile tissue, or even nerves alone, the
organism can only be animal.
SUMMARY OF THE DISTINCTIONS BETWEEN ANIMALS AND VEGETABLES.
AN ANIMAL,
is an apparatus of combusti . n ;
possesses the faculty of locomotion;
1 carbon, ~\ Existing in sugar,
hydrogen, I starch, fat, albu-
ammonium; J men, fibrine, &c.
Exhales carbonic acid,
water,
oxide of ammonium,
nitrogen;
Consumes oxygen,
neutral azotized matters,
fatty matters,
amylaceous matters, sugars,
gums ;
Produces heat,
electricity;
Restores its elements to the air or to the
earth;
Transforms organized into mineral
matters.
A VEGETABLE,
is an apparatus of Reduction ;
is fixed;
Reduces carbon,
hydrogen.
ammonium;
Fixes carbonic acid,
water,
oxyde of ammonium,
nitrogen;
Produces oxygen,
neutral azotized matters,
fatty matters,
amylaceous matters, sugars,
gums;
Absorbs heat,
Abstracts electricity;
Derives its elements from the air or the
earth ;
Transforms mineral into organic matter
(Dumas and Boussaingault's Chemical and Physical Balance of Organic Nature.) A
SYLLABUS, ETC.
23
GENERAL VIEW OF THE ORtaA&IC KINGDOM.
55. Primary division of the animal kingdom into sub-kingdoms
or departments, founded on the arrangement of their nervous
system, which is an index of the general powers of animals,
and consequently of the totality of their organization. Four dif-
ferent types or patterns, according to which the nervous system is
arranged in the different animals possessing such an apparatus.
A large group of organisms reckoned animal, and yet altogether
destitute of nervous material. Hence, five sub-kingdoms, viz.:—
vertebrata, articulata, mollusca, radiata, and protozoa.
56. Vertebrata, Spini-Cerebrata, or Myelencephala
[myalos "spinal marrow," and encephalon, "the brain.") Ani-
mals having the vertebrate type of nervous system, that is, with
a cerebro-spinal axis, consisting of coalesced ganglia inclosed in
a jointed vertebral column of bone or cartilage, and lying on the
dorsal side of the nutritive apparatus- Brain, the anterior ex-
panded part of this axis, consisting of the ganglia of special sense
and certain superadded parts largely developed in the higher spe-
cies. Generally five senses. Bilateral symmetry. Jaws always
open in the line of the axis of the body. Red-blood disks. Never
more than two pairs of special locomotive members. Ex. Fishes,
reptiles, birds, beasts, &c
57. Articulata or Homogangliata, with the Homogangliate
type of nervous system; that is, a double ventral cord with ganglia
at short intervals, generally a pair (right and left), coalesced on
the middle line for each of the jointed annular segments of which
the trunk is composed, and communicating anteriorly by nerves
surrounding the gullet, with a pair of supraoesophageal ganglia
usually coalesced into a bilobed mass connected with the nerves of
special sensation and therefore regarded as a brain. In several of
the higher articulates, the ganglia of several contiguous rings may
coalesce longitudinally, and the resulting mass be drawn into one
of the segments, as in certain insects, spiders, &c. But even
though such coalescence were complete, the sub-abdominal posi-
tion of the nervous axis would distinguish it from the spinal axis
of vertebrates, which always lies on the dorsal side of the abdo-
men. Bilateral symmetry of body. Jaws open laterally. Blood
generally colourless, and when coloured, as in the annelida, it is
due to the liquor sanguinis, and not to the blood corpuscles. Lo-
comotive limbs sometimes absent; when present they are never
fewer than three pairs, and may he very numerous. Ex. worms,
insects, crabs, &c.
58. Mollusca or Heterogangliata. Animals possessing the
Hetero-gangliate type of nervous system; that is, a nervous ring sur-
rounding the gullet from which nerves radiate unsymmetricallyto
be connected with other irregularly scattered ganglia. No definite
type as to form of body; consistence generally very soft, hence
24
SYLLABUS, etc.
named molluscans. Mucular skin or mantle. Many occupy cal-
careous testse or shells, which may be univalve, bivalve or mul-
tivalve. Others constantly naked; many immovably fixed to
rocks, &c.; others with imperfect locomotive members. Appa-
ratus of nutrition very complete; animal powers relatively low.
Ex. Oyster, snail, cuttle-fish, &c.
59. Radiata, or Cyclo-neura, (cyelos, "a circle," and neuron,
" nerve,") with a nervous system disposed with circular and radiate
symmetry. A circular cord around the mouth, sending branches
into each of the ray-like lobes, arms, or tentacula, given off from
the body, or from around the mouth of the animal. According to
Carpenter and others, the nervous ring has gangliform enlarge-
ments opposite the base of each radiated appendage. But this is
denied by Owen, who considers the nervous system of the Radiata
to be characterized by the absence of ganglia, and hence he terms
them nematoneura, that is, animals with a filamentous nervous
system. Sometimes the whole body has the circular and radiate
form, as in the Star-fish, but generally it is only the arrangement
of the mouth and its tentacles, which conform to the type. In
some of the Radiata, no nervous structure has yet been demon-
strated, but their actions are such as to justify the inference that
the elements of such a structure must exist in some form. These
Owen proposes to erect into a special sub-kingdom under the name
Acrita, that is, animals with an undiscernible nervous system.
Examples. Star-fish, (nematoneurose,) Zoophytes, (Acrite).
60. Protozoa, or Aneura. Animals without any nervous sys-
tem. Positive characters too variable to furnish grounds of dis-
tinction. Some are destitute of digestive apparatus, and are also
motionless, their vital powers, like those of plants, being directed
solely to the performance of the formative operations, but they are
yet regarded as animals on account of their general analogies of
structure. Having no common type of form, they have been called
Amorphozoa, but as the same may be predicated of molluscans, the
proposed term is less distinctive than the preferred one, Protozoa,
(protos, " first," and zoon, " animal,") indicating the lowest stage
of animal life.
SUB-DIVISIONS OF THE ANIMAL SUB-KINGDOMS.
61. The subordinate groups next in order to sub-kingdoms are
termed Classes; which are divided into Orders; these into Tribes;
and Families ; these into Genera, and these into Species, which
last comprises all the individuals which may be supposed to have
sprung from a common parentage. In presenting an outline of
the anatomical characteristics of the principal classes of animals,
it is better to begin with the lower and simpler forms, and to pro-
ceed in the ascending series.
syllabus, etc.
25
A. SUB-KINGDOM. PROTOZOA.
I. Class--POLYGASTRICA.
62. Infusorial. Microscopic, from 24W5 inch (monas crepuscu-
lum, in infusions of putrid flesh,) to 5V inch (Bursaria). Under
the name Infusoria, given by Leuwenhook, they were confounded
with Rotifer a of much higher organization. Appearance in their
interior of a multitude of globular sacs, conceived by Ehrenberg to
be multiple stomachs, and hence the class name. Ehrenberg's
views contested by Meyen, Carpenter and others, who consider the
sacs to be imperforate vesicles imbedded in a semi-fluid parenchma
or protoplasma. They present an almost infinite variety of forms ;
a distinct mouth armed, in a few cases, with teeth; a few have a
separate anal outlet. Surface in most species beset to a greater
or less extent, with fine vibratile cilia, fulfilling a three-fold use.
(1) By creating currents of water, they bring food within the reach
of the animal. (2) They subserve respiration by constantly chang-
ing the water on the surface. (3) They propel the whole animal
through the liquid medium. Skin tough, but very flexible, elastic
and contractile. Some have Setae, or stiff, inflexible hairs as or-
gans of support; others have uncini or hooked limbs. They multiply
by fissiparous division; sometimes by gemmation, and finally by
ovulation, when the water in which they are contained, is about to
dry up, &c. This class is not a natural one, being composed of
heterogeneous species.
II. Class—Rhizopoda.
63. Protozoans of a very low grade of organization, most of
which have this peculiarity, that their soft bodies are enclosed in
calcareous or siliceous shells, with minute apertures, through which
they project their pseudopodia (false feet,) which are long, thin,
digitate prolongations of their soft body. These are used as
means both of locomotion and alimentation. Being thus root-like
in appearance and office, they give rise to the class name which
means root-footed. Fossil remains of Rhizopoda of former epochs
were called Foraminifera, from the apertures for the pseudopodia.
Some of the shells are composite, each department containing a
distinct animal, these are called Polythalamia, "many cham-
bered." A few [naked or illoricated Rhizopods, as the Amoeba,
Difflugia, §e., which project portions of their body so as extem-
poraneously to construct their pseudopodia; without oral orifice
they wrap themselves around their food, and apparently secrete
gastric juice by their skin. Infusorial.
26
SYLLABUS, ETC.
III. Class—PORIFERA.
64 The various forms of the sponge tribe are arranged into
a distinct class under the above designation, which indicates a con-
spicuous character common to them all, the perforation ot tbeir
substance by very minute channels leading to a set of intercom-
municating passages and excavations. Larger canals termina-
ting in a set of larger orifices, the oscula, or vents, lwo distinct
parts in the fabric of a sponge : namely, the fibro-corneous skele-
ton, and the soft gelatinous flesh which clothes it. Structure ot
skeleton, which in a few rare species is altogether siliceous like
spun glass, but generally the fibres are of a leathery nature, with
only a few siliceous spicules scattered through it. Naked eye and
microscopic characters of the semi-fluid gelatinous parenchyma,
which is made up of an aggregation of cells ToVo inch> ea°h ot
which has the characters of a distinct proteiform or amoebilorm
animalcule, having a certain power of spontaneous motion, obtain-
ing and assimilating its own food, and altogether living by and for
itself, except so far as it may contribute materials for the forma-
tion of the fibro-siliceous skeleton." Vital phenomena exhibited
by sponges. Multiplication (1) by ciliated gemmules, or detached
portions of the gelatinous flesh, which transport themselves to
distant spots, where they lay the foundations of new sponges ; and
(2) by capsules, bodies of a larger size, and containing numerous
globular bodies set free by the rupture of the capsule. These are
probably true ova, and are developed towards winter, when the
parent structure is about to die; a few fresh water species—all
others marine.
B. Sub-kingdom Radiata.
I. Class—Polypifera or Zoophyta.
65. Definition.—Soft, inarticulate animals, mostly or wholly
Acrite, consisting when single, of a body which forms the walls of
a cylindroid cavity, the animal's stomach, closed at one end by a
suctorial base, and terminated at the other by a circular disk
perforated in its centre by a circular mouth, and giving origin
around the latter to a series of radiating tentacula. It is, therefore,
a mere self-moving stomach, with a single orifice for ingestion and
egestion, fringed with sensitive and prehensile tentacula. Such
structure is exemplified in the genera Hydra and Actinia, both of
which are single and/ree. The former inhabiting fresh water, has
its stomach excavated out of the general parenchyma,—the latter,
a marine group, has a stomach with distinct walls suspended in an
abdominal cavity. An immense majority of Zoophytes are com-
posite, that is, a large number of individual polypi are connected
SYLLABUS, ETC.
27
together by the fusion of the lower parts of their bodies, with a
mass of gelatinous flesh common to the whole, called Polypary,
the whole structure (Polypary and Polypi) being called a Polypi-
dom. In a large majority of such genera the older parts of the
polypary become calcified, when they are called Lithophytes, or
consolidated with horny matter, when they are called Keratophytes.
Sometimes the hard matter is deposited in the central axis, the
fleshy matter bearing polypi being superficial, as in thecommon
Red Coral. Sometimes the hard substance is external, forming
tubes with the polypi emerging from the open ends (terminal) as
the Tubipora Musica, (organ pipe coral,) or from orifices along
their sides.
66. Ordinal sub-division. All the composite Zoophytes may be
arranged in one of two groups, according as the individual polypi
are Hydraform or Actiniform. (1.) Order Hydroida or Hydra-
form Polypi. Composite forms mostly arborescent and tubular,
with the hard matter rather horny or pergamentaceous than cal-
careous. Multiplication by gemmation, fission and ovulation.
(2) Order Actinoida, also called Anthozoa, "animal flowers,"
resembling the Helianthus, Anemone, and such like composite
flowers, both in form and beauty of coloration. Tentacula tubular,
open at the free end, and communicating by the other with the
interseptal compartments of the abdominal cavity, which also
have minute orifices opening into the stomach, whence they receive
water to distend their bodies. Genus Actinia has species
six or eight inches in diameters; other genera very small. Her-
maphrodite, with distinct testes and ovaries, on alternate septa of
the abdominal cavity. Multiply on a compound mass by budding.
Colonies multiplied by eggs, or by detached buds. To this order
belong, besides numerous other families, the Coralidse, Madreporidce
and Madrephyllidse, which form the coral reefs and islands of the
tropical seas.
With the exception of the genus Hydra, found- in stagnant pools
on aquatic plants, all the Zoophytes are marine.
II. Class—Acaleph^: or Arachnodermata.
67. Synonymes.—Sea nettles—sting fish—jelly fish—sea blub-
bler. Definition. Radiate animals of a jelly like consistence,
generally translucent, or even of a glassy transparency, with a
large preponderance of fluid constituents, which drain away when
the animal is taken out of its native element, the sea, leaving only
a light cobweb texture weighing only a few grains, when the
perfect animal weighed as many pounds. Some are splendidly
phosphorescent ; most sting and communicate this property to a
limited quantity of water in which they lie for a short time, and
to which they add a slimy secretion from their own bodies; great
variety of forms ; community of digestive, circulatory and respira-
28
SYLLABUS, ETC.
tory passages; sexes separate. Hence generation oviparous.
Singular phenomena of alternate generation.
68. Ordinal division. (1) Pulmograda, or discophorous Medu-
sans. Disk shaped; mouth inferior and four lipped, or else in
the form of minute pores at the end of long-depending root-like
appendages (as in genus Rhizostoma); locomotion effected by
rythmical contractions of the margin of the disk, resembling the
alternate contractions and dilatations of lungs, hence the ordinal
name. (2) Ciliograda, moving by means of vibratile cilia. (3)
Cirrhigrada, moving by means of the action of curled tendrils .or
cirrhi. (4) Physograda, moving by reason of air vesicles, which
they fill or empty at will. When distended, the animal rises by
its buoyancy to the surface and is moved by the wind or tide, as
Physalia utriculus (Portuguese Man of War.)
III. Class—Echinodermata (spiny-sJcinned radiates).
69. The class name, indicative of a very conspicuous feature in
the best known species (star-fish, sea-urchin, &c), resulting from
the development of calcareous spines in their skin; but a great
many animals now included in this class do not possess the cha-
racter in question. Another character which is very common but
likewise absent in some tribes, is the existence of tubular, retractile
cirrhi, which serve as feet for some, and probably as respiratory
organs for others. A still more common character, which is yet,
however, wanting in a few, is the existence of calcareous plates (not
the spines) in the substance of the skin, serving as a dermo-skele-
ton. In default of any single universal artificial character, the
class is recognized by the ensemble of natural characters. Whereas
the polypifera have no respiratory channels, and only a few fami-
lies exhibit the first traces of lacunar passages for the circulation
of nutritive juices, and the acalephae have a community of diges-
tive, circulatory, and respiratory channels, the higher radiates,
designated by an inconstant artificial character (the prickly skin),
really constitute a natural group, characterized by the possession
of true blood-vessels with pulsatile walls at certain points, and of a
respiratory apparatus, which in some is represented by the
internal free surface of the peritoneum, and in others is a special
localized apparatus. Nervous system distinctly radiate. Minute
eyes found on the end of each ray of star-fish. Sexes distinct.
Sexual organs multiplied. The number 5 and its multiples rem-
nant in this class, as the number 4 is in the parallel class, Arach-
nodumata, or acalephae. All are marine, and feed mostly on
other animals.
70. Ordinal division. (1) Crinoidea or Pinnigrada, mostly
fixed by a jointed calcareous stem to rocks, with the belly up-
wards. But the Comatula, now known to be the mature condition
of the animal, which, when fixed in its early state, is called Pen-
SYLLABUS, ETC.
29
tacrinus Europseus, is free, and moves by flapping the pinnae or
lateral barbs to its arms.
(2) Ophiurida or Spinigrada, like the Ophiurus, crawl by
means of short stiff spines.
(3) Asteriada or Cirrhigrada, walk on solid surfaces by
means of their suctorial, retractile cirrhi, projecting through the
skin along the under surface of the rays. The stomach volumi-
nous, and sends a pair of ramifying lobes into each of the five rays;
which are, therefore, not tentacula or arms as are those of the two
first orders, but merely lobes of the body. No anal outlet dis-
tinct from the mouth as in the other orders.
(4) Echinada or Spini-cirrhigrada, like the echinus (sea
urchin), use both spines and tubular cirrhi as organs of locomotion.
Their skeleton consists of ten meridian bands of calcareous plates,
extending from oral to anal pole, and arranged in five pairs, con-
sisting of tubercular plates, which bear long spines articulated with
the tubercles by perfect ball-and-socket joints! with a muscular
capsular ligament, alternating with five pairs of smaller bands the
plates composing which are destitute of tubercles, but are perfo-
rated for the locomotive cirrhi, and are called ambulacral plates.
Other plates are disposed around the mouth and anus which are
terminal and opposite, the anus being uppermost. The echinus
has a very curious dental apparatus called Aristotle's Lantern.
(5) Cystidea. Fossil remains recently discovered. Seem to
have become extinct before the pentacrinites were called into exist-
ence. Combine some of the distinctive characters of the Crinoidea,
Ophiurida, Asteriada, and Echinida.
(6) Holithurida or Cirrhi-vermigrada, like the Holithuria,
have cirrhi in varying number, for different genera, and variously
disposed ; elongated bodies, and very muscular skin; hence vermi-
grade in water, and cirrhigrade on a solid surface; tentacula
around the mouth; calcareous ring around the mouth, at the base
of tentacula; respiratory tree opening into anal cloaca ; genital ap-
paratus wTith single outlet, &c, &c.
(7) Siponculida or Vermigrada. No cirrhi; no calcareous
plates or spines ; but internal organization strikingly similar to
that of the Holithurida.
C Sub-kingdom. Mollusca or Hetero-gangliata.
I. Class—Bryozoa (animal moss.)
71. Microscopic, or very minute; generally found in composite
masses like true Zoophytes, of which the polypary is either a
creeping stem, or an aborescent trunk, or an irregular mass.
Formerly confounded with true Zoophytes, as a sub-class termed
Ciliobrachiata, their tentacles being fringed with vibratile cilia.
Each individual composed of an external sac of which the outer
30
syllabus, etc.
layer is either membranous, or horny, or rarely calcareous ; ar-
rangement of retractor muscles for drawing the mouth and tentacles
into the tube and closing its orifice. Internal organization mol-
luscan as respects digestive apparatus. They are the only mol-
lusks without a distinct circulatory apparatus ; ciliated ^ tentacula
probably organs of respiration as well as of alimentary ingestion;
a single nervous ganglion between mouth and anus, which are near
together, representing the lowest grade of Heterogangliate type.
Propogation by attached buds growing on the polypary mass;
colonies multiplied by ova, developed and fertilized by the same
individual, the Bryozoans being hermaphrodite.
II. Class—Tunic at a.
72. Body inclosed in a tunic or leathery bag quite distinct from
the muscular mantle, and rather to be compared with the calcareous
shells of the conchiferous species, being very tough, and sometimes
having grains of sand agglutinated on its surface. Two orifices op-
posite to and corresponding with the oral and anal outlets of the true
body of the animal. The oral opening in the tunic surrounded by
short, radiating and ciliated tentacles, the anal separated from the
true anus by a cloaca into which the genital passages also open.
The tunic connected with the mantle at these orifices. Dilated
Pharyux serving also as a respiratory sac, the surface bUVeen,«
divided by regular folds and every where studded with respiVatory
cilia. Digestive apparatus similar to that of Bryozoa. A distinct
circulatory apparatus consisting of a muscular heart with one
cavity, alternately systemic and branchial, and two sets of vessels
without valves, and each being alternately arterial and venous.
