ARMY MEDICAL LIBRARY

         WASHINGTON

             Founaed 1836
ANNEX
 Section.
Number _.J..J_j[.&_'j?_4.
        Form 113c, W. D., S. G. O.
3—10543    (Revised June 13, 1936) 
    E TW<OtUJHi rilUM LAST DATE

  MAR 3 0 1956
EB23igs9
GPO  887422 
 
an
L7/6o
1842 
 

  This edition is  printed  from  the corrected
London  copy,  and is complete,  with  all the
additions.
ANIMAL   CHEMISTRY,
                Sfc. 
I 
ANIMAL  CHEMISTRY,
ORGANIC CHEMISTRY
             IN ITS APPLICATIONS TO
m
PHYSIOLOGY AND PATHOLOGY.


                  BY

'JUSTUS LIEBIG, M.D.,Ph. D., F. R. S., M. R. I. A,
    PROFESSOR OF CHEMISTRY IX THE UNIVERSITY OF GIESSEN.


       EDITED FROM THE AUTHOR'S MANUSCRIPT

 BY WILLIAM GREGORY, M. D., F. R.S.E.,M.R.I.A.
    PROFESSOR OF MEDICINE AND CHEMISTRY I# tJ^uJ^eAtWJ"^
           AND KING'S COLLEGE, ABEB&feN; • • »  •
AND KING S COLLEGE,
     NEwJyORK:|1  £4£a»j \ •
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        161 Broadway
         1842. 
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                    TO

THE  BRITISH ASSOCIATION

                  FOR THE
            J
     ADVANCEMENT OF SCIENCE.
  At the meeting of the British Association  in
Glasgow, in  1840, I had the honour to present the
first part of a report on the then present state of
Organic Chemistry, in which I endeavoured to de-
velop the doctrines of this science in their bearing
on Agriculture and Physiology.
  It affords  me now much gratification to be  able
to communicate to the meeting of the Association
for the present year the second part of my labours ;
in which I have attempted to trace the application
of Organic  Chemistry to  Animal Physiology and
Pathology.
  In the present work an extensive series of  phe-
nomena have been treated in their chemical  rela-
tions ; and although  it would be presumptuous to
consider the questions here raised as being definite-
ly resolved, yet those who are familiar with chemis- 
vi
DEDICATION.
try will perceive  that the only method which can
lead to their final resolution, namely, the quantita-
tive method, has been employed.
   The formulae and equations in the second part,
therefore, although they are not to  be viewed  as
ascertained truths, and as furnishing a complete, or
the only explanation  of the vital processes  there
treated of, are yet true  in this sense : that being
deduced from facts by logical induction,  they must
stand  as long as  no new facts  shall be opposed to
them.
   When the chemist shows, for example, that the
elements  of the  bile, added to those of the  urate
of ammonia, correspond exactly to those of blood,
he presents to us a fact which is independent of all
hypothesis.  It remains  for the physiologist to de-
termine, by  experiment, whether the conclusions
drawn by the chemist from such a fact be accurate
or erroneous.  And whether  this  question be an-
swered in the affirmative or in the negative, the fact
remains, and will some  day find its  true explana-
tion.
   I  have  now to perform  the agreeable duty of
expressing my sense of the services rendered to me
in the preparation of the English edition by my
friend Dr. Gregory.  The distinguished station he
occupies as a chemist; the regular education which 
                  DEDICATION.                vii
he has received in the various branches of medi-
cine ; and his intimate acquaintance with the Ger-
man language—all these,  taken together, are the
best securities that  the translation is  such as to
convey the exact sense of the original;  securities,
such as are not often united in the same individual.
  It is my intention to follow this second part with
a third, the completion of which, however, cannot
be looked for before the lapse of two years.   This
third part will contain  an investigation of the food
of man and animals, the analysis of all articles of
diet, and the study of the  changes which the raw
food undergoes in its preparation ; as, for example,
in fermentation (bread), baking, roasting, boiling,
&c.   Already,  it is true, many analyses have been
made for the proposed work; but  the  number of
objects of investigation is exceedingly large, and in
order to determine with accuracy the absolute value
of seed, or of flour, or of a species of fodder, &c, as
food, the  ultimate analysis alone is  not  sufficient;
there are required comparative investigations, which
present very great difficulties.
                         Dr. JUSTUS LIEBIG.
      GlESSEN,
    3rd June, 1842. 
NOTE.
  I would beg leave to  refer the chemical as
well as  the physiological reader particularly to the
analyses (in  Note (27), Appendix) of the animal
tissues, which ought to have been referred to on
pages 43  and 126, and which at present  are only
referred to in  Note  (7).   Since the work  was
printed, moreover, there has been added, at the end
of the  Appendix, an interesting paper by Keller
(see page 325), confirming the very important ob-
servation of A. Ure, junior, as to the conversion of
benzoic  acid into hippuric acid in the human body;
a fact which I perceive, by the Philosophical Maga-
zine for  June, has also been confirmed by Mr. Gar-
rod, probably at an earlier period than by M. Keller.
The reader will perceive that this fact  strengthens
materially the argument of the Author on the action
of remedies.
                                       W. G. 
PREFACE,
  By the application to Chemistry of the  methods
which had for centuries been followed by philoso-
phers in ascertaining the causes of natural pheno-
mena in physics—by the observation of weight and
measure—Lavoisier laid the foundation of a new
science, which, having been cultivated by a host of
distinguished men, has, in a singularly short period,
reached a high degree  of perfection.
  It was the investigation and determination of all
the conditions which are essential to an observation
or an experiment, and the discovery of  the  true
principles  of scientific research, that  protected
chemists from error, and conducted them, by a way
equally simple and secure, to discoveries which have
shed a  brilliant fight  on those natural phenomena
which were previously the most  obscure and in-
comprehensible.
   The  most useful  applications to the  arts, to in-
dustry,  and to all branches of knowledge related to
chemistry, sprung from the laws thus established;
and this  influence was not delayed till chemistry 
 ■*■                 PREFACE.
 had attained its highest  perfection, but came into
 action with each new observation.
   All existing experience and observation in other
 departments of science reacted, in like manner, on
 the improvement and development of chemistry;
 so that chemistry received from metallurgy and
 form other industrial arts as much benefit as she
 had conferred on them.  While they simultaneously
 increased in wealth, they mutually contributed  to
 the development of each other.
   After mineral chemistry had gradually attained
its present  state of development, the  labors  of
 chemists took a new direction.   From the  study
of the constituent parts of vegetables  and animals,
new and altered views have arisen; and the present
work is an attempt to apply these views to physio-i
 logy and pathology.
   In earlier times the attempt has been made, and
often with great success,  to  apply to the  objects of
the medical art the views  derived from an acquaint-
ance with chemical observations.   Indeed, the great
physicians, who lived towards the end of the seven-
teenth century, were the founders of chemistry, and
in those days the only philosophers acquainted with
it.  The phlogistic system was the dawn  of a new
day ; it was  the  victory of philosophy over the
 rudest empiricism. 
PREFACE.
XI
  With all  its discoveries, modern chemistry has
performed but slender services to physiology and
pathology; and we cannot be  deceived as to the
cause of this failure, if we reflect that it was found
impossible to trace any sort of relation between the
observations  made  in  inorganic chemistry, the
knowledge  of the  characters  of the elementary
bodies and of such of their compounds as could be
formed in the laboratory, on the one hand, and the
living body, with the characters of its constituents,
on the other.
  Physiology took no share  in  the advancement of
chemistry, because for a long period she received
from the  latter science no  assistance  in her own
development.  This state of matters has been en-
tirely changed within five-and-twenty years.  But
during this period physiology has also acquired new
ways and methods of  investigation within her own
province ;  and it is only the  exhaustion of these
sources of discovery which  has enabled us  to look
forward to a change in the direction of the labours of
physiologists.  The time for such a  change is now
at hand; and a perseverance in the  methods lately
followed in physiology would now, from the want,
which must soon be felt, of fresh points of departure
for researches, render physiology more extensive,
but neither more profound nor more  solid. 
XU                 PREFACE.
   No one will venture to maintain, that the know-
ledge of the forms and of the phenomena of motion
in organised beings is either unnecessary or unpro-
fitable.   On the contrary, this knowledge must be
considered as altogether indispensable to that of the
vital processes.  But it embraces only  one class of
the conditions necessary for the acquisition of that
knowledge, and is not of itself sufficient to enable
us to attain it.
   The study of the uses and functions of the differ-
ent organs, and of their mutual connection in the
animal body, was formerly the chief object of phy-
siological researches ;  but lately this study has
fallen into the  back-ground.  The greater part of
all the  modern discoveries has served to enrich
comparative anatomy far more than physiology.
   These researches have yielded the most valuable
results in relation to the recognition of  the dissimi-
lar forms and conditions to be found in  the healthy
and in the diseased organism ; but  they  have
yielded no conclusions calculated to give us a  more
profound insight  into the essence of the vital pro-
cesses.
   The  most  exact  anatomical knowledge of the
structure of the tissues cannot teach us their uses •
and from the microscopical examination of the  most
minute  reticulations of the vessels we can learn no 
PREFACE.
xiii
more  as to their functions than we have  learned
concerning vision from counting the surfaces on the
eye of the fly.  The most beautiful and elevated
problem for the human intellect, the discovery of
the laws of vitality, cannot be resolved, nay, cannot
even be imagined, without an accurate knowledge
of chemical forces ;  of those forces which  do nofi
act at sensible distances ; which are manifested in
the same way as  those ultimate  causes by which
the vital phenomena are determined ;  and which
are invariably found  active, whenever dissimilar
substances come into contact.
   Physiology, even in the present day,  still endea-
vors, but always after the fashion of the phlogistic
chemists  (that  is, by the qualitative method,) to
apply chemical  experience to the removal  of dis-
eased conditions; but with all these countless experi-
ments we are not one step nearer to the causes and
the essence of disease.
   Without proposing well-defined questions, expe-
rimenters have placed blood, urine, and  all the con-
stituents of the  healthy or diseased frame,  in con-
tact with acids, alkalies, and all sorts of chemical
re-agents; and  have  drawn,  from observation of
the changes thus  produced, conclusions as  to their
behaviour in the body.
                        B 
XIV                 PREFACE.
  By pursuing  this  method, useful "remedies or
modes of treatment might  by accident be  disco-
vered; but a rational physiology cannot be founded
on mere re-actions, and  the  living body cannot be
viewed  as a chemical laboratory.
  In  certain  diseased  conditions,  in which  the
blood acquires a viscid consistence, this state can-
not be permanently removed by a chemical action
on the fluid circulating in the blood-vessels.   The
deposit of a sediment from the urine may, perhaps,
be prevented by alkalies, while their action has not
the remotest tendency to remove  the cause of dis-
ease.   Again, when we observe, in  typhus, insolu-
ble salts of ammonia in  the faeces, and a change in
the globules of the blood similar to that which may
be artificially produced by ammonia, we are not, on
that account, entitled to consider the  presence of
ammonia in the body as the cause, but only as the
effect of a cause.
   Thus  medicine, after the fashion of the Aristote-
lian philosophy, has  formed certain conceptions in
regard to nutrition and  sanguification ; articles of
diet  have been  divided into nutritious  and  non-
nutritious ;  but  these theories,  being founded on
observations destitute of the conditions most essen-
tial to the drawing of just conclusions, could not be
received as expressions of the truth. 
PREFACE.
XV
  How clear are  now  to us the  relations  of the
different articles of food to the objects which they
serve in  the body, since organic chemistry  has
applied to the investigation her quantitative  method
of research !
  When a lean goose, weighing 4 lbs., gains, in
thirty-six days, during which it has been fed with
24 lbs. of maize, 5 lbs. in weight and yields  3| lbs.
of pure fat, this  fat cannot have been contained in
the  food, ready formed, because  maize does not
contain the thousandth part of its  weight of fat, or
of any substance resembling fat.  And when a cer-
tain number of bees, the weight of which is exactly
known, being fed with pure honey, devoid of wax,
yield one part  of wax for every  twenty parts of
honey consumed, without any change being percep-
tible in their health or in their weight, it is impossi-
ble  any longer to entertain doubt  as to the  forma-
tion of fat from sugar in the animal body.
  We  must adopt the method which has thus led
to the discovery of  the origin of fat, in the  investi-
gation of the origin  and alteration of the secretions,
as well as in the study of all the other phenomena
of the  animal body.   From  the  moment that we
begin to look earnestly and conscientiously for the
true  answers  to  our questions, that we take the
trouble, by means of weight and measure, to fix our 
XVi                PREFACE.
observations, and express them  in  the form  oi
equations, these answers are obtained without diffi-
culty.
  However numerous our observations may be, yet,
if they only bear on one side of a question, they
will  never enable us  to penetrate  the essence of a
natural phenomenon in its full significance.  If we
are to derive any advantage from  them, they must
be directed to  a well-defined  object ;  and there
must be an organized connection between them.
  Mechanical philosophers and chemists justly as-
cribe to their methods of research the greater part
of the success which has  attended their  labors.
The result of every such investigation, if it bear in
any degree the stamp of perfection, may always be
given in few words ;.  but these few words are eter-^
nal truths, to the discovery of which numberless
experiments  and questions  were  essential.   The
researches themselves, the  laborious experiments
and complicated apparatus, are forgotten as soon as
the truth  is ascertained.  They v. ere the ladders*
the shafts, the  tools,  which were  indispensable to.
enable us  to attain to the rich vein  of ore ;  they
were the  pillars  and air passages  which protected
the mine from water and from foul air.
  Every chemical or physical  investigation, how-
ever insignificant, which lays claim, to  attention, 
PREFACE.
xvii
must  in the present day possess  this character.
From  a certain  number  of  observations it  must
enable us to draw some conclusion, whether it be
extended or limited.
  The  imperfection of the method or system  of
research adopted by physiologists can alone explain
the fact, that for the last fifty years  they have esta-
blished so few new and solid truths in regard to a
more  profound  knowledge of the functions of the
most  important  organs, of the spleen, of the liver,
and of the numerous glands  of the body;  and the
limited acquaintance of physiologists with the me-
thods of research employed in chemistry will con-
tinue  to be the chief impediment to the progress of
physiology, as well as a reproach which that science
cannot escape.
  Before  the time  of Lavoisier,   Scheele,  and
Priestley, chemistry was not  more  closely related
to physics than  she  is now to,physiology.   At the
present day chemistry is  so fused,  as it were, into
physics, that it would be a difficult matter to draw
the line between them distinctly.   The connection
between chemistry and physiology is the same, and
in another half-century it  will be found impossible
to separate them.
  Our questions and our  experiments intersect  in
numberless curved lines the straight line that leads
                       B* 
 XVlii               PREFACE.
 to truth.   It is the points of intersection that indi-
 cate to us the true  direction ; but, owing to  the
 imperfection of the  human intellect, these curve
 lines must be pursued.  Observers in chemistry and
 physics have the eye ever fixed on the object which
 they seek to attain.  One may succeed, for a space,
 in following the direct  line ; but all are prepared
 for circuitous paths.   Never doubting of the ulti-
 mate success of their efforts, provided they exhibit
 constancy and  perseverance, their  eagerness  and
 eourage are only exalted by difficulties.
  Detached  observations, without  connection,  are
points scattered over the plain, which do not allow
us to choose a decided path.  For centuries chemis-
try presented nothing but these points, and  sufEr
eient means were available to fill up the intervals
between  them.   But permanent  discoveries and
real  progress were only made when chemists ceased
to make use of fancy to connect them.
  My object in the present work has been to direct
attention  to the  points of intersection of chemistry
with physiology, and to point out those parts in which
the sciences become, as it were, mixed up together-
It contains a collection of problems, such as chemis-
try at present requires to be resolved; and a number
of conclusions drawn  according to the rules of that
science from such observations as have been made> 
                    PREFACE.                 XIX
  These questions and problems will be resolved r
and we cannot doubt that we shall have in that
case a  new physiology and  a rational pathology.
Our sounding line,  indeed, is not long enough to-
measure the depths of the  sea, but is  not on that
account less valuable to us : if it assist us, in the
mean time, to avoid rocks and shoals, its use is suf-
ficiently obvious.  In the hands of the physiologist,,
organic  chemistry must become  an   intellectual
instrument, by means of which he will  be enabled
to trace the causes of phenomena invisible to the
bodily sight;  and if among the  results which I
have developed or indicated in this work, one alone
shall admit of a useful application, I shall consider
the object for which it was written as fully attained.
The path which has led to it  will open up  other
paths; and this I consider as the most important
object to be gained.
                            JUSTUS  LIEBIG,
  Giessen, April, 1842^ 
 
CONTENTS.
PART I.
Yital'force, vis vitse,. or vitality  .....    f&ge
Distinction between animal and vegetable life
Assimilation the result of chemical forces
Vitality independent of consciousness
Laws of the vital force       ......
Conditions of animal life.....
Nutrition  depends on chemical changes
Amount of oxygen inspired by an adult man
it combines with, carbon and hydrogen in the body
The consumption of oxygen varies
Effect of heat on these variations
The mutual action of oxygen  and carbon in the body is
     the true source of animal heat
The amount of oxygen regulates that of food
Effects  of climate on the appetite
The process of starvation.....
Cause of  death in starvation and chror'c diseases
Nerves  and muscles not the source of animal body
Amount of animal heat.....
Nervous and vegetative life   ......
Nutrition depends on the constituents of blood   .
Identity of organic composition in  fibrine and albumen
Nutrition in the carnivora the  most simple
Li  the  herbivora, depends on the azotised products of
     vegetables     •    «    •    •    •
45 
XXII
CONTENTS.
These products identical with the constituents of blood   •  47
The blood of animals is therefore formed by vegetables    •  48
Uses of the non-azotised ingredients of food     .     •     ^
Chano-es of the food in the organism of carnivora        •   53
Carbon accumulates in the bile.....
Nitrogen in the urine.......59
The carbon is consumed or  burned    .    .    •     •     60
True function of the bile......62
Amount of bile secreted......64
Assimilation more energetic in the young animal   .     .   67
The butter, sugar,  &c, of its food support respiration       68
The same is true of the class of herbivora ...     70
Waste of matter very rapid in carnivora       ...   76
Importance of agriculture to population    ...     77
Assimilation less energetic  in the carnivora   ...   80
Origin of fat in domesticated animals       ...     81
Its formation is a source of  oxygen      ....   86
It is formed when  oxygen is deficient, and is a source of
    animal heat      .          .....88
Elements of nutrition and of respiration       ...   96
Gelatine incapable of serving for nutrition, strictly so called  97
But it may serve to nourish the gelatinous tissues,     .     98
                       PART  II.

        THE METAMORPHOSIS OF TISSUES.

Discovery of proteine.......105
It is formed by vegetables alone       ....     106
Theory of chyraification      ....             108
Use of the saliva.....               H3
Source of the nitrogen exhaled from the lungs and skin  .   114
Composition of proteine      .                           101
Composition of the animal tissues      .     .               125
Gelatine contains no proteine, although formed from it      128
The secretions contain all the elements of the blood         132 
CONTENTS.
XXU1
Formula of blood and metamorphoses of bile  .
Metamorphoses of blood and flesh     ....
The constituents of the urine derived from the  metamor
     phosed tissues......
Relation of blood or flesh and proteine  to the secretions
     and excretions.......
Formation of gelatine......
Origin of bile in the carnivora.....
Origin of bile in the herbivora     ....
Origin of hippuric acid......
Formation of the chief secretions and excretions
Soda essential to the bile......
Relation of urine to bile      .....
Relation of starch to bile......
Uses of common salt......
Certain remedies take a share in the vital transformations
Chief qualities of the blood      .....
Modus operandi  of organic remedies
All organic poisons contain nitrogen   ....
Theine identical with caffeine      ....
Relation of theine and  caffeine to bile
Theory of their action......
Theory of the action of the vegetable alkalies
Composition and origin of nervous matter
It is related to that of the vegetable alkalies
Theory of the action of the latter  ....
Phosphorus seems essential to nervous matter
                       PART III.

1.  The phenomena of motion in the animal organism      195
2.  The  same  subject,  with particular reference to the
    waste and supply or change of matter       .    .    233
3.  Theory of disease.......254
4.  Theory of respiration......265 
xxiv
CONTENTS.
                       APPENDIX.

Containing the analytical evidence referred to in the sec-
    tions  in which are described the chemical processes
    of respiration, nutrition,  and the metamorphosis of
    tissues.........279
On the conversion of benzoic acid  into hippuric acid in
    the human body, by W. Keller   ....     325
INDEX.........329 
      ORGANIC  CHEMISTRY
                   APPLIED TO

PHYSIOLOGY AND PATHOLOGY.
   I. In the animal ovum, as well as in the seed of
a plant, we  recognize a certain remarkable  force,
the source of growth, or increase in the mass, and
of reproduction, or of supply of the  matter con-
sumed ; a force in a slate of rest.  By the action of
external influences, by  impregnation,  by the pre-
sence  of air and moisture, the condition of static
equilibrium of this force is disturbed ; entering into
a state of motion or activity, it exhibits itself in the
production  of a series  of  forms, which,  although
occasionally bounded by right lines, are yet widely
distinct from geometrical forms, such as we observe
in crystallised minerals.  This force is called the
vital force, vis vita or vitality.
  The increase of mass in a plant is determined by
the occurrence of a  decomposition which  takes
place in certain  parts of the plant  under the influ-
ence of light and heat.
  In the vital process, as it goes on in vegetables,
it is exclusively inorganic matter which undergoes
this decomposition ; and if, with the most  distin-
                     1 
2
VEGETABLE  AND
guished mineralogists, we consider atmospherical
air and certain other gases  as minerals, it may be
said that the vital  process in vegetables accom-
plishes  the  transformation  of  mineral substances
into an organism endued with life ; that the mineral
becomes part of an organ possessing vital force.
   The increase of mass in a living plant implies
that certain component parts of its nourishment be-
come component parts  of the  plant;  and a  com-
parison  of the chemical composition  of the  plant
with that of its nourishment,  makes known to us,
with positive certainty, which of  the component
parts of the latter  have been assimilated, and which
have been rejected.
   The observations  of vegetable physiologists and
the researches of chemists  have mutually contri-
buted to establish the fact, that the  growth and
development of vegetables depend on  the elimi-
nation of oxygen, which is separated from the  other
component parts of their nourishment.
   In contradistinction to  vegetable  life, the life of
animals  exhibits  itself in the continual absorption
of the oxygen of the air,  and its combination with
certain component parts of the animal body.
   While no part of  an  organized  being  can serve
as food to  vegetables,  until, by the processes of
putrefaction and decay, it has assumed the form of
inorganic matter,  the animal  organism requires,
for its support and development, highly organised
atoms.   The  food of all animals,  in  all circum-
stances, consists of parts of organisms. 
ANIMAL LIFE.                3
  Animals are distinguished from vegetables by the
faculty of locomotion, and, in general, by the posses-
sion of senses.
  The existence  and activity of these distinguish-
ing faculties depend on  certain instruments which
are never found  in  vegetables.  Comparative ana-
tomy  shows, that the phenomena of motion and sen-
sation depend on certain kinds of apparatus, which
have  no other relation to each other  than this, that
they meet in a common  centre.   The substance  of
the spinal  marrow, the  nerves, and the brain, is in
its composition, and  in its chemical characters, essen-
tially distinct from that of which cellular substance,
membranes, muscles, and skin are composed.
   Every thing in the  animal organism, to which
the name of motion can  be applied, proceeds from
the nervous apparatus.   The phenomena of motion
in vegetables, the circulation of the sap,  for exam-
ple, observed in many  of the  characeae, and  the
closing of flowers  and  leaves, depend on physical
and  mechanical  causes.   A  plant  is destitute of
nerves.  Heat and light are  the  remote causes of
motion in vegetables ; but  in  animals we recognize
in the nervous apparatus a source of power, capa-
ble of renewing itself at every moment of their ex-
istence.
   While the  assimilation of food in vegetables, and
the  whole process of their formation, are depen-
dant on  certain external influences  which produce
 motion,  the  development  of  the  animal  organism
is, to a certain extent, independent of these external 
4
ASSIMILATION  THE  RESULT
influences, just because the animal body can pro-
duce  within  itself that source of motion which is
indispensable to the vital process.
  Assimilation,  or  the process of formation  and
growth—in  other words, the passage  of matter
from a state  of motion to that of rest—goes  on in
the same way in animals and in vegetables.  In both,
the same cause  determines the increase of mass.
This  constitutes the  true  vegetative life, which is
carried on without consciousness.
  The activity of vegetative life manifests itself,
in vegetables, with  the aid of  external influences ;
in animals, by means of influences produced within
their organism.   Digestion, circulation, secretion,
are no doubt under the influence of the  nervous
system;  but the force which gives to  the germ, the
leaf, and the radical  fibres of the vegetable the
same  wonderful  properties, is the  same  as that
residing in the secreting membranes and glands of
animals,  and  which enables every animal organ to
perform  its own proper function.  It is  only the
source of motion that differs in the two great classes
of organised beings.
  While the organs of the vital motions are  never
wanting  in the lowest orders of  animals, as in the
impregnated  germ of the ovum, in which they are
developed first of all, we find, in the higher orders
of animals, peculiar organs of feeling and sensation,
of consciousness  and of a  higher intellectual ex-
istence.
  Pathology informs us that the true vegetative life 
              OP CHEMICAL  FORCES.            5

is  in  no way dependant on the presence of this
apparatus; that the process  of  nutrition  proceeds
in those parts  of the  body  where the  nerves of
sensation and voluntary motion are  paralysed,  ex-
actly  in the same way as in other parts where these
nerves  are in the  normal condition ; and, on  the
other hand, that the most energetic volition is inca-
pable of exerting any influence on the contractions
of the heart, on the motion of the intestines, or on
the processes of secretion.
   The higher phenomena of  mental existence can-
not, in  the present state of science, be referred to
their  proximate,  and still  less  to their ultimate
causes.  We only know  of  them, that they exist;
we ascribe them to an immaterial agency, and that,
in so far as  its manifestations  are connected with
matter, an agency entirely  distinct from the vital
force, with which it has nothing in common.
   It  cannot  be denied that  this peculiar force ex-
ercises a  certain influence on the activity of vege-
tative life, just  as other immaterial  agents,  such
as Light, Heat, Electricity, and Magnetism do ; but
this influence is  not of a determinative  kind,  and
manifests itself only as an acceleration, a retarding,
or a  disturbance of the  process of vegetative life.
In a manner exactly  analogous, the vegetative life
reacts on the conscious mental existence.
   There are thus two  forces which are found in
activity together ;  but consciousness  and intellect
may  be  absent  in animals  as  thev  are in  living
vegetables, without  their vitality being  otherwise
                        1* 
G
VITALITY INDEPENDENT
affected than by the want of a peculiar  source  of
increased energy or  of  disturbance.  Except  in
regard to this, all  the vital chemical processes go
on precisely  in the same way in man and in the
lower animals.
  The efforts of philosophers,  constantly renewed,
to penetrate  the  relations  of the soul  to animal
life,  have all along retarded  the progress of physir
ology.   In this attempt men  left  the  province  of
philosophical  research for  that of  fancy;  physi-
ologists,  carried  away by imagination,  were far
from  being  acquainted  with  the  laws  of  purely
animal life.   None  of them had a clear conception
of the process of development and  nutrition,  or of
the true cause of death.   They professed  to explain
the most obscure  psychological phenomena, and
yet they were unable to say what fever is, and in
what way quinine acts in curing it.
  For the purpose of  investigating the laws of vital
motion  in the animal body, only  one  condition,
namely,  the  knowledge  of the apparatus  which
serves for its production,  was ascertained ; but the
substance of  the organs, the  changes which  food
undergoes in the  living body, its  transformation
into  portions  of organs,  and its re-conversion into
lifeless compounds, the  share  which the  atmos-
phere  takes  in the processes of vitality  ; all these
foundations for future conclusions were  still want-
ing.
   What has  the soul, what have consciousness and
intellect to do with the development of the human 
       OF CONSCIOUSNESS AND INTELLECT.      7

foetus,  or the  foetus  in  a fowl's  egg?  not  more,
surely, than with  the  development  of the  seeds
of a  plant.  Let  us first  endeavour  to refer to
their  ultimate  causes those  phenomena  of life
which  are not physiological; and  let  us beware
of drawing conclusions before  we have a ground-
work.   We know exactly the mechanism  of the
eye; but neither anatomy nor chemistry will ever
explain how the rays of light act on consciousness,
so as to produce vision.  Natural science has fixed
limits which cannot be passed ; and it must always
be  borne in  mind that, with all our  discoveries,
we shall  never know  what light, electricity,  and
magnetism  are in  their essence,  because, even
of those  things which are  material, the human in-
tellect has only conceptions.   We can ascertain,
however, the laws which regulate their motion and
rest,  because  these  are  manifested in  phenomena.
In  like manner the laws of  vitality,  and of all
that disturbs,  promotes, or  alters it, may certainly
be discovered, although we shall never learn what
life  is.  Thus the discovery of the laws of gravita-
tion and of the planetary  motions  led to  an  en-
tirely  new conception of the cause of these phe-
nomena.   This conception  could  not  have been
formed in all its  clearness  without a knowledge
of  phenomena  out  of which  it was  evolved;
for, considered by  itself,  gravity,  like light  to
one born blind, is a mere word, devoid of mean-
ing.
   The modern science  of  physiology has  left the 
8
LAWS OF THE
track of Aristotle.    To the eternal advantage  of
science,  and  to the  benefit  of mankind, it no
longer invents  a horror vacui,  a  quinta essentia,  in
order to furnish  credulous hearers  with solutions
and  explanations of phenomena, whose true con-
nection with others, whose ultimate cause- is  still
unknown.
  If we assume that all  the phenomena exhibited
by the organism of plants and animals are to be
ascribed to a peculiar cause, different in its mani-
festations from  all other causes which produce  mo-
tion or change of condition; if,  therefore, we regard
the vital force as an independent force, then, in the
phenomena of organic life, as  in all other pheno-
mena ascribed to the action of forces, we have the
statics, that is,  the  state of equilibrium determin-
ed by a resistance, and the dynamics, of the vital
force.
  All the parts of the animal  body are produced
from a peculiar fluid, circulating in its organism, by
virtue of an influence residing in every cell, in every
organ, or part of an  organ.  Physiology teaches that
all parts of the body were originally blood ; or that
at least they were brought to the growing organs by
means of this fluid.
  The most  ordinary experience  further  shows,
that  at each  moment of life,  in the  animal organ-
ism,  a continued change of matter, more  or less
accelerated, is going on; that a  part of the structure
is transformed  into unorganised matter, loses  its
condition of life, and must be again renewed. Phy- 
VITAL FORCE.                 9
siology has  sufficiently decisive grounds  for  the
opinion, that every motion, every manifestation of
force, is the result of a transformation of the struc-
ture or of its  substance; that every conception,
every mental affection, is followed by changes in
the chemical  nature of the secreted  fluids; that
every thought, every sensation, is accompanied by
a change  in  the  composition of the  substance of
the brain.
  In order to keep  up  the phenomena of  life in
animals, certain matters are required, parts  of or-
ganisms, which we  call  nourishment.  In  conse-
quence of a series of alterations, they serve either
for the increase of the  mass {nutrition),  or for the
supply of the  matter  consumed Reproduction), or,
finally, for the production of force.