Single nervous ganglion as in Bryozoa. Like the latter, many
tunicata form composite masses. Two orders. (1) Ascidiform,
embracing the single and the compound Ascidians. Both kinds
fixed to rocks; the compound forms being developed from single
individuals by continuous budding from a common stalk. (2) Sal-
pidse, also embracing single and compound forms, both of which are
free, and move by means of currents of water discharged from
their respiratory chambers. In the compound forms, the aggre-
gated individuals have no organic continuity, but adhere pretty
firmly by means of little suckers. Not identical with solitary
individuals. A solitary salpa developes in its body an internal
stolon, (having no true sexual organs,) from which buds sprout out,
and are developed into an aggregated mass of which the separate
individuals are of different sexes. Sometimes a whole chain consists
of males, and others females. The product of true generation between
the sexes is always a single salpa without sexual organs, but de-
veloping the internal stolon. Thus every alternate generation is
a composite mass, and only at the intervening stages do the solitary
individuals appear.
syllabus, etc.
31
III. Class—Brachiopoda, or Palliobranchiata.
73. Bivalve acephalous mollusks, in whom the entire mantle
serves as a branchial or respiratory organ, by having the branchial
vessels distributed over it. In other respects the internal organi-
zation is sufficiently analogous to that of the following class to
render it unnecessary to enter into details. The two long arms
fringed with filaments that spring from either side of the mouth are
neither prehensile nor locomotive instruments, but by means of
the cilia clothing their surfaces, they create currents in the water
for injestion and respiration.
IV. Class—Lamellibranchita.
74. Also bivalve and acephalous, and by reason of their impor-
tance among the acephalous classes, are frequently designated
simply Acephala, as if this were a class peculiarity. The proper
class name derived from a specialized respiratory apparatus in the
form of. four membranous lamallae or leaves lying between the
lobes of the mantle and fringing the body of the animal. Valves
(separate pieces of the shell) connected by a hinge and an elastic
ligament; closed by the action of one or two adducter muscles,
pulling the valves into close contact and compressing the liga-
ment. Valves lateral with hinge on the dorsal side. Many
bivalves fixed, by adhesion of one or both valves to solid bodies,
or by a tendinous cord, or mass of horny filaments, the Byssus.
Others are free; some float; others leap or crawl by means of a
muscular " foot" which, with others, is a boring instrument. Some
have mantle open, (Ostracea). Others have the two lobes of the
mantle more or less completely united, having in some cases simple
apertures, and in others, syphonous tubes for respiration and
defecation. Very large liver, as the dark part of the Oyster. Two-
cavitied heart always systemic, and frequently perforated by the
rectum. Most are dioecious, the genital parts lying back of the
heart. A pair of oesophageal nervous ganglia communicating by
cords over the gullet. Branchial ganglia. Pedal ganglia in those
species which have a foot. One genus, Pecten, supposed to have
ocelli around the margin of the mantle.
V. Class—Gasteropoda.
75. Mollusks whose instrument of locomotion is a muscular disk
on the under surface of the belly. Very extensive class in which
a few species are naked, but most have univalve testaceous shells, of
which the typical form is a cone with expanded base, as in the
Patella, but most frequently the axis is spirally disposed. For
32
SYLLABUS, etc.
structure and mode of growth of testaceous shells generally, see
Carpenter, loc. cit. §§ 280 and 281.
Internal organization of Gasteropods considerably higher than
that of any of the acephalous classes. Distinct head and organs
of special sense. Ganglionic nervous matter above as well as
at the sides of the gullet. Numerous orders mostly artificial.
Order Pulmonea is however natural, exemplified in the genera
Helix (snail) and Limax (slug) which have a respiratory air cham-
ber with vascular walls. The members of this order are Herma-
phrodite, with very complete organs of copulation ; not capable of
self-impregnation; most of the other orders are dioecious.
VI. Class—Pteropoda.
76. Mollusks with a wing-like membranous expansion on each
side of the neck, by means of which they swim through the water
with great activity. « Should, perhaps, be regarded rather as an
aberrant subdivision of the Gasteropoda, than as a distinct class,"
and have no special physiological importance or point of interest.
VII. Class—Cephalopoda.
77. Mollusks whose feet or locomotive appendages are attached
to the head. These same appendages are also instruments of
\ prehension, being armed with powerful suckers. In many, all the
internal organs are collected into what may be called the head;
so that the entire animal is a large head, from the under side of
which there projects a thick circular membranous expansion, which
divides into the long powerful arms that serve as feet when the
animal crawls on a solid surface, with the mouth in the centre of
the disk, downwards. Respiratory chamber in front of abdominal
cavity, with syphonous outlet; the forcible discharge of water
through which serves to propel the animal backwards. Approxi-
mation to vertebrates in the concentration of vesicular nervous
matter above the gullet, and in having a rudimental cranium of
cartilage. Two orders.—(I)Tetrabranchiata. Nautilus, the only
known existing genus or species. (2) Dibranchiata, exemplified
by the genera Octopus, Sepia, Argonauta, Sfc, §c, which possess
an ink-bag, not present in the nautilus. The general organization
indicates a higher grade of animal existence than that of other
molluscan orders. For arrangement of nervous ganglia see Car-
penter, loc. cit. § 854.
SYLLABUS, ETC.
33
D. Sub-kingdom. Articulata or Homogangliata.
I. Class—Entozoa. (Internal Parasites.)
78. As the class name and the definition merely indicate the
habitation of the species, it was a priori probable that, like the
Infusoria, the group would prove not to be a natural one. Some
Entozoa are Protozoans, some Radiates, and even the highest
forms only indicate a tendency towards the articulate type, few,
if any, ever attaining to the higher steps of the development.
Yet there is some convenience in treating them as one group.
ORDINAL SUB-DIVISIONS OF THE CLASS.
79. Order I. Cystica, of which the simpler forms are mere
animal cells, and therefore incontestably Protozoan. Best known
genera and species found in the human being are (1) Acephalocys-
tis Endogena, (Hydatid) a headless cyst, or mere organic cell of
large dimensions, containing other and smaller ones, the product
of endogenous development. (2) Echinococus hominis, or parent
acephalocyst, filled with albuminoid liquid in which float little
animalcules, consisting of a mere head with a circle of hooklets and
four suckers. (3) Cysticercus cellulosse, having a head and neck
like the genus Taenia in the following order, and with an enlarged
cyst for its body and tail, whence the generic name, which means
a cyst-like tail. Another genus having some points of analogy
with the two last, but not found in man, is (4) Grnurus, which is
an acephalocyst with a large number of taenia-like heads project-
ing off from its walls, and organically connected with them. The
parent vesicle thus appears like the common tail of all these
heads, whence the generic name. The Cosnurus Cerebralis is found
in the brain of sheep and causes a fatal disorganization.
80. Order II. Cestoidea, which means fillet-like. Two species
belonging to different but closely allied genera found in man;
namely, (1) Taenia solium, having a head like that of Coenurus
or Cysticercus, which are quite probably abortive taenia with
dropsical bodies. Articulate form—multiplication of genital appa-
ratus, male and female, in each individual; opening on the margin
of the flattened segments, on opposite sides of those that are con-
tiguous. The history of the development of its innumerable ova
is not ascertained. (2) Bothrio-cephalus Latus, distinguished by
the two longitudinal fossae on the head, and by the genital organs
opening in the centre of the surface of each segment instead of
on the margins.
81. Order III.—Trematoda, which indicates as a character-
istic the fact that the body has other openings besides that of the
mouth and anus. This character is, however, in all probability,
3
34
SYLLABUS, ETC.
illusory, and at all events it is unimportant. Still the order is
retained on account of well-marked peculiarities of organization,
which are likewise exemplified in certain non-parasitic aquatic
worms the Planariae. These accordingly are placed in this order.
Mouth in the centre of a suctorial depression sometimes found on
a projecting proboscis, at some distance from anterior end of the
body. Stomach generally with ramifying lateral appendages.
Distinct circulatory system consisting of but few trunks, them-
selves very small, and a minute net-work of capillaries. Organs
of generation more localized than in the Cestoid order. Pair of
ganglia anterior to the mouth, and indicating an arrangement
somewhat intermediate between the molluscan and articulate
types. In the lowest forms the cords from these ganglia diverge,
as in molluscans. In the higher species they approximate towards
the median line on the ventral aspect. The only genus known to
infest the human tissues is the Distoma or Fasciola ; as (1)
Fasciola Hepatica (formerly called Distoma Hepaticum) or Liver
Fluke ; and (2) Fasciola Lanceolata, both species being found in
the liver and gall bladder.
82. Order IV. Acanthocephala (Prickly headed.)—None
found in man. Echinorhynchus Gigas of the hog, a most formi-
dable parasite.
83. Order V. Nematoidea.—The entozoa of this order have
a decidedly higher organization than the preceding. One distinc-
tive trait is the existence of distinct walls to the alimentary pas-
sages, whereas in the preceding these passages seem to be mere
excavations in the general parenchyma. Hence the latter have
been designated as a distinct Radiate class Sterelmintha (solid
worms,) while the Nematoid order has been elevated to a separate
class called Cohlelmintha, (Cavitary worms). Other features of
their organization exemplified by the Ascarls Lumbricoides, the
common round worm. Sexes distinct, female being always larger,
and having near its middle a circular constriction at one side of
which is the vulva leading by a vaginal tube to the so called uterus,
the dilated portion of the tube at the junction of the two ovarian
tubes whose convolutions fill the hinder part of the body, except
the axis, which is occupied by a straight intestinal tube. Male
with an erectile intromittent spiculum projecting from the end of
the tail. Lowest grade of articulate type of nervous system,
namely, small supraoesophageal ganglion with ventral cord desti-
tute of ganglia on it.
Table of Human Entozoa.
84. I. Sub-Class—Protelmintha.
(1) Acephalocystis Endogena, . . Liver and peritoneal cavity.
{■!) Echinococus Ilominis, . • Liver, spleen, omentum.
(.-;) Cysticercus Cclluloscc, . / Areolar tissue between the fasciculi of
( muscles—eye—brain.
SYLLABUS, ETC.
35
II. Sub-class—Sterelmixtha.
(4) Tccnia Solium, )
(5) liothriocephalus Latus, / (TaPe worm) Small intestines.
(6) Fasciola Hepalica, \
(7) Fasciola Lanceolata, / • • Liver, gall-bladder, &c.
III. Sub-class—Ccelelmintha.
(8) Trichina Spiralis, . . Voluntary muscles.
(9) Filaria Mcdinensis, (Guinea worm) Sub-cutaneous areolar tissue.
(10) Filaria Oculi humani..
(11) Filaria Bronchialis,
(12) Tricocephalus l)ixpm\
(13) Spiroptera Hominis, .
(14) Strongylus Giyas,
(15) Ascaris Lumbricoides.
(16) Ascaris Vermicularis,
Crystalline lens.
Bronchial glands.
Caput coli.
Urinary bladder.
Kidneys.
Intestinal canal.
Rectum.
II. Class—RoTIFERA (wheel animalcules.)
85. Infusorial Articulates of microscopic dimensions, from -J- to
too inch; characterized by the presence, in most species, of one
or more fleshy lobes near the mouth fringed with vibratile cilia,
having, when in action, the appearance of revolving wheels:
when at rest the wheels are retracted as if the animal had swal-
lowed them. Their use as means of ingestion. A few loricated
species—skin exceedingly flexible and contractile with scarcely a
perceptible trace of segmental division except in the tail, where
there are several segments sliding upon one another in telescope
fashion; curious dental apparatus at the bottom of the oesophagus;
narrow stomach and straight intestinal tube dilating into a cloaca.
Respiratory(?) syphon. Low development of Homogangliate type
of nervous system. Ocelli in some species.
III. Class—Annelida, or more properly Axnellata.
86. Vermiform Articulates, many of which are entirely apodal,
while the others have only rudimentary inarticulate limbs; all
breathe water except the members of one tribe, which breathe moist
air; in most cases their blood is coloured; there is a much higher
development of both vascular and nervous systems than we find in
the highest entozoa which they resemble otherwise very closely.
Except one order all are aquatic and most are marine. Ordinal
sub-divisions. (1) Dorsibranchiata with dorsal branchial tufts
generally coloured; very elongated segmental body, the segments
being all alike except the terminal ones. Dorsal and ventral oars with
a bundle of setae on each side of bWfy of the segments. (2) Tubicola
36
SYLLABUS, ETC.
resemble the last, except that being enclosed in a tube, they have
no locomotive oars, and the branchiae are concentrated around the
head. Hence have been called Cephalobranchiata. (3) Terricola
includes the terrestrial and aquatic species. Thus the Lumbricus,
common earth worm, lives in moist earth on land. The Arenicola
which has dorsal branchiae, but in other respects resembles the
Lumbricus, lives in the sand under sea-water; organization lower
than that of preceding orders, and resembles that of the Nematoid
Entozoa. (4) Sucto.ria—as the Hirudo medicinalis (medicinal
leech) whose organization resembles that of the Trematoid
Entozoa; but yet they have a well developed homogangliate
nervous system, the brain being connected with five pairs of optic
nerves, and minute ganglia being developed on the ventral cord;
three sharp saws in relation with the mouth for making their
peculiar triradiate puncture.
IV. Class—Myriapoda.
87. Air breathing articulates, with elongated bodies divided into
numerous similar segments, each of which except the terminal ones
bears one or two pairs of articulated but generally feeble limbs.
Integument more or less consolidated by Chitine into a somewhat
firm dermo-skeleton. Respiratory apparatus tracheal like that of
insects which they resemble in other features also of internal
organization, except that in the lowest family, (Julidce) the genital
apparatus opens near the anterior part of the body. Two orders.
(1) Julidae, having for its typical genus the Julus (millepede) with
very numerous segments, (40 to 80 in the perfect animal) each of
which has two pairs of short and feeble legs. Segments cylindroid
and dermo-skeleton not very hard. Development in early life
consists mainly in multiplying the number of segments. (2)
Scolopendridae having the Scolopendra (centipede) as its typical
genus with from 12 to 22 segments. The Scutigera Longipes (the
common house centipede) belongs to this tribe. Genital apparatus
opens behind as in insects.
V. Class—Insecta or Hexapoda.
88. Articulates with tracheal respiration and three pairs of lcu* segments of the
cranium of all the elements of a true vertebra. These cranial
vertebrae are, (1) occipital with haemal or scapular arch dis-
placed in all vertebrates except the Osseous fishes—the vertebra
of audition; (2) the Parietal or Gustative vertebra with the
Hyoid apparatus for its haemal arch; (3) Frontal or Optic verte-
bra with lower jaw for the haemal arch, and (4) Nasal or Olfactory
vertebra with the upper jaw for the haemal arch. The parts which
complete these vertebrae comprise all the bones of the cranium and
face, except the Petrosal, the Ethmoidal, (lateral masses of the
Ethmoid,) Inferior Turbinated and Os Unguis, which are parts of
46
SYLLABUS, ETC.
a splanchno-skeleton. In most vertebrated animals we find a cer-
tain number of hard pieces, generally bony, sometimes cartilagin-
ous, or fibrous, or horny, which do not properly belong to the
endo-skeleton, although in a few cases some of them may, for cer-
tain adaptations, be intercalated among the proper segments of the
endo-skeleton. Some being more or less closely connected with the
external skin, seem to be detached pieces of an incomplete dermo-
skeleton, while others being integral constituents of certain impor-
tant organs or viscera rather than simple protectors of such
viscera, are termed Splanchno-skeleton. The principal pieces of
the splanchno-skeleton in higher vertebrates are, (1) Petrosal bone
or Ear capsule ; (2) Sclerotic capsule or Eye capsule ; (3) Ethmo-
turbinal or nose capsule; (4) Dental apparatus ; (5) Vocal and
bronchial apparatus, &c. The dermo-skeleton is represented by
hair, feathers, scales, bony scutes, &c. In man the os unguis
seems to be the only trace of an ossific portion of dermo-skeleton.
It is only in the higher mammalia, whose large brain required an
expanded cranium, that the pieces of splanchno-skeleton (Petrosal
and Ethmoidal,) are intercalated among the cranial parietes.
Brief notice of the several regions of trunk vertebrae, as (a) cervical
region; (b) thoracic region ; (c) lumbar region; (d) sacral region ;
(e) caudal or coccygeal region.
/ ■ . ' - .'I. Class—Pisces.
101. Cold-blooded vertebrates, breathing water by means of gills,
to which the whole of the blood is sent from a single ventricle,
and from which it is distributed to the system before it is returned
to the heart, which is thus exclusively pulmonic, may be divided
into three sub-classes.
(1) Dermopteri, including all the soft, apodal fishes whose exo-
skeleton and vertical fins have no really hard pieces, either bonv
or cartilaginous, but are simply muco-dermoid in structure, and
whose endo-skeleton is unossified. Two orders, (a) Cirrhostomi,
represented by the amphioxus, a very aberrant animal, having a
longitudinal mouth with lateral cirrhi; (b) Cyclostomi, represent-
ed by the Myxina,-/Hag), and Petromyzon, (Lamprey), with
circular sucking indutBs.
(2) Sub-class. Osteopterygii, (Osseous Fishes) consisting of all
those fishes which have the endo-skeleton more or less completely
ossified. Includes six Cuvierian orders, namely, (a) Acantho-
pterygii, (spiny-finned); (b) Malaco-pterygii abdominales; (c) Ma-
laco-pterygii Sub-brachiati; (d) Malaco-pterygii Apoda; (e) Lo-
phobranchii; (f) Plectognathi.
(3) Sub-class. Chondropterygii (Cartilaginous Fishes) have the
highest organization of the whole class. Two orders (a) chon-
dropterygians with free branchiae, as sturgeons, &c- ; and (b) with
fixed branchiae, as sharks, &c.
SYLLABUS, ETC.
47
102. External forms of Fishes. Two sets of fins in most of the
class, namely, vertical azygous fins and oblique fins in pairs; the
latter never exceeding two pairs, one diverging from the scapular
arch, the other connected with a rudimental pelvic arch, which
may be placed either at the normal position, (abdominales) or
under the throat, (Jugulares) or at intermediate positions, (Thora-
cici). The impair or azygos fins are dorsal, (one or two); Anal
just behind the anus ; Caudal, which may be Homocercal, that is,
vertically symmetrical, an upper and lower piece being similar,
and separated by a notch ; or Hetero-cercal, as found in the carti-
laginous fishes where the rays of the caudal fin are connected with
the bodies of several caudal vertebrae, which run exclusively into
the upper lobe of the fin, the lower being much shorter. Large
gill openings behind operculum. Lateral line of pores, orifices of
mucous glands.
103. Peculiarities of the Piscine Skeleton. No medullary canal
in the long bones. No regular system of haversian canals and
cancelli, but large, irregular, angular lacunae with few but large
radiating canaliculi. Bodies of vertebrae generally with cupped
surfaces, working over convex intervertebral capsules. Very
gradual development of the vertebral axis, from being a mere cel-
lular and gelatinous " Chorda Dorsalis," without segmental divi-
sions, as in the Amphioxus, to the condition found in Lampreys,
where cartilaginous laminae are developed within the folds of a
fibrous membrane surrounding the Chorda Dorsalis, and which by
the separation of its two layers above and below constitute the
neural and haemal arches in the Myxinoid family. Vertebro
cranial axis divided into only three regions in most fishes, namely,
Cranial, Dor so-abdominal and Caudal, there being no neck, or
sacrum, and no distinction between Thoracic and Lumbar regions.
In the Squalidae, however, there is a cervical region. Use of Pec-
toral and Pelvic extremities. Structure of hands with its numer-
ous rays indicating, however, mere irrelative repetition. Ribs
attached to transverse processes, or to vertebral bodies. No
sternum. Peculiarities of the cranium and face.
104. Dermo-skeleton.—(1) Skeleton of the vertical fins either un-
jointed bony spines, (acanthopterygii) or else articulated cartilagi-
nous rays, (malaco-pterygii) resting upon and articulated by a chain
link joint with the dagger-like interspinous bones. (2) Sub-orbital,
supra-orbital, supra-temporal and labial scale-bones. (3) The more
common scales, whether ossified or not, lying between cutis and
cuticle, in a depression of the former. Four varieties of scales.
Placoid, Ganoid, Cycloid and Ctenoid on which Agassiz founds
his ordinal division of the class.
105. Splanchno-skeleton.—In addition to the more common
pieces we note, (1) Branchial apparatus, consisting of the branchial
arches, four in number, attached below to basi-branchial bones,
and above to the cranium ; toothed on their opposed surfaces.
Branchiostegal rays diverging appendages of Hyoid arch. (2)
48
SYLLABUS, ETC.
Pharyngeal bones behind branchial apparatus, often armed with
teeth. (3) Oral teeth, often very numerous ; generally mere cal-
cified papillae, whose base is consolidated with the bones on which
they rest.