  II.  If the first condition  of animal life  be the
assimilation of what is commonly  called  nourish-
ment, the second  is a continual absorption of oxy-
gen from the atmosphere.
  Viewed as an  object of scientific research,  ani-
mal life exhibits itself in  a series of phenomena,
the connection  and recurrence of which are deter-
mined by the changes  which the food  and  the oxy-
gen absorbed from the  atmosphere undergo in the
organism under the influence of the vital force.
  All vital activity  arises from  the mutual action
of the oxygen of  the atmosphere and  the elements
of the food. 
 10       NUTRITION AND REPRODUCTION

   In the  processes  of nutrition and  reproduction,
we perceive the passage of matter from the state of
motion  to  that of rest (static  equilibrium);  under
the influence  of the nervous  system, this  matter
enters again into a state of motion.   The ultimate
causes  of  these  different conditions of the  vital
force are chemical forces.
   The  cause  of the state of  rest is a resistance,
determined by a force of attraction  (combination),
which acts between  the smallest particles of matter,
and is  manifested only when these are in actual
contact, or at infinitely small distances.
   To this peculiar  kind of attraction we may of
course apply different names ;  but the chemist  calls
it affinity.
   The  cause of the state of motion is to  be found
in a  series of changes which the food undergoes
in the  organism, and these are the results of pro-
cesses of decomposition,  to which  either the food
itself, or the  structures formed from it, or parts of
organs, are subjected.
   The  distinguishing character of  vegetable life
is a  continued  passage  of matter from  the  state
of motion  to that of static equilibrium.  While a
plant lives, we  cannot perceive  any  cessation in
its growth ; no part of an  organ in the plant di-
minishes in size.  If decomposition occur, it is the
result of assimilation.  A plant produces  within
itself no cause of motion; no part  of its structure,
from  any influence  residing in its organism,  loses
its state of vitality,  and is converted into unorgan- 
        DEPEND  ON CHEMICAL CHANGES.      11

ised, amorphous compounds; in a word, no waste
occurs in vegetables.  Waste,  in the animal body,
is a change in the state or in the composition of some
of its parts,  and consequently  is the result  of che-
mical actions.
   The influence of poisons  and of remedial agents
on the  living animal  body evidently  shows  that
the chemical decompositions  and combinations in
the body, which manifest themselves in the  phe-
nomena  of vitality, may be increased  in intensity
by chemical forces of analogous  character, and
retarded or put  an end  to by those  of opposite
character; and  that  we  are  enabled  to exercise
an influence on  every part of an  organ  by means
of substances possessing  a well-defined chemical
action.
   As, in the closed galvanic circuit, in consequence
of certain changes which  an inorganic body, a me-
tal, undergoes when placed in contact with an acid,
a  certain something becomes cognizable  by our
senses, which we call a current of electricity ;  so, in
the animal body,  in consequence of transformations
and changes  undergone by matter previously consti-
tuting a part of the organism, certain phenomena of
motion and activity are perceived, and these we
call life, or vitality.
   The electrical  current manifests  itself in certain
phenomena  of attraction  and  repulsion, which it
excites in other bodies naturally motionless, and by
the phenomena  of the formation and decomposi-
tion of chemical compounds,  which occur  every 
12
OXYGEN REQUIRED.
 where, when the resistance is not sufficient to arrest
 the current.
   It is from this point of view, and from no other,
 that chemistry ought to contemplate the phenomena
 of life.   Wonders surround us on every side.  The
 formation of a crystal, of  an  octahedron, is not less
 incomprehensible than the production of a leaf or
 of a muscular fibre; and the  production  of vermi-
 lion  from  mercury  and  sulphur  is  as  much an
 enigma as the formation of an eye from the  sub-
 stance of the blood.
   The first conditions of animal life are nutritious
 matters and oxygen, introduced into the system.
   At every moment of bis life man is taking oxygen
 into his system, by means of  the organs of respira-
 tion ; no pause is observable while life continues.
   The  observations of physiologists have  shown
 that the body of an adult man, supplied with suffi-
 cient food, has neither increased nor diminished in
 weight  at  the end  of twenty-four hours; yet the
 quantity of oxygen taken into  the system during this
 period is very considerable.
   According to  the  experiments of Lavoisier, an
 adult man  takes into his system, from the atmos-
 phere,  in  one year, 746 lbs.,  according to Menzies,
837 lbs., of oxygen ; yet we find his weight, at the
 beginning and  end of the year,  either quite the
 same, or differing, one way or the other, by at most
 a few pounds. (1)*
   What, it may be asked,  has become of the enor-
* The Numbers refer to the Appendix. 
AS WELL AS  FOOD.
13
mous weight of oxygen thus introduced, in the
course of a year into the human system ?
  This question may be answered satisfactorily ;  no
part of this oxygen remains in the system ; but it is
given out again in the form of a compound of carbon
or of hydrogen.
  The carbon and  hydrogen of certain parts of the
body have entered  into  combination with the oxy-
gen introduced  through the lungs and through the
skin, and have been given out in the  forms of car-
bonic acid gas and  the vapour of water.
  At every moment,  with every expiration, certain
quantities of its elements separate from  the ani-
mal organism, after  having entered into combina-
tion, within the  body, with the oxygen of the atmos-
phere.
  If we  assume,  with  Lavoisier  and   Seguin,  in
order to obtain a  foundation for  our calculation,
that an adult man receives into his system  daily
32^oz. (46,037 cubic inches = 15,661 grains, French
weight) of oxygen,  and that the weight of the
whole mass of his  blood, of which 80 per cent, is
water, is 24 lbs.; it then appears,  from  the known
composition  of  the blood, that, in order to convert
the whole of its carbon and hydrogen into  carbonic
acid and  water, 64,103 grains  of oxygen are re-
quired.  This quantity will be taken into the sys-
tem of an adult in four days five hours.  (2)
  Whether  this oxygen enters into combination
with the elements of the blood, or with other  parts
of the body  containing carbon and  hydrogen, in
                       2 
14
OXYGEN COMBINES WITH
either case  the  conclusion is inevitable,  that  the
body of a man, who daily takes into the system
32£ oz. of oxygen, must receive daily in the shape
of nourishment,  as much carbon  and hydrogen as
would suffice to  supply 24 lbs. of blood with  these
elements; it being presupposed that the weight of
the body remains unchanged, and that  it retains its
normal condition as to health.
  This supply is furnished in the food.
  From the  accurate determination of the quantity
of carbon daily  taken into  the system in  the food,
as well as of that proportion of it which passes out
of the body in  the  fasces  and urine, unburned,
that  is, in some  form in which it is not combined
with  oxygen,  it appears that  an adult,  taking
moderate exercise, consumes 13*9 oz. of carbon
daily. (3)
  These 13-ft- oz. of carbon escape through the skin
and lungs as carbonic  acid gas.
  For conversion into carbonic acid gas, 13-ft- oz. of
carbon require 37 oz. of oxygen.
  According to the analyses of Boussingault (Ann.
de Ch. et de Ph. LXXI. p. 136)  a horse consumes
in twenty-four hours 97^ oz. of carbon, a milch cow
69-ft oz.   The quantities of carbon here mentioned
are those given  off from the  bodies of these ani-
mals in the  form of carbonic acid ; and it appears
from them that  the horse consumes, in converting
carbon into carbonic acid, 13 lbs.  3^ oz. in twenty-
four  hours, and  the milch  cow  11 lbs. lOf oz. of
oxygen in the same time. (4) 
THE  CARBON OF  THE FOOD.         15
   Since no part of the oxygen  taken  into the sys-
tem is  again  given off in any other form but that
of a compound of carbon or hydrogen ; since fur-
ther,  the carbon and  hydrogen given  off are  re-
placed  by carbon  and hydrogen  supplied  in  the
food, it  is clear that  the  amount  of nourishment
required by the  animal body must be in a direct
ratio  to the  quantity  of  oxygen  taken  into  the
system.
   Two  animals,  which  in  equal  times  take
up by  means of  the  lungs  and skin  unequal
quantities  of  oxygen,  consume quantities  of  the
same nourishment  which are unequal in the same
ratio.
   The consumption of oxygen  in equal  times may
be  expressed  by the  number of respirations ; it is
clear that, in  the same  individual, the quantity of
nourishment required must vary with the force and
number of the respirations.
  A child, in  whom the organs of respiration are
naturally very active, requires food oftener than an
adult, and bears hunger less easily. A bird, deprived
of food, dies on the third day, while a serpent, with
its sluggish respiration, can live without food three
months  and longer.
  The number of respirations is smaller in a state
of rest than during exercise or work.   The quan-
tity of food necessary in  both conditions must vary
in the same ratio.
  An excess of food  is  incompatible  with  defi-
ciency in respired oxygen, that is, with deficient ex- 
16
EFFECT OF HEAT ON THE
ercise ; just as  violent exercise, which implies an
increased  supply of  food, is  incompatible  with
weak digestive organs.  In either  case the health
suffers.
  But the  quantity of oxygen  inspired is also af-
fected by the temperature and density of the atmos-
phere.
  The capacity of the chest in an animal is a con-
stant quantity.   At every respiration a quantity of
air enters, the volume of which may be considered
as uniform  ; but its  weight, and consequently that
of the oxygen it  contains, is not constant.  Air is
expanded by heat, and contracted by cold, and there-
fore  equal  volumes of hot and  cold air contain un-
equal weights  of oxygen. In  summer, moreover,
atmospherical air contains aqueous vapour, while in
winter it is dry; the space occupied by vapour in
the warm air is  filled up by air itself in winter; that
is, it contains, for the same volume,  more oxygen in
winter than in summer.
  In summer and in winter, at the  pole and at the
equator, we respire an equal volume  of air ; the cold
air is warmed  during respiration, and acquires the
temperature of  the  body.  To introduce into the
lungs a given volume of oxygen, less expenditure of
force is necessary in  winter than in summer; and
for the same expenditure of force,  more oxygen is
inspired in winter.
  It  is obvious, that in an equal number of respira-
tions  we consume more oxygen at  the level of the
sea than on a  mountain.  The quantity both  of 
         AMOUNT OF  OXYGEN  ABSORBED.       17

oxygen  inspired  and of  carbonic  acid expired,
must therefore  vary with the  height of the baro-
meter.
  The oxygen  taken into the system is given out
again in the  same forms, whether  in  summer or
in winter ; hence we expire more  carbon in cold
weather, and when the  barometer is high, than we
do in warm weather; and we  must  consume more
or less carbon in  our food in the same proportion;
in Sweden more than in Sicily ; and in our more
temperate climate a  full eighth more in  winter
than in summer.
  Even when we consume equal weights of food in
cold and warm countries,  infinite wisdom has so
arranged, that the articles of food in  different cli-
mates are most unequal in the  proportion of carbon
they contain.   The fruits on which the natives of
the south prefer to  feed do not  in the fresh state
contain  more than 12 per cent, of carbon, while the
bacon and train  oil used by the inhabitants of the
arctic regions contain from 66  to 80  per cent, of
carbon.
  It is  no difficult matter, in warm climates, to
study moderation in eating, and men can bear hun-
ger for  a long time under the  equator; but cold
and hunger united very soon exhaust the body.
  The mutual action between  the elements of the
food and the  oxygen  conveyed  by  the  circulation
of the blood to every part of the body is  the source
OF  ANIMAL HEAT.
                       2* 
18
SOURCE  OF ANIMAL
  III. All living creatures, whose existence depends
on the  absorption of oxygen, possess  within them-
selves  a source of heat independent of surrounding
objects.
  This truth applies  to  all animals,  and extends,
besides, to  the germination of seeds, to the flower-
ing of plants, and to the maturation of fruits.
  It is only in those parts of the body to which
arterial blood, and with it the oxygen absorbed in
respiration,  is conveyed, that heat  is  produced.
Hair, wool, or feathers, do not  possess an elevated
temperature.
  This high temperature  of the animal body, or,
as it may be  called, disengagement of heat, is uni-
formly and  under  all circumstances the result of
the combination of a combustible substance with
oxygen.
  In whatever way  carbon  may combine with
oxygen, the  act of  combination cannot take place
without the  disengagement of heat.  It is a matter
of indifference whether the combination take place
rapidly or slowly,  at a high or at a  low tempera-
ture ; the amount of heat liberated is  a constant
quantity.
  The carbon of the  food, which is converted into
carbonic acid within the body, must give out ex-
actly as much heat as if it had been directly burnt
in the air or in oxygen gas ; the only  difference is,
that the amount of heat  produced is diffused over
unequal times. In oxygen, the combustion is more
rapid, and the heat more intense; in air it is slower, 
HEAT.--RESPIRATION.
19
the temperature is not so high,  but it  continues
longer.
  It is obvious that the amount of heat  liberated
must  increase  or  diminish with  the quantity of
oxygen  introduced in equal times by  respiration.
Those animals which respire frequently, and conse-
quently consume much oxygen, possess  a higher
temperature than  others,  which,  with a body of
equal size to be heated, take into  the system  less
oxygen.   The  temperature of a  child  (102°) is
higher than that  of an  adult (99-5°).    That of
birds  (104° to 105-4°)  is higher than that of quad-
rupeds (98-5° to 100-4°)  or than  that of fishes or
amphibia, whose proper temperature is from 2-7° to
3-6° higher than that of the medium  in which they
live.  All animals, strictly  speaking,  are warm--
blooded; but in those  only which  possess lungs is
the temperature of the body quite independent of
the surrounding medium.  (5)
  The most trustworthy  observations prove  that
in all  climates, in the temperate zones- as well as
at the equator  or the  poles,  the  temperature of
the body in man, and in what are commonly called
warm-blooded animals, is invariably the same ; yet
how different  are  the circumstances under which,
they live !
  The animal body is a heated mass, which bears
the same relation to surrounding  objects  as  any
other  heated mass. It receives heat when the sur-
rounding objects are  hotter, it loses heat when they
are colder than itself. 
20
UNIFORM TEMPERATUnr,
   We know that the rapidity of cooling increases
with the difference between the temperature of the
heated body and that of the surrounding medium;
that is, the colder the  surrounding  medium  the
shorter the time required for the cooling of the heat-
ed body.
   How unequal, then, must be the loss of heat in a
man at Palermo, where the  external temperature
is nearly equal to that of the  body, and in the polar
regions, where the external temperature is from 70°
to 90° lower.
   Yet, notwithstanding this extremely unequal loss
of heat, experience has shown that the blood of the
inhabitant of the arctic circle has a temperature as
high as that of the native of the south, who lives in
so different a medium.
   This fact, when its true significance is perceived,
proves that the heat given off to the surrounding
medium  is restored within  the  body  with  great
rapidity.  This  compensation takes place more ra-
pidly in winter than in summer, at the pole  than at
the equator.
  Now, in different climates the quantity of oxygen
introduced into the  system  of  respiration, as has
been already shown, varies according to the tem-
perature of the external air; the  quantity of inspir-
ed oxygen increases with the  loss of heat by exter-
nal cooling, and the quantity of carbon or hydrogen
necessary to combine with  this oxygen must be in-
creased in the same ratio.
  It is evident  that the supply of the heat lost 
OF THE ANIMAL BODY.
21
by  cooling  is  effected  by  the mutual  action  of
the elements of the food  and the inspired oxygen,
which combine together.   To make use of a fami-
liar, but  not  on  that account a less just illus-
tration,  the  animal body  acts, in this respect,  as
a furnace, which  we  supply  with  fuel.  It sig-
nifies nothing what intermediate forms  food may
assume,  what changes  it  may undergo in  the
body, the last change is  uniformly the conver-
sion of  its carbon  into carbonic acid, and of its
hydrogen  into  water; the  unassimilated nitrogen
of the  food, along with  the  unburned  or  unoxi-
dised carbon,  is  expelled  in the urine  or  in  the
solid  excrements.    In order  to keep up  in  the
furnace   a constant temperature, we must vary
the  supply   of fuel  according  to  the  external
temperature, that  is, according to the  supply of
oxygen.
  In the animal body the food is the fuel;  with a
proper supply of oxygen we obtain the heat given
out during its oxidation or combustion.  In winter,
when we  take  exercise in a cold atmosphere, and
when consequently the amount of inspired oxygen
increases, the  necessity for food containing carbon
and hydrogen increases in the same ratio; and by
gratifying the  appetite thus  excited, we  obtain the
most efficient protection  against the most piercing
cold.  A  starving man is  soon  frozen  to death;
and every one knows that the animals  of prey in
the arctic regions far exceed in voracity those of the
torrid zone. 
oo
THE  AMOUNT OF OXYGEN
   In cold and  temperate climates, the air, which
 incessantly  strives to consume  the  body,  urges
 man  to  laborious efforts in order to furnish  the
 means of resistance to its action, while, in hot cli-
 mates, the necessity  of  labour  to provide food is
 far less urgent.
   Our clothing is merely an equivalent for a certain
 amount of food.   The more warmly we are clothed
 the less urgent becomes the appetite  for food, be-
 cause the loss of heat by cooling, and consequently
 the amount of heat to be supplied by  the  food, is
 diminished.
   If we   were to go naked, like  certain savage
 tribes, or  if in hunting or fishing we were exposed
 to the same degree of cold as the Samoyedes, we
 should be able with ease to consume 10 lbs. of flesh,
 and perhaps a dozen of tallow candles into the bar-
 gain, daily, as warmly clad travellers have related
 with astonishment of these people.  We should then
 also be able to take the same  quantity of brandy or
 train oil without bad effects, because the carbon and
 hydrogen  of these substances would only suffice to
 keep up the equilibrium  between the external tem-
 perature and that of our bodies.
  According to the preceding expositions, the quan-
 tity of food is regulated  by the number of respira-
 tions, by  the  temperature of the air, and by  the
 amount of heat  given off to the surrounding  me-
 dium.
  No isolated fact, apparently opposed to this state-
ment, can affect the truth of this natural law.—- 
REGULATES THAT OF FOOD.
23
Without temporary or permanent injury to health,
the Neapolitan cannot take more carbon and hydro-
gen in the shape of food than he expires as carbonic
acid and water; and the Esquimaux cannot expire
more carbon and  hydrogen  than he takes into the
system  as food,  unless  in a state of disease or of
starvation.  Let  us examine these states a little
more closely.
  The Englishman in Jamaica sees with regret the
disappearance of  his appetite,  previously a source
of frequently recurring  enjoyment; and  he  suc-
ceeds by the use of cayenne pepper and  the most
powerful  stimulants, in enabling himself to take as
much food as  he was accustomed to  eat  at home.
But the whole of the carbon thus introduced into the
system is not  consumed ; the temperature of the
air is too high, and the  oppressive heat  does not
allow him to increase the number of respirations
by active exercise, and thus to proportion the waste
to the amount of food taken ;  disease of some kind,
therefore, ensues.
  On the other hand, England sends her sick, whose
diseased digestive organs have in a greater or less
degree lost the power of bringing the food into that
state  in  which it is best adapted for  oxidation,
and therefore furnish less resistance to  the oxidis-
ing agency of the atmosphere  than is required in
their  native climate, to southern regions, where the
amount of inspired oxygen is diminished  in so great
a proportion ; and the result, an improvement in the
health, is obvious.  The diseased organs of digestion 
24
HYDROGEN CONTRIBUTES
 have sufficient power to place the diminished amount
 of food in equilibrium with the inspired oxygen ; in
 the colder climate,  the  organs of respiration them-
 selves would have been consumed in furnishing the
 necessary resistance to the action of the atmospheric
 oxygen.
  In our climate, hepatic diseases, or  those arising
 from excess of carbon, prevail in summer ; in win-
 ter,  pulmonic diseases, or those arising from excess
 of oxygen, are more frequent.
  The  cooling of the body, by whatever  cause it
 may be produced,  increases  the amount of food
 necessary.  The mere exposure to the open air, in
 a carriage  or  on the deck of a ship, by  increasing
 radiation  and vaporization, increases the loss of
 heat, and compels us to eat more than usual.  The
 same is true of those who  are accustomed to drink
 large quantities of cold water,  which is given off
 at the  temperature  of the  body,  98-5°.  It in-
 creases the appetite, and  persons of weak consti-
 tution  find it necessary,  by continued  exercise,
 to supply to  the system  the oxygen required to
 restore  the  heat abstracted by the  cold  water.
 Loud and long continued  speaking, the crying of
 infants, moist air, all exert a decided and appre-
 ciable  influence  on the amount of  food which is
 taken.

  IV. In the foregoing pages, it has been assumed
that it is especially carbon and hydrogen which, by
combining with oxygen, serve  to  produce animal 
TO THE ANIMAL HEAT.
25
heat.   In fact, observation proves that the hydrogen
of the food plays a not less important part than the
carbon.
  The whole process of respiration appears most
clearly developed, when we consider the state of a
man, or other animal, totally deprived of food.
  The first effect of starvation is the disappearance
of fat,  and this  fat cannot be traced either in the
urine or in the scanty faeces.  Its carbon and hydro-
gen have been given off through the skin and lungs
in the form of oxidised products; it is  obvious that
they have served to support respiration.
  In the case of a starving man, 32^ oz. of oxygen
enter the system daily, and are given out again in
combination with a part of his body.  Currie men-
tions the case of an individual who was unable t0
swallow, and whose body lost 100 lbs. in  weight
during a month ; and, according to Martell (Trans.
Linn. Soc, vol. xi. p. 411), a fat pig, overwhelmed
in a slip of earth, lived 160 days without food, and
was found to have diminished in weight,  in that
time, more than 120  lbs.  The whole  history of
hybernating animals, and the well-established facts
of the periodical  accumulation,  in  various  ani-
mals,  of fat,   which,  at other periods,  entirely
disappears,  prove  that the  oxygen, in the  res-
piratory process, consumes, without exception, all
such  substances as are  capable  of entering  into
combination  with  it.   It  combines  with  what-
ever  is  presented  to  it;  and the deficiency of
hydrogen is  the only  reason why carbonic  acid
                        3 
26
EFFECTS OF STARVATION.
is the chief  product;  for,  at  the  temperature
of  the  body, the  affinity of  hydrogen  for oxy-
gen  far  surpasses  that of carbon for the  same
element.
  We know, in fact, that the graminivora expire a
volume of carbonic acid equal  to that of the oxy-
gen inspired,  while the carnivora, the only class
of animals whose  food  contains fat,  inspire more
oxygen  than is equal in volume to the  carbonic
acid expired.   Exact  experiments  have  shown,
that in many  cases only half the volume of oxy-
gen is expired in the form of carbonic acid.  These
observations cannot be gainsaid, and  are far more
convincing  than  those arbitrary  and artificially
produced phenomena,  sometimes  called  experi-
ments; experiments which, made as too often they
are,  without regard to the necessary and natural
conditions, possess no value,  and  may be entirely
dispensed with ; especially when, as in the present
case,  nature affords the opportunity for observation,
and when we make a rational use of that  oppor-
tunity.
  In the progress of starvation, however,  it is  not
only the  fat which disappears, but also, by degrees,
all such  of the solids  as are capable  of being dis-
solved.   In the wasted  bodies  of those who have
suffered  starvation, the muscles  are  shrunk and
unnaturally soft, and  have lost their contractility;
all those parts of the body which  were capable of
entering  into  the  state of motion,  have  served to
protect  the remainder  of  the  frame from  the 
         DEATH CAUSED BY  RESPIRATION.     27

destructive influence of the atmosphere.   Towards
the end, the particles of the brain begin to undergo
the process of oxidation, and delirium, mania, and
death close  the  scene ;  that is to say, all resistance
to the  oxidising power of the atmospheric oxygen
ceases, and  the chemical process of eremacausis, or
decay, commences, in which every part of the body,
the bones excepted, enters into combination with
oxygen.
   The  time which is required to cause  death by
starvation depends  on  the  amount  of fat  in  the
body, on the degree of exercise, as in  labour or
exertion of  any kind,  on the temperature  of  the
air,  and finally, on the  presence or absence  of
water.  Through the skin and lungs there escapes
a  certain quantity  of water, and as the presence of
water  is essential to the continuance of the vital
motions, its  dissipation hastens death.  Cases have
occurred, in which  a  full supply of water being
accessible to the sufferer, death has  not occurred,
till after the lapse  of twenty  days.   In  one case,
life was sustained in this way for the  period of sixty
days.
   In all chronic diseases death is produced by  the
same cause, namely, the chemical action of the atmos-
phere.  When those substances are wanting, whose
function in  the  organism is to  support the process
of respiration ;  when the diseased organs are inca-
pable of performing their proper function of produ-
cing these substances ; when they have lost the power
of transforming the food into that shape in which it 
28
RESPIRATION TENDS TO
 may, by entering into combination with the oxygen
 of the air, protect the system from its influence, then,
 the substance of  the organs themselves, the  fat of
 the body, the substance of the muscles, the  nerves,
 and the brain, are unavoidably consumed.*
   The true cause of death  in  these cases  is the
 respiratory process, that  is, the action  of the  at-
 mosphere.
   A deficiency of food, and the want of power to con-
 vert the food into a part of the organism, are both,
 equally a want of resistance ; and  this  is the nega-
 tive cause of the cessation of the vital process.  The
 flame is extinguished, because the  oil is consumed;
 and it is the oxygen of the air which has consumed it.
   In many diseases substances are produced which
 are incapable of assimilation.   By the mere depriva-
 tion of food, these substances are removed from the
 body without leaving a trace behind ; their elements
 have  entered into combination with the oxygen of
 the air.
   From the first  moment that the function of the
 lungs or of the  skin is interrupted or  disturbed,
 compounds, rich in carbon, appear in the  urine,
 which acquires a  brown colour.  Over the whole
 surface of the body oxygen is absorbed, and combines
 with all the substances which offer  no resistance to
it.  In those parts of the body where the access  of

  * For an account of what really takes place in this  process  I
refer to the  considerations on  the  means  by which the  change' of
matter is effected in the body of the carnivora, which will be found
further on. 
              CONSUME THE BODY.            29

oxygen is  impeded ;  for example, in the arm-pits?
or in the soles of the  feet, peculiar compounds are
given  out, recognisable  by  their appearance, or
by  their odour.   These  compounds contain much
carbon.
  Respiration is  the falling weight, the bent spring,
which  keeps the clock in motion ; the inspirations
and expirations  are the strokes of the pendulum
which regulate it.  In our ordinary time-pieces, we
know with mathematical  accuracy the effect pro-
duced  on  their  rate  of  going, by  changes in the
length  of the pendulum,  or in the external tempe-
rature.  Few, however, have a clear conception of
the influence of air and temperature on the health
of the human body ;  and yet the research into the
conditions necessary to keep it in the normal state,
is not more difficult than in the case of a clock.