106. Alimentary apparatus the simplest consistent with the
vertebrate type. Pulmonic bilocular heart with bulbus arteriosus,
looking like a third cavity. Four gills on each side, in most fishes,
receiving all the venous blood, and transmitting all the arterialized
blood, without a second return to the heart, directly to the system,
by the union of the branchial veins into an azygos dorsal artery
after the head has first received its special vessels from the upper-
most branchial veins. The ovaries of the female, known as the
roe, occupy at the breeding seasons much the greater part of the
abdominal cavity ; ova escape into the ovarian sac, to be extruded
prior to fertilization, which is subsequently accomplished by coming
in contact in the water with seminal matter discharged by the
male in a similar way from testicles occupying a similar situation.
Fishes have cold blood with elliptical blood disks.
II. Class—Amphibia.
107. Cold blooded vertebrates with naked, skin, most if not all
of which in the early larval stage of their active existence have
the anatomical and physiological characteristics of fishes, but sub-
sequently undergo a metamorphosis one result of which is the
development of lungs for breathing air, though a portion of the
class retain their gills also, so as to be permanently amphibious in
their powers of respiration. This section of the class termed
Perennibranchiate. The others, named Caducibranchiate, lose
their gills when they acquire lungs, and assume most of the
reptilian characters. Hence by many zoologists the class
Amphibia is ranked as a mere ordinal sub-division of the class
Reptilia, under the name Batrachia. Reasons for rejecting this
classification. Ordinal sub-divisions. (1) Anoura, which during
metamorphosis lose the tail that previously was long and com-
pressed. Other characters of Tadpoles. Branchiae, in some species
drawn into the cheek before metamorphosis. Impregnation effected
' externally during the extrasion of the ova. Common genera in
this order are Rana (Frog) and Bufo (Toad). (2) Urodela.—Tail
long and persistent, rounded in Salamandra, compressed in Triton.
Feet, always four. Ribs very short. Vertebrae numerous and
movable. Tympanum concealed. Impregnation internal. Com-
mon genera are Salamandra and Triton, the latter retaining the
gills much longer than the former. To this order are generally
assigned also the Menopoma and Amphiuma, which, however, are
not knoton to possess branchiae at any period of their existence,
and hence Bell proposes to place them in a separate order under
the designation Abranchia, but it is by no means certain, as he
SYLLABUS, ETC.
49
himself admits, that these genera undergo no metamorphosis. (3)
Apoda.—Body elongate; slender; eel-like; without feet; tail very
short, almost wanting; one lung larger than the other; sternum
wanting; ears concealed; genus Caecilia. The three foregoing
orders constitute the Caducibranchiate section. The Perennibran-
chiates are all included in one order, named Branchifera (Cuvier)
I ! ♦ or Amp&in^urta (Bell) with bodies elongate, formed for swimming ;*
r\L feet eithW Your or two anterior only; tail compressed, persistent,
U/>7cl branchiae external, persistent and coexisting with rudimen- ; ;
tary lungs. Genera, Proteus, Siren, Menabranchus, Axoldij. ■?-.* ^ ';
Changes in the arrangement of the branchial circulation coinciding
with the metamorphosis; circulation now substantially reptilian,
but differs by the permanent retention of the branchial vascular
arches which unite to form the dorsal artery. Blood disks ellip-
tical and very large.
III. Class—Reptilia.
108. Vertebrates with cold blood, pulmonary respiration, tri-
locular heart (in the single ventricle of which the two kinds of
blood received from the two auricles are mixed, to be distributed in
part to the system, and part to the lungs,) and skin covered
with hard and dry cuticle, forming in some imbricated scales,
and in others broad plates. Blood disks ellipical. Ordinal
divisions. (1) Chelonia or Testudinata, covered with broad
horny shells, exhibit a most remarkable consolidation of the skeleton.
Dorsal carapace formed of spinous processes of dorsal vertebrae
and the ribs. Sternal Plastron formed of expanded sternum and
some dermal pieces. Head, tail and limbs of many species may
be withdrawn into the box formed by the carapace and plastron,
the latter being sometimes jointed in the middle. Scapular and
pelvic arches lie within. Edentulous, but have sharp, horny
beaks. Feet unguiculated with or without webs, or else enclosed
in a paddle-like fin. (2) Order Ophidia, covered wTith scales.
United by Bell with the Lacertidoe of the next order, under the
designation of Squamata, which he contends is a more natural
arrangement than the one commonly adopted. Skeleton remarkable
for multiplication of trunk vertebrae (400 in Python) connected by
a very moveable ball-and-socket joint; moveable ribs ; no sternum ;
no locomotive members, and only in a few an imperfect pelvic
arch. Head remarkable for the looseness of the connection between
the bones that surround the mouth. Even the Tympanic pedicle and
the mastoid bone to which it is chiefly attached, hang very loosely.
Numerous small conical teeth of non-venomous species found in both
jaws. Venomous serpents have two large poison fangs on the
front of the upper jaw.
(3) Sauria.—Separating the Lacertidae, which like serpents,
are covered with imbricated scales, and which are closely connected
4
50
SYLLABUS, ETC.
with true serpents by an osculant group, the Saurophidia, that
are apodal but otherwise Lizard-like, the remainder of the Saurian
order may be designated by the term Loricata, as being covered
with bony scutes. Peculiarities of the Saurian type of skeleton
demonstrated by means of drawings and actual preparations;
alimentary apparatus; structure of lungs. Heart with four
cavities in the crocodile, mixture of venous and arterial blood
outside of this heart, the head receiving pure blood. Generation
oviparous in all reptiles, though in some species the eggs are occa-
sionally hatched in the oviducts, simulating viviparous generation.
IV. Class—Aves.
109. Oviparous vertebrates with warm blood, double circulation
and double respiration; anterior or pectoral extremities organized
for flight; body covered with feathers ; mouth edentulous; blood
disks elliptical.
Ordinal sub-divisions. (1) Raptores or Accipitres, with very
strong talons, armed with sharp, hooked claws ; beak also hooked
and sharp, as eagles, hawks, owls, and other "birds of prey." (2)
Insessores or "perchers" with feeble and unarmed toes, one di-
rected backwards and three forwards. Beak generally pointed and
not vaulted above ; wings long and body erect. Swallows, larks,
and the most common birds. (3) Scansores "climbers," two toes
directed backwards and two forwards. Beak and wings as in the
Insessorial order. (4.) Gallinaceae or Rasores (scratchers) supe-
perior mandibles arched or vaulted ; nares partly covered by a
soft, inflated scale; gait heavy; wings short; toes as in the Inses-
sorial order ; but generally the nails are more blunt, and the males
of some genera have a spur. Common fowl, partridge, pheasant,
&c. (5) Grallatores, "waders," feet formed for wading; tarsus
and metatarsus being very long, and the lower part of the leg
naked. Crane, heron, snipe, woodcock, &c. (6) Cursores "run-
ners," included by Cuvier in the preceding order, from which
they differ, however, by the rudimental condition of their wings,
which, when most fully developed, are still only fit for beating the
air while the body is borne along by the rapid progression of the
legs reacting against the ground, as in the ostrich. One genus
(Apteryx) found in New Zealand, has only a scarcely discoverable
rudiment of a wing on each side. (7) Natatores or Palmapedi,
"swimmers;" web-footed; legs generally placed far back, render-
ing swimming easy but walking difficult. Several genera, as ducks,
geese, &c, have their beaks covered with a soft skin.
110. Anatomical peculiarities of Birds. General shape of
body and its several regions. Epidermic appendages, feathers, pe-
culiar to the class ; their form and structure. Cranial bones very
early consolidated; upper jaw slightly moveable, with its lower
jaw edentulous but covered with a horny beak. Tympanic bone
SYLLABUS, ETC.
51
still separate and moveable, as in all other oviparous vertebrates.
Cervical vertebrae from 9 to 23, and very moveable with double diar-
throdial joints separated by a meniscus. Anchylosis of dorsal
vertebrae. Bony sternal as well as vertebral ribs ; extensive keel-
shaped sternum in most birds, but nearly flat in the ostrich. Lumbar
and sacral vertebrae soldered together and to the ossa innominata;
pelvic arch incomplete below; scapular arch very firm and composed
of a narrow rib-like scapula, lying parallel with the spine, and a
thick strong coracoid, articulating by a strong joint with the ster-
num, so as to form a rigid buttress which prevents the shoulders
from being drawn together by the powerful traction of the pectoral
muscles. The two clavicles unite in front of the coracoid to form
the furculum or merrythought; two carpal and two tarsal bones;
three metacarpals partially united ; three fingers; from two to four
toes, most commonly the latter, of which the first looking back-
wards has two phalanges, the second has three, the third has four,
and the fourth has five.
Digestive Apparatus. Mastication effected by the agency of
the wall of a special stomach, called the Gizzard, lined internally
by a hard, horny cuticle, the walls being formed chiefly of very
strong muscles, whose fibres radiate from two central tendons.
Use of the pebbles swallowed by graminivorous birds. Ingluvies
or crop and Proventriculus, with its walls studded with gastric
glands, both being in front of the gizzard. Small and large in-
testine ; cloaca ; very large, and more or less symmetrical liver,
&c, &c. Circulation double as in man ; blood warmer than that of
mammals; blood disks elliptical and greatly smaller than in fishes
and reptiles. Respiration double, that is, the blood besides being
aerated in the lungs, is also partially exposed to the air in the sys-
temic capillaries in most regions of the body, by means of air
sinuses communicating with the lungs. Final causes of this ar-
rangement. In both sexes the genital tubes open into a cloaca.
Males generally destitute of an intromittent organ; copulation
being effected by simple juxtaposition of the sexual orifices, by an
eversion of the cloaca. Some aquatic birds have a true penis,
which, when lax, is withdrawn into the cloaca, but projects when
erect, and is grooved for the transmission of the semen.
V. Class—Mammalia.
111. Warm blooded vertebrates, having viviparous generation,
with which there is invariably found to coincide the presence of
mammary glands, on the secretion of which the new-born mammal
is fed. Circulation double and complete. Respiration complete
but single. Body invested more or less completely with hairs, or
some homologous modification of epidermic cells, except in a few
naked species. Two sub-classes. I. Placentalia with a truly
viviparous generation; the young being born in a comparatively
52
SYLLABUS, ETC.
matured state, after having been connected with the mother by
means of a placenta. II. Implacentalia with only ovo-viviparous
generation. In this case, although a living embryo is extruded,
it is very immature, never having had a placental connection with
the maternal system, and is consequently destined to lead an ex-
clusively organic life for some time after birth, during which it is
firmly fastened by its mouth to the maternal teat.
Ordinal Sub-divisions.
I. Sub-Class—Placentalia.
112. (1) Rodentia; (gnawers); two front teeth in each jaw,
chisel-shaped for gnawing, covered by enamel only in front;
variable number of molars. Squirrel; rat.
(2) Edentata (without teeth); wanting either all the teeth or
having only imperfect molars. Ant-eater, armadillo, sloth.
(3) Ruminantia, which ruminate or chew the cud. Hoofs cleft;
except the camel tribe all want incisors in the upper jaw; the
most common dental formula being, incisors, f, no canine; molars
|-|; with the same exception, all have horns, at least in the male
sex.
(4) Pachydermata or thick-skinned mammals, comprise four
tribes, viz.: (a) P. Proboscidea, as the elephant, (b) P. Ordinaria
as the hog, &c. (c) P. Solidungula, with a single digit in each
foot, as the horse; and (d) P. Cetacea Herbivora, as the du-
gong, &c.
(5) Cetacea ; posterior extremities wanting; anterior converted
into swimming paddles; horizontal tail-fin: some have a dorsal
vertical fin. Fat, called blubber, in the very substance of the skin.
Nostrils on the top of the head, by which cetaceans spout. Peculiar
disposition of vascular sinuses in adaptation to their habit of
remaining submerged for some time; whales, porpoises, &c.
(6) Carnivora, or beasts of prey, comprising three tribes, viz.:
(a) Digiligrada, as the Fdidce or Cat tribe, and Canidce or dog tribe.
In the former, retractile and sharp claws, and peculiar carnivorous
teeth . Claws of Canidae blunt and not retractile, (b) Plantigrada
with teeth partly adapted to vegetable diet, as bears, (c) Amphibia
or Phocidee, with forms adapted for residence in water. Seals.
(7) Insectivora.—Special conformation of teeth adapting them
for crushing hard skins of the coleoptera. Moles, shrews, &c.
(8) Cheiroptera, (winghanded) anterior extremities organized for
flight by enormous elongation of fingers, which support a delicate
duplication of skin. Teeth irregular. Bats.
(9) Quadrumana, with opposable thumbs on all four of the
extremities, (at least in most of the genera) all being prehensile
SYLLABUS, ETC.
53
as well as locomotive members. Dental formula in most of the
families the same as in man; but some have an additional molar
on each side of each jaw. Monkeys and apes.
(10) Bimana—Anterior extremities organized exclusively for
prehension, terminating in hands of which the opposable digit is
a more perfect thumb than we find on any of the extremities of
Quadrumana. Man, the sole species of this order.
II. Sub-Class—Implacentalia.
(11) Marsupialia, (pouched animals). Young born very immature,
and conveyed in some way to the marsupium or abdominal pouch
of the mother, where they grasp the teats with their mouths so
firmly as to appear organically united. Marsupial bones and their
use in the two sexes. Uterus and vagina double and open into a
uro-genital canal, which has a common opening with the rectum,
but there is no true cloaca. Opossum, kangaroo, &c.
(12) Monotremata.—Implacental mammals with a cloaca com-
mon to the uro-genital canal and to the rectum. Even in the male,
the uro-genital canal opens into the cloaca, but the penis is perfo-
rated, and during erection has its hinder orifice drawn to that of
the uro-genital canal, so as to receive the semen which is projected
through numerous papillary orifices on its free end. Two uteri and
vaginal canals, which are quite separate on the two sides, and open
by separate orifices into the uro-genital canal. A very aberrant
group, resembling birds in several other respects, besides the dis-
position of the genital organs. Only two known genera, namely,
the Ornithorhynchus (Duck-bill) and Echidna, covered with strong
spiny bristles, which it can erect like a hedge-hog. Found only in
New Holland, where also all the existing marsupialia reside, except
the Didelphys (opossum) which is only found in America.
113. Anatomical peculiarities of Mammals—Two pairs of ex-
tremities present throughout the class, except only in the true
Cetacea and the Cetacea Herbivora, which lack the hinder extremi-
ties, and have only a rudimental pubes. In all, the head is marked
off from the trunk by a neck, though this is much obscured in the
fish-like Cetaceans. All except Cetaceans more or less completely
covered with hair, sometimes modified in a very extraordinary way,
as in the quills of the Porcupine, or the imbricated scales of the
Pangolin, or in the ossified plates of the Armadillo, or in wool,
which is a kind of hair very fine and twisted in all directions, or
finally in down. The Rhinoceros has an azygos solid horn, formed
of agglutinated fibres like whalebone, growing upon the nose.
Ruminants, except the Camelidse, have a pair of frontal horns,
either solid and permanent like the Giraffe, or solid and annually
deciduous as the deer-tribe, or finally hollow and permanent. The
solid horns are bony processes from the frontal bone, covered by
54
SYLLABUS, ETC.
a fine velvety skin, which, in the deciduous variety, dies at a certain
period of the year, leaving the horns or antlers bare, when they
too soon die, and drop off to be replaced by a new set, larger and
with more branches than the old. The hollow horns are hollow
cones of horny tissue implanted upon bony prominences filled with
air cells that communicate with the nose. Great expansion of the
neural arches of all the cranial vertebrae, especially the parietal,
for the protection of the progressively developing brain. In most
of the class an additional cranial element is gained by the expan-
sion of the distal end of the diverging appendage from the supe-
rior maxillary bone, namely, the squamosal bone. Tympanal bone
displaced by the intervention of the squamosal and reduced in size;
mandibular arch (lower jaw) coalesced into one piece on each side,
(these often united at the symphisis) always articulates with the tem-
poral bone by an undivided condyle; occiput articulates with atlas
bjtivo condyles; cervical vertebrae always seven in number, except
in the Pangolin, which has only six, and the three-toed sloth which
has eight or nine. Coracoid bone, so conspicuous an element of
the scapular arch in the oviparous vertebrates is not, in most mam-
mals, sufficiently developed to reach the sternum; clavicles more
frequently connect the scapula with the sternum, but they are
often wanting, as in horses and most mammals which use the
anterior limbs exclusively for station and progression by moving
only forwards and backwards.
Digestive apparatus.—Peculiar straining apparatus of the
whalebone-whale (Bala?na mysticetus). Numerous small, conical
reptilian teeth of the porpoise, dolphin, armadillo, &c. In mam-
malian teeth, except those which grow from a persistent pulp (as
the tusks of the elephant, the chisels of the Rodentia, and the
molars of the Edentata) the dental cavity is closed in at its lower
part, and the base of the tooth is prolonged into a fang, which is
implanted in a proper socket formed by a projection of the bony
substance of the jaw that grows up to invest it; this is peculiar
to this class, and further, no known vertebrate but a mammal has
teeth implanted by bifid fangs. Fleshy lips, tongue, salivary glands,
velum pendulum palati, epiglottis, muscular pharynx, and oesopha-
gus. Stomach either (1) simple, or (2) complex, as in kangaroo,
&c.; or (3) compound, as in Ruminants. Small and large intestine.
Gall bladder sometimes wanting, as in the horse, &c. Heart
double. Portal circulation. Respiration single. Special pro-
visions for the safety of aquatic mammalia, who remain submerged
for some time. Blowing apparatus of Cetaceans.
The skin of all quadrupeds contains innumerable sebaceous fol-
licles, furnishing an unctuous matter for lubrifying the skin.
Sometimes a number are aggregated together so as to form secret-
ing pouches, as just below the orbit in stags, furnishing a secretion
commonly called the " Stag's tears." Often such pouches furnish
a highly odorous material, especially in the vicinity of the organs
of generation, as the castor glands of the Beaver, the musk gland
SYLLABUS, ETC.
55
of the musk Deer, and the anal glands of the Carnivora. which have
an intolerable stench in the Skunk and Polecat. Genital apparatus
among the Placental orders does not deviate largely from the
human type; and that of the Implacentalia has already been
noticed.
The peculiarities of the kidneys, of the absorbent system of
vessels and glands, of the brain and organs of sense of Mammalia
and other vertebrates, will be noticed in connection with the phy-
siology of these organs.
ON THE OBJECTS AND PRINCIPLES OF ZOOLOGICAL CLASSIFICATIONS.
114. Why this topic was reserved for this point in the course
of lectures. Immense number of animal species, each with its
double name generic and specific. Definition of a natural classi-
fication. Relation of analogy ; relation of affinity or homology,
which is more fruitful as the basis of a natural classification. Illus-
tration from the comparison of Whales with Fishes on the one
hand, with which they are connected by relations of analogy, and
with quadrupeds on the other, with whom they differ in general
appearance and habits, but agree in all the important features on
which the class Mammalia is founded. Hence to class whales
with man and beasts is a far more natural arrangement than
that which the unlearned make from contemplating their fish-
like habits. So, too, Bats are unnaturally classed with Birds.
their real place being with other mammals. An artificial classi-
fication is one which does not necessarily indicate the natural
affinities of the objects classified, as the Sexual System in
Botany. Possible advantages of such a classification, if skilfully
constructed. Characteristics of a natural classification. Advan-
tage to be derived from having some single and easily discovered
external character, even though it be artificial, as an index or ex-
ponent of a group of natural characters with which it is found to
coincide. Examples, feathers, a sign of all those natural characters
which are indicated by the term Bird; hair, significant of mamma-
lian organization, &c. &c.
115. The entire collection of animals called the Animal King-
dom. The primary divisions, termed sub-kingdoms, have each, in
addition to the characters which belong to the whole kingdom,
some other features common to all its own members, but not pos-
sessed by other sub-kingdoms. The zoological sub-kingdoms,
founded on the varying types of nervous system, which seem to
govern the whole organization, are exceedingly natural, if Ave
except only the Protozoan, which is founded on negative charac-
ters. The primary divisions of a sub-kingdom termed Classes.
Most of the animal classes are natural groups, as for example, the
Vertebrate classes, Mammalia, Aves, Pisces, and even Reptilia,
56
SYLLABUS, ETC.
if we exclude the Batrachians, and raise them to the rank of a
separate class, Amphibia. But there are some instances of classes
founded on artificial characters, as Entozoa, a group which really
includes animals belonging to three different sub-kingdoms. The
immediate sub-division of classes termed Orders, which are more
frequently founded on some single character, and therefore less
natural than either the higher or the lower groups. Orders are sub-
divided into Tribes or Families ; and the animals included in such
a group are marked by a natural family likeness, as for example,
the Canidae, the Dog tribe or family, which includes the Dog, the
Wolf, the Fox, and the Jackal; and the Felidoe, including the Cat,
Lion, Tiger, Leopard, &c. Families include a number of Genera,
that is, collections of animals resembling each other in all the im-
portant features of their organization; and finally, a genus
includes, or may include a large number of species, which is the
term applied to all those individuals which are constantly marked
by the same characters with only such slight occasional variations
as are compatible with the idea of a common parentage. Such a
group is altogether natural therefore. Any constant or invariable
difference, however slight, is yet adequate to indicate a difference
of species, a necessary consequence of the law of resemblance be-
tween parent and offspring. To go over the same ground in the
reverse order, we observe that nearly allied species, that is, species
recognized as different by some constant point of distinction, which
however is intrinsically unimportant, while the points of resem-
blance are numerous, and have respect to all the important fea-
tures of organization, are grouped together as one Genus. In the
same manner closely allied genera are ranked as one family or
tribe. Families, resembling each other in natural, or even in cer-
tain artificial characters, are placed in the same order; allied
orders make a class, and classes having a certain degree and kind
of affinity, are grouped together as a sub-kingdom. " Thus as we
pass from species to genera, from genera to families, from families
to orders and from orders to classes, the characters of agreement
become fewer and fewer ; whilst those of difference manifest them-
selves more and more strongly. And when we arrive at classes,
we may generally say that the points of difference are stronger
than those of agreement." Typical representatives of any natural
group of animals. Genus Felis, a typical genus of the family
Felidae, the latter being a typical family of the order Carnivora;
the order Insessores, a type of the class Aves. So Annelidans
and Myriapods may be regarded as retaining more of the dis-
tinctive characters of the sub-kingdom Articulata, than either the
Arachnidans, Crustaceans or Insects, all of which in their higher
forms diverge in different directions and nearly equal degrees from
the common fundamental type. Aberrant groups. Osculant
groups. Examples: Sub-class Cirrhopoda are aberrant Crusta-
ceans, being osculant between the typical Crustaceans and Aceph-
alous Mollusks. The class Bryozoa osculant between the mol-
SYLLABUS, ETC.
57
luscan sub-kingdom to which it truly belongs, and the Radiate class
Polypifera, to which it bears some points of resemblance.
ON SPECIES AND VARIETIES IN THE ANIMAL KINGDOM.
116. Species defined by Cuvier to be the " collection of all the
beings descended the one from the other, or from common parents,
and of those which bear as close a resemblance to these as they
bear to each other ;" by others to be " a race of animals or plants
marked by any peculiar character which has always been constant
and undeviating." These are substantially the same, the one as-
serting what is implied in the other. May be deduced from the
law of resemblance between parent and offspring, upon which
depends the possibility of identifying species. Flexibility of this
law within certain limits, under the operation of external influences;
the results of the partial modification thus induced being then per-
petuated under the operation of the original law. Illustrations
derived from the transmission throughout a large family of pecu-
liar traits originating in a given individual ancestor, when a pe-
culiarity thus acquired becomes permanent in a group of individuals
breeding among themselves. Such a group is designated a variety.
A variety is thus a group of animals marked by the permanent
reproduction of some distinctive feature, which feature however,
may be shown to have been acquired in superaddition to, or as
a modification of the characters of the species to which the animal
truly belongs.
117. Tests of unity of species in the case of groups of animals
characterized by such permanent peculiarities as to constitute the
distinctions of varieties, (a) Historical evidence. Varieties of the
hog, of the horse, of the dog, and of horned cattle now found in
America, and known to have issued from domestic breeds intro-
duced by Columbus and his followers. Notice of the kind and
extent of diversity exhibited by these varieties as compared with
the original stock, (1) as to structural characters; (2) as to physi-
ological and psychological qualities. Habits acquired by certain
animals and then transmitted to their offspring, which thus inherit
traits originally acquired by the parent.
(b) Value of structural differences in the discrimination of spe-
cies. The peculiarities which mark a variety being liable to dis-
appear on the removal of the causes which originally produced
them, there are generally found intermediate gradations tending
to connect the most extreme varieties with each other, and with
the typical characters of the original and common stock. On this
ground, all the varieties of dogs are assumed to belong to one spe-
cies, since it is impossible to mark off the boundaries of more than
one species, by reason of the intermediate grades which connect
the extreme varieties with each other and with the wild stock
whence all have, doubtless, sprung. On the other hand a differ-
58
SYLLABUS, ETC.
ence of species is indicated " when the characters which separate
two races are transmitted with complete uniformity, when there
are no intermediate gradations tending to connect them, and when
no such tendency to variation has manifested itself in either race,
as shall make it probable, or, at any rate, possible, that their dif-
ferences may be attributed to some unusual divergence in the cha-
racters of the offspring from those of the parents." (Carpenter—
" Varieties of Mankind." (c) Value of physiological and psycho-
logical peculiarities in the discrimination of species—often a surer
criterion than structural characters. Sterility of hybrids rendering
impossible the existence of a hybrid species. Constant and uni-
form agreement among animals of the same species, but of diver-
sified varieties, as to the great laws of the vital functions, such as
those " which express the periods and duration of life, the economy
of the sexes, and the phenomena of parturition and reproduction."
Decided differences in regard to the same peculiarities among races
which, though very nearly resembling each other are yet speci-
fically distinct.
Every species characterized by the possession of instincts and
propensities peculiar to itself, so that the instincts of different,
though nearly allied species may differ remarkably, while those of
different varieties of the same species, notwithstanding very strong-
ly marked diversities of physical structure, are fundamentally the
same.
118. Application of these principles to the case of the Races
of Mankind. Setting aside the historical evidence, on account of
the doubts entertained by some naturalists as to the correct inter-
pretation of the teachings of Scripture on this point, (although the
statements of the inspired writers appear to be sufficiently explicit,
and in accordance with the inductions of science,) it is to be observed
that the peculiarities which distinguish the several races of mankind,
run into each other by changes so numerous and gradual as to
make it utterly impossible to determine the boundaries of more
than one species. No two naturalists can agree as to the number
and characteristics of the different races. Taking the Western
Europeans and their American descendants, as one extreme, and
the Bushmen of Southern Africa as the other, we find interme-
diate grades which connect these very remote extremes by gradual
transitions. Again, within the limits of a single variety there oc-
casionally appear as an accidental anomaly, traits of conforma-
tion identical with those which distinguish a different variety.
And finally, on this head, an entire race marked by certain pecu-
liar traits of conformation have, on changing their mode of life,
after some centuries lost those traits and acquired others. Three
general types, into which the varieties of the human race fall, as
regards their physical characteristics. (1) Prognathous type of
savage and hunting tribes ; (2) Type of the Pyramidal skull, found
in the nomadic and pastoral tribes ; (8) Type of the oval or ellip-
tical skull, belonging to those races that have been subjected to
SYLLABUS, ETC.
59
the influences of civilization. " Turks of Europe now exhibiting
the oval skull, are known to be descendants of the Turks of mid-
dle Asia, who exhibited the pyramidal form. So, too, the Magyars
of Hungary." " The very fact of the extensive dispersion of a
race, and of its existence under a great variety of external con-
ditions implies a marked capacity for variation ; since without such
capacity the race could not continue to flourish." (Carpenter,
loc. cit.) So far, then, as structural peculiarities are concerned,
they lead to the doctrine of the specific unity of the several races
of mankind. " The conformity among these races as to physio-
logical phenomena, furnishes a yet stronger argument; for in-
stance, the power of indefinite cross breeding, often with the re-
sult of improving the parent stock. The average duration of life un-
der the same circumstances, is the same for all; the extremes of lon-
gevity the same ; the epoch of the first and last menstruation and
the length of the intermenstrual interval, the duration of preg-
nancy, the periods of dentition, &c, &c, all point to the con-
clusion of the unity of the human species, while they establish a
specific difference between man and the most anthropoid apes.
Again, the correspondence between the different races of mankind in
j. ., respect to physical endowments, leads to the same results, all having
'. the same intuitive convictions, the same primary faculties of mind,
<■( (. the same kind of susceptibility to improvement, though, perhaps,
not always equal in degree, and the same feelings of fear or hope
in reference to a future state of existence beyond the grave.
(Prichard.)
119. In accordance wdth the terms of the definition given in §
116, it has commonly been held that all individuals belonging to
the same species must have sprung from one original pair. Thus
Latham says, " a multiplicity of protoplasts (original parents) for a
single species is a contradiction in terms. If two or more such
individuals or pairs, as like as the two Dromios, were the same
protoplasts to several classes of organized beings (the present
members being as like each other as their ancestors were,) the
phenomenon would be the existence in nature of more than one
undistinguishable species, not the existence of more than one
protoplast to a single species." (Latham—Races of Mankind.)
Notice of recent attempts to draw a distinction between unity of spe-
cies and community of origin, and to show that the several species
were originally created in the same relative numbers in which they
now exist,—that all the original individuals of the same species pos-
sessed the same essential nature, modified, however, in accordance
with the special conditions in which each was destined to exist. No-
tice of the argument of Agassiz, the leading supporter of this novel
doctrine, in supporting which he very eloquently demonstrates the
specific unity of the races. Opposite conclusions of eminent
Zoologists and Geologists. Thus, Prof. E. Forbes rejects the
whole hypothesis of the radiation of species from separate centres,
and avers "that the peculiarities in the geographical distribution
60
SYLLABUS, ETC.
of existing species are quite reconcileable with the idea of migra-
tion from single centres, and that, generally speaking, they lead
necessarily to that idea." (Carpenter, loc. cit.) So, too, Sir. C.
Lyell declares, that "there appears to be no sound objection to
the doctrine that all the leading varieties of the human family
have originally sprung from a single pair."
120. Tabular view of the leading divisions of the Animal
Kingdom.
A. Sub-kingdom Protozoa. No
positive characteristics, except such
as belong to all animals. The
distinctive character is the negative
one of the absence of a nervous sys-
tem ; no special vascular system; no
localized respiratory apparatus; gen-
ital system diffused, &c, &c.
/ 1. Class. Polygastrica. Infusorial, mi-
croscopic. Supposed to be characterized
by multiple stomachs ; but this character is
doubtful, and the class is probably not
natural.
2. Class. Rhizopoda. Mere organic cells
filled with granular semi-fluid matter, ca-
pable of altering their shape by projecting
the integuments in various directions.
Most species loricated, with root-like feet
projecting through pores in the shell.
3. Class. Porifera. Motionless andun-
irritable ; flesh supported on a fibro-cor-
neous skeleton, covered with pores and
vents.
B. Sub-kindgom Radiata or Cy-
cloneura, characterized by the pre-
sence of a nervous sj-stem which,
when discernible, consists of nervous
threads arranged in a circular form
around the mouth with radiated
branches. In some the nerves have
not been discerned, (Acrita,) but
their actions imply the existence of
such organs. Circular symmetry of
the body, or of the parts around the
mouth. Alimentary canal with its
own special walls in all except the
Hydroid Polypi. Blood-vessels first
appear in this group, at first as mere
continuations of the alimentary pas-
sages (Acalepha), but soon as dis-
tinct organs with pulsatile walls in
some places (Echinodermata), but en-
tirely wanting in most Polypifera.
Respiratory apparatus also gradually
evolved, being localized in the Holo-
thuridans as an arborescent set of
tubes. Generative apparatus, very
simple and of the monoecious type in
Polypi, rises to the dioecious type in
the other two classes. Alternate
generation.
/ 1. Class. Polypifera. Soft, inarticulate,
acrite. Of saccular form with orifice sur-
rounded by prehensile tentacula. Some-
times single ; more frequently composite,
with a common polypary partly fleshy and
partly horny or stony. Two orders, Hy-
droida and Actinoida.
2. Class. Acalepho?. Mostly acrite. Of
various shapes ; of glassy transparency and
gossamer texture, with an enormous rela-
tive amount of water ; stinging property;
phosphorescence. Four orders. Pulmo-
grada. Ciliograda. Cirrhigrada and Phy-
sograda.
3. Class. Echinodermata, with a dis-
tinctly radiate nervous system ; a contrac-
tile skin having, commonly, calcareous
plates imbedded in it. Many have prickly
spines; many also have tubular cirrhi for
locomotion ; but the class is naturally cha-
racterized by its advanced grade of organi-
zation as compared with the other radiate
classes, having a distinct vascular system
and a progressive developement of a dis-
tinct respiratory apparatus, &c. &c. Six
existing orders, as Crinoidea, Ophiurida,
Asteriada, Echinida, Holohurida and Sipun-
\ culida.
SYLLABUS, ETC.
61
C. Sub-kingdom. Mollusca or
Hetero-gangliata. Hetero-gang-
gliate nervous system. Body asym-
metrical, soft and without dermo-
skeleton, having only a muscular
skin called "Pallium" or mantle.
Whole body often inclosed in a testa
or calcareous shell, univalve, bivalve,
or multivalve. Preponderating deve-
lopment of nutritive apparatus and
great deficiency, in most cases, of
the powers of animal life. Long,
convoluted intestinal tube ; large and
active liver. Heart, found in all but
the Bryozoa, systemic except in
Tunicata, where it is alternately sys-
temic and pulmonic. Distinct respi-
ratory apparatus in all except the
class Bryozoa, and in all except the
Ascidian family of the Tunicata it
opens at or near the anus.
Multiplication by budding in the
lower classes, Bryozoa and Tunicata.
Hermaphrodism quite common a-
mong Gasteropods. All the higher
classes organized on the Dioecious
type.
D. Sub-kingdom. Articulata.
Homogangliata, or Diploneura.
Animals which exhibit the Homo-
gangliate type of nervous system;
that is a nervous system consisting
mainly of separate ganglia, which are
similarly arranged in the different
segments of the body. In general
the body is composed of similar seg-
ments, succeeding each other longitu-
dinally and by their connection pre-
senting the jointed appearance from
which the most common name (Arti-
culata) of the sub-kingdom is deriv-
ed. In the more typical forms there
is a double ganglion in each seg-
ment, the first or cephalic segment
having its ganglion above the oeso-
phagus, while the ganglia of all the
succeeding segments are ventral, or
below the alimentary canal. In the
lower forms the ventral chain of
ganglia is replaced by a double nerv-
ous cord without ganglia, and hence
the use of the term Diploneura, as
one of the synonymes of the sub-
kingdom.
f 1. Class. Bryozoa. Zoophytic mol-
lusks ; microscopic; no heart; no special
respiratory system. Single nervous gang-
lion.
2. Class. Tunicata. Low molluscans
inclosed in a leathery tunic with two ori-
fices. Single nervous ganglion. Heart
with one cavity. Respiratory chamber.
3. Class. Palliobranchiata or Brachio-
poda. Bivalve mollusks with the whole
mantle arranged for respiration.
4. Class. Lamellibranchiata. Bivalves
with respiratory organs in the form of four
lamellae between the two lobes of the
mantle. One or two muscles; three or
more ganglia. All the foregoing are ace-
phalous.
5. Gasteropoda. Under surface of the
belly, or a part of it developed into a disk
adapted for sluggish locomotion. Distinct
head bearing tentacula, eyes, oral appara-
tus, &c. Supra (Esophageal ganglion or
brain; other scattered ganglia ; one order
breathing air by means of pulmonary cham-
bers, others breathing water by localized
branchiae ; most inhabit univalve shells.
6. Pteropoda. With lateral alar appen-
dages for swimming.
1. Cephalopoda. Mouth in the centre of
a disk, surrounded by large fleshy arms.
Very large brain protected, in some species,
by a rudimental cranial cartilage.
1. Class. Entozoa, not a natural group ;
including the members of at least three
classes belonging to as many different sub-
kingdoms, but all exhibiting a tendency to
the articulate type in which the highest of
them culminate. These form the Nematoid
order, characterized by diploneurose grade
of Homogangliate type. Straight alimen-
tary tube ; a few longitudinal blood-ves-
sels ; dioecious type of genital apparatus ;
very long and convoluted ovaries; vulva
in front of the middle of the body.
2. Rotifera. Microscopic and infusorial
articulates with one or more rota; or fleshy
lobes being vibratile cilia.
/ 3. Annelida or Anncllata. Soft-skinned
vermiform articulates either entirely apo-
dal (Leech), or with only rudimental legs
in the form of unjointed setae ; nonparasi-
tic ; elaborate development of vascular
system with arteries, veins and multiple
hearts, (i. e. portions of the arteries dilated
and pulsatile); ventral chain of ganglia.
The absence of these characters in the
non parasitic Planariae causes them to be
ranked with Entozoa, leaving the Annelida
a natural class.
4. Class. Myriapoda. Articulates of
numerous similar segments, all of which,
except the two terminal ones, bear one or
two pairs of feeble but jointed legs.
^.Breathe air by tracheae.
62
SYLLABUS, ExC.
Sub-kingdom—Articulata.
tinued.)
(Con-
Some are without legs, (vermi-
form.) Some have locomotive appen-
dages to all the segments except the
two terminal ones, (myriapoda) others
have such appendages to special seg-
ments only.
Mouth sometimes suctorial, and
more or less circular, but when
armed with mandibles, maxillae, &c,
these are always at the sides and
move laterally. Every variety of
alimentary, circulatory and respira-
tory apparatus found in the different
classes of this sub-kingdom. The
dioecious type of generative appara-
tus prevails, but there are instances of
hermaphrodism in the lower classes.
Articulate classes. (Continued.)
5th class.—Insecta. Body in the embryo
state consisting of thirteen segments, which
subsequently in most species become more
or less consolidated into three regions,
namely, head consisting of one segment,
thorax of three, and abdomen of nine. In
a few there are fourteen, of which two
form the head, (Hymenoptera and Diptera.)
Three pairs of legs attached to thorax;
most have two pairs of wings; one order
has only one pair, and some orders are en-
tirely apterous. Tracheary respiration.
Vasiform heart or dorsal vessel. Blood
vessels mostly lacunar passages. Salivary,
biliary, urinary, ovarian and testicular or-
gans, all tubular; generative organs always
dioecious. Most undergo metamorphosis,
passing through the several conditions of
Larva, Pupa and Imago.
6th class.—Arachnida. Air-breathing
articulates with four pairs of legs. Head
and thorax united into cephalo-thorax; no
antennae; but very large maxillary palpi
which appear like a fifth pair of legs, espe-
cially in the Scorpionidw, or Pedipalpi. Two
orders: Pulmonaria, breathing by air
chambers, and having a well developed
vascular system ; and Trachearia, breathing
by ramified tracheae.
7th class.—Crustacea. Embracing all
water-breathing articulates with jointed
locomotive members, and divided into four
sub-classes. (1) C. Malacostraca, the soft
shelled or ordinary crustaceans, contain-
ing the familiar genera, crabs, lobsters, &c.
(2) C. Entomostraca, minute crustaceans
of stagnant water, often enclosed in bivalve
shells.
(3) C. Suctoria. External parasites;
aberrant; osculant between true Crusta-
ceans and Entozoa.
(4) C. Cirrhopoda. Soft, acephalous,
with cirrhiform arms; muscular and
mantle-like skin ; testaceous ; very aber-
rant, osculating with molluscans, but yet
distinctly articulate in the arrangement of
the nervous system, and in lateral sym-
metry with a faint indication of segmental
structure. In the larval condition it is free,
and resembles an entomostracan. When
mature, it is enclosed in a shell, and fixed
either by the fusion of its shell to the rock,
(Sessile order) or by means of a long con-
tractile pedicle. (Pedunculated order.)
SYLLABUS, ETC.
63
E. Sub-kingdom—Vertebrata, Spi-
ni-cerebrata or Myelbncephala.
Animals with a cerebro-spinal axis;
that is, a dorsal column of ganglionic
matter in one continuous cord, swell-
ing out at the anterior end into a
multiple mass called the brain ; the
whole being lodged in and protected
by a jointed bony case, composed of
a series of annular segments called .
vertebrae. Generally five senses. }
Blood always red, a character due to
the blood disks which are peculiar to
the members of this sub-kingdom.
Nutritive apparatus well developed in
correspondence with the rapid waste
of the active nervous apparatus, and
exhibiting spleen, pancreas, portal
system and absorbent system, in ad-
dition to the organs found among the
higher invertebrata. Respiratory,
circulatory and generative apparatus
variable in the different classes.