  V. The  want of a  just conception of force and
effect, and  of the connection of natural phenomena,
has led chemists to attribute a part of the heat gene-
rated  in the  animal body to the action of the ner-
vous system.  If this view exclude chemical action,
or changes in the arrangement  of  the elementary
particles, as a condition of nervous agency, it means
nothing else than to derive the presence  of motion,
the manifestation of a force, from nothing.   But no
force, no power can come of nothing.
  No one will seriously deny the share which the
nervous apparatus has in the respiratory process;
for no  change of condition can occur in the body
                       3* 
30
NERVES AND  MUSCLES
without the nerves; they are essential to all vital
motions.  Under their influence,  the  viscera  pro-
duce  those compounds, which, while they protect
the organism  from the action of  the  oxygen  of
the atmosphere, give  rise  to  animal  heat;  and
when the  nerves cease  to perform their functions,
the whole process of the action of oxygen must
assume another form.  When the pons  Varolii is
cut through in the  dog, or  when a stunning  blow
is inflicted on  the back of the head, the animal con-
tinues to  respire for some time, often more rapidly
than  in the  normal  state; the  frequency of the
pulse at first rather increases  than  diminishes, yet
the animal  cools  as rapidly  as  if sudden death
had occurred.   Exactly similar observations have
been  made on the cutting of the  spinal  cord, and
of the par vagum.  The respiratory motions con-
tinue  for a time, but the oxygen does not meet with
those  substances with which,  in  the normal state,
it would  have combined ; because the  paralyzed
viscera will no longer furnish them.   The singular
idea  that the  nerves produce  animal  heat, has
obviously  arisen  from the notion  that the inspired
oxygen combines with carbon, in the blood itself;
in which  case the temperature  of the body,  in
the above  experiments,  certainly, ought  not  to
have  sunk.    But, as we  shall  afterwards  see,
there cannot be a more erroneous conception than
this.                                  r
   As  by  the  division of the pneumogastric nerves
the motion of  the stomach and the secretion of the 
       NOT  THE SOURCE OF ANIMAL  HEAT.     31

gastric juice are arrested,  and an immediate check
is thus given to the process of digestion,  so the pa-
ralysis of the organs of vital motion in the abdomi-
nal viscera  affects the  process of respiration.—
These processes  are most intimately connected;
and every disturbance of the nervous system or of
the nerves of digestion re-acts visibly on the process
of respiration.
  The observation has been made, that heat is pro-
duced by the contraction of the muscles, just as in a
piece  of caoutchouc, which, when rapidly drawn
out, forcibly contracts again, with disengagement of
heat.   Some have gone so far as to ascribe a part of
the animal heat to the  mechanical motions of the
body, as if these motions could exist without an ex-
penditure of force consumed  in  producing them ;
how then, we may ask, is this force produced ?
  By the combustion of carbon, by the solution of
a metal in an  acid, by the combination of the two
electricities, positive and negative, by the absorption
of light, and even by the rubbing of two solid bodies
together with a certain degree of rapidity, heat may
be produced.
  By a number of causes, in appearance entirely
distinct, we can thus produce one and the same ef-
fect.  In combustion and in the production of gal-
vanic electricity, we have a change of condition in
material particles;  when heat is produced  by the
absorption of light or by friction, we have the con-
version of one  kind  of  motion into another, which
affects our senses differently.  In all such cases we 
32
TRUE  SOURCE OF
have a something given, which merely takes another
form ;  in all we have a force and  its effect.   By
means of the fire which heats the boiler of a steam-
engine we can  produce every kind of motion, and
by  a certain amount of motion we can produce
fire.
  When we  rub a  piece of sugar briskly  on an
iron grater, it undergoes, at the surfaces of contact,
the same change as  if exposed  to  heat; and two
pieces of ice, when  rubbed together, melt  at  the
point of contact.
  Let  us remember that the most distinguished
authorities  in physics consider  the phenomena of
heat as phenomena  of motion,  because the very
conception  of the  creation of matter,  even though
imponderable, is absolutely  irreconcilable with its
production by mechanical causes, such as friction or
motion.
  But, admitting all the influence  which electric
or magnetic disturbances  in the animal body can
have on the functions of its organs, still the ultimate
cause of all these forces is a change of condition in
materia] particles, which may be expressed by  the
conversion, within  a  certain time, of the elements
of the food  into oxidised products.   Such of these
elements as do not undergo this process of slow com-
bustion, are given off unburned or incombustible in
the excrements.
  Now, it  is absolutely  impossible that a  given
amount of  carbon  or hydrogen,   whatever  dif-
ferent  forms  they may  assume in the progress 
ANIMAL HEAT.               32
of the combustion,  can produce more heat than
if directly burned into atmospheric air or in oxy-
gen gas.
  When we kindle a fire under a steam-engine, and
employ the  power  obtained  to produce heat by
friction, it is impossible that the heat thus obtained
can ever be  greater than that  which was required
to heat the boiler ; and if we use the galvanic cur-
rent to produce heat, the amount of heat obtained
is never  in any  circumstances, greater than we
might have  by the combustion of the zinc  which
has been, dissolved in the acid.
  The contraction of muscles  produces heat; but
the force necessary for the contraction has manifes-
ted itself through the organs  of motion, in  which
it has been excited by chemical changes.  The ul-
timate cause of the heat produced is therefore to be
found in these chemical changes.
  By dissolving a metal in an acid, we produce an
electrical current; this current, if passed through a
wire, converts the wire into a  magnet, by means of
which, many different  effects may be  produced.—
The  cause  of this phenomena is  magnetism; the
cause of the magnetic phenomena is to be found in
the  electrical  current; and the ultimate cause of
the  electrical  current is  found to be  a chemical
change, a chemical action.
   There are various causes by which force  or mo-
tion  may be produced.  A bent spring,  a  current
of  air, the  fall of water,  fire  applied to a boiler,
the solution of a metal in an acid,—all these differ- 
34
GREAT AMOUNT
 ent  causes  of  motion  may  be  made  to  pro-
 duce the same  effect.   But in  the animal  body
 we recognize  as the  ultimate  cause of all  force
 only  one cause,  the  chemical  action  which the
 elements  of  the  food  and the  oxygen  of the
 air mutually  exercises on  each other.   The only
 known  ultimate  cause of vital  force,   either  in
 animals  or  in plants,  is a chemical process.  If
 this  be prevented,  the phenomena of life do not
 manifest themselves,  or  they cease to  be recog-
 nizable  by our senses.   If the chemical action  be
 impeded, the  vital  phenomena  must  take  new
 forms.
   According to the experiments of Despretz,  1 oz.
 of carbon evolves, during its combustion,  as much
 heat as would raise the  temperature of  105 oz.  of
 water at 32° to 167°,  that is, by 135 degrees; in
 all, therefore,  105 times 135°=14207  degrees of
 heat.   Consequently,  the 13-9 oz. of carbon which
 are daily converted into  carbonic acid in the body
 of an adult,  evolve 13-9xl4207°=197477-3 degrees
 of heat.   This amount of heat is sufficient to  raise
 the temperature of 1 oz. of water by that number of
 degrees,  or  from 32° to 197509-3°; or to cause
 136-8 lbs. of water at 32°  to boil; or to heat 370 lbs.
of water to  98-3° (the temperature of the  human
body); or to convert  into vapour 24 lbs. of water
at 98-3°.
  If  we  now  assume  that the quantity of water
vaporized through the skin and lungs in 24 hours
amounts to 48  oz. (3 lbs.), then there will remain 
               OF ANIMAL  HEAT.             35

after  deducting  the  necessary amount of  heat,
146380-4 degrees of heat, which are dissipated by
radiation,  by heating  the expheJ  air, and  in  the
excrementitious matters.
  In this calculation, no account has been taken of
the heat evolved by the hydrogen of the  food, dur-
ing its conversion into water by oxidation  within
the body.   But if we consider that the specific heat
of the bones, of fat, and  of the organs generally, is
far less than that of water,  and that consequently
they require, in order  to be heated to 98-3°,  much
less heat than an equal weight of water, no  doubt
can be entertained, that when all the concomitant
circumstances are included  in the  calculation, the
heat  evolved in the  process  of   combustion,  to
which the food is subjected  in the body, is  amply
sufficient  to  explain  the  constant  temperature  of
the body,  as well as the evaporation from the skin
and lungs.

  VI. All experiments hitherto made on  the  quan-
tity of oxygen which an animal consumes in a given
time, and  also the conclusions deduced  from them
as  to the origin  of animal  heat, are  destitute of
practical value in regard to  this question, since we
have  seen that the  quantity of oxygen  consumed
varies according to the temperature   and  density of
the air, according to  the degree of motion,  labor,
or exercise,  to the amount and quality of the food,
to the comparative warmth of the clothing, and also
according to the time within which the food is taken 
36
AMOUNT OF OXYGEN
Prisoners in the Bridewell atMarienschloss (a prison
where labor is enforced), do not consume more than
10-5 oz. of carbon daily;  those in the House of Ar-
rest at Giessen, who are  deprived of all exercise,
consume only 8-5 oz.; (6) and in a family well known
to me, consisting of nine individuals, five adults, and
four children of  different ages,  the  average  daily
consumption of carbon  for  each, is not  more than
9-5 oz. of carbon.*  We  may safely assume, as an
approximation,  that the quantities of oxygen con-
sumed in these different  cases are in the  ratio of
these numbers ; but where  the food contains meat,
fat, and wine, the proportions are altered by reason
of the hydrogen  in these  kinds of  food which is
oxidised,  and which, in being converted into water,
evolves much more heat for equal weights.
  The attempts  to ascertain  the  amount  of heat
evolved in an animal  for a given consumption  of
oxygen have  been equally unsatisfactory.  Animals
have been allowed to respire in close chambers sur-
rounded with cold water; the  increase of tempera-
ture in the water  has been measured by the ther-
mometer, and the quantity of oxygen consumed has
been calculated from the analysis of  the air before

  * In this family, the  monthly consumption was  151  lbs. of brown
bread, 70 lbs. white bread, 132 lbs. meat, 19 lbs. sugar, 15-9 lbs. butter,
57 maass (about 24  gallons) of milk; the carbon of the potatoes and
other vegetables, of the poultry, game, and  wine consumed, having been
reckoned as equal to that contained in the excrementitious matters, the
carbon of the above  arlicles was  considered as being  converted 'into
carbonic acid. 
CONSUMED BY ANIMALS.
37
and  after the experiment.   In  experiments  thus
conducted, it has been  found that the animal lost
about ^  more heat than corresponded to the oxygen
consumed ; and  had the windpipe of  the animal
been tied, the strange result would have been ob-
tained of a rise  in  the  temperature  of the water
without any consumption of oxygen.   The animal
was  at  the temperature of 98° or  99°, and the
water, in the experiments of Despretz, was at 47-5°.
Such experiments consequently prove, that when
a great difference exists between the temperature
of the  animal body and that  of the surroun ling
medium, and when  no motion  is allowed,  more
heat is given off than  corresponds to the oxygen
consumed.  In equal times, with free  and unim-
peded  motion, a  much larger quantity of oxygen
would be consumed without a  perceptible increase
in the  amount of heat lost.  The cause of these
phenomena is obvious.  They  appear naturally
both in man and animals at  certain  seasons of the
year, and we say  in  such  cases  that  we are
freezing, or experience the sensation of cold.  It
is plain, that if we were to  clothe a  man  in  a
metallic dress, and  tie  up his  hands and feet, the
loss of heat, for the same consumption of oxygen,
would be far greater than if we were to wrap him
up in fur  and woollen cloth.   Nay, in the  latter
case, we should see him begin to  perspire, and
warm water would  exude, in drops, through the
finest pores of his skin.
  If to  these considerations we  add, that decisive
                       4 
38
NERVOUS AND
experiments are on record, in which animals were
made to respire  in  an unnatural position, as for
example, lying on the back, with the limbs tied  so
as to preclude motion, and that the temperature of
their bodies was found to sink in a degree appreci-
able by ihe thermometer, we can hardly be  at  a
loss what value we  ought  to  attach to the conclu-
sions drawn from such experiments as  those above
described.
   These experiments and the  conclusions deduced '
from them, in short, are incapable of furnishing the
smallest support to the opinion that there exists, in
the animal  body, any  other  unknown  source  of
heat, besides the mutual chemical action between
the elements of the food and the oxygen of the air.
The existence of the  latter cannot be doubted  or
denied, and it is amply sufficient to explain all the
phenomena.

   VII. If we designate the production of force, the
phenomena of motion in the animal body as nervous
life, and the resistance, the condition of static  equi-
librium, as vegetative life; it is obvious that in all
classes of animals the latter, namely, vegetative life,
prevails over the former, nervous life, in the earlier
stages of existence.
   The passage or change of matter from a state of
motion to a state of rest appears in an increase of
the mass, and  in  the  supply of waste ;  while the
motion itself, or the production of force, appears in
the shape of waste of matter. 
VEGETATIVE LIFE.
39
  In a young animal, the waste  is less  than  the
increase;  and the female retains, up  to a certain
age, this peculiar condition of a more intense  vege-
tative life.  This condition  does not cease in  the
female as in the male, with the complete  develop-
ment of all the organs of the body.
  The female  in the lower animals, is, at certain
seasons,  capable of reproduction of  the  species.
The vegetative  life  in her  organism  is  rendered
more  intense  by certain  external conditions, such
as temperature,  food, &c.; the organism  produces
more than is wasted, and the result is  the capacity
of reproduction.
  In the  human species, the  female  organism is
independent of those external causes  which increase
the intensity of vegetative life.  When the organ-
ism is  fully developed, it is at all times capable of
reproduction of the  species;  and infinite  wisdom
has given to the female body the power, up to a cer-
tain age, of producing all parts of its  organisation in
greater quantity than is required to supply the daily
waste.
   This excess of production can be shown to contain
all the elements of a new organism,  it is constantly
accumulating, and is periodically expelled from the
body,  until it is expended in reproduction.   This
periodical discharge ceases when the ovum has been
impregnated, and from this time every drop of the
superabundant  blood goes  to produce an organism
like that  of the mother.
   Exercise and labor cause a  diminution  in the 
 40        NUTRITION DEPENDS ON THE

 quantity of the menstrual discharge ; and when it is
 suppressed in consequence of disease, the vegeta-
 tive life is manifested in a morbid production of fat.
 When  the equilibrium  between  the  vegetative
 and nervous  life is  disturbed in  the male, when,
 as  in  eunuchs,  the intensity  of  the   latter  is
 diminished, the  predominance of the former  is
 shown  in the same form, in  an increased deposit
 of fat.

   VIII. If we hold, that increase of mass in the
 animal body, the  development  of its organs* and
 the supply of waste,—that  all this is dependant  on
 the blood, that is,  on the ingredients of the blood,
 then only those substances can  properly be called
 nutritious, or  considered as  food which are capable
 of conversion into blood.  To determine, therefore,
 what substances are capable of affording nourish-
 ment, it is only necessary to ascertain the composi-
 tion  of  the food, and to compare it with that of the
 ingredients of the blood.
   Two substances  require especial consideration  as
 the  chief ingredients of  the  blood ; one  of these
 separates immediately from the  blood when with-
 drawn from the circulation.   It is well known  that
in this case blood coagulates, and separates into a
yellowish liquid, the serum of the blood, and  a gela-
tinous mass, which adheres to a rod or stick in soft,
elastic fibres,  when coagulating blood is  briskly
stirred.   This is  the fibrine  of the blood, which  is
identical in all its  properties with  muscular fibre, 
CONSTITUENTS OF  BLOOD.
41
when the latter is purified from all foreign  mat-
ters.
  The second principal ingredient of the blood is
contained in the serum, and gives to this  liquid all
the properties of the white of eggs, with which it is
identical.  When heated, it coagulates into a white
elastic mass, and the coagulating substance is called
albumen.
  Fibrine  and  albumen, the chief ingredients  of
blood, contain,  in  all, seven chemical   elements,
among which  nitrogen, phosphrus, and sulphur
are found.  They contain  also  the  earth of bones.
The  serum retains  in  solution  sea  salt  and  other
salts  of  potash  and  soda,  in which  the  acids are
carbonic, phosphoric,  and sulphuric acids.   The
globules of the  blood contain fibrine and albumen,
along with a red  coloring matter, in which iron is
a constant element.   Beside these,  the blood con-
tains  certain  fatty  bodies  in  small  quantity,
which differ  from ordinary fats in several of their
properties.
   Chemical analysis has led to the remarkable re-
sult,   that fibrine  and albumen contain  the  same
organic elements united in the same proportion, so
that two  analyses, the one of fibrine and the other
of albumen, do not differ more than two analyses of
fibrine or two  of albumen respectively  do,  in the
composition of 100 parts.
   In  these two ingredients of blood the particles
are arranged  in a different order, as is shown by the
difference of  their external properties ;. but in che-
                        4* 
42            IDENTITY OF  ANIMAL

mical composition, in the ultimate proportion of the
organic elements, they are identical.
  This conclusion  has  lately  been  beautifully
confirmed by a distinguished physiologist (De-ms),
who  has  succeeded  in converting  fibrine  into
albumen,  that is,  in giving it  the  solubility, and
coagulability by beat, which characterize the white
of egg.
  Fibrine and albumen,  besides having the same
composition* agree also in this, that both dissolve in
concentrated muriatic acid,  yielding a solution of an
intense purple colour.  This solution, whether made
with  fibrine  or albumen, has the very same re-ac-
tions  with all substances yet tried.
  Both albumen and fibrine, in the process of nutri-
tion, are capable of  being  converted into muscular
fibre, and muscular fibre is  capable  of being recon-
verted into blood.  These facts have long been esta-
blished by physiologists, and chemistry has merely
proved that these metamorphoses  can be  accom-
plished under the influence  of a  certain force,  with-
out the aid  of a third substance, or  of its elements,
and without the addition of  any  foreign element, or
the separation of any element previously present in
these substances.
  If we now compare the composition of all organ-
ised parts with that of fibrine and albumen, the fol-
lowing relations present themselves  :—
  All parts of the animal body which have a decided
shape, which form parts of organs, contain nitrogen.
No  part of an organ which possesses motion ancTlife 
FIBRINE AND ALBUMEN.           43
 is destitute of nitrogen ;  all of them contain like-
 wise carbon and the elements of water, the  latter,
 however, in  no  case  in the proportion to form
 water.
   The  chief  ingredients  of  the blood contain
 nearly  17 per cent, of nitrogen, and no part of an
 organ  contains  less  than 17  per cent, of nitro-
 gen. (7)
   The  most convincing experiments and observa-
 tions have proved that the animal body is absolute-
 ly incapable of producing an elementary body, such
 as carbon or nitrogen, out of substances which do
 not  contain it;  and it obviously  follows, that  all
 kinds of food  fit for the production either of  blood,
 or of cellular tissue* membranes, skin, hair, muscu-
 lar fibre, &c, must  contain  a certain amount of
 nitrogen, because  that  element is essential  to the
 composition of the above  named organs ; because
 the organs cannot create it from the other elements
 presented to them; and, finally, because no nitro-
 gen  is absorbed from the atmosphere  in the vital
 process.
   The substance of the brain and nerves contains a
large quantity of albumen, and, in addition to this,
two  peculiar fatty acids,  distinguished from other
fats by  containing phosphorus  (phosphoric acid ?).
One  of these contains nitrogen (Fremy).
  Finally, water and  common  fat are  those  ingre-
dients of the body which are destitute  of nitrogen.
 Both are amorphous or unorganised, and only so far
take part in the  vital process as that their presence 
44       NUTRITION OF GRAMINIVORA.

is  required  for  the due performance of the vital
functions.  The inorganic constituents of the body
are,  iron, lime, magnesia,  common  salt, and  the
alkalies.

  IX.  The nutritive process in the carnivora is seen
in its simplest form.   This class of animals lives on
the blood and flesh of the graminivora; but  this
blood and flesh is, in all its properties, identical with
their own.   Neither chemical  nor physiological  dif-
ferences  can be discovered.
   The nutriment of carnivorous animals is derived
originally from blood ;  in their stomach  it becomes
dissolved, and capable of reaching all other parts
of the body; in its passage it is again  converted  into
blood, and from  this blood are  reproduced all those
parts of  their organisation  which have undergone
change or metamorphosis.
   With the exception  of hoofs, hair, feathers, and
the earth of bones,  every part of the food of carni-
vorous animals is capable of assimilation.
   In a chemical sense,  therefore,  it may be said
that a carnivorus animal, in supporting the vital pro-
cess, consumes  itself.   That  which  serves for its
nutrition  is identical with those parts of its organi-
sation which are to be renewed.
  The process of nutrition in graminivorous animals
appear at  first  sight  altogether  different.  Their
digestive organs are less simple, and their food con-
sists of vegetables, the great  mass of which con-
tains but little nitrogen. 
               VEGETABLE  FIBRINE.            45

   From what substances, it may be asked, is the
 blood formed, by means of which their  organs are
 developed.?   This question may be  answered  with
 certainty.
   Chemical researches have shown, that all  such
 parts of vegetables as can afford nutriment to  ani-
 mals contain certain constituents which are rich in
 nitrogen ; and the most ordinary experience proves
 that animals require for their support and nutrition
 less of these  parts of plants in proportion as  they
 abound in the nitrogenised constituents.   Animals
 cannot  be fed on matters destitute of these nitro-
 genised constituents.
   These important products of vegetation are es-
 pecially abundant in the seeds of the different kinds
 of grain,  and of pease,  beans, and lentils ;  in the
 roots and the  juices of what are commonly called
 vegetables.   They exist, however,  in all plants,
 without exception, and  in every part  of plants in
 larger or smaller quantity.
   These  nitrogenised  forms of nutriment in the
 vegetable kingdom may be reduced to three substan-
 ces, which are easily distinguished by their external
 characters.   Two of them are soluble in water, the
 third is insoluble.
  When the newly-expressed juices  of vegetables
are  allowed  to stand,  a separation  takes  place
in  a few  minutes.    A  gelatinous precipitate,
commonly of a green tinge,  is  deposited,  and this,
when acted on by liquids which remove the colour-
ing  matter, leaves a grayish white substance, well 
46            VEGETABLE FIBRINE,

known to druggists  as the deposit from vegetable
juices.   This is one  of the nitrogenised compounds
which serves for the nutrition  of animals,  and has
been named  vegetable fibrine.   The juice of grapes
is  especially rich  in this  constituent, but  it is
most abundant in  the seeds of  wheat, and of the
cerealia generally.   It may be obtained from wheat
flour by a mechanical operation, and in a state of
tolerable purity ; it  is then  called  gluten,  but
the glutinous property belongs,  not to vegetable
fibrine,  but  to  a foreign substance,   present  in
small  quantity, which  is not  found in the other
cerealia.
   The method by which it is obtained sufficiently
proves that it is insoluble in  water; although we
cannot doubt that it  was originally dissolved in the
vegetable juice, from which it afterwards separated,
exactly as fibrine does from blood.
   The second nitrogenised compound remains dis-
solved in  the juice  after the  separation  of the
fibrine.   It  does not separate  from the  juice at
the  ordinary temperature, but is instantly coagu-
lated when  the liquid containing it is heated to
the boiling point.
   When the clarified juice of nutritious  vegetables,
such as cauliflower,  asparagus, mangel  wurzel, or
turnips, is made to boil, a coagulum is formed, which
it is absolutely impossible to distinguish from the
substance  which  separates   as   coagulum, when
the.  serum  of blood  or  the white of an  egg,
diluted with  water, are heated to the boiling point. 
ALBUMEN, AND CASEINE.
47
This is vegetable albumen.   It is found in the great-
est  abundance in certain  seeds, in  nuts, almonds,
and others, in which the starch of the  gramineae is
replaced by oil.
  The  third nitrogenised  constituent of the  vege-
table  food of  animals is vegetable caseine.  It is
chiefly found in  the  seeds of pease, beans, lentils,
and  similar leguminous   seeds.   Like  vegetable
albumen, it is soluble in water, but differs from it
in this, that  its solution is not coagulated by heat.
When  the  solution  is  heated  or  evaporated, a
skin forms  on its  surface, and  the addition  of an
acid causes a coagulum, just as in animal milk.
  These three nitrogenised compounds, vegetable
fibrine, albumen,  and caseine,  are  the true  nitro-
genised  constituents  of the  food of graminivorous
animals ; all other nitrogenised compounds, occur-
ring in plants, are either rejected by animals, as in
the case of the characteristic principles of poisonous
and medicinal plants, or else they occur in the food
in  such very  small  proportion, that  they cannot
possibly contribute to the increase  of  mass in the
animal bod}'.
   The chemical analysis of these three substances
has led to the  very interesting result that they
contain  the  same  organic elements,  united  in the
same  proportion by weight;  and,  what is  still
more  remarkable, that they  are identical in com-
position with  the  chief constituents of blood,  ani-
mal fibrine, and albumen.  They all  three dissolve
 in concentrated  muriatic  acid with the same deep 
48         IDENTITY OF  ANIMAL WITH

purple colour, and even  in  their physical charac-
ters, animal fibrine and albumen are in no respect
different from vegetable fibrine and  albumen.   It
is  especially to be  noticed, that by  the phrase,
identity of  composition, we  do not  here  imply
mere similarity,  but  that even in  regard to the
presence and  relative amount of sulphur, phos-
phorus, and  phosphate of lime, no difference can
be observed: (8)
  How beautifully and admirably simple, with the
aid of  these  discoveries, appears the process  of
nutrition in  animals, the  formation of their organs,
in  which vitality chiefly resides !  Those vegeta-
ble principles, which in  animals are  used to form
blood, contain the  chief  constituents  of  blood,
fibrine and albumen,  ready formed, as far  as  re-
gards their  composition.  All  plants, besides, con-
tain  a certain  quantity  of iron, which re-appears
in  the colouring malter  of  the blood.   Vegetable
fibrine and animal fibrine, vegetable  albumen and
animal  albumen, hardly differ, even  in  form ;  if
these principles be  wanting in the food, the nu-
trition of  the animal is  arrested ; and when they
are present,  the  graminivorous animal obtains  in
its food the very same principles on  the presence
of which  the nutrition  of  the  carnivora entirely
depends.
  Vegetables produce in  their  organism the blood
of all animals, for the  carnivora, in consuming the
blood and flesh of the graminivora, consume, strictly
speaking, only the vegetable principles which have 
VEGETABLE  FIBRINE,  &c.
49
served for the nutrition of the latter.   Vegetable
fibrine and albumen take the same  form in the
stomach  of the graminivorous animal  as  animal
fibrine and albumen do in that of the carnivorous
animal.
  From  what  has  been said, it  follows that the
development  of  the  aairrraK organism and  its
growth are  depeu<J§ifcr on  the  -reception of certain
principles identic*! ^with^tW^ehief «bnstituents of
blood.              « ^v ►* . |^ y  v  1
  In this sense we may say that the  animal organ-
ism gives to blood only its  form ;  that it  is incapa-
ble of creating blood out of other substances which
do not already contain  the chief constituents of that
fluid. . We cannot, indeed, maintain that the animal
organism has no power to  form other  compounds,
for we know that  it  is capable of producing  an ex-
tensive series of  compounds, differing  in composi-
tion from the chief constituents of blood;  but these
last, which form the starting point of the series, it
cannot produce.
  The animal organism is a  higher kind of vege-
table, the development of which begins with those
substances, with the production of which  the life of
an ordinary vegetable ends.  As soon as  the latter
has borne seed, it dies, or a period of its life comes
to a termination.
  In  that endless series of compounds, which be-
gins with carbonic acid, ammonia, and water, the
sources of the nutrition of  vegetables, and includes
the most complex constituents of  the animal brain,
                        5 
50           USES  OF THE STARCH,

there is no blank, no  interrupt ".on.  The first sub-
stance  capable of affording nutriment to animals  is
the last product  of the  creative  energy of vege-
tables.
  The  substance of  cellular tissue and of mem-
branes, of the brain and nerves, these the vegetable
cannot produce.
  The  seemingly  miraculous  in  the  productive
agency of vegetables  disappears in a great  degree,
when we  reflect that  the  production of the consti-
tuents  of  blood cannot appear more surprising than
the  occurrence of the fat of beef and  mutton  in
cocoa-beans, of human fat in olive oil, of the prin-
cipal ingredient of butter  in palm oil, and of horse
fat and train oil in certain oily seeds.