1st. class.—Pisces. Cold blooded, breath-
ing water by localized gills; circulation
single and pulmonic; body generally cov-
ered by scales: locomotion effected chiefly
by lateral flexions of the trunk and tail.
Generation oviparous, the ova being fertil-
ized after extrusion in most cases.
2d. class.—Amphibia. Cold blooded
vertebrates, which when first hatched
have the anatomical and physiological
characters of fishes, &c. Subsequently
undergo a metamorphosis, as the result of
which they acquire lungs for breathing air
and other reptilian characters. Skin
naked. Generation oviparous.
3d class.—Reptilia. Cold blooded; breath-
ing air by means of lungs. Circulation
imperfectly double, the two kinds of blood
being mixed in a single ventricle, or shortly
after issuing from two ventricles. Body
covered with scales, or else with bony
scutes. Generation oviparous. Three
orders presenting as many different types
of reptilian development, namely, Chelonia,
Ophidia, and Sauria.
4th class.—A ves. Warm blooded, breath-
ing air by lungs and disseminated sinuses,
making a double respiration. Circulation
completely double, or heart with four
cavities. Body covered with feathers ; an-
terior extremities formed into wings. Gene-
ration oviparous.
5th class.—Mammalia. Warm blooded.
Single respiration by localized but very
perfect lungs. Circulation as in birds.
Body covered with hairs ; anterior extre-
mities organized for station or for prehen-
sion, very rarely for flight, (Cheiroptera—
Bats.) Generation viviparous, or, among
the Implacentalia ovoviviparous.
64
SYLLABUS, ETC.
7 ■■'-'
SPECIAL PHYSIOLOGY.
CLASSIFICATION OF THE FUNCTIONS OF MAN.
121. The special functions are subservient to one of two pur-
poses, the well-being of the individual or the perpetuation of the rac e.
Hence the basis of a primary division into two great sections.
(I.) Those which have reference to the life of the individual be-
ing ; and (II.) Those which look to the propagation of the species.
The first of these sections sub-divided into two subordinate classes,
viz.: (1) Those which are subservient to the development, growth
and maintenance of the fabric, and which are therefore termed
nutritive or vegetative functions, or the Functions of Organic
Life; and (2) those which serve to establish relations between the
individual and the surrounding world, or Functions of Relation
which, being peculiar to animals, are also called Functions of
Animal Life. The second great section, embracing the Func-
tions of Reproduction, as executed by man and other higher
animals, both vertebrate and invertebrate, will admit of a similar
binary sub-division ; but inasmuch as the essential part of these
functions is exclusively organic, it will be convenient to class them
with the nutritive functions pertaining to individual life under the
general term, functions of organic life.
A.—functions of organic life.
I. Functions of Reproduction or Generation.
122. These consist (1) of acts executed by parents of different
sexes, and which, although in man and the higher animals gene-
rally they involve incidentally the co-operation of animal func-
tions, are yet organic in their essential nature, as they are ex-
clusively so in lower animals and in all plants. (2) Of a series
of intra-oval and intra-uterine developments constitutinc the evo-
lution of the embryo.
II. Functions of Nutrition or Assimilation.
These consist in a series of acts whereby crude alimentary
matter is converted into pure arterial blood, and the several parts
of the fabric are developed and maintained at the expense of the
blood, with certain incidental phenomena important to the in-
SYLLABUS, ETC.
65
tegrityof the system. (1) Digestion; (2) Chylosis; (?>) Hsema-
tosis ; (4) Respiration as a means of the ingestion of oxygen ;
(5) Circulation; (6) Secretion; (1) Nutrition; (8) Respiration as
a means of excretingcarbonic a/rid; (9) Urinary, Biliary, Cutane-
ous and other excretions ; (10) Calorification.
B.—FUNCTIONS OF RELATION, OR OF ANIMAL LIFE.
These include the functions of the nervous system and the
actions of those muscles which in respondence to nervous stimu-
lation effect the different movements of the trunk and its appen-
dages. By the instrumentality of these acts even in the lowest
grade of their manifestation, the simplest animals, save only
those unconscious organisms called Protozoa, are brought into re-
lation with the external world in two ways, (1) by receiving and
feeling impressions of external agents on the organs of sense
(sensorialfaculty), and (2) by reacting on external objects by means
of the muscles and bones, under the stimulus of a nervous force
generated by the will (volitional exercise of the motorial faculty),
or else excited by a prior action of an impressed nerve indepen-
dently of either consciousness or volition. (Physico-reflex ex-
citement of the motorial faculty.) In this connection are to be
noticed the phenomena of animal instinct, and the connection be-
tween the mind and the brain as its instrument.
FUNCTIONS OF ORGANIC LIFE.
I. FUNCTIONS OF GENERATION.
123. Reasons for commencing the course with the consideration
of this subject. Statement of certain general laws of genera-
tion. (1) Omne vivum ex ovo—proof of this law. (2) Law of
resemblance between parent and offspring. Qualifications of this
law. (a) Admissibility of variations, so as to form varieties within
the limits of species, when the variations are inherited and trans-
mitted to a group of individuals which are isolated from those of
the same species that do not exhibit the same peculiarities, (b)
The phenomenon of "alternate generation" another apparent
exception. Statement of examples and true interpretation of
the phenomena.
(3) Susceptibility of multiplication by budding (gemmiparous
reproduction) and by spontaneous division (fissiparous), exhibited
by certain low organisms. But in such cases it would seem that
developmental power is expended, and the race would be annihi-
lated after a time, unless this power were renewed in some other
way, as (4) True Generation, which seems always to require the
66
SYLLABUS, ETC.
union of the contents of two cells, the female or germ cell,^ and
the male or sperm cell, whether these be found in the same indi-
vidual (Monoecious, Hermaphrodite, or Androgynous type), or in
different individuals (Dioecious type). Three principal modes of
effecting this union observed in the vegetable kingdom, but only
one in the animal world.
124. Action of the Female in Generation.—Essential element
of the female generative apparatus a cell of peculiar endowments,
the " Germ Cell." Diffusion of such cells as also of the male or
" Sperm Cells," in a few of the lowest animals, with whom mul-
tiplication by budding or by division may present the conditions
of true generation. Germ cell, under the name of germinal
vesicle, with its germinal spot in its centre, is found in the centre
of a mass of oily and albuminous matter, called vitellus (yolk),
inclosed in a thick membrane, the membrana vitelli or zona pel-
lucida, the whole structure being termed ovule, or when fertilized,
ovum. Ovarium, any special arrangement of tissues for the de-
velopment of ova. Oviduct, tube for extrusion of mature ova.
TABULAR VIEW OF THE VARIETIES OF OVARIES.
125. (1) No true ovarium, ova being developed throughout the
general parenchyma, as in the Porifera or Sponge tribe.
(2) Ova developed in a mass in particular localities, but without
any special arrangement of the tissues; as at the base of the body
in the genus Hydra, the sperm cells being developed near the base
of the tentacula.
(3) Ova developed in the substance of a simple membrane, not
arranged into a tube or sac, and when mature, being discharged
first into the general peritoneal cavity, whence they issue by
various means ; as in the Actiniform Polypi, Eels, Lampreys,
Frogs, $c.
(4) Ova developed in the substance of a membrane forming the
walls of cylindrical tubes, into which the ova are received when
mature, by a rupture of the enveloping membrane. Echinoder-
mata and most Entozoa, §c.
(5) Similar in form to the last; but the tubes are very dilatable,
and when distended with ripe ova are large sacs. Insects, Arach-
nidans, Crustaceans, Osseous Fishes, §c, §c.
(6) Similar to the last, except that the ova are developed in
masses suspended by narrow pedicles to the walls of the sac, like
bunches of grapes. Cephalopod Mollusks.
(7) Ova in various stages of maturity developed in ovisacs in
racemose branches without any tube, being merely bound down by
the peritoneum and a little areolar tissue. Reptiles and Birds.
(8) Ova developed in ovisacs which are lodged in the meshes of
a fibro-areolar stroma, and the whole covered by peritoneum.
Mammals.
SYLLABUS, ETC.
67
VARIETIES OF OVIDUCTS.
126. The three first named varieties of ovaria require no oviduct,
if we except only the special arrangement in frogs, described
below (number 2); the ova in other cases being voided directly
from the place of original development, or after being discharged
into the peritoneal cavity they escape by slits at or near the anus.
(1) Oviduct a simple continuation of the tubular or saccular
ovaria, with, in some cases, a special dilatation for the temporary
detention of the ova, in order to. receive a mucus covering, or to
be fecundated by means of sperm previously received into such
spermotheca. This variety of oviduct is found in connection with
varieties (4), (5), and (6) of ovaria.
(2) Special oviduct with trumpet-shaped orifice at some distance
from the ovaria, so that the ova have to pass through the interve-
ning space in the peritoneal cavity; oviduct opening into cloaca.
Frogs.
(3) Similar to the last, except that the dilated orifice of the
oviduct lies near the ovarium, and applies itself around the mature
ovum when the latter is about to be discharged. Reptiles and
Birds.
(4) Somewhat similar to the last in its relation with the ovarium,
but the two oviducts now called fallopian tubes present dilatations
in their course, such as one or two uterine cavities, in which the
ovum is retained in order to establish a secondary connection with
the maternal system, and a vaginal canal or organ of copulation.
Mammals.
127. Structure of the ovarian or unfertilized ovum in oviparous
vertebrates. Large amount of vitellus, of which a small portion
near the germinal vesicle is lighter and less opake (Discus Vitel-
linus) and probably corresponds with the whole vitellus of the ma-
malian ovum. Ovisac. " White" of,the egg; membranaputaminis ;
shell.
128. Characters of the mammalian ovule. Graafian vesicle of
two layers, the external being the condensed vascular stroma, the
internal a non-vascular ovisac; membrana granulosa; Discus
Proligerus. Dimensions of human ovum. Zona Pellucida or
vitelline membrane ; vitellus ; germinal vesicle and germinal spot.
Development of the several constituents of the ovum. Changes
in the ovum and ovarium preparatory to fecundation. Sympathetic
actions of the uterus. Phenomena of "heat" in brutes, and of
menstruation in the human female. Analogies between these phe-
nomena; their dependence on the maturation and discharge of
unfertilized ova and other correlative ovarian changes. Difference
between the corpus luteum of the virgin and that belonging to the
condition of pregnancy.
129. Male Sexual Functions.—The only essential part of a
68
SYLLABUS, ETC.
male apparatus of generation is an organ for the development of
the male or sperm cell, the union of which with the germ cell is
an indispensable condition for the formation of a body endowed
with developmental capacity; accordingly, in very low animal
organisms the male apparatus, as simple as that of the female,
consists in a mass of sperm cells developed in the general paren-
chyma and escaping like any other excretion. But in higher
beings, parts are superadded for conveying outwardly the sperm
cells, the product of the secretion of particular glands called
Testes ; and in very many animals for injecting this product into
the vaginal passage of the female by means of an erectile organ of
intromission. General view of the whole apparatus in man;
sensible characters of the seminal liquid; microscopic characters
and development of spermatozoa. Their true nature in relation
to the process of fecundation. Reasons for believing that fecun-
dation is accomplished in the outer part of the fallopian tube rather
than in the ovary or in the uterus.
130. Development of the Embryo.—Changes in the ovum
immediately subsequent to a fecundating copulation and while the
ovum is yet in the fallopian tube. Changes of the ovum within the
uterus, divided into three stages. (1) Changes prior to the forma-
tion of the omphalo-mesenteric vessels. (2) Development of the
allantois as a temporary organ of aeration of the blood of the
embryo, and representing the only vascular connexion which is
established between the maternal system and the embryos of non-
placental mammalia. (3) Changes connected with and subsequent
to the development of the placenta.
SUMMARY RECAPITULATION OF THE PHYSIOLOGY OF GENERATION.
131. A. Assignment of organs in each of the sexes, with a speci-
fication of the uses of each part of the complicated apparatus in
the human species. B. Explanation of the function ; (a) to assign
proximate cause ; any and every formative or developmental ope-
ration in a living organism involves the necessity of a threefold
condition ; (1) a germ or body which is to undergo development;
(2) alimentary or nutritive materials at the expense of which the
fabric is built up ; and (3) certain dynamical stimuli, such as a proper
temperature and degree of moisture, &c, &c. But the germ must
be endowed with developmental power; and three theories have
been maintained with regard to the origin of such germinal capacity;
some supposing that it resides inherently in the germ-cell, and
only requires to be stimulated by the seminal liquid, which is thus
held to act like heat or any other mere dynamical stimulus
(ovarists); others asserting that the developmental capacity resides
exclusively in the sperm-cell; and that the germ-cell as well as its
vitellus is to be regarded as a mass of peculiar nutriment that also
SYLLABUS, ETC.
69
acts as a dynamical stimulus, (Animalculists); while a third and
now generally accepted theory termed Epigenesis, maintains that
neither parent furnishes a complete germ, but that the latter is
formed or generated by the conjugation of elements derived from
both. ^ This appears to be demonstrated by the phenomena of
Hybridity.
(b) To assign exciting causes. The developmental capacity with
which a duly formed germ is endowed by the act of conjugation
between the germ and sperm-cell, is not manifested as & force, that
is, the developmental changes do not take place, except under
certain favoring conditions, which are therefore termed stimuli or
exciting causes, of which heat and oxygen are especially neces-
sary. In viviparous animals, these, as well as nutritive materials,
are abundantly supplied in the maternal system and immediately
after fecundation. In warm blooded oviparous vertebrates, a
small amount of change takes place in the maternal system, but
the ova being soon extruded, the process is arrested for want of
the requisite heat until this is subsequently applied either artificially
or by natural incubation. In cold blooded ovipara the animal heat
of the parent is seldom sufficient and the ova have to be subjected
to the influence of solar heat more or less directly.
(c) Laws.—In addition to the laws already stated (§ 123), we
note the following, which apply to the human species. (1) Ova be-
come mature and are discharged periodically from the ovary, inde-
pendently of fecundation and coinciding with the catamenia. (2)
Fecundation cannot, it is probable, occur in the ovary nor in
the uterus, but must be accomplished in the fallopian tube. (3)
There is an intermenstrual epoch at which fecundation is almost or
quite impossible, namely, ten or twelve days after one menstrual
period to within a few days, perhaps, of the next. (4) Fecunda-
tion is most likely to occur at or near a menstrual period.
(d) Final cause—to perpetuate the species.
(e) Local and general sympathies. Morning sickness in the
earlier stages of pregnancy ; areola around the nipple; kiestine
in the urine; and certain later phenomena, the consideration of
which belongs to the subject of Practical Midwifery.
II. NUTRITIVE OR VEGETATIVE FUNCTIONS.
132. Necessity for the execution of this class of functions, (1)
from the instability of the chemical compounds which constitute
the proximate components of the tissues, by reason of which
they are constantly undergoing decomposition, and require to be
replaced by new material. (2) The more rapid and abundant
waste which is one of the conditions of the actions of the organs
of animal life, by reason of which no nervous or muscular fibre is
equally fit for two successive actions unless it have regained in
70
SYLLABUS, ETC.
the interval what it lost by the first action. The raw material for
this restoration is obtained from without in the form of food, and
has to undergo a series of changes before it can be used for such
purposes ; and these several changes are the results of the several
nutritive operations. These are (1) Digestion ; (2) Chylosis ; (3)
Haematosis; (4) Respiration as a means of absorbing oxygen ; (5)
Circulation ; (6) Nutrition proper ; (7) Secretion ; (8) Respiration
as a means of excreting carbonic acid ; (9) other purifying excre-
tions ; (10) Calorification.
FUNCTION OF DIGESTION.
133. Definition.—Enumeration of the subordinate acts, namely,
(1) Prehension; (2) Mastication ; (3) Insalivation ; (4) Degluti-
tion ; (5) Chymification or action of the stomach; (6) Intestinal
digestion or action of small intestine, and (7) Defecation or action
of large intestine. Brief statement of the character of each.
134. Organs concerned in the execution of this function as
exhibited in different classes of animals. (1) Animals without
any special digestive apparatus, and either absorbing food which
is already sufficiently comminuted, or else having their whole
tegumentary surface capable of secreting a digestive juice ; as the
Sponge tribe.
(2) Animals without any permanent stomach, which when feed-
ing bend themselves around their food, and make an extempora-
neous stomach of their skin : as the Amoeba, a naked Rhizopod.
(3) The entire animal a mere self-moving stomach with a single
orifice surrounded by prehensile tentacula, as the Hydra.
(4) Similar to the last, except that the stomach is suspended in
a peritoneal cavity. Actiniform Polypi.
(5) Stomach with radiating tubes for diffusing the digested mat-
ters, and thus increasing the extent of absorbing surface. The
tubes are either coecal, admitting only chylific matter, the excre-
mentitious portion of the food being retained in the central cavity
to be ultimately ejected either at the mouth (star-fish,) or by a
separate anus at the opposite end of the body, (some annelidans),
or some of the radiating tubes themselves terminate in anal open-
ings (Pulmograde Acalephans.)
(6) Alimentary canal of some length, commencing by a mouth
at one end, and terminating by a single anus at the other. The
tube may be bent upon itself so as to bring the anus near the
mouth, as in Molluscans; mouth sometimes organized for suction,
but most frequently adapted for cutting, filing, or trituration by
means of horny Mandibles and jaws, or by means of a special
dental apparatus found in a few invertebrates, and in all verte-
brates, except Birds and Chelonian Reptiles: anus guarded generally
by a sphincter muscle; intervening tract generally divided into
gullet, stomach, small and large intestine. Glandular appendages, as
SYLLABUS, ETC.
71
salivary, gastric, biliary and pancreatic glands secreting fluids that
are subservient to digestion. Follicles of Lieberkuhn secreting a pro-
tective mucus, andPeyer's glands, organs of depuratory excretioD.
135. Changes of the food effected in the Mouth. Mastication, its
mechanism and its uses; difference in function between the separate
classes of teeth. Indications furnished by the character of the teeth i
in man of his adaptation for an omnivorous diet. In salivation ;—-4^
sensible and chemical characters of saliva ; rate of secretion. Its ■
manifold uses in digestion, and especially its influence in trans-
forming starch into dextrine and grape sugar.
136. Passage of food into the stomach. Three stages of deglu-
tition ; mode of protecting the Larynx and the posterior nares
during the passage of food through the fauces in the second stage.
137. Chymification or Digestion in the Stomach. Structure of
the stomach in man, and especially the minute structure of its mucous
membrane and of the gastric glands; sensible and chemical char- --f-j
acters of the gastric juice ; circumstances under which it is secre-
ted normally; stimuli which increase or diminish the amount; its
effects on alimentary substances substantiated by experiments on
artificial digestion; nature of the change which albuminous food
undergoes; mechanism of the movements of the stomach and
their uses.
138. Influence of the nervous system on gastric digestion. This
is threefold; (1) in giving rise to the sensations of hunger and
thirst which induce to the taking of food; (2) in influencing the
secretion of gastric juice as to its amount, and probably also as to
its quality, either directly, or indirectly through the sympathies of
the stomach with the organ of taste more especially ; (3) in deter-
mining the movements of the stomach and the passage of food
into or from this organ.
139. Changes of food in the Intestines. Structure and secre-
tions of the intestinal tube; Brunner's glands ; follicles of Lie-
berkuhn ; Peyer's glands; Pancreas and its secretion; Liver and
its secretion ; influence of these several agents in digestion ; two-
fold nature of the biliary secretion as a digestive agent and a
depuratory excretion ; changes of the food in the large intestine ;
movements of the intestinal tube; defecation, &c, &c.
Summary recapitulation of the Physiology of Digestion.
140. (1) Digestion of Albuminous or Proteinaceous food, which
by the action of the stomach is converted into a low kind of
albumen, being at the same time dissolved. Explanation of
this act by Muller, who ascribes the solvent property to muriatic
acid, the pepsin being held to act as a dynamical stimulus; Liebig's
theory, who compares the phenomenon to one of fermentation, the
pepsin acting the part of a ferment. Another stage of the diges-
tive acts accomplished in the intestines; precipitation of the un-
digested particles of food by the influence of bile, some of the
72
SYLLABUS, ETC.
constituents of which unite with the precipitated mass to consti-
tute the Faeces, the others uniting with dissolved albumen and with
fat in emulsion to form chyle. The preliminary processes serve
to put the food into more advantageous relation with the gastric
juice.