  X. While the preceding considerations leave
little or no  doubt as  to the way in which  the in-
crease of  mass in  an animal,  that is,  its growth,
is carried  on, there is yet to be  resolved  a most
important question, namely, that  of the function
performed in the animal system by substances con-
taining no nitrogen,  such as sugar, starch, gum,
pectine, &c.
  The most extensive class of animals, the grarni-
njvora, cannot live without these  substances ; their
food must contain a certain amount of one or more
of them, and if these compounds are not supplied,
death quickly ensues.
  This important inquiry  extends also to the con-
stituents of the food of carnivorous animals  in the 
SUGAR, &c. IN THE  FOOD.
51
earliest periods of life ; for this food also  contains
substances, which are  not  necessary for their sup-
port in the adult state.
  The nutrition of the young of carnivora is  obvi-
ously accomplished by means  similar to those  by
which the graminivora are  nourished ;  their de-
velopment is dependant on the  supply of a  fluid,
which the body of the mother secretes in the shape
of milk.
  Milk  contains only one  nitrogenised  constituent,
known  under the name of caseine; besides this,
its chief ingredients  are butter (fat), and  sugar of
milk.
  The  blood  of  the young  animal, its muscular
fibre,  cellular tissue, nervous  matter,  and bones,
must  have derived their origin from the nitrogenised
constituent of  milk,  the  caseine;  for  butter and
sugar of milk contain no nitrogen.
  Now, the analysis of caseine has led to the result,
which, after the details given in the last  section, can
hardly excite surprise, that this  substance also is
identical in composition with the chief constituents
of blood, fibrine and albumen.   Nay, more, a com-
parison of its properties  with those of vegetable
caseine has shown that these  two substances are
identical in all their properties; insomuch,that cer-
tain plants, such as  peas, beans, and  lentils, are
capable of producing the  same substance which is
formed from the blood of the mother, and employed
in yielding the blood of the young animal.  (9.)
  The young animal, therefore, receives, in the form 
52
ANIMAL AND VEGETABLE
of caseine, which is distinguished from  fibrine  and
albumen by its great  solubility, and by not coagu-
lating  when  heated,  the chief constituent of the
mother's  blood.   To convert caseine  into blood
no foreign substance  is  required, and  in  the con-
version of the mother's blood into  caseine, no ele-
ments  of the  constituents of the blood have  been
separated.  When chemically  examined,  caseine
is found  to contain  a  much larger  proportion of
the earth of bones than blood  does, and that in
a very soluble  form, capable of  reaching every
part of  the body.   Thus,  even  in  the  earliest
period of its life, the  development of  the organs, in
which  vitality resides, is, in the carnivorous animal,
dependant on the supply of a substance,  identical
jn organic composition  with  the chief  constituents
of its blood.
  What,  then,  is  the use of the  butter  and the
sugar of  milk ?  How  does  it  happen that these
substances are indispensable  to life ?
  Butter and sugar of milk contain no fixed bases,
no soda or potash.  Sugar of milk  has  a  composi-
tion  closely allied  to that  of the other kinds of
sugar,  of  starch, and of gum; all of them  contain
carbon  and the elements of water, the latter pre-
cisely in the proportion to form water.
  There is added, therefore, by means of these com-
pounds, to the nitrogenised constituents of food, a
certain amount of carbon, or, as in the case of but-
ter, of  carbon and  hydrogen ; that is, an excess of
elements, which cannot possibly be employed in the 
CASEINE  IDENTICAL.
53
production of blood, because  the  nitrogenised sub-
stances contained in the food already contain exactly
the amount of carbon which is required for the pro-
duction of fibrine and albumen.
   The following considerations will show thathardly
a doubt can be entertained, that this excess of car-
bon alone, or of carbon and hydrogen, is expended
in the production of animal heat, and serves to pro-
tect the organism from  the action of the atmospheric
oxygen.

   XI.  In  order  to obtain a clearer insight into the
nature of  the nutritive process in both the great
classes of  animals, let us first consider the changes
which the food  of the carnivora undergoes in their
organism.
   If we  give  to  an  adult  serpent,  or boa con-
strictor, a goat, a rabbit, or  a bird,  we  find that
the hair,  hoofs, horns, feathers, or bones  of these
animals,  are expelled  from  the  body  apparently
unchanged.   They  have  retained their natural
form and  aspect, but  have  become brittle,  be-
cause  of  all their component parts they have lost
only  that one  which  was  capable  of  solution,
namely, the gelatine.  Fasces, properly  so called,
do not occur in serpents any more than in carnivo-
rous birds.
   We find, moreover, that, when the serpent has
regained  its original weight, every other part of its
prey, the flesh, the blood, the brain, and nerves, in
short,  every thing has disappeared.
                       #5 
54
NUTRITION OF  CARNIVORA.
   The only excrement, strictly speaking, is a sub-
 stance expelled by the  urinary  passage.  When
 dry, it is pure white, like chalk; it contains much
 nitrogen, and a small quantity of carbonate and phos-
 phate of lime mixed  with the mass.
   This excrement is urate of ammonia, a chemical
 compound, in which the nitrogen bears to the carbon
 the same  proportion as in bicarbonate of  ammonia.
 For every equivalent of nitrogen  if contains two
 equivalents  of carbon.
   But muscular fibre, blood membranes, and skin,
 contain four times as much carbon for  the same
 amount of nitrogen, or eight equivalents to one; and
 if we add to this the carbon of the fat and nervous
 substance, it is  obvious that the  serpent has con-
 sumed for every equivalent of nitrogen, much more
 than eight equivalents of carbon.
   If now we assume that the urate of ammonia con-
 tains all the nitrogen of the animal consumed, then
 at least six equivalents of carbon, which were in
 combination with  this nitrogen, must have been
 given  out  in  a  different  form  from  the  two
 equivalents  which are found in  the  urate of am-
 monia.
   Now we know,  with  perfect certainty, that this
 carbon has been given out  through  the  skin and
lungs, which could only take place in the form of an
oxidised product.
   The excrements  of a buzzard which had been fed
with beef, when taken out of the rectum, consisted,
according toL. Gmelin and Tiedemann, of urate of 
USES OF CARBON IN THEIR FOOD.      55
ammonia.   In  like  manner,  the  faeces, in lions
and  tigers  are  scanty  and dry, consisting  chiefly
of bone  earth,  with mere traces  of compounds
containing  carbon;  but  their urine  contains,  not
urate of ammonia,  but  urea,  a  compound  in
which  carbon and  nitrogen  are  to  each  other
in the  same ratio as in neutral carbonate of am-
monia.
  Assuming that their  food (flesh, &c.) contains
carbon and nitrogen in the ratio of eight equivalents
to one, we find these elements in their urine in  the
ratio of one equivalent to one ;  a smaller proportion
of carbon, therefore, than in serpents, in which
respiration  is so much less active.
  The whole of the carbon and hydrogen which the
food of these animals contained, beyond the amount
which  we find in their excrements, has disappeared,
in the process of respiration, as carbonic acid and
water.
  Had the  animal food been burned  in a furnace,.
the change produced in it would only have differed
in the form of combination assumed by the nitrogen
from that  which it underwent in  the body of the
animal.  The nitrogen would have appeared, with
part of the carbon  and  hydrogen, as carbonate of
ammonia, while the rest of the carbon and hydrogen
would  have formed carbonic acid and water.  The
incombustible parts would have taken the  form of
ashes,  and  any part of the carbon unconsumedfrom
a deficiency of oxygen  would have  appeared as
soot, or lamp-black.  Now the solid excrements are 
56
FOOD OF  CARNIVORA
nothing else than the incombustible, or imperfectly
burned, parts of the food.
  In the preceding pages it has been assumed that
the elements of the food are converted by the  oxy-
gen absorbed  in the lungs into oxidised products ;
the carbon  into carbonic acid, the hydrogen into
water,  and the nitrogen into a  compound  con-
taining  the  same  elements as carbonate  of am-
monia.
  This  is  only true  in  appearance; the body,
no doubt, after  a  certain  time,  acquires its ori-
ginal  weight.    The  amount  of  carbon, and  of
the other elements, is not  found  to be increased
—exactly as  much carbon, hydrogen, and nitro-
gen  has  been  given  out  as was  supplied  in
the food ; but nothing is more certain  than  that
the carbon, hydrogen, and nitrogen  given  out,
although equal  in  amount to what  is  supplied
in that  form,  do  not  directly proceed  from the
food.
  It would be utterly irrational to suppose that the
necessity of taking food, or the satisfying the appe-
tite,  had no other  object than the  production  of
urea, uric acid, carbonic acid, and  other excremen-
titious  matters—of substances which the system
expels, and consequently applies to no useful  pur-
pose in the economy.
  In the adult  animal, the food serves to restore
the waste of matter;  certain parts of its organs
have lost the state of vitality, have been  expelled
from the substance of the organs,  and have been 
        IDENTICAL WITH THEIR BODIES.       57

metamorphosed into new combinations, which  are
amorphous and unorganised.
  The food of the carnivora is at  once converted
into  blood ; out  of the  newly-formed blood those
parts of organs  which have  undergone metamor-
phoses are reproduced.   The carbon and  nitrogen
of the food thus become constituent parts of organs.
  Exactly as much carbon and nitrogen is supplied
to the organs by the blood, that is,  ultimately,  by
the food,  as they  have lost by the  transformations
attending  the exercise of their functions.
  What then, it may be asked, becomes of the new
compounds produced by the transformations of the
organs, of the muscles, of the membranes  and cel-
lular tissue of the nerves and brain ?
  These new compounds  cannot,  owing  to their
solubility, remain  in the situation  where they are
formed, for a well-known force, namely the circu-
lation of the blood, opposes itself to this.
  By  the expansion  of the heart, an  organ in
which two systems of tubes meet, which are rami-
fied  in a most minute network of vessels through
all parts of the body, there is produced a vacuum,
the  immediate effect  of which  is, that  all fluids
which  can penetrate  into  these vessels are urged
with great force towards one side  of the heart  by
the external pressure of the atmosphere.  This mo-
tion is  powerfully assisted  by the contraction of
the  heart,  alternating with its  expansion,  and
caused by a force  independent of the atmospheric
pressure. 
58          CARBON  IS ACCUMULATED
   In a word, the  heart is  a forcing  pump,  which
 sends arterial blood into all parts of the body; and
 also a suction pump, by means of which all fluids
 of whatever kind, as soon as they enter the absorb-
 ent vessels which communicate with the veins, are
 drawn  towards the heart.   This  suction, arising
 from the vacuum  caused by the expansion  of the
 heart, is a purely mechanical act, which  extends,
 as above stated, to fluids of every kind,  to saline
 solutions, poisons,  &c.   It is obvious, therefore,
 that  by the forcible  entrance  of arterial blood
 into  the capillary vessels, the fluids  contained
 in  these,   in  other  words,   the  soluble   com-
 pounds formed  by the transformations of organised
 parts, must be compelled  to  move towards the
 heart.
   These compounds  cannot be  employed for the
 reproduction of those tissues from  which  they are
 derived.   They pass  through  the  absorbent  and
 lymphatic vessels into the veins, where their accu-
 mulation would speedily put a stop  to the nutritive
 process, were it not that this accumulation is pre-
 vented by  two  contrivances adapted expressly to
 this purpose, and which may be compared  to filter-
 ing machines.
   The venous blood, before reaching  the heart, is
 made to pass through the liver; the arterial blood,
on the other hand, passes through  the kidneys; and
these organs separate from both all substances'inca-
pable of contributing to nutrition.
   Those newcompounds which contain the nitrogen 
IN THE BILE.
59
■.a the transformed  organs are collected in the uri-
nary bladder, and  being utterly incapable of any
further application in the system, are expelled from
the body.
  Those, again,  which  contain the carbon of the
transformed tissues, are collected in the gall-blad-
der in the form  of a  compound of soda,  the  bile,
which is miscible with water in every proportion,
and which, passing  into the duodenum, mixes with
the chyme.  All those  parts of  the  bile  which,
during the digestive process, do  not  lose their so-
lubility, return  during  that process into the circula-
tion  in  a state of extreme division.  The soda  of
the  bile, and  those  highly carbonised  portions
which are not precipitated by a weak acid (together
making ,Voms  °f tne  solid contents  of the bile,)
retain the capacity  of resorption by the absorbents
of the small  and large intestines ; nay, this capa-
city  has been  directly proved  by the administra-
tion  of  enemata  containing bile,  the  whole of the
bile  disappearing  with the  injected  fluid  in the
rectum.
  Thus we know with certainty, that  the nitrogen-
ised compounds,  produced by the metamorphosis  of
organised tissues, after  being separated from the
arterial  blood by  means of the kidneys are expelled
from the body as utterly incapable of further altera-
tion ; while the compounds rich in carbon, derived
from the  same souroe, return  into the system  of
carnivorous animals.
  The  food  of the carnivora is identical with the 
60
THE  CARBON  OF THE BILE
chief constituents  of their bodies,  and  hence the
metamorphoses which their organs undergo must be
the same as those which, under the influence of the
vital force, take place in  the matters which consti-
tute their food.
   The flesh and blood consumed as food yield their
carbon  for  the  support of the respiratory process,
while its nitrogen appears as uric  acid, ammonia,
or urea.   But previously to these final changes, the
dead flesh and blood become living flesh  and blood,
and  it  is,  strictly speaking, the carbon of the
compounds formed  in  the metamorphoses of liv-
ing tissues that serves for  the production of animal
heat.
   The food of the carnivora is converted  into blood,
which is destined for the reproduction of organised
tissues ;  and  by means of the circulation a current
of oxygen is conveyed  to every  part of the body.
The globules of the blood, which in themselves
can  be  shown  to  take no share  in the nutritive
process,  serve to transport the oxygen, which they
give up in  their passage  through  the capillary
vessels.  Here the current of oxygen  meets with
the compounds produced by the transformation of
the tissues, and combines with their carbon to form
carbonic acid,  with their hydrogen to form water.
Every portion of these substances which escapes this
process of oxidation is sent back into the circulation
in the form of the bile, which by degrees completely
disappears.
  In the carnivora the bile contains the  carbon of 
UNDERGOES COMBUSTION.
61
the metamorphosed tissues;  this  carbon  disap-
pears in the animal body, and  the  bile likewise
disappears in the vital process.   Its carbon and
hydrogen are  given   out  through the  skin  and
lungs as carbonic acid and v/ater;  and hence it
is obvious that the elements of the bile serve for
respiration and for the production of animal heat.
Every part of the food  of carnivorous animals
is  capable of  forming blood;  their  excrements,
excluding the  urine,  contain  only inorganic  sub-
stances,  such as phosphate of lime ; and the small
quantity of organic matter which is  found  mixed
with  these is derived from  excretions, the use of
which is to promote their  passage through the in-
testines, such as  mucus.  These excrements  con-
tain no bile and no soda; for  water extracts  from
them no trace of any substance resembling bile,
and yet bile is very soluble  in  water, and mixes
with it  in every proportion.
   Physiologists can entertain  no doubt as  to the
origin of the constituent parts of the  urine and of
the bile.    When, from  deprivation of food, the
stomach contracts itself so as to resemble a portion
of intestine, the gall-bladder, for want of the motion
which the full stomach gives to it, cannot pour out
the bile it contains; hence in  animals starved to
death we fine the gall-bladder distended  and full.
The  secretion of bile and of urine goes on  during
the winter sleep  of hybernating  animals ; and we
know that the urine of dogs,  fed for three weeks
exclusively on pure sugar, contains as much  of the
                         6 
62
USES OF  THE URINE,
most highly nitrogenised constituent, urea, as in the
normal condition.   (Marchaud.  Erdmaun's Journal
fur praktische Chemie, XIV. p.  495.)
   Differences in  the  quantity  of urea secreted in
these and  similar experiments are explained by
the  condition  of the  animal  in  regard to  the
amount of the natural motions permitted.   Every
motion  increases  the  amount of organised tissue
which undergoes metamorphosis.   Thus after a
walk, the secretion  of urine in man is invariably
increased.
   The  urine of the mammalia, of birds, and  of
amphibia, contains  uric acid or urea ;  and the ex-
crements of the mollusca, and of insects, as of can-
tharides and of the butterfly of the silkworm, con-
tain  urate of ammonia.  This constant occurrence of
one  or  two  nitrogenised  compounds in the excre-
tions of animals, while so great a difference exists
in their food, clearly proves that these  compounds
proceed from one and the same source.
   As little doubt can be entertained in regard to
the function of the bile in the vital  process.  When
we consider, that the acetate  of potash, given in
enema, or simply as a bath for  the feet, renders the
urine strongly alkaline (Rehberger in Tiedemann's
Zeitschrift fur Physiologic, II.  149), and that  the
change which the acetic acid here undergoes cannot
be conceived without  the addition  of oxygen,  it is
obvious, that the  soluble constituents  of the bile
prone to change in a high degree as we know them
to be, and which, as already stated, cannot be em- 
AND OF THE BILE.
63
ployed in the production of blood,  must, when re-
turned through  the intestines into the circulation,
in like manner yield to the influence of the oxygen
which they meet.   The bile  is  a compound  of
soda, the elements  of which, with the exception of
the soda,  disappear in the  body of a carnivorous
animal.
   In the  opinion of  many of the most distinguished
physiologists, the bile is  intended solely to be ex-
creted ; and  nothing is  more  certain,  than  that
a substance containing so very small a proportion
of nitrogen can  have  no share in  the  process of
nutrition  or  reproduction  of organised tissue.—
But quantitative physiology  must at once and de-
cidedly reject the opinion,  that the bile serves no
purpose in the economy, and is incapable of further
change.
   No part of any organised structure contains soda;
only  in the serum  of  the blood, in  the fat of the
brain, and in the bile, do we meet with that alkali.
When the compounds of soda in the blood are con-
verted into muscular fibre,  membrane, or cellular
tissue, the  soda they contain must enter into new
combinations.    The  blood  which  is  transformed
into organised tissue gives up its soda to the  com-
pounds formed  by  the metamorphoses of the pre-
viously existing tissues.  In the bile we find one of
these compounds of soda.
   Were the bile intended merely for excretion, we
should find it, more or  less altered, and also the
soda  it contains, in the solid excrements.   But, 
64        AMOUNT OF  BILE SECRETED.

with the exception of common salt, and of sulphate
of soda, which occur in all the animal fluids, only
mere traces of soda are to be found in the fseces.—
The soda of the bile, therefore,  at all events, must
have returned from the intestinal canal into the or-
ganism, and the  same  must be true of the organic
matters which were in combination with it.
   According to the observations of physiologists,  a
man  secretes daily from 17  to 24 oz. of bile;  a
large dog,  36 oz.; a horse, 37 lbs. (Burdach's Phy-
siologie, V. p. 260.)  But the  fssces  of a  man do
not  on an average weigh  more  than  5^ oz.; and
those of a  horse 28^ lbs., of which 21 lbs.  are wa-
ter, and 7-| lbs. dry faeces.   (Boussingault.)  The
latter yield to alcohol only -2J0-th part of  their weight
of soluble  matter.
   If we assume the bile to contain 90 per cent, of
water, a horse secretes daily 592 oz. of bile,  con-
taining 59*2  oz.  of solid  matter; while 7^ lbs. or
120 oz. of  dried excrement yield only 6 oz. of mat'
ter soluble in alcohol, which might possibly be  bile.
But  this matter is not bile ; when  the  alcohol is
dissipated  by evaporation, there remains a  soft,
unctuous mass,  altogether insoluble in  water, and
which, when incinerated, leaves no alkaline ashes*
no soda. (10)
  During the digestive  process, therefore, the soda
of the bile, and, along with it, all the soluble parts
of that fluid, are returned into the circulation. This
soda re-appears  in  the newly-formed blood, and,
finally, we  find it in the urine in the form of phos- 
IN MAN AND  ANIMALS.
65
phate, carbonate, and hippurate of soda.   Berzelius
found in 1,000 parts of fresh human faeces only nine
parts of a substance similar to bile ; 5 ounces, there-
fore,  would  contain only 21 grains of dried bile,
equivalent to 210 grains of fresh bile.   But a man
secretes daily from 9,640 to 11,520 grains of  fluid
bile, that is, from 45 to 56 times  as much as can be
detected in the matters discharged by the intestinal
canal.
   Whatever opinion we  may  entertain of the accu-
racy  of the physiological experiments, in regard to
the quantity of bile secreted by the different classes
of animals; thus much is certain,  that even the max-
imum of the supposed secretion,  in  man and in the
horse, does not contain as much  carbon as is given
out in respiration.  With all the  fat which is mixed
with  it, or enters into its  composition, dried bile
does  not contain more than 69 per cent, of carbon.
Consequently, if a horse secretes 37 lbs. of bile, this
quantity will contain  only 40   ounces  of carbon.
But the horse expires daily nearly twice as much in
the form of carbonic acid.  A precisely similar pro-
portion holds good in man.
   Along with the matter destined for the formation
or  reproduction  of organs, the circulation conveys
oxygen to all parts of the  body.  Now, into what-
ever  combination the  oxygen   may  enter  in the
blood, it must be held as certain, that such of the
constituents of blood as are employed for reproduc-
tion,  are not materially altered by it.   In muscular
fibre we find fibrine, with all the properties it had
                         t* 
 66         THE  CARBON  OF THE FOOD

 in venous blood;  the albumen in the blood does not
 combine with oxygen.  The oxygen  may possibly
 serve  to  convert into  the  gaseous state some un-
 known constituent of the blood;  but  those  well-
 known constituents, which  are  employed in repro-
 duction, cannot be destined to  support the respira-
 tory process ;  none of their properties  can justify
 such an opinion.
   Without  attempting in this place to  exhaust the
 whole question of the share taken by the bile in the
 vital operations,  it follows, as has been observed,
 from the  simple  comparison  of those parts of the
 food of the carnivora which are capable of assimila-
 tion, with the ultimate products  into which it is con-
 verted, that all the carbon of the food, except that
 portion which -is found in the  urine, is given out as
 carbonic acid.
   But this carbon was  ultimately derived from the
 substance of the metamorphosed tissues; and  this
 being admitted, the question of the neccessity of sub-
 stances containing much carbon  and  no nitrogen in
 the food of the  young of the carnivora, and in that
 of the graminivora, is resolved in a strikingly simple
 manner.

  XII.  It cannot be disputed that in an adult carni-
vorous animal,  which neither gains nor loses weight
perceptibly from day to day,  its nourishment, the
waste of organised tissue, and  its consumption of
oxygen, stand to each other in a well-defined  and
fixed relation. 
SUPPORTS  RESPIRATION.
67
  The carbon of the carbonic acid given  off,  with
that of the urine;  the nitrogen of the urine, and the
hydrogen given off as ammonia  and water; these
elements, taken together, must be exactly equal in
weight to the carbon, nitrogen, and hydrogen of the
metamorphosed tissues, and since these last are ex-
actly replaced by the food, to the carbon, nitrogen,.
and hydrogen of the food.   Were this not the case,
the weight of the  animal could not possibly remain
unchanged.
  But, in the young of the carnivora, tfie weight
does not  remain  unchanged;  on the contrary,
it increases  from day to  day by an appreciable
quantity.
  This fact presupposes, that the assimilative pro-
cess  in the  young  animal is more energetic, more
intense, than  the  process  of transformation in the
existing tissues.  If both processes were equally ac-
tive,  the weight of the body could not increase ;
and were the waste by transformation greater, the
weight of the body would  decrease.
  Now, the circulation in the young animal is not
weaker, but, on the contrary, more rapid ;  the res-
pirations are more frequent; and, for equal bulks, the
consumption of oxygen must be greater rather than
smaller in  the young than  in  the adult  animal.
But, since the metamorphosis  of  organised parts
goes on more slowly, there  would ensue a deficiency
of those substances, the carbon and hydrogen of
which  are adapted for combination with oxygen;
because, in the carnivora it is the new compounds, 
68         BUTTER, SUGAR, STARCH, &c

produced by the metamorphosis of organised parts,
which nature has destined to furnish the necessary
resistance to  the action of the oxygen, and to pro-
duce animal heat.   What is wanting for these  pur-
poses an infinite wisdom has supplied to the young
animal in its natural food.
  The carbon and hydrogen of butter, and the car-
bon of the  sugar of milk, no part of either of which
can j'ield blood, fibrine, or  albumen, are destined
for the support of the  respiratory process, at an age
when a greater resistance is opposed  to  the meta-
morphosis of existing organisms ; or, in other words,
to the production of compounds, which in the adult
state are produced in "quantity amply sufficient for
the purpose of respiration.
  The young animal receives the constituents of its
blood in the caseine of the milk.   A metamorphosis
of existing organs goes on,  for bile and  urine are
secreted ;  the  matter of the metamorphosed parts is
given off in the form of urine, of carbonic acid, and
of water;  but  the butter and sugar of milk  also
disappear ; they cannot be detected in.the fasces.
  The butter and sugar of milk are given out in the
form of carbonic acid  and water, and their conver-
sion into oxidised products furnishes the clearest
proof that far more oxygen is absorbed  than is re-
quired to  convert the carbon and hydrogen of the
metamorphosed  tissues into  carbonic  acid  and
water.
  The change and metamorphosis of organised tis-
sues going on in  the  vital process in the young 
CONSUMED IN RESPIRATION.         69
animal, consequently yield, in a given time, much
less carbon and hydrogen in the form  adapted for
the respiratory process than corresponds to the oxy-
gen taken up in the lungs.   The substance of its
organised parts would undergo a more rapid con-
sumption, and would necessarily yield to the action
of the oxygen,  were not the  deficiency of carbon
and hydrogen supplied from another source.
   The continued increase of  mass, or growth, and
the free and unimpeded development of the organs
in the young animal, are dependent on the presence
of foreign substances, which,  in the nutritive  pro-
cess,  have  no  other  function than  to protect the
newly-formed  organs from the action of  the oxy-
gen.   It is the elements of these substances  which
unite with the oxygen ; the organs themselves could
not do so without being consumed ; that is, growth,
or increase of mass in the body, the consumption
of oxygen remaining the same, would be utterly
impossible.
   The preceding considerations leave no doubt as
to the purpose  for which Nature has  added to the
food of the young  of carnivorous mammalia  sub-
stances  devoid of nitrogen,  which their organism
cannot employ for nutrition, strictly  so called, that
is, for the production of blood ; substances which
may be entirely dispensed with in their nourishment
in the adult  state.  In the  young of carnivorous
birds, the want of all motion  is an obvious cause of
diminished waste in the organised  parts ;  hence,
milk is not provided for them. 
70          PROPERTIES OF  STARCH
  The nutritive process in the carnivora thus pre-
sents itself in two distinct forms ; one of which we
again meet with in the graminivora.

  XIII. In the class of graminivorous animals, we
observe, that during their  whole life, their exist-
ence depends  on the supply of substances having
a composition identical with that of sugar of milk,
or closely resembling it.  Every thing that they
consume  as  food contains a certain quantity of
starch, or gum, or sugar, mixed with other matters.
  The most abundant and widely-extended of the
substances  of this  class  is  amylon  or  starch; it
occurs in roots,  seeds, and  stalks, and even in
wood,  deposited  in  the  form of  roundish  or
oval  globules, which differ  from  each  other  in
size alone,  being identical in  chemical  composi-
tion. (11) In  the same plant,  in the pea, for ex-
ample,   we  find starch,  the  globules  of which
differ in  size.   Those in the expressed  juice  of
the stalks have a  diameter of from aio  to TsT of
an inch,  while those in the seed are three or four
times larger.  The globules in  arrow-root  and  in
potato  starch  are  distinguished by their large
size ; those  of rice and  of wheat are remarkably
small.
  It is well known that starch  may  be converted
into  sugar by very different means.   This change
occurs in the process of germination, as in malting
and it is easily accomplished by the action  of acids.
The metamorphosis of starch into  sugar  depends 
         EASILY CONVERTED INTO SUGAR.      71

simply, as  is  proved by analysis, on  the  addition
of the elements of water. (12)   All the carbon  of
the starch  is  found in the sugar; none of its ele-
ments have been separated, and,  except  the ele-
ments of water, no foreign element has been added
to it in this transformation.
   In  many, especially in pulpy fruits, which when
unripe are sour and  rough to the taste, but when
ripe are sweet, as, for example, in apples  and pears,
the sugar is produced from the starch which the un-
ripe fruit contains.
   If we rub unripe apples or pears on a grater  to
a  pulp, and wash this with cold  water  on a fine
sieve, the  turbid liquid which  passes  through de-
posits a very fine flour of  starch, of  which not
even  a trace can be detected  in  the  ripe  fruit.
Many varieties become sweet while yet on the tree ;
these are  the  summer or early apples and pears.
Others, again, become sweet only after having been
kept  for a  certain  period  after  gathering.  The
after-ripening, as this change is  called, is a purely
chemical process, entirely independent of the  vital-
ity of the plant.   When vegetation ceases, the fruit
is capable of  reproducing the  species, that is, the
kernel, stone, or true seed  is fully ripe, but the
fleshy covering from this period is subjected to the
action of  the atmosphere.   Like  all  substances
in  a  state of eremacausis,  or  decay,  it absorbs
oxygen, and gives off a certain quantity of  carbonic
acid gas.
    In  the  same  way as the  starch in  putrefying 
72         SUGAR OF MILK,  GUM, &c.
paste,  in  which  it is in  contact  with decaying
gluten, is  converted into  sugar, the starch in the
above-named fruits, in a  state of decay, or erema-
causis, is transformed into grape sugar.   The more
starch  the unripe fruit contains, the sweeter does
it become when ripe.
  A close connection thus exists  between sugar
and starch.   By means of a  variety of chemi-
cal actions,  which exert no  other influence  on
the  elements of  starch  than  that of  changing
the direction  of  their mutual attraction,  we can
convert starch into sugar, but it is always grape
sugar.
  Sugar  of   milk in  many  respects  resembles
starch  ; (13) it is, by itself, incapable of the vinous
fermentation,  but it acquires the property of resolv-
ing itself  into alcohol and carbonic acid when it is
exposed to heat in contact with a substance  in  the
state of  fermentation (such  as putrefying cheese
in  milk).   In this case,  it is  first  converted into
grape sugar;  and it undergoes the  same  transfor-
mation, when it  is kept  in  contact with acids—
with sulphuric acid, for example—at the  ordinary
temperature.
  Gum has the same composition in 100 parts as cane
sugar.  (14)  It is distinguished from the  different
varieties of sugar by its not possessing the  property
of being resolved into alcohol and carbonic acid by
the process of putrefaction.   When placed  in con-
tact with  fermenting  substances, it undergoes no
appreciable change, whence we may conclude, with 
            COMPARED WITH STARCH.          73

some degree of probability, that its  elements,  in
the peculiar arrangement according to which they
are united, are held together with a  stronger force
than the elements of the different kinds of sugar.
  There is,  however, a certain relation between
gum and  sugar of milk, since both of them, when
treated with nitric acid, yield the same oxidised pro-
duct, namely mucic  acid, which cannot, under the
same circumstances,  be formed from any of the other
kinds of sugar.
  In order to show more distinctly the  similarity of
composition in these different substances, which per-
form so important a  part in the nutritive process of
the graminivora, let  us represent one equivalent of
carbon by C (= 75-8), and one equivalent of water
by aqua (= 112-4), we shall then have  for the com-
position of these substances the following  expres-
sions :—

    Starch.....= 12C + 10aqua.
    Cane Sugar . .  = 12 C+10 aqua+1 aqua.
    Gum......= 12 C-f- 10 aqua+1 aqua.
    Sugar of milk . = 12 C-f-10 aqua-f-2 aqua.
    Grape Sugar . = 12 C-f-10 aqua+4 aqua.

  For  the  same number of equivalents of carbon,
starch contains  10 equivalents, cane-sugar and gum
11 equivalents, sugar of milk  12 equivalents, and
grape-sugar 14  equivalents, of water, or the ele-
ments of water.
7 
74           GRAMINIVORA REQUIRE
  XIV. In these different substances, some one of
which is never wanting in the food  of the gramini-
vora, there is added to the nitrogenised constituents
of this food, to the vegetable albumen, fibrine, and
caseine, from which their biood is formed,  strictly
speaking, only a certain excess of carbon, which the
animal organism cannot possibly employ to produce
fibrine or albumen, because the nitrogenised consti-
tuents of the food already contain the carbon neces-
sary for the production of blood,  and because the
blood in the body of the carnivora is formed without
the aid of this excess of carbon.
   The  function performed  in the  vital process of
the graminivora by these substances (sugar, gum,
&c.) is  indicated in a very clear  and convincing
manner, when we take into  consideration  the  very
small relative  amount of the carbon which these
animals  consume  in the  nitrogenised constituents
of their  food,  which  bears no  proportion what-
ever to the oxygen absorbed through the  skin  and
lungs.
   A horse, for example, can be  kept  in  perfectly
good condition, if he obtain as food 15 lbs. of hay
and 4^ lbs, of oats daily.  If we now calculate the
whole amount of nitrogen in  these matters, as ascer-
tained  by analysis (1-5 per cent, in the hay, 2-2 per-
cent, in the oats), (15) in the form of blood, that is, as
fibrine and albumen, with the due proportion of water
in blood (80 per cent.), the  horse receives daily no
more than 4^ oz. of nitrogen, corresponding to about
8 lbs. of blood.  But along with this nitrogen, that is, 
MUCH CARBON.
75
combined with it in the form of fibrine or albumen,
the animal receives only about 14^ oz. of carbon.—
Only about 8 oz. of this can be employed  to sup-
port respiration,  for with  the nitrogen expelled in
the urine there are combined, in  the form of urea,
3 oz.,  and in  the form of  hippuric acid, 3^ oz., of
carbon.
   Without going further into the calculation, it will
readily be admitted,  that the volume of air inspired
and expired by a horse, the quantity of oxygen con-
sumed, and, as a necessary consequence, the amount
of carbonic acid given  out by the  animal, is much
greater than in the respiratory process in man.  But
an adult man consumes daily  about 14 oz. of car-
bon, and the determination of Boussingault,  accor-
ding to which a horse expires 79 oz. daily, cannot be
very far  from the truth.
   In the nitrogenised constituents of his food, there-
fore, the horse receives rather less than the fifth part
of the carbon which his organism requires  for the
support of the respiratory process ; and we see that
the  wisdom of the Creator has added to his  food
the  fths  which are wanting, in various forms, as,
starch, sugar, &c. with which the animal must be
supplied, or his organism will be destroyed by the
action of the oxygen.
   It is obvious, that  in the system of the gramini-
vora, whose food contains so small a proportion, re-
latively, of the constituents of blood, the process of
 metamorphosis in existing tissues, and consequently
 their restoration or reproduction, must go on far less 
76       WASTE  OF ORGANISED TISSUES
rapidly than  in the carnivora.  Were  this not the
case, a vegetation a thousand times more luxuriant
than the  actual  one  would  not suffice for  their
nourishment.  Sugar,  gum, and starch,  would  no
longer be  necessary to support life in these animals,
because, in that case, the products of the waste, or
metamorphosis of the organised tissues, would con-
tain enough  of carbon to support the respiratory
process.
  Man, when confined to animal food, requires for "
his support and  nourishment extensive  sources of
food, even more widely extended than the lion and
tiger, because, when he has the opportunity, he kills
without eating.
  A nation of hunters, on a limited  space, is utter-
ly incapable of increasing  its numbers  beyond  a
certain point, which is soon attained.  The carbon
necessary for respiration must be  obtained  from
the animals, of which only a  limited  number can
live on   the  space  supposed.   These  animals
collect from plants  the constituents  of their or-
gans  and of their  blood, and  yield  them,  in
turn,  to the savages who live  by the  chase alone.
They,  again,  receive  this  food unaccompanied
by  those compounds, destitute of nitrogen, which,
during the  life  of the animals, served to  sup-
port the respiratory process.  In  such men,  confi-
ned to an animal diet, it is the  carbon  of the flesh
and  of the blood which must take the place  of
starch and sugar.
  But 15 lbs. of flesh contain not  more carbon than 
VERY RAPID IN CARNIVORA.
77
4 lbs.  of starch, (16) and while the savage  with
one animal and an equal weight of starch  could
maintain life and health  for a certain  number of
days,  he would be compelled, if confined to flesh,
in order to procure  the  carbon necessary for respi-
ration, during the same time, to consume five such
animals.
  It is easy to see,  from these considerations, how
close the connection is between agriculture and the
multiplication of the human  species.  The cultiva-
tion of our crops has ultimately no other object than
the production of a maximum of those substances
which are adapted for assimilation and respiration, in
the smallest possible space.  Grain and other nutri-
tious vegetables yield us, not only in starch, sugar,
and gum, the carbon which protects  our organs from
the action of oxygen, and  produces  in the organism
the heat  which is essential to life,  but  also in the
form of  vegetable  fibrine, albumen, and  caseine,
our blood,  from which the other parts of our  body
are developed.
  Man, when confined to  animal food, respires, like
the carnivora, at the expense of the matters pro-
duced  by the metamorphosis of organised tissues;
and, just as the lion, tiger, hyaena, in the cages of a
menagerie, are compelled to accelerate the waste of
the organised tissues by incessant motion, in order
to furnish the matter necessary for respiration,  so,
the  savage,  for the very same object, is forced to
make the most laborious exertions and go through a
vast amount of muscular exercise.   He is compelled 
78
PHOSPHATES ABOUND IN
 to consume  force merely in order to supply matter
 for respiration.
   Cultivation is the economy of force.   Science
 teaches us the  simplest means of obtaining  the
 greatest effect  wiih  rle  smallest expenditure  of
 power, and with given means to produce a maxi-
 mum of force.   The unprofitable exertion of power,
 the waste  of force in agriculture, in other branches
 of industry, in science, or in social  economy, is
 characteristic of the savage state, or of the want of
 cultivation.

  XV.  A  comparison  of the  urine  of the  car-
nivora  with that of the graminivora shows very
clearly,  that the  process  of  metamorphosis  in
the tissues is different,  both  in form and in rapid-
ity, in the two classes of animals.
  The  urine of carnivorous animals  is  acid, and
contains alkaline  bases united  with  uric, phos-
phoric,  and  sulphuric  acids.  We know perfectly
the source  of the  two  latter  acids.   All the
 tissues,  with  the  exception  of  cellular  tissue
 and  membrane,  contain  phosphoric  acid   and
 sulphur, which  latter  element  is  converted  into
 sulphuric  acid  by  the oxygen  of  the  arterial
 blood.  In  the  various fluids of  the  body there
 are only  traces of phosphates  or sulphates, ex-
 cept in the urine, where both are  found in abun-
 dance.  It  is  plain that  they  are derived  from
 the  metamorphosed  tissues;  they enter into the
  venous blood in the  form of soluble salts,  and 
THE  URINE OF  CARNIVORA.
79
are separated from it in its passage  through the
kidneys.
   The urine of the graminivora is alkaline ; it con-
tains alkaline carbonates in abundance, and so small
a  portion of alkaline  phosphates  as to have  been
overlooked by most observers.
   The deficiency or absence of alkaline phosphates
in the mine of the graminivora, obviously indicates
the slowness with which  the tissues in this class of
animals are metamorphosed; for  if we assume that
a  horse consumes a  quantity of vegetable fibrine
and albumen corresponding to the amount of nitro-
gen in his  daily food (about 4^  oz.), and that the
quantity of tissue metamorphosed is equal  to that
newly formed, then the quantity of phosphoric acid
which on these suppositions would exist in the urine
is not so  small  as not to be easily detected  by
analysis in the daily secretion of urine (3 lbs.  accord-
ing to Boussingault);  for it would amount to 0-8 per
cent.  But, as  above  stated, most observers  have
been unable to detect phosphoric acid  in  the urine
of the horse.
   Hence  it is obvious,  that the  phosphoric  acid,
which  in  consequence  of the  metamorphosis of
tissues is  produced  in the form of soluble  alka-
line phosphates, must re-enter  the circulation in
this class  of animals.   It is there employed in
forming brain  and   nervous  matter, to  which  it
is  essential, and also, no doubt, in contributing to
the supply of the earthy part of the  bones.  It is
probable,  however,  that the greater part of  the 
80        ASSIMILATION IN CARNIVORA
earth of bones is  obtained  by the  direct assimila-
tion of phosphate of lime, while the soluble  phos-
phates are better adapted  for  the production  of
nervous matter.
  In the  graminivora, therefore, whose  food con-
tains so small  a proportion  of phosphorus  or  of
phosphates, the organism  collects  all the soluble
phosphates produced by the  metamorphosis of tis-
sues, and employs them for  the  development of
the bones and of the phosphorised constituents of
the brain; the organs of  excretion  do not separate
these salts from the blood.  The  phosphoric acid
which, by the change of  matter, is separated  in the
uncombined state, is not  expelled from the body as
phosphate of soda; but  we find it  in  the solid
excrements in  the form of insoluble  earthy phos-
phates.

   XVI. If we now compare the  capacity for  in-
crease of mass, the assimilative power in the grami-
nivora and carnivora, the  commonest  observations
indicate a very marked difference.
   A spider, which sucks with extreme voracity the
blood of the first  fly, is not disturbed  or excited by
a second  or third.  A cat will eat the first, and per-
haps the second mouse presented  to  her, but even
if she kills a third, she does not devour it.   Exactly
similar observations  have been made in regard to
lions and  tigers, which only devour their prey when
urged by  hunger.  Carnivorous animals, indeed re-
quire less food for their mere support,  because their 
      LESS ENERGETIC THAN IN HERBIVORA.   81

skin is destitute of perspiratory pores, and because
they consequently lose, for equal bulks, much less
heat  than graminivorous animals,  which are com-
pelled to restore  the lost heat by means  of food
adapted for respiration.     *
  How  different is the energy  and  intensity  of
vegetative  life in the graminivora.  A  cow, or a
sheep, in the meadow, eats, almost without interrup-
tion, as long as the sun is above the horizon.  Their
system  possesses  the  power of converting into or-
ganised tissues all the food they devour beyond the
quantity required for merely supplying the waste
of their bodies.
  All the excess  of blood  produced is converted
into cellular and muscular tissue ; the graminivorous
animal becomes fleshy and plump, while the flesh
of the carnivorous  animal  is  always tough  and
sinewy.
  If  we  consider   the  case  of a stag,   a roe-
deer, or  a  hare,  animals  which  consume the
same food as cattle  and sheep, it is evident that,
when  well  supplied  with  food,  their growth  in
size,  their  fattening, must  depend  on the quan-
tity of  vegetable   albumen,  fibrine,  or  caseine,
which they consume.  With free  and unimpeded
motion  and  exercise,  enough  of oxygen  is ab-
sorbed to consume  the  carbon of the gum, sugar,
starch,  and  of all  simular  soluble constituents of
their food.
  But all this is  very differently  arranged in our
domestic animals, when with  an  abundant  supply 
82
ORIGIN OF FAT IN
of food, we check the processes of cooling and  ex-
halation, as  we do when we feed  them in stables,
where free motion is impossible.
   The stall-fed animal eats,  and reposes merely for
digestion.   It  devours  in the shape of nitrogenised
compounds far more food than is required for repro-
duction, or the supply  of waste alone ;  and at  the
same time it eats far more of substances devoid of
nitrogen than is necessary merely to support  respi-
ration and  to keep up  animal  heat.    Want of
exercise and  diminished cooling  are equivalent to
a deficient supply  of oxygen;  for when  these
circumstances occur,  the  animal absorbs  much
less oxygen than is required to convert into  car-
bonic acid  the carbon of the substances destined
for respiration.   Only a  small part of the excess
of carbon  thus  occasioned is expelled from the
body in the horse and ox,  in the  form of hippuric
acid ; and all the remainder is  employed in the
production  of a  substance which, in the normal
state, only occurs  in small quantity as a consti-
tuent of  the  nerves and brain.   This substance
is fat.
   In the normal condition, as to exercise and labour,
the urine  of the horse and ox  contains benzoic  acid
(with J 4 equivalents of carbon);  but as soon as the
animal is  kept quiet in the stable, the urine contains
hippuric acid  (with 18 equivalents of carbon).
   The flesh of wild animals is devoid of fat; while
that of stall-fed animals is  covered with that  sub-
 stance.   When the fattened  animal is allowed  to 
            DOMESTICATED ANIMALS.           83

move more freely in the air, or compelled to draw
heavy burdens, the fat again disappears.
  It is evident, therefore, that the formation of fat
in the  animal body  is  the  result of a want of
due  proportion  between the food taken into  the
stomach and the oxygen absorbed by the lungs and
the skin.
  A pig, when fed with  highly nitrogenised  food,
becomes  full of  flesh ;  when  fed with potatoes
(starch) it acquires little flesh, but a thick layer of
fat.   The milk of a cow, when stall-fed, is very rich
in butter, but in  the meadow is  found  to  contain
more caseine, and in the same proportion less butter
and sugar of milk.  In the human female, beer and
farinaceous diet increase the proportion  of butter
in the milk ; an animal diet yields less milk,  but it
is richer in caseine.
   If we reflect, that in the entire class of carnivora,
the  food of which contains no substance devoid of
nitrogen except fat, the production of fat in the body
is utterly insignificant ; that even in these animals,
 as in dogs and cats, it increases as soon as they  live
 on a mixed diet; and that we can increase the forma-
 tion of fat in other domestic animals at pleasure, but
 only by means of food containing no  nitrogen; we
 can  hardly  entertain a doubt that such food, in its
 various forms of starch,  sugar, &c, is closely con-
 nected with the production of fat.
   In the natural course of scientific  research, we
 draw  conclusions from  the food in  regard  to the
 tissues or substances formed from it; from the ni- 
84
ORIGIN OF FAT IN
 trogenised  constituents of plants we draw certain
 inferences as to the nitrogenised constituents of the
 blood; and it is quite in accordance  wi.h this, the
 natural method, that  we should seek lo<? blablish the
 relations of those parts of our food which are devoid
 of nitrogen and those parts of the boi'y which con-
 tain none of that element.  It is impossible to over-
 look the very intimate connection between them.
   If we compare the composition of sugar of milk,
 of starch, and of the other varieties of sugar, with
 that of mutton and beef suet and of human fat, we
 find that in all of them the proportion of carbon  to
 hydrogen is the same, and that they only differ  in
 that of oxygen.
   According to the analyses of Chevreul, mutton
 fat, human fat, and hogs lard, contain 79 per cent.
 of carbon to 11-1, 11-4, and 11*7 per cent, of hy-
 drogen respectively. (16)

   Starch contains  4491 carbon to 611 hydrogen
   Gum and sugar  4253------to 6-37  ditto. (17)

   It is obvious that  these  numbers representing
the relative proportions of carbon and hydrogen in
starch, gum, and sugar, are in the same ratio as the
carbon and hydrogen in the different kinds of fat; for
            44-91 : 6-11 = 79 : 1099
            425S : 637 = 79 : 11-80

From which it follows, that sugar, starch, and gum,
by the mere separation  of a part of  their oxygen,
may pass into fat, or at least into a substance having
exactly the composition of fat.  If from the formula 
DOMESTICATED  ANIMALS.
89
of starch, C12H10O10, we take 9  equivalents of oxy-
gen, there will remain in 100 parts-—
           C12  .............  79 4
           H10.............10-8
           O.............   9-8
  The empirical formula of fat which comes nearest
to this is CnH10O, which gives in 100 parts—
           Cu  .............78-9
           H10.............11-6
           O   .............   9 5
  According to this formula, an equivalent of starch,
in order to be changed into fat would lose 1 equi-
valent of  carbonic acid,  C02, and 7 equivalents of
oxygen.
  Now  the composition of all saponifiable fatty
bodies agrees very closely with one or other of these
two formulae.
  If from  3 equivalents of sugar of milk, SC^H^O*,
^ggHgeOae, we take away four equivalents of water
and 31 of oxygen, there will remain C36H2aOj,  a
formula which accurately represents the composition
of cholesterine, the fat of bile.  (18)
  Whatever views we may entertain regarding the
origin of  the  fatty constituents of the body, this
much at least is undeniable, that the herbs and roots
consumed  by the cow  contain no butter;  that in
hay or the other fodder of oxen no beef suet exists;
that no hog's lard can be found in the potato refuse
aiven to swine ; and that the food of geese or fowls
contains no goose  fat or  capon fat.   The masses of
                        8 
86
THE  FORMATION OF FAT
fat found in the bodies of these animals are  formed
in their organism ; and  when the full value of this
fact is  recognized, it entitles us to conclude that a
certain quantity of oxygen, in  some form or other,
separates from the constituents of their  food; for
without  such  a separation of oxygen, no fat could
possibly  be formed  from  any one  of these  sub-
stances.
  The chemical analysis of the constituents of the
food of the graminivora shows in the clearest man-
ner that  they contain carbon and oxygen in certain
proportions;  which,  when  reduced  to  equivalents,
yield the following series :—
  In vegetable fibrine, albumen, and caseine, there are con-
     tained, for.......120 eq. carbon, 36 eq. oxygen
  In starch.........120......100
  In cane sugar......120......110
  In gum..........120......110
  In sugar of milk .... 120......120
  In grape sugar  .... 120......140
  Now in all fatty bodies there  are  contained,  on an
average—
     for ..........120 eq. carb. only 10 eq. oxygen.
   Since the carbon  of the fatty constituents of the
animal body is derived from  the food, seeing that
there is no other source whence it  can be derived,
it is obvious if we  suppose fat to be formed  from
albumen, fibrine, or caseine, that, for every 120 equi-
valents of carbon deposited as  fat, 26 equivalents of
oxygen must be separated from the elements of these
substances; and further,  if  we conceive fat to be 
IS A SOURCE OF OXYGEN.
87
formed from starch, sugar, or sugar of milk, that for
the same amount of carbon there must be separated
90, 100, and 110 equivalents of oxygen  from these
compounds respectively.
  There is, therefore, but one  way in  which  the
formation of fat in the animal body is possible, and
this is absolutely the same in which its formation in
plants takes place ; it is a separation of oxygen from
the elements of  the food.
  The carbon which we find deposited in the seeds
and fruits of vegetables, in the form of oil and  fat,
was previously a constituent of the atmosphere, and
was absorbed  by the plant  as  carbonic acid.  Its
conversion into fat was accomplished under the in-
fluence of light, by the vital  force of the vegetable ;
and the greater part of the oxygen of this carbonic
acid was returned to the atmosphere  as oxygen
gas.*
  In  contradistinction  to  this   phenomenon  of
vitality in  plants, we know that the animal sys-
tem absorbs  oxygen  from  the  atmosphere,  and
that  this  oxygen  is again given  out  in com-
bination with carbon  or  hydrogen;  we know,
that  in the   formation  of carbonic  acid   and
water,  the heat necessary  to sustain the  constant
temperature  of the  body  is   produced,  and  that
a process of  oxidation is the  only  source of  ani-
mal heat.
   Whether fat be formed by the decomposition o*
   * See Appendix, No. 19, on the  formation of wax and honey by
 the bee. 
88        FAT IS FORMED WHEN  THE

fibrine  and  albumen,  the  chief  constituents  of
blood, or by that of starch, sugar, or gum, this
decomposition must be  accompanied  by  the se-
paration of oxygen from  the  elements of  these
compounds.  But  this  oxygen  is not given  out
in the free state, because it meets  in  the organ-
ism  with  substances possessing  the  property of
entering into combination  with  it.  In fact,  it is
given  out  in  the  same  forms  as that which  is
absorbed  from  the  atmosphere  by  the  skin and
lungs.
   It is easy to see, from the  above considerations,
that a very remarkable  connection exists between
the formation of fat and the respiratory process.

   XVIII. The  abnormal  condition,  which causes
the deposit of fat in the animal  body,  depends, as
was formerly stated, on a disproportion between the
quantity of carbon in the food and that of oxygen
absorbed  by the  skin and lungs.   In  the normal
condition, the quantity of carbon given out is  ex-
actly equal to that which is taken in  the food, and
the body acquires no increase of weight from the
accumulation of substances containing much carbon
and no nitrogen.
  If we  increase the supply of highly carbonised
food, then the normal state can only be preserved
on the condition  that, by exercise and labor,  the
waste of the body is increased, and  the supply of
oxygen augmented in the same proportion.
  The production of fat is always a consequence of 
              OXYGEN IS DEFICIENT.           89

a  deficient  supply of oxygen, for oxygen is abso-
lutely indispensable for the dissipation of the excess
of carbon in the food.   This excess of carbon, de-
posited in the form  of  fat, is never  seen  in the
Bedouin or  in the Arab of the desert, who exhibits
with pride to the traveller his lean, muscular, sinewy
limbs, altogether free from fat; but in  prisons and
jails it appears as  a puffiness in the inmates, fed,
as  they are,  on  a poor  and scanty diet;  it  ap-
pears in the sedentary females of oriental countries ;
and finally, it is produced under the well-known
conditions of the fattening of domestic animals.
   The formation of fat depends on a deficiency of
oxygen ; but in this process, in the formation of fat
itself, there  is opened  up a new source of oxygen,
a new cause of animal heat.
   The  oxygen set free  in  the formation of fat is
given  out in  combination  with  carbon or hydro-
gen ;  and whether this carbon and hydrogen  pro-
ceed from the substance that yields the oxygen, or
from other compounds, still there  must have been
generated by  this formation of  carbonic acid or
water as much heat as if an equal weight of  car-
bon or hydrogen had been burned in air or in oxygen
gas.
  If we suppose that from 2 equivalents of  starch
18 equivalents of oxygen are disengaged, and  that
these  18  equivalents of oxygen  combine with 9
equivalents of carbon, from the bile, for  example,
no one can doubt that, in this case, exactly as much
heat must be developed, as if these 9 equivalents of
                         8* 
 90        THE FORMATION  OF FAT IS

 carbon had been directly burned.  In  this form,
 therefore,  the  disengagement of  heat  as a con-
 sequence of the formation of  fat would be un-
 deniable ;  and  it could only be  considered hy-
 pothetical, on  the  supposition that  carbon  and
 oxygen were disengaged from one and the  same
 substance, in  the  proportions to yield  carbonic
 acid.
   If, for example, we suppose that from  2 atoms
 of starch, C21H29O20,  the elements of 9 equivalents
 of carbonic acid are separated, there will remain a
 compound containing, for 15 equivalents of carbon,
 20 of hydrogen and 2 of oxygen ;  for
            C2jH2i)C2o = C9018 -f- Ui5ri20O2.
 Or,  if we assume  that oxygen  is separated from
 starch in the form both of carbonic acid  and water,
 then, after subtracting  the  elements of 6  equiva-
 lents of water and 6 of carbonic acid, there would
 remain the compound C,8Hu02; for
       C^H^O^ = C6012 -f- H606 + C18H1402.
   Assuming, then, the separation of oxygen in either
 of these forms, it remains to be decided whether the
 carbonic  acid and water given off were  contained,
 as such, in the starch, or not.
   If  they were ready  formed in the  starch, the
 separation might occur without the disengagement
 of heat;  but if the carbon and hydrogen were pre-
 sent  in any other form in the starch (or in the com-
pound from which the fat was produced), it is obvious
 that a change in the arrangement of the atoms must
 have occurred, in consequence of which  the atoms 
           A SOURCE  OF ANIMAL HEAT.         91

of the carbon  and of the hydrogen have united
with those of the oxygen, to form carbonic acid and
water.
   Now, so  far as chemical researches  have gone,
our knowledge of the constitution of starch, and of
the varieties of sugar, will justify no other conclu-
sion than this,  that these substances contain no ready
formed carbonic acid.
   We are acquainted with a large number of pro-
cesses of metamorphosis of a similar kind, in which
the elements of carbonic acid and water are sepa-
rated from certain pre-existing compounds ; and  we
know with  certainty that  all these processes are
accompanied by  a disengagement of heat, exactly
as if the  carbon  and hydrogen combined directly
with oxygen.
   Such a disengagement of carbonic acid, for ex-
ample, occurs in all processes of fermentation or
putrefaction, which are,  without exception, accom-
panied with a generation of heat.
   In the  fermentation of a saccharine  solution, in
consequence of a new arrangement of the elements
of the sugar, a certain part of its carbon and oxygen
unite to form carbonic acid, which separates as gas;
and as another result of this decomposition, we ob-
tain a volatile combustible liquid, containing little-
oxygen, namely,  alcohol.
   If we add to 2 equivalents of sugar the elements
of 12 equivalents of water,  and  subtract from the
sum of the atoms 24 equivalents of oxygen, their  re-
main 6 equivalents of alcohol. 
 92         THE  FORMATION OF FAT IS

  (C^H^O^ -f HiaOM) — 021 = C2;H360ia= 6 eq. alcohol.
   These 24 equivalents of oxygen suffice to oxidise
 completely a third equivalent of sugar—that is, to
 convert its carbon into carbonic acid and its hydro-
 gen into water, and by this oxidation we recover the
 12 equivalents of water supposed to be added in the
 former part of the process, exactly as if this water
 had taken no  share in it.
          CuHjAa + Oai = 12C02 + 12H0.
   According to the ordinary view, 12 equivalents of
 carbonic  acid separate from 8 of sugar, yielding 6
 of alcohol—that  is, exactly the  same amount of
 these  products as  if two-thirds  of the sugar had
 yielded oxygen to the remaining third, so as com-
 pletely to oxidise its elements.
           CssHaAs = C24H36012 -f- 12C0, *
   By a comparison of these two  methods of repre-
 senting the same change, it will easily be seen that
 the division or splitting of a compound like  sugar
 into carbonic acid,  on the  one  hand,  and   a
 compound  containing   a  little   oxygen  on the
 other,  is   in  its  results  perfectly  equivalent  to
 a  separation  of  oxygen  from a  certain  portion
 of the  compound  and the oxidation  or combus-
 tion  of another portion of it at the expense of this
 oxygen.
   It is well known that  the temperature of a fer-
menting liquid rises ; and if we assume that a hogs-
head of  wort, holding  1,200  litres = 2,400 lbs.,

 * For an explanation of the formulae and equations employed, see the
Introduction to the Appendix. 
          A SOURCE OF ANIMAL HEAT.         93

French weight, contains 16  per cent, of sugar, in
all 384  lbs., then, during  the fermentation of this
sugar, an amount of heat must be generated equal
to that which would be produced by the combustion
of 51 lbs. of carbon.
  This  is equal to  a quantity of  ^eat by which
every pound of the  liquid  might be heated  by
297*9°; that is, supposing  the  decomposition of
the sugar to occur in a period of time  too  short
to be measured.   This is  well known not to  be
the case ; the fermentation  lasts five or  six days,
and each  pound of liquid  receives the 297*9  de-
grees of heat during a period of  120 hours.  In
each hour there is, therefore, set free an  amount
of heat capable of  raising the  temperature  of each
pound of liquid 1«4  degree ;  a  rise of tempera-
ture which is very  powerfully counteracted by ex-
ternal cooling and by the vaporization of alcohol
and water.
  The  formation   of fat,  like  other  analogous
phenomena in  which oxygen is  separated in  the
form  of  carbonic acid,  is  consequently  accom-
panied by a disengagement of heat.  This  change
supplies  to the  animal body a certain  propor-
tion of the oxygen  indispensable  to the  vital pro-
cesses ; and  this  especially in  those  cases in
which  the  oxygen  absorbed by the skin  and
lungs is not  sufficient to convert into carbonic
acid the whole of  the carbon adapted for this com-
bination. 
94
FORMATION OF FAT
  This excess of carbon, as it cannot be employed
to form a part of any organ, is deposited in the cellu-
lar tissue in the form of tallow or oil.
  At every period of animal life, when there occurs
a disproportion between the carbon of the food and
the inspired oxygen, the latter  being  deficient, fat
must be formed.   Oxygen separates from  existing
compounds, and this oxygen is given out as carbonic
acid or water.  The heat generated in the formation
of these  two  products contributes  to  keep up the
temperature of the body.
  Every pound of carbon which obtains the oxy-
gen necessary to convert it into carbonic acid from
substances which thereby pass into fat, must dis-
engage  as much heat as  would raise the tempera-
ture of 200 lbs. of water by 70°,—that is, from 32°
to 102°.
  Thus, in the formation of fat, the vital force
possesses   a   means  of  counteracting  a  defici-
ency in  the  supply of oxygen, and  consequently
in  that of  the heat  indispensable for  the  vital
process.
  Experience teaches us that in poultry, the maxi-
mum of fat is obtained by tying the feet, and by a
medium  temperature.   These  animals in such cir-
cumstances may be compared to a plant possessing
in the highest  degree  the power of converting all
food into  parts of its own structure.   The excess
of the constituents  of blood  forms flesh and other
organised  tissues,  while that of starch, sugar, &c, 
CONSTITUENTS OF  FOOD.
95
is  converted into fat.  When  animals are fattened
on food destitute  of nitrogen,  only certain parts of
their structure increase in  size.  Thus, in a goose,
fattened in the method above  alluded to,  the liver
becomes three or four times larger than in the same
animal, when well fed with free motion, while we
cannot say that the organised structure of the liver
is  thereby increased.   The liver of a goose fed in
the ordinary way is firm  and elastic ; that of the
imprisoned animal is soft and spongy.  The differ-
ence  consists in a greater or  less expansion of its
cells which are filled with fat.
   In some  diseases,  the starch, sugar, &c, of the
food obviously do not undergo the changes which
enable them to assist in respiration, and consequent-
ly to be converted into fat.   Thus, in diabetes mel-
litus, the starch is only converted  into grape sugar,
which is expelled from the  body without further
change.
   In other diseases, as for  example in inflammation
of the liver, we find the blood loaded with fat and
oil; and in  the  composition   of the  bile  there  is
nothing at all inconsistent  with the supposition that
some of its constituents may be transformed into fat.