(2) Digestion of fatty aliments. Not a chemical but a mechani-
cal change; an emulsion formed under the influence of Bile and
Pancreatic Juice in the small intestine; in the stomach they are
melted, and if taken as adipose tissue the fat cells are ruptured.
(3) Digestion of the neutral Hydro-Carbons. Gum, sugar, &c,
very soluble, hence their gastric digestion would appear to be a
simple solution. After being absorbed by the Portal veins they un-
dergo a chemical change in the Hepatic circulation, being con-
verted into the fatty elements of Bile, at least in part. Starch,
on the contrary, being entirely insoluble undergoes a true di-
gestion in the alimentary passages, being converted under the in-
fluence of the saliva swallowed with it, into dextrine and sugar.
Final causes of Digestion. A. Special and immediate ; (1) to dis-
solve solid aliments ; (2) to convert certain organic compounds
into others of similar chemical composition ; (3) to separate the
insoluble ingredients by precipitation. B. More remote final causes
of digestion, or sources of demand for food; (1) to build up the
fabric from the condition of infancy to that of maturity ; (2) to
supply the constant waste connected with ordinary nutrition ; (3)
to supply the more rapid waste connected with the action of the
muscular and nervous apparatus; (4) to furnish fuel for respira-
tory combustion; (5) to supply extraordinary expenditures such
as occur in pregnancy, lactation, haemorrhages, profuse suppura-
tion, &c, &c. For one of these purposes, that namely of main-
taining the animal temperature, the nonazotized aliments, whether
fats or neutral Hydro-carbons will suffice. For all the other uses
we require plastic albuminous compounds.
DIFFERENT DIETETIC QUALITIES OF FOOD.
141. (1) Digestibility or facility of undergoing digestion, measu-
red by the mean time of digestion in a given amount of gastric juice.
But of two substances, one which is less digestible intrinsically may
yet be soonest digested in the living stomach, because it may by
its sapidity or stimulating character provoke a more abundant
supply of gastric juice. Intrinsic digestibility dependent chiefly
on the physical properties of the food ; actual digestibility largely
dependent on the physiological relations of the food with the
living system..
(2) Nutritiousness. Absolute nutritiousness measured bv the
percentage of plastic or proteinaceous matter in the "food.
But the virtual quality depends on the amount duly digested
and assimilated. Hence that which is absolutely richest in nutri-
ment may be the least nutritious in point of fact because the least
SYLLABUS, ETC.
73
digestible. Hence too the actual nutritiousness of the same ele-
ments varies according to the state of the digestive organs.
(3) Calorifacient property. The absolute capacity measured
by the percentage of alimentary fuel, that is of free carbon and
hydrogen, which food contains. But some hydro-carbonaceous
compounds being less easily digested than others, may be virtually
less calorifacient though absolutely richer in combustible elements,
since these must be digested before they can be burnt off.
(4) Sapidity. Different kinds and degrees of this property;
highly important with reference to the actual digestibility of food,
by reason of the sympathy between the organ of taste and the
stomach. Hence the value of indirect condiments. Direct condi-
ments ; danger of using them too freely.
(5) Irritating property. That which causes the morbid con-
dition termed Irritation; for example the gastralgia or enteralgia
caused by green acid fruit, cabbage, kc. Some articles of diet
as mucilage, fyc, are entirely devoid of this quality and are even
positively soothing.
(6) Stimulating property. Or the power of stimulating the
system irrespective of the excitement that may be due to defective
digestion, or to excess of nutrition or to local irritation. Pheno-
mena remotely analogous to the effects of alcoholic drinks. Lobster,
Crabs, &c, sometimes stimulate in this way.
ALIMENTARY PRINCIPLES.
I. Class—Aliments which are calorifacient but aplastic.
142. (1) Gum=C H O. (2) Sugars; cane sugar=C H 0
12 n n 12 n n
sugar of milk =C H 0 and grape sugar =C H 0. (3) Starch
n 12 12 12 M 14
= C H 0. (4) Lignine or woody fibre=G HO. (5) Pectine
12 10 10 12 8 8
and Pectic acid= C H 0. (6) Vegetable acids, as acetic, citric,
12 8 10
tartaric, malic and oxalic acids. (7) Oily or fatty matters, as
oleine, margarine, stearine, &c. (8) Alcoholic principle=C H 0.
II. Class—Plastic or nutritive alimentary principles.
143. (1) Proteinaceous principles. Three varieties all of which
are found in both the animal and vegetable kingdoms. Proteine,
artificially prepared=C H N 0 . Fibrine=10 Pr. + P-f S.
40 31 5 12
Albumen=10 Pr. + P + S . Caseine=10 Pr. + S.
2
(2) Gelatinous principles. Two varieties, Collin or Gelatine
74
SYLLABUS, ETC.
proper, and Chondrin. Sensible and chemical characters; doubt-
ful dietetic qualities.
(3) Alimentary principles contained in the juice of muscular
flesh. AsKreatine; Kreatinine; Inosinic acid; Lactic acid, &c,
which are probably both condiments and elements of nutrition.
III. Class—Inorganic alimentary principles.
144. (1) Water. (2). Saline alimentary principles. Chlorides
of sodium and potassium, alkaline phosphates, sulphates, lactates
and carbonates, all of which are soluble, and phosphates of lime and
magnesia which are insoluble. Inasmuch as iron is a necessary
ingredient of the blood, some of its salts must be contained in
our food; otherwise disease ensues, which can only be relieved by
the administration of ferruginous tonics.
145. Changes of food produced by the different culinary pro-
cess. (1) Boiling ; difference of effect according as the meat is
plunged into water already boiling, or into cold water which is
gradually raised to the boiling temperature. (2) Roasting. (3)
Broiling. (4) Baking: (5) Stewing. (6) Frying.
COMPOUND ALIMENTS.
I. Animal Food.
146. (1) Mammalia furnish a number of solid tissues for the
food of man, while the milk of a few species, especially the cow,
is also employed. The most important is muscular flesh streaked
with fat, containing fibrine, albumen, gelatine, and the sapid
juice. Bones, fibrous tissue, cartilage, brain, liver, kidneys,
pancreas, thymus gland, stomach of ruminants, (tripe) and skin
are likewise used. Notice of the principal kinds of meat, beef,
veal, mutton, lamb, pork fresh and cured, &c. &c. Composition
and dietetic qualities of cow's milk; composition and dietetic
qualities of cheese.
(2) Birds.—Muscular flesh, viscera and eggs; dietetic qualities
varying with the species.
(3) Reptiles.—Eggs and flesh of several species of the Chelonia
highly esteemed, but they are rich, stimulating and often irritating.
(4) Fishes.—Smaller species eaten whole ; of the larger, all the
viscera except the ovaria (roe), are rejected; dietetic qualities
varying with the species; very irritating, or even poisonous when
not fresh.
(5) Crustaceans.—Lobster, crab, shrimp, prawn, &c, have a
white firm flesh difficult of digestion; apt to irritate, highly
stimulating.
(6) Molluscans.—Oysters, clams, snails, &c, &c, nutritive and
stimulating, but often difficult of digestion, j
SYLLABUS, ETC. 75
II. Vegetable Food.
147. (1) Farinaceous or amylaceous vegetables.—Two varieties ;
(a) the cereal grains, as wheat, rye, barley, &c.; composition of
wheat flour. Unfermented bread. Fermented bread; mode of
preparation; liability to turn sour, &c. Why stale fermented
bread is more Avholesome than hot or fresh bread, (b) The legu-
minous seeds, as peas, beans, &c, containing besides starch, a large
amount of legumin (vegetable caseine), but deficient in some of
the important saline principles, (c) Under the head of farinaceous
aliments ought to be included some tubers, such as the Irish potato,
because of the large amount of starch which they contain.
2) Oily seeds. Almonds, hazelnuts, filberts, walnuts, &c, &c.
3) Fleshy fruits. Apples, peaches, plums, pears, apricots,
cherries, &c, &c, &c.
(4) Vegetable roots and tubers. Turnips, parsnips, carrots,
beets, &c, &c.
(5) Buds and young shoots. Onions, shallots, asparagus, &c, &c.
(6) Leaves and leaf stalks. Cabbage, cauliflower, broccoli,
lettuce, &c, &c.
(7) Fungi or mushrooms. Most species poisonous, even the
edible species are difficult of digestion and when digested are very
stimulating.
III. Liquid compound aliments.
148. (1) Mucilaginous drinks, or solutions of many of the varieties
of Gum; demulcent and calorifacient; but may turn sour, espe-
cially when flavored with sugar. Gum Arabic; slippery elm;
flaxseed ; barley water ; Mexican seed; toast water; varieties of
gruel.
(2) Aromatic or astringent drinks.—Tea; its composition and
physiological effects. Coffee ; chocolate ; cocoa; broma.
(3) Acidulous drinks.—Lemonade; tamarind water; straw-
berry acid, &c, &c.
(4) Animal teas, containing only the juices of meat separated
from the flesh previously finely divided, by long simmering in
water kept a little below the boiling point, in order to avoid a
solution of the gelatine; as beef tea, chicken water, &c.; sapid,
easily absorbed and probably nutritious.
(5) Soups have dissolved gela'tine for their basis, and there-
fore the flesh must be boiled. Portable soup or stock; dietetic
qualities of soups.
SYMPATHIES OF THE DIGESTIVE ORGANS.
149. State of the system coincident with the feeling of natural
76
SYLLABUS, ETC.
hunger and thirst. Debility and diminished action of all the
organs except those concerned in absorption, which process being
physical and dependent on the state of the blood-vessels as to
fulness, is more actively performed. Hence danger of exposure
to malaria on an empty stomach. Diminution of bodily tempera-
ture ; diminution of secretions ; but the gastric and salivary glands
are in a condition to respond actively on the first application of a
normal stimulus.
150. Phenomena of prolonged fasting and starvation. May be
conveniently divided into three stages or degrees. (1) Intense
feeling of hunger; sense of great debility, which is, however,
mainly sympathetic. (2) Dragging pain at epigastrium ; dryness
of throat and fauces ; acidity of saliva; urine scanty and acrid ;
redness of the eyes, &c, &c. (3) Phenomena which precede death,
varying according as the demand is most urgent for plastic or calori-
facient food. In the former case furious delirium succeeds the
phenomena above mentioned. In the latter the proximate cause
of death is depression of the animal temperature, and is attended
by a passive quietness and torpor in striking contrast with the
fierce excitement characteristic of the death from want of plastic
nutriment.
151. Physiological effects of healthy digestion.—Feeling of sat-
isfaction and increased strength; glow at the epigastrium radia-
ting over the system ; slight increase in the heart's action and the
energy of respiration; organ of taste loses some of the keenness
of its susceptibility; deglutition becomes more difficult; limit to
the quantity of saliva and gastric juice.
152. Physiological effects resulting from the habitual use of
aliments defective in quantity or quality. See Carpenter's
Elements, § 416 to § 421.
153. Physiological effects of overloading the stomach. Sensation
of painful distension ; nausea; torpor; chilliness, or perhaps fever ;
liability to irritation, which is soonest relieved by an emetic of warm
water, if the offending substance had not passed the stomach, or
by an active purgative if it had.
154. Physiological effects resulting from the frequent or habitual
digestion of more food than is needed for the wants of the system.
—These vary according as the excess consists, (1) of albuminous
or plastic food. (2) Of fat, or substances convertible into fat.
See Carpenter, loc. cit., § 421—§ 426.
VARIETIES OF DIET AS SUITED TO DIFFERENT CLASSES OF INVALIDS.
155. (1) Cooling and abstemious regimen. Often required in cases
of fever, &c. ; acidulous drinks; but their irritating qualities must
be guarded against wherever there is liability to gastric or intestinal
irritation.
SYLLABUS, ETC.
77
(2) Soothing or demulcent diet ; required when the alimentary,
urinary or respiratory passages are irritated or inflamed; such as
the different mucilaginous drinks. See § 148.
(3) Light plastic diet, which shall tax the digestive powers but
little, and yet subserve nutrition. Animal teas ; water crackers ;
stale bread ; boiled milk, &c.
(4) Ordinary diet.
(5) Generous or rich diet.—Boiled eggs ; tender and juicy
meat broiled or roasted ; oysters, especially if roasted ; porter or
ale ; for persons reduced by profuse suppuration, loss of blood,
lactation, &c, who yet have good powers of digestion.
(For a full exposition of the proper dietetical rules as to the
most suitable times of eating, the quantity to be taken at a meal,
the character of the different meals, the condition to be observed
before and after eating, and the due regulation of the bowels, the
students are referred to the admirable treatise of Andrew Combe on
"Digestion and Dietetics")
FUNCTION OF CHYLOSIS AND LYMPHOSIS.
156. Definition and enumeration of organs concerned.—(1) In-
testinal villi, containing each a loop of lacteal vessels and a group
of absorbent cytoblasts, which during absorption become developed
into cells. (2) Lacteal and other lymphatic vessels with their
appended glandulee especially the mesenteric. See Carpenter's
Elements, § 489 to § 505.
157. Explanation of the Function___The term chylosis ex-
pressive of a double act; (1) the passage of soluble matters from
intestinal canal into the lacteal vessels. (2) The transformation
of the digested but yet unvitalized matters into living chyle. So
also for lymphosis. Notice of the phenomena exhibited during the
execution of the function by different vessels, as (1) by the lacteals.
(2) By other lymphatic vessels. (3) Properties of chyle and
lymph. (4) Office of the lacteal and lymphatic vessels and glands.
(5) Absorption by the veins. See Kirkes '
PHYSIOLOGY OF THE SENSORY GANGLIA.
208. Comparative anatomy of the Encephalon.—(1) Fishes.
Four ganglionic masses, namely, from before backwards, olfactory
ganglia, cerebral ganglia, optic ganglia and cerebellum. The
cerebrum of most fishes probably homologous with the corpora
striata of man, and not with the true cerebral hemispheres.
(2) Reptiles.—Cerebrum larger than any of the other ganglia,
and consists of true cerebral hemispheres developed over the corpora
striata with lateral ventricles between them. Cerebellum of variable
dimensions.
(3) Birds.—Cerebrum very much larger than the other masses
covers in the olfactory and in part the optic ganglia also. Ceie
bellum large and striated.
(4) Mammals.—Cerebrum still larger, covering entirely the
optic as well as the olfactory ganglia, and in part also the cere-
bellum, which in man alone is completely covered by the cerebrum.
In all but the Implacentalia the two cerebral hemispheres are con-
nected by the great transverse commissure called the corpus
callosum.
209—Enumeration of the sensory ganglia.—(1) Olfactory—(2)
optic, (Tubercula Quadrigemina). (3) Auditory, (a mass of vesi-
cular matter at the roots of the auditory nerve on the floor of the
Uh ventricle. (4) Gustative, a small mass of cineritious substance
at the root of the glossopharyngeal nerve into which a part of the
sensory root of the 5th pair may also be traced.) (5) Ganglion of
common or tactile sensibility. The optic thalami, receiving the
greater part if not the whole of the sensory tract coming up from
the medulla oblongata, probably stand in the same physiological
relation within the nerves of common sensibility which obtains
between the other sensory ganglia and the nerves of the special
senses. # Carpenter associates the Corpora striata with the optic
thalami;^ but it is more probable that they are independent centres
of motorial power, having a connection with all the sensory ganglia
through which they are commonly excited. The muscular actions
of man being chiefly guided by tactile sensations, especially those
seated in the muscles themselves, the corpora striata have a closer
SYLLABUS, ETC. qo
connection with the optic thalami than with the ganglia of snecial
sensation. F
210. Functions of the sensory ganglia.—(1) Centres of Sensa-
tion, but not of Perception, the former being wholly a subjective
process, while by the latter the mind takes cognizance of objective
realities. (2) But the sensory ganglia, (or rather, perhaps, the
corpora striata connected with them) are also centres of motor in-
fluence which is reflected involuntarily in respondence to sensorial
impressions (consensual or sensori-reflex acts). 3. And further
the sensory ganglia exercise a sort of control over even the vol-
untary movements in so far as sensations are necessary to guide
the will as to the extent and direction of its action. Examples
stated and explained. Such operations are wholly different from
the simple sensori-reflex phenomena and ought not to be confounded
with them under the common term "consensual," as Carpenter
seems to have done.
211. Proof of the assigned functions.—(1) Effects of removing
the cerebral hemispheres, so as to show that the power of sensation
may be retained. (2) Effects of removing any one of the sensory
ganglia in permanently destroying the sensibility peculiar to its
action and temporarily impairing the motorial powers. The im-
pairment consists not in the loss of the control of the will over any
muscle, but in an inability on the part of the animal to regulate
its actions so as to maintain steadiness of gait. Examples cited
and explained.
212. The animal Instincts are assigned by Carpenter to the
sensory ganglia on the following grounds. (1) The instinctive
acts are involuntary, and are performed in immediate respondence
to sensations, that is, they are consensual. (2) The animals most
remarkable for the variety and scope of their instincts, namely,
the class of insects, have no cerebral hemispheres, their supra-
cesophageal ganglia corresponding to the sensory ganglia of ver-
tebrates. But the definition of Instinct implied in the first of
these statements leaves out of view that which is in fact its very
essence, namely the peculiar mental impulse that prompts animals
to perform acts (often involving a complicated series of voluntary
as well as of involuntary movements) subservient to their own well-
being or that of their unborn progeny, but exhibited under such
circumstances as to preclude the idea that they could possibly for-
see such result. There is an admirable adaptation of means to secure
useful ends, but the adaptation is contrived not so much by the
animals as for them. And yet, though the instinctive propensity be
thus implanted, the acts whereby the propensity is gratified may be
and often are strictly voluntary in the physiological sense of the
term. The peculiar instincts of animals are, therefore, to be con-
trasted, not with the volitional power, but with the reasoning facul-
ties, by which man compares, judges, discriminates and adapts
means to secure a forseen end. Tests of instinct as contradis-
tinguished from reason. (1) The uniformity of the means by
94
SYLLABUS, ETC.
which animals of the same species accomplish the same ends, even
where they have been secluded from the moment of their birth from
all intercourse with their fellows, and often too when a change of
circumstances has rendered such means nugatory. (2) The per-
fection of the adaptation which often defies all attempts at successful
rivalry on the part of reasoning man, this perfection being attained
without previous training.
Thus the instincts of animals have more points of analogy with
the intellectual and moral faculties than with the animal faculty of
sensation, and hence it is presumable that they are located in the
cerebral hemispheres rather than in the sensory ganglia. Nor is this
conclusion invalidated by Carpenter's second proposition, for if it
be shown that certain insects manifest some degree of intelligence,
his anatomical doctrine of the non-existence of cerebral hemis-
pheres in this class of animals falls to the ground. Examples
cited from Alison (Cyclopedia of anatomy and physiology) Kirby
and Spence, Huber and others, of acts executed by bees, ants, &c,
which have all the distinctive characteristics of reason.
FUNCTIONS OF THE CEREBELLUM.
213. (1) Comparative development of the organ in the different
vertebrate classes. (2) Effects resulting from the removal of one
or both lobes of the organ. (3) Effects of disease. Acute disease
generally attended with symptoms of apoplexy, and reveals nothing
as to the characters of the special functions of the cerebellum.
Chronic disease of the cerebellum rare. Yet the few cases re-
corded confirm the conclusion derived from comparative anatomy
and experiments, that the cerebellum has for its office to coordinate
the combined muscular actions necessary for executing locomo-
tion, Sfc.
214. Phrenological doctrine as to the office of the cerebellum,
that it is the seat of the sexual instinct, refuted by the foregoing
considerations. And besides, the alleged facts on which the
doctrine is supported are disproved by later and more accurate
observers. Thus it is not true that the castration of young males
is followed by atrophy or arrest of development of the cerebellum,
but the contrary effect is sometimes produced, as shown by Leueet
and Lassaigne, who found that the average weight of the cerebel-
lum in 21 geldings was 70, that of the same organ in 10 stallions
being 61; the superiority of the former being probably due to their
employment for draught and to the consequent habitual exercise
of the organ in connection with that of the motorial powers. Nor
is it true that there is such a frequent coincidence between diseased
states of the cerebellum and functional disorders of the genital
organs as to favour the phrenological doctrine, for out of 178 cases
collected by Burdach, only ten, or but little more than one in 18,
presented such coincidence. Probable explanation of the coinci-
SYLLABUS, ETC.
95
dence when it exists. Finally there is one case on record in
which the sexual propensity was strongly manifested, and yet the
cerebellum was entirely wanting. (Cruveilhier's Pathological
Anatomy, 15th livraison.)