   XIX.  According to what has been laid down in
the  preceding pages,  the  substances of which the
food of man is composed may be divided into two
classes ; into nitrogenised and non-nitrogenised.   The
former are capable of conversion into  blood; the
 latter incapable  of this transformation. 
96   NITROGENISED  AND NON-NITROGENISED.
  Out of those  substances which are adapted to
the formation of blood are formed all the organised
tissues.   The  other class of substances, in the nor-
mal state of health, serve  to  support the process of
respiration.  The former may be called the plastic
elements of nutrition; the latter, elements of respiration.
  Among the former we reckon—

                Vegetable fibrine.
                Vegetable albumen.
                Vegetable caseine.
                Animal flesh.
                Animal blood.

  Among the elements of respiration in  our  food,
are—
Fat.	Pectine.
Starch.	Bassorine
Gum.	Wine.
Cane Sugar.	Beer
Grape Sugar.	Spirits.
Sugar of milk.	
   XX.  The most recent and exact Researches have
established as a universal fact, to which nothing yet
known is opposed, that the nitrogenised constituents
of vegetable food have a composition identical with
that of the constituents  of the blood.
  No nitrogenised  compound, the  composition of
which  differs  from  that of fibrine, albumen,  and
caseine, is capable of supporting the  vital process
in animals.
  The animal organism unquestionably possesses the 
ELEMENTS OF  FOOD.
97
power of forming, from the constituents of its blood,
the substance of  its membranes and cellular tissue,
of the nerves and brain, of the organic part of carti-
lages and bones.  But the blood must be supplied
to it ready formed in every thing but its form—that
is, in its chemical composition.  If this be not done,
a  period  is rapidly  put to the  formation of blood,
and consequently to life.
   This consideration  enables us easily to  explain
how it happens  that the tissues  yielding gelatine or
chondrine, as,  for example, the gelatine  of skin or
of  bones,  are   not  adapted for the support of
the vital  process ; for their composition is different
from that of fibrine  or  albumen.   It is obvious
that this means nothing more  than that those
parts  of  the animal  organism  which  form   the
blood do not possess the power of effecting a trans-
formation in  the arrangement  of the elements of
gelatine,  or  of those tissues   which  contain it.
The gelatinous tissues, the  gelatine of the bones,
the  membranes,  the  cells, and  the  skin,  suffer, in
the  animal body, under the influence of oxygen
and  moisture,  a progressive   alteration;  a  part
of these tissues is separated, and must be restored
from the blood ; but this alteration  and  restora-
tion is  obviously  confined  within  very  narrow
limits.
   W hile, in the body of a starving or sick individual,
the fat disappears, and  the  muscular tissue takes
once more the  form  of blood, we find that the ten-
dons and membranes retain their natural condition ;
                         9 
98
GELATINE MAY SERVE TO
the limbs of the dead body retain their connections,
which depend on the gelatinous tissues.
  On the other hand, we see that the gelatine of
bones devoured by a dog entirely disappears, while
only the bone  earth  is found in his  excrements.
The same is true of man, when fed on food rich
in gelatine,  as, for  example, strong soup.   The
gelatine is not to be found either in the urine or
in the  faeces,  and  consequently must have under-
gone a change, and must have served  some pur-
pose in the  animal  economy.  It is clear, that the
gelatine must be expelled from the body in  a form
different from that  in which it was introduced as
food.
  When we  consider the  transformation  of  the
albumen of the blood into a part of an organ com-
posed of fibrine, the identity in composition of the
two substances renders the change  easily conceiva-
ble.   Indeed we find the change of a dissolved sub-
stance into an insoluble organ of vitality, chemically
speaking, natural and easily  explained, on  account
of this  very identity of composition.   Hence  the
opinion is not unworthy of a closer investigation,
that gelatine, when  taken in the dissolved stale, is
again converted, in the body, into  cellular tissue,
membrane and  cartilage; that it may serve for the
reproduction of such  parts of these tissues  as have
been wasted, and for their growth.
  And when  the powers of nutrition in the  whole
body are  affected by a change of the health, then,
even should the power of forming blood remain the 
       NOURISH THE GELATINOUS TISSUES.     99

same, the organic force by  which the constituents
of the blood are transformed into cellular tissue and
membranes must necessarily be enfeebled by sick-
ness.   In the sick man, the intensity of the vital
force, its power to produce metamorphoses, must be
diminished as well in  the  stomach as in all other
parts of the body.   In this condition, the uniform
experience of practical physicians shows that gela-
tinous matters in a dissolved state exercise a most
decided influence on the state of the health.   Given
in a form adapted for assimilation, they  serve to
husband the vital force, just as may be done, in the
case of the stomach, by due preparation of the food
in general.  Brittleness in  the bones of graminivo-
rous animals is clearly owing to a weakness in those
parts of the organism whose function it is to convert
the constituents of the blood into cellular tissue and
membrane; and  if we can trust to the  reports of
physicians who have resided in the East, the Turk-
ish women, in their diet of rice, and in the frequent
use of enemata of strong soup, have united the con-
ditions necessary for the formation both of cellular
tissue and of fat. 
 
PART II.
          THE




METAMORPHOSIS OF TISSUES, 
I 
                 THE

METAMORPHOSIS  OF  TISSUES.
  1.  The absolute identity of  composition in the
chief constitutents  of  blood  and the nitrogenised
compounds in vegetable food would, some years ago,
have furnished a plausible reason for denying the
accuracy of the chemical analysis leading to such a
result.   At that period, experiment had not as yet
demonstrated the existence of numerous compounds,
both containing nitrogen and devoid of that element,
which with the greatest diversity in external charac-
ters, yet possess the very same composition in 100
parts ;  nay, many of which even contain the same
absolute  amount of equivalents of each  element.
Such examples are now very  frequent,  and are
known by the names of isomeric  and polymeric com-
pounds.
  2. Cyanuric acid, for example, is a nitrogenised
compound which crystallizes in beautiful transparent
octahedrons,  easily soluble in water and  in acids,
and very permanent.   Cyamelide is a second body,
absolutely insoluble  in  water  and  acids,  white
and opaque like porcelain or magnesia.  Hydrated 
104
ISOMERIC BODIES.
cyanic acid is a third compound, which is a liquid,
more volatile than pure acetic acid,  which blisters
the skin,  and cannot  be brought in contact with
water without being instantaneously resolved  into
new products.   These three  substances  not only
yield, on  analysis,  absolutely the  same  relative
weights of the  same  elements, but  they  may be
converted and reconverted into one another, even
in hermetically closed  vessels—that is, without the
aid of any foreign matter.   (See Appendix,  21.)
Again,  among those substances  which contain no
nitrogen, we have aldehyde,  a combustible liquid
miscible with water, which boils at the temperature
of the hand, attracts oxygen from the  atmosphere
with aviditj', and is thereby changed into acetic acid.
This compound cannot be preserved, even in close
vessels; for after some hours or days, its consistence,
its volatility,  and its  power of  absorbing oxygen,
all are  changed.  It  deposits long,  hard,  needle-
shaped  crystals, which  at 212° are not volatilized,
and the  supernatant liquid  is  no longer  alde-
hyde.   It now  boils  at 140°,  cannot be  mixed
with water, and when  cooled to a moderate degree
crystallizes  in  a form   like  ice.   Nevertheless,
analysis  has proved,  that these  three bodies, so
different in their characters* are identical in com-
position. (21)
   3. A similar group of three occurs in the case of
albumen, fibrine, and caseine.   They differ in exter-
nal character, but contain exacdy the same propor-
tions of organic elements. 
            DISCOVERY OF PROTEINE.         105

  When animal  albumen, fibrine, and caseine are
dissolved in a moderately strong solution of caustic
potash,  and  the  solution is exposed for some time
to a high temperature,  these substances are decom-
posed.  The addition of acetic acid to the solution
causes, in all  three, the separation of a gelatinous
translucent precipitate, which  has exactly the same
characters and composition, from whichever of the
three substances  above mentioned it has  been ob-
tained.
  Mulder, to whom we owe the discovery of this
compound, found, by  exact and careful  analysis,
that  it  contains  the same organic  elements, and
exactly  in the  same  proportion, as  the animal
matters from which  it  is prepared;  insomuch,
that  if we  deduct  from the analysis of albumen,
fibrine,  and  caseine, the  ashes they yield  when
incinerated, as well as the sulphur  and  phospho-
rus they contain,  and then calculate the remainder
for 100  parts, we  obtain the same  result as  in
the  analysis  of  the precipitate above  described,
prepared by  potash, which is  free from inorganic

  Viewed in this light, the chief constituents of the
blood .i.nd the caseine of milk  may be regarded  as
compounds  of phosphates and  other salts, and  of
sulphur and phosphorus, with a compound of car-
bon, nitrogen, hydrogen, and ox\'gen, in which the
relative proportion of these elements is invariable;
and  this compound may be considered as the com-
mencement and  starting-point of all  other animal 
106       PROTEINE exists in fibrine,
tissues, because  these are  all produced from  the
blood.
  These  considerations  induced  Mulder to give to
this product of the decomposition of albumen, &c.
by potash,  the name of proteine  (from itguTeiw,  " I
take the first rank.")   The blood, or the  constitu-
ents of the  blood,  are consequently  compounds of
this proteine with variable proportions of inorganic
substances.
  Mulder,  further  ascertained,  that the insoluble
nitrogenised  constituent of wheat flour (vegetable
fibrine,)  when treated with potash, yields  the very
same  product, proteine;  and it  has recently been
proved  that  vegetable  albumen and  caseine are
acted on  by  potash  precisely as animal  albumen
and caseine are.
   4.  As  far,   therefore, as  our researches  have
gone,  it  may be laid  down   as   a  law, found-
ed   on experience,  that  vegetables  produce,  in
their  organism,  compounds of  proteine;  and that
out of these compounds of proteine the  various  tis-
sues  and parts of  the animal body  are developed
by the  vital  force,  with  the  aid  of the oxygen
of the atmosphere and of the elements of water.*

   The experiment of Tiedemann and Gmelin, who found it impossible
to sustain the life of geese by means of boiled white of egg, may be easi-
ly explained, when we  reflect that a graminivorous animal, especially
when di-prived of free motion, cannot obtain, from the transformation
or waste of the tissues alone, enough of carbon for  the respiratory
process. 2 lbs. of albumen contain only 3J  oz. of carbon, of which,
among the last products of transformation, a  fourth part is  given off in
the form of uric acid. 
ALBUMEN, AND CASEINE.         107
  Now, although it  cannot be demonstrated  that
proteine  exists ready  formed  in  these  vegetable
and  animal products, and  although  the  difference
in their  properties  seems  to  indicate  that their
elements are  not  arranged in the same manner,
yet  the  hypothesis  of the pre-existence of  pro-
teine, as a point  of departure in developing and
comparing   their properties, is exceedingly  con-
venient.  At  all  events,  it  is  certain  that  the
elements of these  compounds assume  the same
arrangement when acted on by potash  at  a  high
temperature.
  All the  organic nitrogenised constituents of the
body, how  different soever they may be in composi-
tion, are derived from  proteine.   They are  formed
from it, by the addition  or subtraction of the ele-
ments of water or of oxygen, and by  resolution
into two or more compounds.
   5. This  proposition must be received  as  an un-
deniable truth, when  we  reflect on  the develop-
ment of the  young animal in the egg  of a fowl.
The egg can be shown to contain  no other nitro-
genised  compound except  albumen.  The  albu-
men of the  yolk  is  identical with  that  of the
white ; (23) the yolk contains, besides, only a yel-
low fat, in which cholesterine and  iron may  be
detected.   Yet  we  see,  in the process  of  incuba-
 tion, during which no food  and no foreign  matter,
 except the oxygen of the air,  is introduced, or can
 take part  in  the  development of the animal, that
 out of the albumen,  feathers, claws, globules of 
108
DIGESTION COMPARED.
the blood,  fibrine, membrane and cellular tissue,
arteries and veins,  are  produced.   The fa*, ot
the yolk may  have contributed,  to a  certaia ex- >
tent,  to the  formation  of  the  nerves  and brair :
but the carbon of this fat cannot have been  eu.
ployed  to  produce the organised tissues in which
vitality resides, because the  albumen of the white
and  of the yolk already  contains, for the quan-
tity of  nitrogen  present,  exactly the  proportion
of carbon  required  for  the  formation of  these
tissues.
   6.  The true  starting-point for  all the tissues is,
consequently, albumen ; all nitrogenised articles of
food, whether derived from the animal or from the
vegetable  kingdom,  are converted  into  albumen
before they can take part in the process of nutri-
tion.
   All the  food consumed by an animal becomes in
the stomach  soluble, and capable of entering into
the circulation.  In the process by which this solu-
tion is effected, only one fluid, besides  the  oxygen
of the air,  takes a part; it is that which is  secreted
by the lining membrane of the stomach.
  The most decisive  experiments of physiologists
have  shown  that the process  of cbymification is
independent of the vital force ;  that it takes place
in virtue of a purely chemical action, exactly simi-
lar to those processes of decomposition  or transfor-
mation which are known as putrefaction, fermenta-
tion,  or decay (eremacausis).
  7.  When expressed in the simplest  form,  fer- 
TO FERMENTATION.           109
mentation, or putrefaction,  may be described as a
process of transformation—that is, a new arrange-
ment of the elementary particles, or atoms,  of a
compound, yielding two or  more new  groups or
compounds, and caused by contact with  other sub-
stances, the elementary particles of which are them-
selves in a state of transformation or decomposition.
It is a  communication, or an imparting of a state of
motion, which the atoms  of a body in a state of
motion are capable of  producing  in  other bodies,
whose elementary  particles  are held together only
by a feeble attraction.
  8. Thus the clear gastric juice contains a sub-
stance in a  state  of transformation, by the con-
tact of which  with those constituents of the food
which, by themselves,  are  insoluble  in  water,  the
latter  acquire, in  virtue  of a  new  grouping of
their atoms,  the  property  of  dissolving in that
fluid.  During digestion, the  gastric juice, when
separated,  is  found  to  contain  a  free  mineral
acid, the  presence of  which  checks  all further
change.   That the food is rendered soluble  quite
independently of  the  vitality  of the  digestive
organs has been proved by  a number of the most
beautiful  experiments.   Food,  enclosed  in  per-
forated metallic  tubes, so that it could not  come
into contact with  the  stomach, was found to dis-
appear  as  rapidly,  and  to be as perfectly di-
gested, as if the covering  had been absent; and
fresh  gastric juice, out of the  body, when boiled
white of egg, or muscular fibre,  were kept in
                        10 
110       POWER OF ANIMAL MEMBRANE

contact with it  for  a  time at the temperature of
the body, caused these substances to lose the solid
form and to dissolve in the liquid.
   9. It can hardly be  doubled that the substance
which  is  present in the gastric juice in a s>ute of
change is  a  product of the transformation oi the
stomach  itself.  No  substances  possess, in so high
a  degree  as  those arising from the progressive de-
composition of the tissues containing gelatine  or
chondrine, the property of  exciting  a  change  in
the arrangement of the elements  of other com-
pounds.    When  the   lining membrane  of  the
stomach  of any animal, as, for example,  that of
the calf,   is  cleaned by continued  washing  with
water, it  produces no  effect whatever, if brought
into  contact  with  a  solution of sugar,  with milk,
or other  substances.   But if the same membrane
be exposed for some time to the air, or dried, and
then placed  in contact with such  substances, the
sugar is changed, according to the  state of decom-
position of the  animal matter, either  into  lactic
acid, into  mannite and mucilage, or into alcohol
and carbonic acid; while milk is instantly coagu-
lated.  An ordinary animal bladder retains, when
dry, all its properties  unchanged ;  but when ex-
posed  to  air and  moisture, it undergoes a change
not indicated by any obvious external signs.  If, in
this  state, it be  placed in a  solution of sugar of
milk, that  substance is  quickly changed into lactic
acid.
   10. The fresh  lining  membrane of the stomach of 
TO PRODUCE FERMENTATION.       Ill
a calf, digested with weak muriatic acid, gives to
this fluid no power of dissolving boiled flesh or co-
agulated white of egg.   But if previously allowed
to dry, or if left for a time in water, it then yields,
to water acidulated with muriatic acid, a substance
in minute quantity, the  decomposition of which is
already commenced, and is completed in  the  solu-
tion.   If coagulated albumen  be placed  in  this
solution, the state of decomposition is  communi-
cated to it, first at the edges, which become trans-
lucent, pass into a mucilage, and  finally dissolve.
The  same  change  gradually  affects  the  whole
mass, and at last it  is entirely dissolved, with the
exception of fatty particles, which render the solu-
tion turbid.  Oxygen  is conveyed to every  part
of  the body  by the  arterial  blood ; moisture  is
every where present; and thus we have united the
chief conditions of all  transformations in the ani-
mal body.
   Thus, as in the germination of seeds, the presence
of a body in a state of decomposition or transforma-
tion, which has been called diastase, effects the solu-
tion of the starch—that is, its conversion into sugar ;
so, a  product of the metamorphosis of the substance
of the stomach, being itself in  a state of metamor-
phosis which  is  completed in  the stomach, effects
the dissolution of all such parts of the food as are
capable of assuming a soluble form.  In certain
diseases, there are produced from the starch, sugar,
&c,  of the food,  lactic acid and mucilage. (24)
These are  the very same products which we can 
112        LACTIC ACID  NOT FORMED

produce out of sugar by means of membrane in a
state of decomposition out of the body ; but in a
normal state of health, no lactic  acid is  formed in
the stomach.
   11. The property possessed by many substances,
such as starch and the varieties of sugar, by contact
with animal substances in a state of decomposition,
to pass into lactic acid, has induced physiologists,
without further inquiry,  to assume  the  fact of the
production of lactic acid during digestion ; and the
power which this acid has of dissolving phosphate of
lime has led them to ascribe to it  the character of a
general solvent.  But neither Prout nor Braconnet
could detect lactic acid in the gastric juice; and even
Lehmann (see his " Lehrbuch der Physiologischen
Chemie," torn. i. p. 285) obtained from the  gastric
juice of a cat only microscopic  crystals, which he
took for lactate  of  zinc, although  their chemical
character could not be ascertained.  The presence
of free muriatic acid in  the  gastric juice, first  ob-
served by Prout, has been  confirmed by all those
chemists who have examined that fluid since.  This
muriatic acid is obviously derived from common salt,
the soda of which plays a very decided part in the
conversion of fibrine and caseine into blood.
   Muriatic acid yields to no other acid in the power
of dissolving bone earth, and even acetic acid, in this
respect,  is equal to lactic acid.   There is conse-
quently no proof of the  necessity of lactic acid in
the digestive process ; and we know with certainty,
that in artificial digestion it is not formed.   Berze- 
           IN  THE HEALTHY STOMACH.       H3

bus indeed  has found  lactic  acid  in the blood
and flesh of animals ;  but when his experiments
were made, chemists  were  ignorant  of the ex-
traordinary  facility and  rapidity with which this
acid is formed  from a  number of substances con-
taining its elements,  when in contact with animal
matter.
  In  the gastric juice of  a dog, Braconnet found,
along with free muriatic  acid,  distinct traces of a
salt of iron, which he at first held to be an acciden-
tal  admixture.   But in the gastric juice of a second
dog,  collected  with the utmost care, the iron was
again found.   (Ann.  de  Ch. et de Ph. lix. p.  249.)
This occurrence of iron is full of significance in re-
gard to the formation of the blood.
  12. In the action of the gastric juice on the  food,
no  other element  takes a  share, except the oxygen
of  the  atmosphere and   the  elements of water.
This oxygen  is  introduced directly into the stomach.
During the mastication of the food, there is secreted
into the  mouth from organs specially destined to
this function, a  fluid, the saliva, which possesses the
remarkable property of enclosing air in the shape of
froth, in a far higher degree  than even soap-suds.
This  air,  by means of the saliva, reaches the sto-
mach with the  food, and there its oxygen enters into
combination, while its nitrogen is given out through
the skin and lungs.  The longer digestion  conti-
nues, that is, the greater resistance offered to the sol-
vent action by  the food, the more saliva, and conse-
quently the more air enters the stomach.  Rumina-
                       10* 
114
USE OF  THE  SALIVA.
tion, in certain graminivorous  animals, has plainly
for one object a renewed  and repeated introduction
of oxygen; for a more minute mechanical division
of the food only shortens the time required for solu-
tion.
 .  The unequal quantities  of air which reach the
stomach  with the saliva in  different classes of ani-
mals explain  the accurate observations made by
physiologists, who have established beyond all doubt
the fact, that animals give out pure nitrogen through
the skin and lungs, in variable quantity.  This fact
is so much the more important, as it furnishes  the
most decisive proof, that the nitrogen of the air is
applied to no use in the animal economy.
   The fact  that nitrogen is given out by the skin
and lungs, is explained by the property which ani-
mal membranes possess of allowing all gases to per*
meate them, a property which can be shown to exist
by the most simple experiments.  A bladder, filled
with carbonic acid, nitrogen, or hydrogen gas, if
tightly closed  and suspended in the air, loses in 24
hours the whole of the enclosed gas; by  a kind of
exchange, it passes outwards  into the atmosphere,
while its place is occupied  by atmospherical air. A
portion of intestine, a stomach, or a piece of skin
or membrane, acts precisely as the bladder, if filled
with any gas.  This permeability to gases is a me-
chanical  property,  common to all  animal tissues ;
and it is  found in the same degree  in the living as
in the dead tissue.
   It is known  that in cases  of  wounds of the lungs 
         GASES PERMEATE MEMBRANES.      115