FUNCTIONS OF THE CEREBRAL HEMISPHERES.
215. Structure of the cerebral hemispheres in man. A stratum
of cineritious matter 3-16th of an inch thick, forming the super-
ficies of the brain, and overlying a contained mass of white
matter, which consists (1) of diverging fibres radiating from below
upwards through the corpora striata and optic thalami towards the
surface; and (2) of converging fibres returning as it were from
every part of the surface and crossing the middle line to connect
correspondent points of the two hemispheres. These last are
called commissures. The former may be commissures between the
corpora striata and optic thalami on one hand, and the cerebral
hemispheres on the other.
216. Functions of the hemispheres ascertained (1) by the me-
thod of exclusion—(2) by evidence derived from comparative
anatomy. Pretty regular gradation of development from class
to class among all the vertebrata, and from the lower to the higher
orders of the mammalian class. There is no such gradation as to
the powers of sensation and motion, but there is a correspondent-
ly progressive development of intellectual and moral powers.
Thus fishes have corpora striata and rarely a perceptible trace of
cerebral hemispheres, and are almost or wholly destitute of intellec-
tual faculties. A few families (as the squalidse for example,) rise
above the piscine standard of psychical endowment, and these are
remarkable for a greater development of the hemispheres. Exam-
ples cited from the other vertebrate classes. The average weight
of the human encephalon in proportion to that of the body is
about as 1 to 40. The average of a large number of mammalian
orders, is 1 to 186; of birds, 1 to 212; of reptiles, 1 to 1321,
and of fishes, 1 to 5668. Apparent exceptions : in the goldfinch
the proportional weight of the encephalon compared wTith that of
the body is as 1 to 24, and the field-mouse as 1 to 31; but the great
relative weight of the encephalon in these and some similar cases
is not due to superior development of the cerebral hemispheres,
but only to that of the sensory ganglia. The true cerebral hemis-
pheres are larger in man in proportion to the whole encephalon,
to the whole of the nervous system, and to the whole body, than in
any other animal. (3.) By evidence derived from experiments—
effects resulting from the removal of the hemispheres—effects pro-
duced by removing the cerebellum and sensory ganglia, the cere-
bral hemispheres being left entire. (4.) Evidence derived from
pathological observations on man. Extensive lesion of the surface
of both hemispheres always attended with mental aberration,
d6
SYLLABUS, ETC
whereas extensive disease of other parts of the encephalon may
exist without any impairment of intellect.
217- Conditions of the action of the cerebral hemispheres—
encephalon receives nearly or about one-fifth of all the blood in
the system—arrangement of the arteries at the base of the brain
for insuring an active arterial circulation through the organ and at
the same time preventing any sudden and violent impulse of the
blood upon the cerebral substance when the heart's action is sud-
denly increased. A certain amount of pressure also necessary,
which is equalized by means of the easy displacement of the cere-
brospinal sub-arachnoid liquid.
218. Connection between the mind and the cerebral or-
ganization. Statement of the opposed doctrines of material-
ism and spiritualism. Physiology lends no countenance to the
former, while the latter seems to be a legitimate induction from the
facts of consciousness. It is held by the materialist (1) that inas-
much as the mental faculties are developed pari passu with the
development of the brain, partake of its disorders and cease to be
manifested when it ceases to act, hence mind is nothing but a set
of faculties attached to the brain in the same way as contractility
is a faculty attached to muscle, or electricity a set of properties
attached to sealing wax and other bodies. But all these facts are
equally well explained on the hypothesis of a separate mental
entity operating through the brain as its instrument. (2.) That
there is no evidence of the existence of mind in a state separate
from organization; to which it has been well replied, " that the
whole universe displays the most striking proofs of the existence
and operation of intellect or mind, in a state separate from or-
ganization, and under conditions which preclude all reference to or-
ganization." (3.) That the weight of proof rests with those who
assert the independent existence of a mental entity ; to which it
may be replied, that since the belief in mind as separate from mat-
ter is one of those "first truths" which constitute the "primary
elements of human reason," it devolves upon those who deny the
validity of such intuitions to sustain their position, which thus ap-
pears to be at variance with the common and instinctive belief of
mankind. But further, as regards material phenomena we observe
that they have all "a certain relation to each other, so that they
may be referred to certain general principles, but no analogy of
this kind can be detected with respect to mind" in its connextion
with the brain.—The foregoing heads of arguments expanded and
illustrated.
PHYSIOLOGY OF THE SENSES.
219. Definition of Sensation as that state of consciousness
which is excited by the appropriate action of a sensory ganglion,
which is usually, but not invariably dependent on a prior impres-
sion upon the peripheral expansion of a sensory nerve. Exclu-
SYLLABUS, ETC. 07
sively subjective operation of the mind in simple sensation, as
PriblJ» m the case of the earlier experiences of infancy
220. Definition of Perception, as the faculty by which the mind
refers sensations to an outward cause and forms certain notions
with regard to the qualities of the outward agent. Examples.
221. Physiological mechanism of sensation. (1) Impression on
the peripheral expansion of a sensory nerve effected in different
ways—(2) conducting action of the nerve fibres—(3) action of a
sensory ganglion consequent on the reception of the influence thus
conducted. Possibility of stimulating the ganglion abnormally
so as to supersede the two first processes without altering the char-
acter of the resulting sensations, as in dreaming, delirium, con-
gestion of the brain, &c.
222. Classification of sensations. I. External sensations, of
which there are five kinds, namely, touch, taste, smell, hearing,
and sight. II. Internal sensations, resulting from organic changes
in the organs independent of direct impressions from without,
as flashes of light seen in cases of inflammation of the retina
though the eye be excluded from all source of illumination. Hun-
ger, thirst, the feeling of lassitude, &c, are instances of in-
ternal sensations. All of the internal sensations which are not
clearly referrible to one of the special senses are believed to
depend on the action of the same nervous apparatus which when
impressed by an external agent gives rise to simple tactile sensa-
tions, and hence the sense of touch is called the common or gene-
ral sense.
223. General physiological laws of perception. I. Every sen-
sation of whatever kind immediately attended by certain intuitive
general perceptions, as (1) the reference of the sensation to some
outward cause, constituting the foundation of our belief in an ex-
ternal world, and (2) the location of the impressing agent at the
extremity of the sensory nerve, even when in reality the impres-
sion has been abnormally applied elsewhere. It follows as a corol-
lary from this law that where the elementary fibres of certain
sensory nerves (those of touch and sight) may be separately im-
pressed the perception of superficial figure will be likewise intui-
tive. II. Each special sensation is attended by certain intuitive
special perceptions peculiar to its own class. Thus perception of
colour is peculiar to the eye. Such perceptions are immediately
dependent on the associate sensations, and are independent of the
mode in which the nerves are impressed, or of the nature of the
impressing agent. Hence the transference of special sensibility
from one set of nerves to another is impossible. Electricity ex-
cites the action of all sensory nerves, but the resulting sensations
are very different in the different cases, in each case being the
sensations peculiar to the nerve impressed. III. Therefore the
immediate object of perception is not the impressing agent but
the change produced by it in the organs of sense, but inasmuch as
the organs of sense participate in the properties of matter, having
7
98
SYLLABUS, ETC
extension, being susceptible of pressure, motion, alteration of tem-
perature, &c, we reason from these changes to the qualities of the
agents which produce them and thus have certain acquired percep-
tions. IV. While the passive susceptibility of sensation is
blunted by habit, the active power of discrimination, or the delicacy
of the perceptive faculty is increased by frequent exercise. V. The
intensity of the sensation and consequently the distinctness of
the perception depends more on the relative than on the absolute
change in the sensorium—illustrations :
SENSE OF TOUCH.
224. Class of nerves concerned. Proof that tactile sensibility
is merely one mode of general or common sensibility. Structure
of the skin as an instrument of touch.
225. Varieties of common sensation, external and internal; as
tact or pricking, pressure, temperature, itching, hunger, thirst,
venereal feeling, coenaesthesis, muscular sense, &c, &c.
Special intuitive perceptions connected with such sensations,
as the idea of resistance, weight, temperature, as a quality of ex-
ternal bodies; dryness or moisture, &c, &c. Tactile perception
of superficial figure and dimensions, in what degree intuitive -and
to what extent acquired. Assistance derived from the muscular
sense in giving greater precision to our intuitive tactile percep-
tions.
SENSE OF TASTE.
226. Structure of the organ. Physical state of the surface
essential to its action. Nerves concerned. The cause of sapidity
in bodies only cognizable by its power of impressing the organ
of taste. Its varieties as indicated by the terms, sour, sweet,
bitter, acrid, &c., &c, as well as the infinite nameless varieties.
The perception of the differences between these varieties is
intuitive, but the association of each with a certain body or class
of bodies is, of course, acquired, and becomes important as a
means of distinguishing such bodies. Sympathies of the organ of
taste.
SENSE OF SMELL.
_ 227. Proof of the olfactory sensibility of the first pair of cran-
ial nerves. Physical condition of the pituitary membrane es-
sential to the exercise of this function. Use of the antrum and
other sinuses. Physical cause of odors. Varieties of odors.
Intuitive perception of these variations. Acquired perception
SYLLABUS, ETC
99
of other qualities of bodies by means of their association with
peculiar varieties of odors. Affinity between the sense of taste
and smell.
SENSE OF HEARING.
228. Anatomy of the apparatus of hearing in different animals.
(1) A simple sacculus on the inner walls of which the auditory
nerve is distributed, imbedded in the flesh without any fenestral
opening into the chamber; as in gasteropods and cephalopods.
(2) The same kind of sacculus lodged in a chamber which has a
fenestral opening closed with a vibratile membrane; as in the
basal segment of the lesser antennae of certain crustaceans. (3)
Fishes have, in addition to the sacculus, a vestibule and semi-
circular canals of which except in the lowest order, there are always
three arranged as in man. The whole apparatus lodged in a
depression of the inner surface of the cranium, which communicates
with the cranial cavity, except in the higher cartilaginous fishes. (4)
Reptiles have rudimental cochlea, fenestra ovalis, stapes, and all
but the lower amphibians and ophidians have a tympanic cavity.
(5) Birds have a more highly developed cochlea divided into two
scalse although still straight, fenestra rotunda, tympanum, colu-
mella, &c. (6) Mammalia have a spiral cochlea and an external
ear or auricle in addition to the parts existing in the lower classes.
Proof of the special character of the portio mollis nerve.
229. External cause of sounds. Modes of propagating sonorous
vibrations from the sounding body to the ear. (1) Conduction by
progressive vibrations excited by the stationary waves in which
the sound originates. Loss of energy in the transference of pro-
gressive vibrations from one medium to another of different physi-
cal nature. (2) Reciprocation, or the excitement of secondary
stationary vibrations in certain bodies which are particularly sus-
ceptible of such action, particularly organic membranes and strings
made elastic by tension, when they are placed near to, but not in
contact with sonorous agents with which they can vibrate in unison.
Conditions necessary for the production of these secondary re-
ciprocating vibrations, which giving an additional impulse to the
air, increase the intensity of the sound as produced by the primary
sounding body. Water conducts the vibrations thus produced in
reciprocating solids, and thus we obtain a means whereby sound
may be imparted from air to water.
(3) Resonance, consists in increasing the extent of surface of a
soniferous medium, similar in kind to the primary sounding body.
It is thus, a kind of reciprocation, but differs from the foregoing in
this, that the sounding board must be in contact with the sonorous
body, and need not have the peculiar susceptibility of organic
membranes. Resonance much favoured by the insulation of the
resonant medium.
100
SYLLABUS, ffJC.
230. Mechanism of the ear in audition, and uses of the several
parts of the complicated apparatus. The essential part of an
organ of hearing being a nerve of special endowments, so disposed
as to receive sonorous impressions to the greatest advantage, it
will be more natural and easy to consider the uses of those parts
which exist in all the varieties of such apparatus, and those of the
superadded structures in the order in which they successively ap-
pear. (1) Uses of the endolymph; probably, to maintain on the
surface of the nerve the same physical condition which necessarily
exists in its interior parts. (2) The sacculi and the ear dust.
" Sonorous vibrations are not only imparted from water to solid
bodies bounded by definite surfaces which are in contact with the
water, but are also returned with increased intensity by these bodies
to the water, so that the sound is heard loudly in the vicinity of
those bodies in situations where, if it had its origin in the conduct-
ing power of the water alone, it would be faint."—(Muller). Ex-
perimental evidence of the effect produced by solid bodies floating
in the liquid of a sac whose walls are thrown into vibration. (3)
Perilymph and fenestra ovalis with its membrane. The latter a
reciprocating medium by means of which vibrations of the air are
transferred to water which is the final impressing agent. (4) Semi-
circular canals. Conjectural view of their office as connected with
the perception of the direction of sounds. (5) Cochlea—supposed
to be an arrangement for the advantageous reception of the vibra-
tions conducted by the bones of the head. Spiral form, not
essential and exists only among mammals, being, as is probable,
an arrangement for convenience of package. (6) Fenestra rotunda
and its membrane. This membrane and that of the fenestra
ovalis being unequally distant from the auditory nerves the phe-
nomena of "interference" of the sonorous waves ensue, whereby
there is occasionally produced a more intense impression on the
nerve. (7) Tympanum, with its ossicles. The vibrations of the
air may be communicated to the perilymph by the simple interpo-
sition of the membrane of the fenestra touching the water on one
side and the air on the other, but in a far more perfect manner,
as proved by experiments, by connecting this membrane by means
of a rod with a second membrane having air on both sides, par-
ticularly if the rod be insulated in a space bounded by definite
walls like the tympanum. Explanation and application to the case of
the natural tympanum. (8) 3Iechanism and uses of the membrana
tympani, as adjusting the ear to sounds of different degrees of in-
tensity and pitch. Experimental method of increasing the tension
of this membrane, by a voluntary effort and its effect in blunting
the sensibility of the ear for all except very acute tones. (9)
Eustachian tube serves to carry off secretions, and also to main-
tain an equilibrium of pressure on the two sides of the membrana
tympani. (10) Mastoid cells are resonant cavities. (11) Auditory
canal a resonant medium, both by the air in its cavity and by its
walls, which also conduct the vibrations of (12) Auricle, a recipro-
SYLLABUS, ETC. ,101
eating instrument with various inflexions of its surface of which
the probable use is to receive the progressive undulations at right
angles from whatsoever direction they come. The concha with
the auditory canal forms a hearing trumpet.
231. Perceptions connected with the exercise of this sense
(1) Of the variations of intensity of sound. (2) Of musical pitch,
which is dependent on the number of vibrations in a second, or
rather on the interval between two successive impulses, as exempli-
fied by experiments with the "siren." Physical condition of
harmony and melody. The "musical ear" whether dependent on
the conformation of the ear or on the organization of the brain.
(3) Tone or timbre, varies with the physical nature of the sound-
ing body, &c.
Physiology of Sight.
232. Possible forms of organs of vision. The sensation and
perception of luminousness may exist without any optical appa-
ratus, and require only the presence of a nerve with special en-
dowments. In general, however, we find associated with such a
nerve one of three forms of optical apparatus for supporting the
nervous expansion and for concentrating or otherwise modifying
the luminous rays. (1) Ocelli or Eye-dots, found in many of the
Annelida and in the larva state of many insects, &c. (2) Com-
pound eyes of insects and crustaceans, of which there are several
varieties. (3) Simple eyes of cephalopod molluscans and all the
vertebrate classes.
233. Optical principles involved in the exercise of the eye as
an organ of vision. (1) Physical cause of the visibility of bodies.
Self-luminous bodies and bodies luminous by reflection. (2) Ra-
diation of light in all directions from a luminous centre and its
passage in straight lines so long as it is in the same medium.
(3) Laws of reflection of light from the surface of bodies—opake
and transparent bodies. (4) Laws of refraction. Index of re-
fraction or the ratio of the sine of the angle of incidence to that
of the angle of refraction constant for all angles, the media being
the same. (5) Effect of the convexity of a refracting medium
in causing diverging incident rays to converge on passing out.
(6) Relation between the distance of a luminous point in front of
the lens and focal distance. (7) Aberration of sphericity—how
obviated. (8) Aberration of refrangibility or dispersion of colored
rays. Achromatism, how obtained. (9) Mechanism of the ca-
mera obscura.
234. Mechanism of the human eye. A globular camera ob-
scura. Advantage resulting from the globular form. Cornea,
aqueous humour, crystalline lens and vitreous humour appear to
form an aplanatic and achromatic combination. Fluidity of the
aqueous humour necessary for admitting the movements of the
102
SYLLABUS, etc.
iris, a diaphragm or stop for cutting of the peripheral rays when
the light is too intense, or when looking at very near objects when
spherical aberration would be likely to ensue. Muscularity of the
the iris and its mechanism. Adjustment of the eye to vision at
different distances, probably by the agency of ciliary processes
and the ciliary muscle.
235. Explanation of the phenomena of vision. (1) Simple per-
ceptions of light dependent on any adequate excitement of the
organ of vision though the sensation be entirely internal and be
produced in perfect darkness. This is probably the sole function
of certain forms of ocelli. (2) Simple perception of colour. Phy-
sical explanation of the colour of transparent and opake bodies.
Physiological explanation of the perception of colour, according
to the undulatory theory. Complementary colours. Colored
spectra whether positive or complementary, and their physiological
explanation. (3) Perception of the position of a luminous point;
size of aliquot portions of the retina possessing the power of in-
dependent sensation; law of visible direction. (4) Perception of
superficial extension shewn to be a necessary consequence of the fore-
going law and therefore intuitive. Error of Locke and other meta-
physicians in denying the identity of tactile and visual percep-
tions of plane figures, whereas only the sensations and not the con-
sequent notions differ. See case of young man restored to sight by
an operation for cataract, performed by Dr. Franz and recorded in
the London Philosophical Transaction for the year 1841. (5) Per-
ception of solidity. With the use of one eye only this perception
must be acquired; but with both eyes the notion is intuitive.
Mechanism of the stereoscope invented by Wheatstone; physio-
logical interpretation. (6) Single vision when both eyes are used.
Theory of identical or correspondent points on the two retinae with
the assumed physiological explanation. Objections to the theory.
(7) Erect vision, the image on the retinae being inverted, does not
need explanation, since the images of all surrounding objects that
might be used for comparison, are likewise inverted. (8) Esti-
mate of the size of visible objects. Actual and ideal size of the
field of vision; " visual angle'' or measure of the size of the image
on the retina dependent on the size and distance of the visible
object. Hence when the latter element is not known we are sub-
ject to deception in our estimate of the former. (9) Appreciation of
distance determined in part by visual angle when the size of an
object is previously known. Angle of convergence of the axis of
the two eyes. Interposition of known objects. Variations of the
intensity of light and shade. (10) Visual perception of the motion
of objects. (11) Duration of visual sensations giving rise to lu-
minous spectra. (12) Vanishing of images which fall at the
entrance of the optic nerve. (13) A7isual representation of the
retina itself by the experiment of Purkinje.
SYLLABUS, ETC
103
SPECIAL PHYSIOLOGY OF THE CEREBRO-SPINAL, AND OF THE
SYMPATHETIC NERVES.
236. Method of determining the special functions of a nerve.
Effects resulting from the experimental irritation of a nerve ac-
cording as it may prove to be a nerve of motion, or of sensation,
or an afferent nerve belonging to the physico-reflex system.
Effects resulting from the section of a nerve belonging to either
of these classes.
237. Functions of the spinal nerves at their anterior and pos-
terior roots. Subsequent mingling of the fibres in trunks and
branches of mixed functions. Formation and function of the
phrenic and other spinal nerves.
238. Physiological classification of the cranial nerves. Reference
to the text-book for a detailed account of the functions of each.
239. Reference to text-book for account of the actions of the
Sympathetic nerve, the office of which is, probably, to establish
a harmony of action between the organic operations of distant
parts. Sometimes this is accomplished by means of physico-reflex
movements, of which the nervous centre is one of the sympathetic
ganglia, as seems to be the case with the peristaltic movements of
the intestinal canal. But frequently the sympathy is exhibited by
an exaggerated, diminished, or perverted secretion, or act of nu-
trition, which cannot be explained by supposing that the reflected
nervous influence operates on the muscular function of the small
arteries. We must, therefore, admit that some efferent nerves
convey an influence which operates on the nutritive functions
directly. It is true that this influence is not essential to the per-
formance of the nutritive acts, as has been erroneously represented
by Paget, but it is capable of accelerating, retarding or modifying
the character of those acts. Examples cited.
240. Summary recapitulation of the physiology, general and
special, of the nervous system.—The final causes of the nervous
functions may be summed up as follows:—(1) As subservient to
the excitement of those movements of animals which depend upon
stimuli not felt but reflected from an impressible surface, through
a circle composed of an efferent nerve, a ganglionic centre and an
efferent nerve, to distant muscles, (physico-reflex movements.) (2)
As subservient to the manifestations of the conscious mmd and to
bringing it into relation with the external world, either by receiving
sensorial impressions which give rise to certain fundamental ideas
of perception or by reacting on matter through the instrumen-
tality of the motorial apparatus stimulated by sensations, (sensori-
reflex or consensual), emotions (emotional), thoughts (ideo-motor),
or the will (volitional movements). (3) To establish a harmony of
action between different parts of the system. See above, § 239.
104
SYLLABUS, ETC.
PHYSIOLOGY OF THE SENSIBLE MOTIONS OF ANIMALS.
241. Locomotion occasionally though rarely exhibited by vege-
table structures, and only strictly peculiar to animals as executed
in respondence to stimuli acting through a nervous system. Con-
tractile cells of certain vegetable structures—phenomena of ciliary
motion (see § 27).—In both these cases the action seems to be
inherently rythmical, that is, a single excitement is adequate to
give rise to a prolonged series of contractions alternating with re-
laxations.
242. General Physiology of muscular action. Statement of
the functions—(1.) Sudden and rythmical contractions causing
the displacement of moveable parts to which the muscles are at-
tached, or the propulsion of matters contained in hollow viscera
whose walls are formed by the contractile muscular fibres. (2.)
A more slow and permanent contraction which gives tone to the
muscle itself and often subserves the office of regulating the calibre
of tubes around whose walls the contractile fibres are circularly
disposed.
Explanation. I. Rythmical contractions excited normally by
nervous influence, but may be excited by direct mechanical or
chemical stimulation of the fibres themselves. The proximate
cause of such contractions is a peculiar inherent vital property
which has been called irritability, but is more appropriately termed
contractility, and this endowment of the muscular fibre is an
" ultimate fact." Proof of this statement. Laws of muscular
contractility—(1.) Disintegration of tissue coincident with each
contraction.—(2.) Necessity of active arterial circulation—(3.)
necessity for intervals of rest after prolonged action—(4.) force
of contraction proportional to energy of stimulation—(5.) de-
velopment of heat—(6.) production of a peculiar murmur—(7.)
velocity of contraction under certain circumstances. II. Tonic
contractions either dependent on a distinct vital property, tonicity,
or else on the ordinary contractility kept in a state of sustained
operation by the influence of a permanent stimulus. Phenomena
of cadaveric rigidity.
PHYSIOLOGY OF THE VOICE.
243. The human voice consists of the sounds produced by the
air m its passage through the larynx with a certain degree of
expiratory force, and in a certain position of the inferior laryngeal
ligaments. The organs concerned include not only the whole'res-
piratory apparatus with that portion of the nervous system which
is subservient to the excitement of the respiratory muscles, but
certain superadded parts, such as the pharynx, mouth, tongue,' lips
and nasal cavities, which modify the laryngeal sounds so as to
SYLLABUS, ETC.
105
constitute articulate language. The special organs are the inferior
laryngeal ligaments, therefore called vocal cords, which are thrown
into vibration by the impulse of the air in expiration, after being
first placed in a vocalizing position by the thyro-arytenoid mus-
cles.
244. Preliminary notice of some of the phenomena of acous-
tics. Physical cause of sounds and the circumstances which de-
termine the pitch, the intensity, and the timbre of sounds.
245. Laws of vibrating strings. The fundamental note being
that which is due to the vibrations of the string by its entire
length, the number of vibrations for shorter lengths is inversely
proportional to the length, thus:
Fundamental. Third. Fifth. Octave.
No. of vibrations, - 1----1----£----4----§----f----is----2
Length of string, - 1----«----f----J-----|----f----1%----1
Names of notes, - C. D. E. F. G. A. B. C1.
The length being constant, the number of vibrations is propor-
tional to the square root of the tension.
246. Wind instruments. In these the contained air is the seat of
sonorous undulations passing backwards and forwards from one end
of the column of air to the other, the rapidity depending on the length
of the wave or of the space which it traverses. Hence the number
of vibrations is inversely proportional to the length of the tubes.
A tube open at its extremity yields a fundamental note an octave
higher than a closed one, a nodal point being formed in the mid-
dle of the column of air. In either kind higher notes are produced
by increasing the force of the blast, but the nearest note to the
fundamental one is, under such circumstances, its octave.
247. Instruments in which the properties both of solid and of
fluid elastic bodies come into play. Reed or tongued instru-
ments. Laws of the vibrations of membranous tongues with
superadded tubes. The pitch of such a tongue may be raised
almost an octave in successive semitones by altering^ the force and
manner of the blast.
248. Structure of the larynx. Classification of the laryngeal
muscles.
(1) MUSCLES WHICH REGULATE THE TENSION OF THE VOCAL CORDS AND
THUS GOVERN THE PITCH OF THE NOTES.
f Depress the front of the Thyroid cartilage on the cricoid,
Crico-Thyroidei J ftnd sire(ch the vocal cords. Thev are assisted bythe Aryte-
Stcrno-Thyroidei | noideus Transversus, and the Crico-arytenoidei postici.
Thyro-Arytenoidei / Elevate the front of the Thyroid cartilage and draw it
Thyro-Eyoidei \ towards the Arytenoid and thus relax the vocal ligaments.
106
SYLLABUS, ETC.
(2) MUSCLES WHICH GOVERN THE APERTURE OF THE GLOTTIS.
Crico-arytenoideipostici . . . Open the glottis.
Crico-arytenoidei laterales f Press together the inner edges of the Arytenoid
Arytenoideus transversus \ cartilages and close the glottis.
249. Position of the vocal cords in simple respiration ; vocal-
izing position; mean length of the cords of the adult male, 0.728
of inch in repose and 0.912 in greatest tension. Of the adult
female 0.498 and 0.617. Shape of the aperture in different
positions of the ligaments and of the arytenoid cartilages.
250. Modulation of the voice. Muller's experiments on the
artificial production of the voice with the larynx separated from
the dead body. Upper ligaments and epiglottis shown to be merely
or chiefly reciprocating and resonant media for increasing the
loudness of sound, but not for altering their pitch. Pitch of the
notes regulated by the length and tension of the vocal cords.
Compass about two octaves. Two distinct series of notes, namely,
the ordinary and the falsetto register. The highest notes always
belong to the falsetto, and the lowest always to the ordinary register,
but if a moderate tension of the ligaments be maintained, it depends
on the manner of blowing whether the ordinary or falsetto note
be produced, (the latter being most easily produced by blowing very
gently,) and the two different notes thus produced may be very
distant from each other in the musical scale, even as much as an
octave. Muller's explanation of the falsetto notes. ^ Mode of
successively raising the pitch of the ordinary voice without run-
ning into the falsetto register. Influence of narrowing the
diameter of the larynx immediately below the vocal cords, which
is effected by the action of the Thyro-arytenoid muscles. Other uses
of these muscles. Condition of the vocal cords in the production
of different notes from the deepest bass to the highest tenor.
SYLLABUS, ETC.
107
I u o
w
251. Theory of the voice. The human
voice held to be a reed instrument with a
double-membranous tongue. When simple
vibrating strings are very strongly touched
deeper notes are produced, whereas the note
given out by a moist membranous tongue is
raised by a stronger blast the extent of many
semitones.
252. Three different kinds of sequence in
the notes of the human voice.
(1) Monotonous, as in speaking, only occa-
sional syllables receiving a slightly higher
intonation for the sake of accent.
(2) Successive transitions from high to low
notes and vice versa, as in the involuntary
cries of pain, &c.
(3) Musical sequence. Compass of the
voice in different individuals. Varieties of
male voice, technically called bass, barytone
and tenor, and of the female, contralto,
mezzo-soprano and soprano. The ordinary
compass of each may be seen on the scale
placed in the margin.
These different kinds of voice differ also in
timbre so as to be distinguished when sound-
ing the same note. Difficulty in hitting upon
the right note when passing suddenly in
singing from the natural to the falsetto
register, or from a low to a loud tone.
253. Differences of the voice as to timbre, dependent on the
form of the air-passages and on their resonance. A nasal tone
may be given in two ways. (1) When the external openings to
the nares are closed, the voice may become nasal by the approxi-
mation of the arches of the fauces, and by the larynx ascending
higher than when the voice has its natural character. ^ Obstruction
of the nostrils by mucus has the same effect as closing the ante-
rior nares, but neither the one nor the other can alone give the
nasal tone to the voice. (2) The nasal twang may also be given when
the nostrils are open, the mouth being either open or closed. In this
case likewise the larynx ascends considerably ; the arches of the fau-
ces contract; and the dorsum of the tongue is approximated to the
palate or brought into contact with it; and the air merely passes be-
tween the narrowed arches of the fauces and receives the resonance
108
SYLLABUS, -ETC.
of the nasal cavities without that of the cavity of the mouth.—
(Muller.) Character of the voice at different epochs of life.
254. Strength of the voice as dependent partly on the capability
of vibration of the vocal chords and partly on the fitness of the
membranes and cartilages of the larynx and of the adjacent organs
for resonance. Increased intensity of vocal sounds produced by an
increase in the force of the blast; but as this same change alters
the pitch of the notes, there must be some means of compensating
this tendency to emit a higher note, which probably consists in re-
laxing the vocal chords in a suitable proportion.
255. Perfectness of notes. Cause of dissonance after long
singing; cause of habitual dissonance. Explanation of the
power to reproduce given notes in singing by ear or by note.
Musical sounds formed in the mouth as in whistling where
the air is the source of the sounds, by friction against the borders
of the opening.
256. Articulate sounds or speech. Division of articulate sounds
into vowels and consonants and mode of producing each. Mute
vowel and consonant sounds. Explosive and continuous sounds.
Ventriloquism.
SYLLABUS, etc
109
GENERAL CONSIDERATIONS HAVING REFERENCE TO
THE CONDITIONS OF VITAL ACTIONS.
I.—On the connection between Life and Organization or nature of
the Vital Principle.
257. Some of the actions of man the result of mechanical ar-
rangements^ of parts endowed with purely physical properties.
Examples cited and explained. So also other actions result from
the operation of purely chemical forces. But a large number of
the actions of the human organs cannot be referred to either of
these classes, and are found to indicate the existence of properties
or forces peculiar to living organized structures, and accordingly
these forces are denominated vital. The investigation of the laws
of these forces must be. pursued by the same inductive process
which is employed in other departments of positive science.
258. Is there an essential distinction between vital and physical
forces ? Two opposing views in regard to this question which is
rather speculative than practical. (1) Doctrine of the vitalists
who hold that the proximate cause of all the truly vital acts is a
special entity which they denominate the vital principle and
which they consider to be as independent in its essence of the tis-
sues which it animates as the soul is of the brain through which
it acts. According to this view a tissue, an organ, or the whole
body may die, by reason of the vital principle deserting its ma-
terial tenement, though the latter may be uninjured. (2) The
advocates of the opposing doctrine hold that the vital properties
depend on the structure of organized tissues, just as physical
properties depend on the special forms of matter by which they are
manifested, the main difference being that the structure of organi-
zed tissues is in many of its features so refined and delicate that
it can never be successfully imitated and therefore no vital act,
not even the simplest, can ever be artificially exhibited. This
would seem to be the most philosophical view of the subject, on
the simple ground of the entire absence of any satisfactory founda-
tion for the opposing doctrine, which also seems to be disproved
by the fact that each tissue and even minute fragments of tissue
possess independent vitality, which would require us in adopting
such a doctrine to admit the existence of several hundred vital
principles. Thus Brown—Sequard has shewn that entirely dead
muscles of one animal may have their power of vital contractility
restored to them by connecting their blood-vessels with those of a
living animal of the same species, in such a manner as to cause
the circulation of living blood through the previously dead muscle.
259. Examination of the arguments adduced by the vitalists.
(1) Unity of the vital acts all of which point to a common pur-
pose. But this only indicates the final cause and not the instru-
HO syllabus, etc
mental method; and the same argument might be used with reference
to the operations of any machine exhibiting design, and the skilful
adaptation of means to a specific end. It is clear in all such cases
that the cause of the unity, lies in the designing mind of the con-
triver and architect, who arranges a mechanism with reference to
the production of such an effect; and in the case of living machines,
it would be not less derogatory to the Great Author of Nature, to
ascribe the wonderful unity of plan and purpose to an imaginary
vital principle, than to refer it to a property of brute matter. It
is just as easy to suppose, that the Almighty uses brute matter as
his immediate instrument in the production of vital acts, as that
certain intermediate agencies or vital entities are indispensable.
Indeed, the latter hypothesis is much the grosser of the two, and
seems to have its origin in an unconscious ascription to the
Almighty of some of the imperfections which belong to man,
namely, the impossibility of acting upon matter except through
secondary instrumentalities. Again, if this argument of the vi-
talists were valid, then by a parity of reasoning the universe should
have its vital principle, since it may be said to be organized in the
sense of being composed of diverse but mutually adapted parts,
the operations of each of which tend to the stability of the whole,
as abundantly shown by writers on natural theology. Accordingly
those vitalists who have logically followed out their principles have
naturally ended in Pantheism.
260. (2) The limited duration of organized structures, each
species of plants and animals having an appointed term of life, is
adduced as an argument in favor of vitalism. But it is as easy to
believe that the structure of a living body is such as to wear out
after a certain amount of use, as that an immaterial principle
enters the germ at conception, remains in connection with the
growing plant or animal and after a certain time leaves it.
261. (3) The bodies of living animals resist (the vitalists assert)
the operation of the ordinary forces of matter, as for example, the
tendency to putrefaction, which is restrained by the controlling in-
fluence of life, and which ensues immediately after the withdrawal
of life. But it may be shown that the ordinary forces of matter
are not resisted however their effects may be counteracted by the
vital acts. For example a decay analogous to putrefaction is con-
stantly going on, but the products are separated from the blood by
the depuratory glands, and finally discharged from the body in the
form of the different excretions.
262. (4) It is alleged that sometimes life is destroyed without in-
jury of the material fabric, as when death suddenly ensues from men-
tal emotion, from a stroke of lightning, &c. But this is an unproved
and highly improbable assumption. In very many such cases
adequate lesions are found in the heart and brain, and when we
reflect upon the complicated composition of the blood and of the
semi-solid substance of the nervous system, we can readily conceive
SYLLABUS, ETC -,...,
that there may be many kinds of disturbance incompatible with
health, and even with life, and yet not appreciable to the eye
263. ■ (5) Impossibility of artificially exhibiting vital phenomena
This is, admitted, for we cannot artificially construct the material
frame. The simplest and at the same time the most essential
structural element of organization is the primordial cyto-blast or
cell germ of so refined a structure and composition as to be inca-
pable of exact appreciation. Of course this microscopic body
cannot be imitated. The argument can have no value until a per-
fect organism has been constructed and then be found to need the
Promethean heat of a vital principle.
264. The charge of materialism cannot be fairly brought against
the doctrine here contended for, since in rejecting the hypothesis of
an independent vital principle reference is had to those vital pheno-
mena which man possesses in common with the lower animals, and
which are irrespective of the sentient and conscious mind. Where-
ever sensation or any other mental act is concerned, it is admitted
that an immaterial and independent agent is operating through a
material organ. The question here considered is whether the or-
ganic acts depend on a similar entity to be called the Vital Princi-
ple. The arguments in favor of the immateriality of the sentient
and thinking principle do not in the least degree apply to the case
in question, but on the contrary the materiality of the phenomena
of organic life may be legitimately inferred from their very con-
trast with the phenomena of mind.
565. Notice of a metaphysical sense in which vital forces, as
mere objects of cognition, may be regarded as distinct from the
organized tissues by which they are exhibited. But this is equally
true of all forces, physical as well as vital, and cannot give any
countenance to the doctrine of vitalism, which affirms the exist-
ence of an independent vital entity, but denies the existence of
any correspondent inanimate material principle, on the ground of
an essential difference between the two classes of acts.
266. In the absence, then, of any proof to the contrary, we
conclude that the vital phenomena are the results of vital forces
operating through organized matter, precisely as other natural
phenomena are the results of physical forces acting through inani-
mate matter, and that we have no better reason to ascribe an in-
dependent existence to the former than to the latter, but that on
the contrary, the remarkable correlation between these two classes
of forces constrains us to admit their essential similarity. (See
Carpenter's Elements of Physiology, § 52 to § 73.)
II.—ON THE EXTERNAL CONDITIONS OP VITAL ACTIVITY.
267. Threefold condition of vital actions—(1) an organism—
(2) alimentary materials requisite for the construction and mainte-
nance of the organism, and (3) the dynamical conditions, or the
112
SYLLABUS, ETC.
forces or powers on which its operations are dependent. Now the vital
forces seem themselves to result from the operations of certain phy-
sical forces, especially light and heat, on duly organized structures.
The higher the organization the greater the dependence on these
forces. Their influence rather relative than absolute. Apparent
distinction between living bodies and inanimate masses of matters
in this respect. The proper interpretation of this fact, as con-
nected with the change which the organism itself undergoes by
any considerable alteration of the doses of stimuli to which it may
be exposed.
(a) OF LIGHT AS A CONDITION OF VITAL ACTIVITY.
268. Notice firstly the influence of light as a condition of chem-
ical action, sometimes determining the union of bodies, as of hy-
drogen and chlorine, and sometimes effecting chemical decomposi-
tion. Secondly, its influence on the functional activity of plants,
as (1) on the development of the vegetable structures, acting in
two ways, namely, by directly exciting the chemical acts concerned
in the fixation of carbon and by regulating the action of the sto-
mata, so as indirectly to regulate the absorption of fresh material.
Hence exclusion of light arresting these processes, causes plants
to become pale, succulent and dropsical; a condition which often
increases their value as aliments but renders them unhealthy as
natural beings. Germination retarded by light, a plant during
germination resembling an animal in its relation to heat and con-
sequently to carbon, which it then consumes. (2.) Influence of light
on the motion of plants, as the direction of the growing stem,
the expanding of flowers and their turning towards the source of
light.
269. Influence of light on the functions of animals—(1) on the
development of the body; Humboldt's testimony with regard to
the perfect development of the bodies of savages who go habitually
uncovered. Deprivation of this influence seems to be one of the
causes of scrofula, rickets and other diseases leading to bodily
deformity. Tadpoles prevented from undergoing metamorphosis
by confinement in the dark. (2) On the functions of the skin.
Ruddy complexion of health belonging to persons living in the
country contrasted with the etiolation of inhabitants of the city.
An excess of the stimulus produces freckles and other diseases of the
skin. (3) On the functions of the nervous centres. The influence
in moderation is wholesome; in excess produces excitement, pain,
or even delirium and death by sun-stroke; lunar influence on
maniacs. (4) On the general health, as indicated by liability to
disease and by the rate of mortality under the operation of disease.
(See Carpenter, loc. cit. § 95.)
On the whole subject of the influence of light as a vital stimulus. See Ibid.
g T9 to I 97.
SYLLABI'.-!, ErlY.
(b) ON HEAT, AS A CONDITION OF VITAL ACTIVITY.
270. Notice of the influence of heat as an exciting cause of
mechanical and chemical changes. Its influence on vegetation on a
large scale, exhibited in the changes produced by summer and
winter and confirmed by the experiment of artificially inverting the
seasons. Geographical distribution of plants at different distances
from the equator, and precisely parallel phenomena at different alti-
tudes above the level of the sea at the same latitude. Explanation
of the effect of excessive heat in destroying life. Too consider-
able an abstraction of heat may produce the same result by effect-
ing some mechanical change inconsistent with vital action, or else
it may merely suspend without destroying the power of vital action,
producing the phenomenon of dormant vitality.
271. Influence of heat on the actions of animals. Distinction
between warm and cold-blooded animals, as to the range of bodily
and external temperature compatible with vital activity and the
retention of vital power. Hence cold-blooded animals best ex-
emplify the influence of this agent on the different functions;
(1) nutritive functions; (2) on respiration and circulation; (3) ner-
vous functions; (4) motorial power; (5) functions of the skin.
See Carpenter, loc. cit. § 97 to § 141.
For a notice of other external conditions of vital activity, such as Electricity,
Moisture,