a peculiar condition is produced, in which, by the
act of inspiration, not only oxygen but atmospheri-
cal air, with its whole amount (fths) of nitrogen,
penetrates into the cells of the lungs.  This air  is
carried by the circulation to every part of the body,
so that every part is inflated or puffed up with the
air, as  with water  in dropsy.   This slate  ceases,
without pain, as soon as the entrance of the air
through the wound is stopped.  There  can be no
doubt that the oxygen of the air, thus accumu-
lated in the cellular tissue, enters into combination,
while its  nitrogen is expired  through the skin  and
lungs.
   Moreover, it is well known that in many gramini-
vorous animals, when the digestive organs have been
overloaded with fresh juicy  vegetables,  these sub-
stances  undergo  in the  stomach the  same de-
composition as they would  at the same  temper-
ature  out of the body.  They pass into  fermen-
tation and putrefaction, whereby so great a quan-
tity of carbonic acid gas  and of inflammable gas
is  generated, that these organs are enormously dis-
tended,  sometimes even  to  bursting.   From the
structure of their stomach or stomachs, these gases
cannot escape  through  the oesophagus;  but  in
the course of  a few  hours, the  distended  body
of the  animal becomes less  swoln, and at  the end
of twenty-four hours  no trace of  the gases  is
left. (25)
   Finally, if we consider the fatal accidents which
so frequently occur in  wine countries from the 
116        SOURCES  OF THE  NITROGEN
 drinking of what is  called feather-white  wine (der
fedcrweisse Wein), we can no longer doubt that gases
 of every kind, whether soluble or insoluble in water,
 possess the property of permeating animal tissues,
 as water penetrates unsized paper.   This  poison-
 ous  wine is wine still in a state of fermentation,
 which  is increased by  the heat  of the stomach.
 The carbonic acid gas which is disengaged pene-
 trates through the parietes of the stomach, through
 the  diaphragm,  and through all  the  intervening
 membranes, into  the air-cells  of the lungs, out
 of which it displaces the atmospherical air.  The
 patient dies with all the symptoms  of asphyxia
 caused by an  irrespirable  gas;  and the surest
 proof  of  the  presence of  the  carbonic  acid in
 the  lungs  is  the fact, that the inhalation  of  am-
 monia  (which combines with  it)  is  recognized
 as the best antidote  against  this  kind of  poison-
 ing.
   The carbonic acid of effervescing wines and of
 soda-water,  when taken into the  stomach, or of
 water saturated with this gas, administered in the
 form of enema, is  given out again  through the
 skin and lungs ; and this  is equally  true of the
 nitrogen which is introduced into the stomach with
 the food in the saliva.
   No doubt a part of these gases may enter the ve-
 nous circulation through the absorbent and lymphatic
 vessels, and thus reach the lungs, where they are
 exhaled ; but the presence of membranes offers not
 the slightest obstacle to their  passing  directly  into 
EXHALED FROM THE LUNGS.        117
the cavity of the chest.  It is, in fact, difficult to
suppose that the  absorbents  and lymphatics have
any peculiar  tendency to absorb air, nitrogen or
hydrogen,  and convey these  gases  into the circu-
lation, since the intestines, the  stomach,  and all
spaces in  the  body not filled with solid or liquid
matters, contain gases, which only  quit their posi-
tion when  their  volume  exceeds a certain point,
and which, consequently, are not absorbed.  More
especially  in  reference to nitrogen, we must sup-
pose that  it is removed from the stomach by some
more direct means,  and not by the blood, which
fluid must already,  in passing  through the lungs,
have become saturated with  that gas, that is, must
have absorbed  a quantity of it, proportioned to
its solvent power, like any other liquid.   By the
respiratory motions  all the  gases  which  fill the
otherwise empty spaces  of the body  are urged
towards the  chest; for by  the  motion of the di-
aphragm and the expansion of the chest  a  par-
tial vacuum is produced, in  consequence of which
air is forced into the chest from all  sides by the at-
 mospheric pressure.  The equilibrum is, no doubt,
 restored, for  the most part, through the windpipe,
 but all  the gases in  the body must  nevertheless,
 receive  an impulse towards the chest.   In birds and
 tortoises these arrangements are reversed.  If we
 assume that a man introduces into the stomach in
 each minute only ith of a cubic inch of air  with the
 saliva, this makes in eighteen hours 135 cubic inches;
 and if  ith be deducted as oxygen, there will still 
118
TRUE  NATURE OF THE
remain  108 cubic inches  of nitrogen,  which  oc-
cupy the space of 3 lbs. of water.  Now whatever
may be the actual amount  of the  nitrogen thus
swallowed,  it is  certain that the whole of it is
given out again by the mouth, nose, and skin ;  and
when we  consider the very large quantity of nitro-
gen found in the intestines of executed criminals by
Magendie,  as well as the entire absence of oxygen
in these organs (26), we must assume that air, and
consequently nitrogen, enters the stomach by resorp-
tion through the skin, and is afterwards exhaled by
the lungs.
   When animals  are made to respire in gases con-
taining  no  nitrogen, more of that gas is exhaled,
because in this case the nitrogen within the  body
acts towards the external space as if the latter were
a  vacuum.  (See Graham, " On  the Diffusion  of
Gases.")
   The differences in the amount of expired nitrogen
in different classes  of animals are thus  easily ex-
plained ; the herbivora swallow with the saliva more
air than the carnivora; they expire  more nitrogen
than the latter,—less when fasting than immediately
after taking food.
   13. In the same way as  muscular fibre, when
separated from the body, communicates the state of
decomposition existing in  its elements to the per-
oxide of hydrogen,  so a certain product, arising by
means of the vital process,  and in consequence of the
transposition of the elements of parts  of the sto-
mach and of the other digestive organs, while its own 
DIGESTIVE PROCESS.
119
metamorphosis is accomplished in the stomach, acts
on the food.  The insoluble matters become soluble
—they are digested.
  It is certainly remarkable, that hard-boiled white
of egg or fibrine, when rendered soluble by certain
liquids, by organic acids, or weak alkaline solutions,
retain all their  properties except the solid  form
(cohesion) without the slightest change.   Their ele-
mentary molecules, without doubt, assume a new
arrangement; they do not, however,  separate into
two or more groups, but remain united together.
   The  very same thing occurs in  the  digestive
process ;  in the  normal  state,  the food  only  un-
dergoes  a change in its state  of cohesion,  be-
coming  fluid  without any other change  of pro-
perties.
   The greatest obstacle to forming a  clear concep-
tion of the nature of the digestive process, which is
here reckoned among those chemical matamorphoses
which have been called fermentation and putrefac-
tion,  consists  in  our involuntary recollection of the
phenomena which accompany the fermentation  of
sugar and of animal substances (putrefaction), which
phenomena we  naturally associate with any similar
change ;  but there are numberless cases in which a
complete chemical metamorphosis of the elements
of a compound  occurs without the smallest  disen-
gagement of gas, and it  is chiefly these which must
be borne in mind, if we  would acquire a clear and
 accurate idea of the chemical notion or conception of
 the digestive process. 
120
NATURE OF  FERMENT.
  All substances which can arrest the phenomena
of fermentation and putrefaction in liquids, also ar-
rest digestion when taken into the stomach.  The
aciion of the empyreumatic  matters in coffee and
tolacco-smoke, of creosote,  of mercurials, &c. &c,
is on this account worthy of peculiar attention with
reference to dietetics.
  The identity in composition of  the chief consti-
tuents of blood and of the nitrogenised constituents
of vegetable food has certainly furnished, in an un-
expected manner, an explanation  of the  fact that
putrefying  blood, white of  egg, flesh,  and  cheese
produce the same effects in a solution of  sugar  as
yeast or ferment; that sugar, in contact with these
substances,  according to the particular stage of de-
composition in  which the  putrefying matters may
be, yields,  at one time, alcohol  and  carbonic acid;
at another, lactic  acid,  mannite, and  mucilage.
The explanation is  simply  this, that ferment,  or
yeast, is nothing but  vegetable fibrine, albumen, or
caseine in a state of decomposition, these substan-
ces having the same composition with  the constitu-
ents of flesh, blood, or cheese.   The  putrefaction of
these animal  matters  is a  process  identical  with
the metamorphosis of the vegetable matters iden-
tical with them; it  is a separation  or splitting up
into  new and  less complex compounds.    And  if
we consider the transformation  of the elements of
the animal  body  (the waste of matter in animals)
as a chemical process which goes on under  the in-
fluence of the  vital force,  then the putrefaction  of 
COMPOSITION  OF PROTEINE.        121
animal matters  out of the body is a division into
simpler compounds,  in which the vital force takes
no share.   The  action in both cases is the same,
only the  products differ.   The  practice  of medi-
cine has  furnished the most beautiful and inter-
esting  observations on   the  action of empyreu-
matic  substances,  such  as wood,   vinegar,  cre-
osote, r&c,  on   malignant  wounds  and  ulcers.
In such morbid  phenomena two actions are going
on  together; one  metamorphosis,  which  strives
to complete itself under the  influence of the  vital
force,  and  another,  independent  of that  force.
The latter is a  chemical  process, which is entire-
ly  suppressed or arrested by empyreumatic sub-
stances ;   and this effect  is precisely opposed  to
the poisonous influence exercised on the  organism
by  putrefying blood when introduced into  a fresh
wound.
  14. The formula C  H^NeOn* is that which  most
accurately expresses the composition of proteine,
or the relative proportions of the organic  elements
in the  blood, as ascertained by analysis.   Albu-
men, fibrine,  and caseine contain  proteine; ca-
seine contains, besides,  sulphur, but no  phospho-
rus ; albumen and fibrine contain both these sub-
stances chemically combined—the former more sul-
phur than the latter.  We cannot directly ascertain
in  what form the phosphorus exists, but we  have
decided  proof that  the  sulphur cannot  be in the
  * For the method of converting this and other formulae into proportions
per cent, see Appendix. 
122         COMPOSITION OF  FIBRINE,
oxidised state.  All these substances,  when  heat-
ed with  a moderately  strong  solution of potash,
yield  the sulphur which  we  find in the  solution
as siilplijret of  potassium ; and on  the addition
of an acid it is  given  off as  sulphuretted hydro-
gen.   When pure fibrine  or  ordinary  albumen
is dissolved in  a weak solution of  potash,  and
acetate of lead is added to the solution, in  such
proportion that the  whole  of the oxide  of  lead
remains  dissolved in the  potash, the  mixture,  if
heated to the boiling point, becomes black like ink,
and sulphuret of lead is deposited as  a fine black
powder.
   It is extremely probable, that by the  action  of
 the alkali the  sulphur is  removed as  sulphuretted
hydrogen, the phosphorus as  phosphoric  or phos-
phorus acid. Since,  in  this case, sulphur and phos-
phorus are eliminated on the one hand, and oxygen
and hydrogen  on the other, it might be concluded
that fibrine and albumen, when analysed with their
sulphur and phosphorus, would yield a larger pro-
portion  of oxygen and hydrogen  than is found  in
proteine.  But this cannot be shown in the analysis;
for fibrine,  for example, has been found to contain
0-36  per cent, of sulphur.  Assuming, then, that
this sulphur is  eliminated by the alkali in combina-
tion with  hydrogen,  proteine  would  yield 0*0225
per cent, less hydrogen than fibrine ; instead of the
mean  amount of 7-062  per cent, of hydrogen, the
proteine should yield 7-04 per cent.   In like man-
ner, by the elimination of the phosphorus in combi- 
ALBUMEN, AND CASEINE.         123
nation with oxygen, the amount of oxygen in fibrine
would be reduced from 22-715—22-00 per cent, to
22-5—21-8 per cent, in proteine.  But the limits of
error  in our analyses are, on an average, beyond
i\th per cent, in the hydrogen, and beyond Aths
per cent, in the oxygen ; while in the supposed case
the difference in the hydrogen would not be greater
than Ath per cent.
  Finally,  if we reflect,  that  the  elimination  of
oxygen and hydrogen with the sulphur and  phos-
phorus does not exclude  the addition of the ele-
ments of  water, and  if we assume that fibrine
and albumen, in passing  into proteine, do  com-
bine  with a certain quantity of  water, an occur-
rence which is highly probable,  we  shall  see
that  there  is  no  probability  that the  ultimate
analysis of these  compounds shall  ever enabh
us to  decide such questions, or to  fix the chemi-
cal view  of the relation  of  proteine  to  albu-
men,  fibrine, or caseine, farther than has been done
above.
  Some have endeavored to prove the existence of
unoxidised phosphorus in albumen and fibrine from
the formation of sulphuret of potassium when they
are acted on by potash, supposing the oxygen of the
potash to  have  formed phosphoric acid with  the
phosphorus ; but caseine, which contains no  phos-
phorus, yields sulphuret of potassium, just like  the
other substances; and  here its formation cannot be
accounted  for, unless we admit the previous pro-
duction of  sulphuretted hydrogen.    In  the  mere 
124       COMPOSITION OF FIBRINE, &<••

boiling of flesh, for the purpose of making soup,
sulphuretted hydrogen, as Chevreul has shown, is
disengaged.
  Moreover, the proportion of sulphur, for the same
amount of phosphorus, is not the same in fibrine
and albumen, from which no  other conclusion  can
be drawn, but that the  formation of sulphuret of
potassium has no relation to  the presence of phos-
phorus.  Sulphuret of potassium is  formed from
caseine, which is not supposed to contain  any un-
combined phosphorus; and it is formed, also, from
albumen, which contains  only half as  much phos-
phorus as fibrine.
  Every  attempt  to  give   the  true   absolute
amount of the atoms in  fibrine  and albumen in
a rational formula, in which the sulphur and phos-
phorus are  taken,  not in fractions,  but in entire
equivalents, must be fruitless, because we are  ab-
solutely unable to determine  with perfect accuracy
the exceedingly minute quantities of sulphur  and
phosphorus  in  such compounds;  and  because a
variation  in the  sulphur  or phosphorus,  smaller
in extent than the usual limit of errors of observa-
tion, will affect the number of atoms of  carbon,
hydrogen, or oxygen to the extent of  10  atoms or
more.
  We must be careful not to deceive  ourselves in
our expectations of  what chemical analysis can do.
We know, with certainty, that the numbers repre-
senting the relative proportions of the  organic ele-
ments are the  same in albumen and fibrine, and 
            COMPOSITION OF TISSUES.         125

hence  we conclude that they have the  same com-
position.  This conclusion is not  affected by  the
fact, that we do not know the absolute number of
the atoms of their  elements, which have united to
form the compound atom.
   15. A formula   for  proteine  is nothing  more
than the nearest  and  most  exact  expression in
equivalents, of the result of the best analyses ; it is
a fact  established so far, free from doubt, and this
alone is, for the present, valuable to us.
   If we  reflect, that from the albumen  and fibrine
of the  body all the other tissues  are derived, it is
perfectly clear,  that  this  can  only  occur in
two ways.  Either certain  elements have  been
added   to,  or  removed from,  their  constituent
parts.
   If we now, for  example,  look  for  an analytical
expression  of the  composition of cellular tissue, of
the tissues  yielding gelatine, or tendons, of hair, of
horn, &c, in which the number of atoms of carbon
is  made invariably the same as in  albumen and
fibrine, we can then see at the first glance, in what
way the proportion of the other elements has been
altered ; but this  includes all that physiology re-
quires  in order  to  obtain  an insight into the true
nature  of the formative and nutritive  processes in
the animal body.
   From the researches of Mulder and Scherer we
obtain  the following empirical formulas.
                       11* 
126        DIFFERENCES IN COMPOSITION.
          Composition of organic tissues.
  Albumen  ..........C^N^Ou + P + S*
  Fibrine   ...........(VWkOh + P + 2S
  Caseine...........CuNgHasOu + S
  Gelatinous tissues, tendons . C48N7.5H41019
  Chondrine..........C48N6II40Oi0
  Hair, horn..........Ci^H^O,,
  Arterial membrane.....C^NeHajOig

  The composition of these  formulae shows, that
when proteine passes into chondrine (the substance
of the cartilages of the ribs), the elements of water,
with oxygen, have been added to it; while in the
formation  of the  serous membranes, nitrogen also
has entered into combination.
  If  we  represent the formula of proteine, C48N6
H^014 by Pr, then nitrogen, hydrogen, and oxygen
have been added to  it in the form of known com-
pounds,  and in the following proportions,  in form-
ing the gelatinous tissues,  hair, horn, arterial mem-
brane, &c.

               Proteine. Ammonia. Water.  Oxygen.
  Fibrine, Albumen . Pr
  Arterial membrane . Pr......-f  2HO.
   Chondrine......Pr......-f- 4HO.  -f- 20.
  Hair, horn......Pr -f   NH3.....+ 30.
  Gelatinous tissues. 2Pr -f-  3NH3 + HO. + 70.

   17. From this  general  statement it appears  that
 all the  tissues of the body  contain, for the same

  * The quantities of sulphur and phosphorus here expressed by S and
 Pare not equivalents, but only  give the relative proportions of these two
 elements to each other, as found by analysis. 
OF ORGANIC  TISSUES.
127
amount of carbon, more oxygen than the constituents
of blood.   During their formation, oxygen,  either
from the atmosphere or from the elements of water,
has been added to the elements of proteine.   In hair
and gelatinous membrane we observe, further, an ex-
cess of nitrogen and hydrogen, and that in  the pro-
portions to form ammonia.
  Chemists are not yet agreed on  the question, in
what manner the elements of sulphate  of potash are
arranged ; it would therefore be going  too far, were
they to pronounce arterial membrane a hydrate of
proteine,  chondrine a hydrated oxide of proteine
and hair  and membranes compounds of ammonia
with oxides of  proteine.
  The above formulae express with  precision the
differences of composition in the chief constituents
of the animal body; they show, that  for the same
amount of carbon the proportion of the  other  ele-
ments varies, and  how much more oxygen or nitro-
gen one compound contains than another.
   18. By  means of these formulae we can trace
the production of  the  different  compounds from
the constituents of blood ; but the explanation of
their production may  take two  forms,  and  we
have to decide which of these comes nearest to the
truth.
   For the same amount of carbon, membranes and
the tissues which yield gelatine contain more nitro-
gen,  oxygen, and hydrogen  than  proteine.  It is
 conceivable that they are formed from albumen by
 the addition of oxygen, of the elements of water, 
128    GELATINE CONTAINS NO  PROTEINE.
and of those of ammonia, accompanied by the sepa-
ration of sulphur and phosphorus; at all events, their
composition is entirely different from that of the chief
constituents of blood.
  The action of caustic alkalies on the tissues yield-
ing gelatine shows distinctly that they no longer con-
tain proteine;  that substance cannot in any way be
obtained from them ; and all the product? formed by
the action of alkalies  on them differ entirely from
those produced by the compounds of proteine in the
same circumstances. Whether proteine exist, ready
formed, in fibrine, albumen, and  caseine, or not, it
is certain  that their elements, under the influence of
the alkali, arrange themselves so as to form  pro-
teine ; but this property is wanting in the elements
of the tissues which yield gelatine.
   The other, and perhaps the more probable expla-
nation of the production of these tissues  from pro-
teine, is that which makes it dependent on a sepa-
ration of carbon.
   If we assume the nitrogen  of proteine to remain
entire in  the  gelatinous tissue,  then the composi-
tion  of the latter calculated  on 6 equivalents  of
nitrogen,  would be  represented by the formula,
CggNgH^O^.  This formula approaches most closely
to the analysis of Scherer, although it  is not an exact
expression of  his results.  A formula corresponding
more perfectly to the analyses, is CaN^Ou; or cal-
culated according to Mulder's analysis, C54N9H4Ao-*

  * The formula CsjN8HioO<j<., adopted by Mulder, gives, when reduced 
ORIGIN OF GELATINE.
129
   According to the first formula, carbon and hydro-
gen have  been separated ; according to  the  two
last, a certain proportion  of all the  elements  has
been removed.
   19.  We must admit, as the most  important re-
sult of the study of the composition  of  gelatinous
tissue, and as a point undeniably established, that,
although formed from compounds of proteine, it no
longer  belongs to the series  of the compounds of
proteine.   Its chemical characters and composition
justify this conclusion.
   No  fact is  as  yet opposed to the law,  deduced
from observation, that nature  has  exclusively  des-
tined compounds of proteine for the  production of
blood.
   No substance analogous to the tissues  yielding
gelatine is  found in vegetables.   The  gelatinous
substance  is  not a  compound of proteine; it  con-
tains no sulphur, no  phosphorus,  and it  contains
more nitrogen or less carbon than proteine.   The
compounds of proteine, under the influence of the
vital energy of the organs which  form  the  blood,
assume a new form, but are not altered in com-
position ;  while these organs,  as far as our ex-
perience  reaches,  do not possess the power  of
producing compounds of proteine, by virtue of any
influence, out of substances which contain no  pro-
teine.   Animals  which  are fed  exclusively  with

to 100 parts, too little nitrogen to be considered an exact expression of
his analyses. 
 130           ORIGIN  OF GELATINE.

 gelatine, the most  highly  nitrogenised element of
 the food of carnivora, died with  the  symptoms of
 starvation ; in short, the gelatinous tissues are in-
 capable of conversion  into blood.
   But there is no doubt that  these  tissues are
 formed  from  the  constituents of the  biood ; and
 we  can  hardly avoid  entertaining the supposi-
 tion, that the fibrine of venous blood, in becoming
 arterial  fibrine, passes  through  the  first stage of
 conversion  into gelatinous  tissue.    We cannot,
 with much probability, ascribe to membranes and
 tendons the power  of forming  themseh es out of
 matters  brought by the blood ; for how  could any
 matter become a portion of cellular tissue, for ex-
 ample, by virtue of a  force  which has  ;;s yet  no
 organ  ?  An already existing cell may  possess the
 power of reproducing  or of multiplying itself, but
 in both cases the presence of a substance identical
 in  composition  with  cellular tissue  is  essential.
 Such  matters  are formed in the organism,  and
 nothing can be better fitted for their prod action than
 the substance of the cells and  membranes which
 exist in  animal food,  and become soluble in the
 stomach during digestion, or which are  taken by
 man in a soluble form.
  20.  In the following pages I offer to  the  reader
 an  attempt  to develop  analytically  the  principal
 metamorphoses which  occur  in  the  animal body;
and, to preclude all  misapprehension, I : o this with
a distinct protest against all conclusions and deduc-
tions which may now or at any subsequent period be 
          METAMORPHOSIS OF TISSUES.        131

derived f om it in opposition to the views developed
in the preceding part of this work, with which  it
has no u.anner of connection.  The results here to
be described have surprised me  no less than they
will othcis, and have excited in  my mind the same
doub  s as others will conceive ; but they are not the
creations of fancy, and I give them because  I  en-
tertain the deep conviction that the method which
has led to them  is  the only one by which we can
hope to acquire insight into the nature of the organic
processes.
  The numberless qualitative investigations of ani-
mal matters which are made  are equally worthless
for physiology and for chemistry, so long as they are
not instituted with a well-defined object,  or  to  an-
swer a question clearly put.
  It* we take the letters of a sentence which we
wish to decipher, and place them in a line, we  ad-
vance  not a  step towards the  discovery of their
meaning.   To resolve an enigma, we must have  a
perfectly clear conception of the  problem.  There
are many ways to the highest pinnacle of a moun-
tain ;  but those only can hope to reach  it who keep
the  summit constantly  in  view.  All  our  labour
and all our efforts, if we  strive to attain it  through
a morass, only serve to cover us  more completely
wit:i mud ;  our progress is impeded by difficulties
of our own creation, and  at last  even the great-
est  strength must give way when so  absurdly
wasted.
  21. If it be true that all parts of the  body  are 
132        THE SECRETIONS CONTAIN

formed and developed from the blood or the con-
stituents of the blood, that the existing organs at
every moment of life are transformed into new com-
pounds under *he influence of the oxygen introduced
in the blood,  then  the animal secretions  must of
necessity contain the products of the metamorphosis
of the tissues.
  22. If it be further true, that the urine  contains
those products  of  metamorphosis  which  contain
the most  nitrogen,  and  the  bile those which are
richest in carbon, from all the  tissues which in the
vital process have been transformed into unorgan-
ised compounds, it  is clear that the elements of the
bile and of the urine, added together, must be equal,
in the relative proportion of these elements to the
composition of the  blood.
  23. The organs are formed from the blood, and
contain  the elements of the  blood; they  become
transformed into new  compounds, with the addition
only of oxygen  and of water.  Hence the  relative
proportion of carbon and  nitrogen must be the same
as in the blood.
  If  then we subtract  from the  composition of
blood  the  elements  of the   urine, then  the re-
mainder, deducting the oxygen and water which
have been added, must give the composition of the
bile.
  Or if from the elements of the blood, we subtract
the  elements of the bile, the  remainder must give
the  composition of  urate of ammonia, or of urea
and carbonic acid. 
       ALL THE  ELEMENTS OF THE BLOOD.    133

   It will surely appear remarkable that this man-
ner of viewing the subject has led to the  true
formula  of bile, or,  to speak  more  accurately,
to the  most  correct  empirical  expression of its
composition;  and  has furnished the  key to  its
metamorphoses,  under the  influence of acids and
alkalies,  which  had previously been  sought  for
in vain.
   24. When fresh drawn blood is made to trickle
over a plate of silver, heated to  140°, it dries  to a
red, varnish-like matter, easily reduced  to powder.
Muscular flesh,  free   from fat,  if dried first in
a gentle heat,  and then at  212°,  yields  a brown,
pulverizable mass.
   The analyses of Playfair and Boeckmann (28)
give for flesh (fibrine, albumen, cellular tissue, and
nerves)  and for blood, as the most exact expression
of their numerical results, one and the same formu-
la, namely, C^NeH^Ois.  This may  be  called  the
empirical formula of blood.
  25. The chief constituent of bile,  according to
the  researches  of  Demarcay,  is  a compound,
analogous to  soaps, of soda with a  peculiar sub-
stance, which has been named choleic acid.  This
acid is obtained in combination with oxide of lead,
when bile, purified by  means of alcohol from all
matters insoluble in that menstruum, is mixed with
acetate of lead.
  Choleic acid is resolved,  by the action of muriatic
acid, into ammonia, taurine,  and a new acid, choloi-
dic acid, which contains no nitrogen.
                        12 
134        METAMORPHOSES OF BILE.

  When boiled with  caustic potash,  choelic acid
is resolved into carbonic acid, ammonia, and another
new acid, cholic acid (distinct from the cholic acid
of Gmelin.)
  Now it is clear  that the true formula of choleic
acid must include the analytical expression of these
modes  of decomposition ;  in other  words, that
it  must  enable us  to show that  the  composi-
tion  of the products derived  from it  is related
in a  clear and simple manner* to the  composi-
tion  of the acid  itself.   This is  the  only  satis-
factory test of a formula; and the  analytical ex-
pression thus  obtained loses nothing  of its truth
or value, if  it should  appear,  as the  researches
of Berzelius  seem to  show,  that  choleic  and
choloidic acids are  mixtures of different  com-
pounds ;  for  the  relative proportions  of the  ele-
ments cannot in any  way be altered by this circum-
stance.
   26.  In  order  to  develop the   metamorphoses
which choelic  acid  suffers  under  the  influence  of
acids and alkalies, the following formula alone can
be adopted as the empirical expression of the re-
sults of its analysis,

      Formula of choleic acid : CTCNaHgeOa.  (29)

   I repeat, that this formula may express the com-
position  of one, or of two  or more compounds ; no
matter of how many compounds the so-called cho-
leic acid may be made up, the above formula repre-
sents the relative proportions of all  their elements
taken together. 
            METAMORPHOSES OF BILE.        135

   If now we  subtract from the elements of choleic
 acid, the products formed by the action of muriatic
 acid, namely, ammonia and taurine, we  obtain the
 empirical formula of choloidic acid. Thus : from the
   Formula of choleic acid......    CnN.HasQa
     Substract—
   1 atom taurine *.....C,NH,0,n i
                       ^4.1.^ xx7vy10 > __ P TSJ XI H
   1 eq. ammonia.....  NH3    ]     4  2  10 la
   There remains the formula of cho-
     loidic acid...........= C«  Hs6Ol2 (30)
   27. Again,  if from the  formula  of choleic acid
 we  subtract the elements of  urea and  2 atoms of
 water (= 2 eq. carbonic acid and 2 eq.  ammonia),
 there will remain the  formula and  composition of
 cholic acid.  Thus ; from the
   Formula of choleic acid.....= 0^,^3660,8
    subtract—
   2 eq. corbonic acid = C2  04)   p
   2 eq. ammonia     =  N2H6  $ ~  2 2±1<iU4
   Remains the formula of cholic acid — C74 H^Oxs (31)
   When we consider the very close coincidence be-
 these formulae and  the  actual results of analysis
 (see Appendix, 29,  30,  31), it is scarcely possible
 to doubt  that the formula above adopted  for choleic
acid expresses, as accurately as is to be expected in
the analysis of such compounds, the relative propor-
tion of its elements, no matter in how many differ-
ent forms they may be united to produce that acid.
   28. Let us now  add the half of the numbers
which represent the formula of choleic acid, to the 
136       RELATION OF BILE TO  FIBRINE.
elements of the urine of serpents—that is, to neutral
urate of ammonia, as follows :
  \ the formula of choleic acid .....= C^NH^On
    Add to this—
  1 eq. uric acid.....= C10N4H4O6 >  ^ ci0NsH,O6
  1 eq. ammonia.....=   NH3   >---------
    The sum is...............= C48N6H40Ol7
  29.  But this last formula  expresses the  composi-
tion of blood, with the  addition of 1 eq. oxygen and
1 eq.  water.
    Formula of blood..........C48N6H39015
    1  eq.  water........= HO » =    H q^
    1  eq.  oxygen.......=  O J---------
       The sum is............= C48N6H40On
  30.  If moreover, we add to the elements of pro-
teine  those of 3 eq. water, we  obtain,  with  the ex-
ception of 1 eq. hydrogen, exactly the same formula.
    Formula of proteine........= C^Ns^O^
    Add 3 eq. of water.........=     H3 03

       The sum is.............C48N6H390,7
differing only by 1 eq.  of hydrogen from the formula
above obtained by adding together choleic acid and
urate  of ammonia.
  31.  If, then, we consider  choleic  acid and urate
of ammonia the products of the transformation of
muscular fibre,  since  no  other tissue in  the body
contains proteine (for albumen passes into  tissues,
without our being able to  say, that in the vital pro-
cess it is  directly  resolved into  choleic acid,  and
urate  of ammonia), there  exist in fibrine, with the 
OXIDATION OF URIC ACID.         137
addition of the elements of water, all the elements
essential to this metamorphosis;  and,  except  the
sulphur and phosphorus, both of which are probably
oxidised, no element is separated.
  This form of metamorphosis is applicable to  the
vital transformations in the lower classes of amphi-
bia,  and perhaps  in worms  and insects.   In  the
higher classes of animals  the  uric acid  disappears
in the urine, and is replaced by urea.
  The disappearance of uric acid and the  produc-
tion of urea plainly stand  in a very close relation to
the amount of oxygen absorbed in respiration, and to
the quantity of water consumed by different animals
in a given time.
  When uric acid  is  subjected  to  the action of
oxygen, it  is first  resolved,  as is well known,  into
alloxan and  urea. (32)   A  new supply of oxygen
acting on the alloxan causes it to  resolve itself
either into oxalic   acid  and urea,  into  oxaluric
and parabanic acids, (33)  or into carbonic acid  and
urea.
   32. In  the so-called mulberry calculi we  find
oxalate of lime, in other calculi urate of ammonia,
and always in persons, in whom, from  want of ex-
ercise and labor, or from other  causes, the supply
of oxygen has  been diminished.  Calculi contain-
ing  uric  acid or  oxalic  acid are never found in
phthisical patients ; and it is a common  occurrence
in France, among patients suffering  from calculous
 complaints,  that  when  they go to the  country,
 where they take more  exercise, the  compounds  of
                         12* 
138      TJRIC ACID AND UREA DERIVED
uric  acid, which were  deposited  in  the  bladder
during their residence in town, are succeeded by
oxalates  (mulberry calculus),  in  consequence  of
the  increased  supply  of  oxygen.   With a still
greater supply of oxyge.i they would  have yielded,
in healthy subjects, only  the  laot product of the
oxidation of uric acid,  namely, carbonic  acid and
urea.
   An  erroneous interpretation of the  undeniable
fact  that all substances  incapable of further use in
the organism are separated by the kidneys and ex-
pelled  from  the  body in  the urine,  altered  or
unaltered,  has led practical medical men  to  the
idea, that the food, and  especially nitrogenised food,
may have  a direct influence on  the formation of
urinary calculi.   There are no reasons  which sup-
port this opinion, while those opposed to  it are  in-
numerable.  It is possible that there may be taken,
in the food, a  number of matters changed by the
culinary art, which, as  being no longer adapted to
the  formation of blood, are expelled  in the urine,
 more  or  less altered  by the respiratory process.
 But roasting and boiling alter in  no  way the com-
 position of animal food. (34)
   Boiled and roasted flesh is converted at once into
 blood ; while the uric acid and  urea  are derived
 from the metamorphosed tissues.   The quantity of
 these products increases with the  rapidity of trans-
 formation in a  given time, but bears  no  proportion
 to the amount of food taken in the same period.  In
 a starving man who is any way compelled to undergo 
      FROM THE  METAMORPHOSED TISSUES.   139

severe and continued exertion, more urea is secreted
than in the most highly fed individual, if in a state
of rest.  In fevers and during rapid emaciation the
urine contains more urea than in the state of health.
(Prout.)
  33. In the same way, therefore, as the hippuric
acid, present in the urine of the  horse when at rest,
is converted into benzoate of ammonia and carbonic
acid as soon as  the animal is compelled  to  labor,
so the uric acid disappears in the  urine of man,
when he  receives, through the  skin  and lungs,  a
quantity of oxygen sufficient to oxidise the products
of the transformation of the  tissues.   The use of
wine and  fat, which are only so far altered in the
organism that they combine with oxygen,  has a
marked influence on the  formation  of uric acid.
The urine, after fat food has been taken,  is turbid,
and deposits minute crystals of uric acid.  (Prout.)
The same thing is observed after the use of wines
in  which the alkali  necessary  to retain  the uric
acid in solution  is wanting,  but never from  the
use of Rhenish wines,  which  contain  so  much
tartar.
   In animals which drink much water, by means of
which the sparingly soluble uric acid is  kept dis-
solved, so that the inspired oxygen can act on it, no
uric acid is found in the urine, but  only urea.  In
birds, which seldom drink, uric acid predominates.
   If to one atom of uric acid we add  6  atoms of
oxygen and 4 atoms of  water, it resolves itself into
urea and carbonic acid: 
140      RELATION  OF BLOOD TO URINE.
1 at. uric acid C10N4H4O6 \    <2at>urea  .  .   C< N4H804
4 at. water   >     a 0l. ( ~ * 6 at. carbonic acid C.    Om
6 at oxygen  £          )                   _________
           CioN* Hs Ois                    CioN4H8Oi6
   34.  The urine of the herbivora contains  no uric
acid, but ammonia, urea,  and hippuric or benzoic
acid.  By the addition of 9 atoms of oxygen to the
empirical formula of their blood multiplied by 5, we
obtain the elements  of  6  at. of  hippuric  acid,  9
at. of urea, 3 at. of choleic acid, 3 at. of water, and
3 at. of ammonia ; or, if we suppose 45 atoms of
oxygen to  be added to  the blood  during  its meta-
morphoses, then we obtain 6 at. of benzoic  acid,
 13£ at. of urea, 3 at. of choleic acid, 15 at. of car-
bonic acid, and 12 at. of water.
         5 (C48N6H39015) + 09 = C^NsoH.sbQm
     6 at. hippuric acid, 6 (Cl8NH805)  = C108N6 H^C^,
     9 at. urea.....9 (C2 N2H402)  = C18Nl8H36018
     3 at. choleic acid . 3 (C^N H»0„)  = C114N3H99033
     3 at. ammonia  .  . 8 (   N H3   )  =    N3 Hfl
     3 at. water  .... 3 (      H3 03)  =       H3 Qg
         The sum is...........    CjmNsoHusOm
          or—
        5 (C48N9H3901S) + 045 = C^oNgoHiasO^
      6 at. benzoic acid 6 (C14 Hs03)  = C^   H30 Ol9
     27|8 at. urea ... 27 (C  NH20 )  = C27 N2,H54 027
      3 at. choleic acid  3 (CsgNH^O,,) = C114N3 H99 033
     15 at. carbonic acid 15 (C     02)  = Cl5      0M
     12 at. water  ... 12 (    H O )  =        Hl2012
           The sum is...........  C^N^H^O,,*,
    35. Lastly,  let us follow the  metamorphosis  of 
     RELATION OF PROTEINE  TO ALLANTOINE.  141

the tissues  in the foetal calf, considering the pro-
teine furnished  in the blood  of the mother as the
substance which  undergoes  or has  undergone  a
transformation ; it will appear that 2 at. of proteine
without the addition of oxygen or any other foreign
element, except 2 at. of water, contain the elements
of 6 at.   of allantoine  and  1 at. of choloidic acid
(meconium ?)
2 at. proteine = 2 (C^Ne^Ou) _j- 2 at. water = 2 HO = C^N^^Oso
      C 6 at. allantoine, 6 (C4N2H303)=C24N12H180,8
      \ 1 at. choloidic acid         = C72   H560,2
                                   Cg6N12H74O30
   36. But the elements of the six  atoms of allan-
toine in  the last equation correspond  exactly to
the  elements  of 2 at. of  uric acid,  2 at.  of urea,
and  2 at. of water.
                           C 2at.uricacidC20N8H8OiS
6at.of allantoine=C24N12H18Oi8= < 2 at. urea   C4N4 H804
                           ( 2 at. water     H2Oa


   The relations of allantoine, which is found in the
urine of  the foetal calf, to the nitrogenised constitu-
ents of the urine in  animals which respire, are, as
may be seen by comparing the above formulas, such
as cannot  be overlooked  or doubted.   Allantoine
contains  the elements of uric acid  and  urea—that
is, of the nitrogenised products of the transforma*
tion of the compounds of  proteine.
   37. Further,  if to the formula of proteine, multi-
plied by 3, we  add the elements of 4 at. of water, 
142   RELATION OF  PROTEINE  TO GELATINE.

and if we deduct from the sum of all the elements
half of the elements of choloidic acid, there remains
a formula which expresses very nearly the composi-
tion of gelatine.  From
     3 (C48N6H36014) -f- 4 HO ... = C144N18H112048
     Subtract £ at. choloidic acid = CM   H^ 06

          There remain......C108N18H84O40 (3-r>)
  38. Subtracting from this  formula  of gelatine
the elements of 2  at. of proteine, there remain the
elements of urea, uric acid, and water, or of 3 at. of
allantoine and 3 at. of water.   Thus—
      Formula of gelatine (Mulder) C188NI8H84O40
      Subtract 2 at. proteine . .  . .  C ^N^H-nOa
                            3at.allantoine C12N6H9Og
                            3 at. water ..     H303

             C12N6H120I2                C12N6H12012

   39.  The  numerical proportions  calculated from
the above formula differ from those actually obtain-
ed in the analyses of Mulder and Scherer in
this, that the latter indicate somewhat less of nitro-
gen in gelatine ; but if we assume the formula to be
correct, it  then appears, from  the statement just
given, that  the elements  of two atoms of proteine,
plus the nitrogenised products of the transformation
of a third atom of proteine (uric acid  and urea) and
water ; or three atoms of  proteine, minus  the ele-
ments of a compound containing no nitrogen, which
       There remain .
lat.uric acid C10N4H4O6 }
1 at. urea . . C2N2H402 i
4 at. water      H404 ) 
             ORIGIN OF GELATINE.           143

actually occurs as one of the products of the trans-
formation of choleic acid, yield in both cases a for-
mula closely  approaching to the composition  of
gelatinous tissues.  We must, however, attach  to
such  formulae, and  to the considerations arising
from  them, no more  importance than justly be-
longs to them.  I would constantly  remind the
reader that their use  is to serve as points of con-
nection,  which  may  enable  us  to  acquire  more
accurate views as to  the production and decom-
position of those compounds  which  form the  ani-
mal tissues.   They are the first attempts to dis-
cover the path which we  must follow in order  to
attain the object of our researches ; and this object,
the goal we strive to  reach,  is, and must be,  at-
tainable.
   The experience of all those who  have occupied
themselves with researches into natural phenomena
leads to this general result, that  these phenomena
are caused, or  produced, by means far more simple
than was  previously  supposed, or  than  we even
now  imagine; and it  is precisely their  simplicity
which should  most powerfully excite our wonder
and admiration.
   Gelatinous  tissue is formed  from  blood, from
compounds of  proteine.  It may be produced  by
the addition, to the elements of proteine,  of allan-
toine and water, or of water, urea, and uric  acid ;
or by the separation from the elements of  proteine
of a compound containing no nitrogen.   The solu-
tion of such problems becomes  less difficult, when 
144
ORIGIN OF THE BILE.
the problem to be solved, the  question to be  an-
swered, is matured  and clearly put.  Every ex-
perimental decision of  any  such question in the
negative funis the starting-point of a new question,
the solution of which, when obtained, is  the neces-
sary consequence of our having put the first ques-
tion.
   40. In  the  foregoing sections,  no  other consti-
tuent of  the bile, besides  choleic acid, has been
brought into the calculation ;  because  it alone  is
known  with certainty to contain nitrogen.  Now, if
it be admitted that its nitrogen is derived from the
metamorphosed  tissues, it  is not improbable that
the carbon, and  other elements which it contains,
are derived from the same  source.
   There cannot be the smallest doubt, that  in the
carnivora, the constituents of the  urine and the bile
are derived from the transformation of compounds
of proteine ; for, except fat, they consume no food
but such as contains proteine,  or  has  been formed
from that substance.  Their food is identical with
their blood ; and it is a matter of indifference which
of the  two we  select as the  starting-point of the
chemical development of the vital metamorphoses.
   There  can be no greater contradiction, with re-
gard to the nutritive process, than to suppose that
the  nitrogen of the  food can pass into the urine  as
urea, without having previously become part of an
organized tissue ; for albumen, the only constituent
of blood, which,  from its amount, ought to be taken,
into consideration, suffers not the slightest change 
ORIGIN OF THE BILE.          145
in passing through the liver or kidneys; we find it
in every part of the body with the same appearance
and the same  properties.   These organs cannot be
adapted  for the alteration  or decomposition of the
substance from  which all  the other organs of the
body are to be formed.
  41. From the characters of chyle and lymph, it
appears with certainty that the soluble parts of the
food or of the chyme acquire the form of albumen.
Hard-boiled  white of  egg,  boiled  or coagulated
fibrine,  which have  again become  soluble in the
stomach, but  have  lost their coagulability by the
action of ait or  heat,  recover  these  properties by
degrees.  In  the chyle,  the acid  re-action of the
chyme  has already passed into the weak  alkaline
re-action of the blood;  and the chyle,  when, after
passing  through the  mesenteric  glands, it  has
reached the thoracic duct,  contains albumen coagu-
lable by heat;  and,  when left to  itself,  deposits
fibrine.  All the compounds of proteine, absorbed
during the passage of the chyme through the intes ,
tinal canal, take the form of albumen, which, as the
results of incubation  in the fowl's egg testify, con-
tains the fundamental elements of  all organized
tissues,  with the exception of iron, which  is ob-
tained from other sources.
   Practical medicine has long ago  answered the
question, what becomes in man of the compounds of
proteine taken in excess, what change is undergone
by the superabundant nitrogenised food ? The blood-
 vessels are distended with excess of blood, the other
                        13 
146
ORIGIN OF  THE  BII/E.
vessels with excess  of their fluids, and if the too
great supply of food  be kept up, and the blood, or
other  fluids adapted  for  forming  blood,  be not
applied  to  their natural purposes, if the  soluble
matters be  not taken up by the proper organs, va-
rious  gases are disengaged,  as  in processes  of
putrefaction,  the  excrements  assume an  altered
quality in colour, smell, &c. Should the fluids in the
absorbent and  lymphatic vessels undergo a similar
decomposition,  this  is immediately visible  in the
blood, and the nutritive process then assumes new
forms.
   42. No one of all these appearances should occur,
if the liver and kidneys were capable of effecting
the resolution of the  superabundant compounds of
proteine into urea, uric acid, and bile.  All the ob-
servations which have been made in reference to the
influence of nitrogenised food on the composition of
the  urine  have failed entirely to  demonstrate the
existence of any direct influence  of the  kind ; for
the phenomena are susceptible of  another and a far
more  simple interpretation, if, along with the food,
we consider the mode of life and habits of the  indi-
viduals who have been the  subjects of investigation.
Gravel and calculus  occur  in persons who use  very
little animal food.   Concretions of uric acid have
never yet been observed in carnivorous mammalia,
living in the wild state,* and among nations which live

  * The occurrence of urate of ammonia in a concretion found in a dog,
which was examined by Lassaigne, is to be doubted, unless Lassaigna
extracted it himself from the bladder of the animal. 
IN THE HERBIVORA.           147
entirely on flesh, deposits of uric acid concretions in
the limbs or in the bladder are utterly unknown.
   43. That which must be viewed  as an undeni-
able truth in regard to the origin of the bile, or, more
accurately speaking, of choleic acid in the carnivora,
cannot hold in regard to all the constituents of the bile
secreted by the liver in  the herbivora, for  with the
enormous quantity of bile produced, for example,
by the liver of an ox,  it  is absolutely impossible to
suppose that all its carbon is derived from the me-
tamorphosed tissues.
   Assuming the 59 oz. of dry bile (from 37 lbs. of
fresh bile secreted by an ox) to contain the same
percentage  of nitrogen as  choleic acid (3-86 per
cent.), this would amount to nearly  2| oz. of nitro-
gen;  and  if  this  nitrogen, proceed  from  meta-
morphosed tissues, then, if  all the carbon of these
tissues passed into the  bile, it would  yield, at the
utmost, a quantity of  bile corresponding to 7-15 oz.
of carbon.  This is, however, far below the  quan-
tity which, according to observation, is secreted in
this class of animals.
   4'*. Other substarces, besides compounds of pro-
teine, must inevitably take  part in the formation of
 bile  in  the organism of the herbivora; and  these
 substances can only  be the non-nitrogenised  con-
 stituents of their food.
    45.  The sugar  of bile of Gmelin (picromel or
 biline of Berzelius), which  Berzelius  considers  as
 the chief constituent of bile, while Demar§ay as-
 signs that place essentially to choleic acid, burns, 
148     STARCH, &c. CONTRIBUTE  TO THE

when heated in the air, like resin, yields ammonia-
cal products, and when  treated with  acids, yields
taurine and the products of the  decomposition of
choleic acid; when  acted on by alkalies, it yields
ammonia and cholic acid.  At all  events, the sugar
of bile contains nitrogen, and much less oxygen than
starch or sugar, but more oxygen than the oily acids.
When,  in  the  metamorphosis  of sugar of bile or
choleic acid by alkalies, we cause the separation of
the nitrogen, we obtain a  crystallized acid, very
similar to the oily acids (cholic acid),  and  capable
of forming with bases salts, which have the general
characters of soaps.  Nay,  we may even consider
the  ehief  constituents  of the bile, sugar of bile
and  choleic acid, as compounds of oily acids with
organic oxides, like the fat oils, and  only differ^
ing from these in containing no oxide of  glycerule.
Choleic acid, for example, may be viewed as a
eompound of choloidic acid  with  allantoine and
water:
  Choloidic acid; Allantoine   Water. Choleic acid.
    C^HsA, + C4N2H303 + H-A = C^NjHeA*
Or as a compound of cholic acid, urea, and water:
   Cholic acid.    Urea.    Water. Choleic acid.
     C74H„018 + C2N2.H402 + H202 ^ C76N2H66OiB
  46. If, in point of fact, as can hardly be doubted,
the elements of such substances  as starch, sugar,
&c,  take  part  in  the  production of bile in  the
organism of the herbivora, there is nothing opposed
to. such a  view in  the composition of  the  chief 
       FORMATION  OF BILE IN HERBIVORA.    149

constituents of bile, as far as our knowledge at pre-
sent extends.
  If starch be the chief agent in this process, it can
happen in no other way but this—that, as when it
passes into fat, a  certain  quantity  of oxygen is
separated  from the elements  of the  starch, which,
for the same amount of carbon (for 72 atoms,)  con-
tains five times as much oxygen as choloidic acid.
   Without the separation of oxygen from the ele-
ments of starch,  it  is impossible to conceive its con-
version into bile ; and this separation being admit-
ted, its conversion into a  compound intermediate in
composition  between  starch and  fat  offers no
difficulty.
   47.  Not to  render  these  considerations a mere
idle play with formulae, and not  to lose sight of
our chief object, we observe, therefore, that the con-
sideration of the quantitative proportion of the bile
secreted in the herbivora leads to the following con-
clusions :—
   The chief constituents  of the bile of the herbivora
 contain  nitrogen, and this nitrogen is  derived from
 compounds of proteine.
   The bile of this class of animals contains  more
 carbon  than corresponds to the quantity of nitro-
 genised  food  taken,  or to  the  portion  of tissue
 that has undergone metamorphosis  in  the vital
 process.
    A part of this carbon  must, therefore, be derived
 from the non-nitrogenised parts of the food (starch,
 sugar, &c.) ; and  in order to be  converted  into a -
                         13* 
150     PRODUCTION OF  HIPPURIC ACID.

nitrogenised constituent of bile, a part of the  ele-
ments of these bodies must necessarily have com-
bined with a nitrogenised compound derived from a
compound of proteine.
  In reference to this conclusion,  it is  quite in-
different  whether that compound  of proteine be
derived from the  food or from  the tissues of the
body.
  48.  It has very lately been stated'by A. Ure, that
benzoic acid, when administered internally, appears
in the urine in the form of hippuric acid.
   Should this observation be confirmed,* it will ac-
quire great physiological  significance, since it would
plainly prove  that the act of transformation of the
tissues in the  animal body, under the influence of
certain matters taken in  the food, assumes  a  new
form with  respect  to the  products which  are its
result; for hippuric acid contains  the elements of
lactate of urea, with-the addition of those of benzoic
acid:
1 at. urea.....C2N2H4 02>    r
1 at. lactic acid  . . G6  H4 04 1= \ 2 aL crystallized hippuric
2 at. benzoic acid . C*  Hl0O6 J   Lacid = 2 (c«NH906)

               C36N2Hi80i2
  49.  If we consider the act  of transformation  of
the tissues in the  herbivora as we have done in the
  *  The analysis of the  crystals deposited from the urine on the addition
of muriatic acid has not been performed.  Besides, the statement of A.
Ure, that hippuric acid, dissolved in nitric acid, is reddened by ammonia,
is erroneous, and shows that the crystals he obtained must have contained
uric acid,. 
IN THE URINE OF HERBIVORA.       151
carnivora, then the blood of the former must yield,
as the last products of the metamorphosis, from all
the organs taken together, choleic acid-, uric  acid,
and ammonia (see p. 136) ;  and if we ascribe to the
uric acid an action similar to that of the benzoic
acid in  Ure's observation—such, namely, that the
further  transformation,  owing to the presence  of
this acid, assumes another form, the elements of the
uric acid being incorporated in the final products—
it will appear, for example, that  2  at. of proteine,
with the addition of the elements of  3 at.  of uric
acid and 2 at. of oxygen, might give rise to the pro,*
duction of hippuric acid and urea.

       2-at. proteine, 2 (C48N6H36,014) = CgeNiaHisOia
       3 at. uric acid, 3 (C10N4H4O6 ) = C3oNi2Hi2pi8
       2. at. oxygen              =        O2
           The sum is........= Ci26N24H84048 =
    _ ( 6 at. hippuric acid, 6 (Ci8N H805) = Cio3N6H4803o
    = { 9 at. urea.....9 (C2N2H4Q2 ) = CiaNwHaOa
            The sum ia .............. = CiKNiiH^O^

    50. Finally, if we bear in mind, that, in the her-
 bivora,  the  non-nitrogenised constituents of their
 food (starch, &c.)  must, as we have shown, play an
 essential part in the  formation of the bile ; that to
 their elements  must of necessity be added those of
 a  nitrogenised compound,  in order to produce  the
 nitrogenised constituents of the bile, the most strik-
  ing  result  of the  combinations thus suggested is
  this, that  the elements of  starch added  to those o£ 
152        PRODUCTION OF  THE  CHIEF

hippuric acid are equal to the elements of choleic
acid, 'plus, a certain quantity of carbonic acid :
    2 at. hippuric acid, 2 (C18NH8Os) = C,-,NaH„O10
    5 at. starch  .... 5 (C12  H10O10) = C60  rxmOsa
    2 at. oxygen ....              =        02
          The sum is.........= C95N.jH66062
     ( 2 at. choleic acid  2 (CagNH^Ou) = C76N2H6S022
   ~~ I 20at.carbonicacid20(C      02 ) = C2!)     O40
             The sum is.........= C96N2H660,j2

   51. Now,  since hippuric acid may be  derived,
along with urea, from the  compounds  of proteine,
when to the  elements of the latter are added those
of uric  acid (see p. 151);  since, further, uric acid,
choleic acid, and ammonia contain the elements of
proteine in a proportion almost identical with that
of proteine itself (see p. 136); it is obvious that, if
from 5 at. of proteine, with the addition of oxygen
and of the elements of water, there be  removed the
elements of  choleic  acid  and  ammonia,  the re-
mainder will represent the  elements  of  hippuric
acid and of. urea; and that if, when this separation
occurs, and  during the  further transformation, the
elements of starch be present and enter into  tbe new
products, we shall obtain an additional quantity of
choleic  acid, as well  as a certain  amount of car-
bonic acid gas.
   That is to say—that if the elements of proteine  and
starch, oxygen and water being also present,  undergo
transformation together and mutually affect each other,
w& obtain, as  the products of this metamorphosis, ureat 
SECRETIONS AND EXCRETIONS.      153
choleic acid, ammonia, and carbonic acid,  and besidei
these, no other product whatever.
  The elements of
       5 at. proteine ^   f  9  at. choleic acid
      15 at. starch   I   j   9  at. urea
      12 at. water   [   i   3  at. ammonia
       5 at. oxygen J   1.60  at. carbonic acid
       In detail
    5 at. proteine,  5 (C^NsHsgO^) = CmlS 3oH18u070
   15 at. starch,  15 (C12   H10O10) = Clso   Hi5oOia)
   12 at. water,  12 (     HO  ) =      H120„
    5 at. oxygen                =         Os
        The sum is........=s k42o-N3oH342C%j
          and—
    9 at. choleic acid,  QfCggNHaOu^ C^NjH^Om
    9 at. urea, ...... 9 (C2N2H402) = CuNuHg, Q«
    S- at. ammonia, .  . 3. (   N H3   ) =   N3H9
   60 at. carbonic acid, 60 (C     02) = C60     O120
        The sum is ....  .. ..... = C420N3uH342O237

  The transformation of the  compounds of proteine
present in the body is effected  by means  of the
oxygen conveyed by the  arterial blood, and if the
elements of starch, rendered soluble in the stomach,
and thus carried to every part, enter into the newly
formed compounds,  we have the chief constituents
of the animal secretions  and excretions ;  carbonic
acid, the excretion of the lungs, urea and carbonate
of ammonia, excreted by the kidneys, and choleic
acid, secreted by  the liver.
   Nothing, therefore,  in  the chemical composition
 of those matters  which may be supposed to take  a 
154         SODA ESSENTIAL TO THE
share in these metamorphoses, is  opposed to the
supposition  that a part of  the  carbon  of  the
nonazotised food enters into the  composition of
the bile
  52v Fat, in the  animal  body, disappears when
the supply of oxygen is abundant.   When that sup-
ply is deficient, choleic  acid may be converted into
hippuric acid, lithofellic acid, (37)  and water.  Li-
thofellic  acid is  known  to be  the chief constituent
of the bezoar stones, which  occur in certain  her-
bivorous animals:
                           f 2 at. hip. acid CseNsJhsOu .,
 2 at. choleic acid C76N2H66O22 ) _ 1  1 at. lith. acid do H3608
10 at. oxygen . ,       O,o ), j 14 at. water, . . H(4014 :
              C76N2H66032               C7sN2H66032
   53.  For  the  production ,of. bile in  the animal
body a  certain  quantity of soda isr in  all  circum-
stances, necessary ; without the presence of a com-
pound of sodium  no bile  can be formed.   In the
absence of soda, the metamorphosis of the tissues
composed of proteine can yield only fat and urea.
If we suppose fat to be composed according to the
empirical formula CuH10O, then, by the addition of
oxygen and the  elements of water  to the elements
of proteine, we  have the elements of fat, urea, and
carbonic acid.
         Proteine.    Water.  Oxygen.
  2 (C48N6H36014)  +  12 HO + 14 O = CBeNwH840M -
           f 6 at. urea . . . . = C^N^H^O^
         = \  Fat  .......= C*  H60O6
           i IS at carbonic acid = Cl3     O^

                              CssN^H^O^ 
FORMATION  OF THE BILE.         155
   The composition of all fats lies  between the em-
pirical formulae C„H10O and C12H10O.  If we adopt
the latter, then  the elements of 2 at. proteine, with
the addition of 2 at. oxygen and  12 at. water, will
yield 6 at. urea, fat  (C72H60O6), and 12 at. carbonic
acid.
   It is  worthy of observation, in reference  to  the
production of fat, that the absence of common salt
(a compound of sodium which furnishes soda to the
animal  organism) is  favorable  to the formation of
fat; that the fattening of an  animal is rendered
impossible, when we add to its food an  excess of
salt, although short of the quantity required to pro-
duce a purgative effect.
   54. As a kind of general  view of the  metamor-
phoses of the nitrogenised animal secretions, atten-
tion may here  be very properly  directed to  the
fact, that the nitrogenised products of the transfor-
mation of the bile are identical in ultimate compo-
sition with  the constituents of the urine, if  to  the
latter be added a certain proportion of the elements
of water.
 1 at. uric acid Ci0N4H4 06)   , «  *  *   •     nivrw/n
             „ MUa     ( 3 at. taurine   Ci2N3H2lOM
 1 at. urea . .  . C2 JN2H4U2 \ _ ?
                tt /-*   i   t '«* at.
22 at. water .  .    H^Ok )
ammonia
N3H9
           CuNgHaAH,                   CisNgHsoOaa
1 at. allantoine C4N2H8 03 ) _ ( 1 at. taurine  C4 N H7 Oi0
1 at. water  . .     H7 07 J — ( 1 at. ammonia   N H3

           C4N2H10Ol0                C4N2H10Oio
55. In reference to the metamorphoses of uric 
156        RELATION  OF URINE  TO BILE.
acid and of the products of the  transformation  of
the bile, it  is  not less significant, and worthy  of
remark, that the  addition of oxygen  and  the ele-
ments of water to the elements of uric acid may
yield either taurine and urea, or taurine, carbonic
acid, and ammonia.

  1 at. uric acid C10N4H A ^          t&urine Cg ^H, A,
 14 at. water . .     H14Ol4 \ - J  ^ ^  ^^  ^
  2 at. oxygen . .     U2  )               _^_____
            doN.HiA, ^                  CuN.HjAa
                           r 2 at. taurine . CgNaHuOjjo
                          = ? 2 at.carbon acid C2      04
Add 2 at. water  H202y   { 2 at. ammonia    N2H6
            Ci0N4H2uO24                   C10JN4xi20O24

   56.  Alloxan, plus  a certain amount of water, is
identical in the proportion of elements with taurine ;
and finally, taurine contains the elements  of super-
oxalate of ammonia.

     1 at. alloxan* C8N2H4 01( ^     Taurine.
 q  )     x aui me.
  '°   =(2COT,O10)
o'-'io )
   10 at. water        H10v
                        (  2 at. oxalic acidC4   06
1 at. taurine C4NH7O10=<  1 at. ammonia    NH3
                        (  4 at. water .  .      H404
                                        C4NHAo

  • It would be most interesting to investigate the action of alloxan on
the human body.  Two or three drachms, in crystals, had no injurious
action on rabbits to which it was given.  In man, a large dose appeared
to act only on the kidneys.  In certain diseases of the liver, alloxan would
yery probably be found a most powerful remedy.—J. L. 
         RELATION  OF STARCH  TO BILE.      157

  57. The comparison of the amount of carbon in
the bile secreted by  an herbivorous animal, with the
quantity of carbon of its  tissues, or of the nitrogen-
ised constituents of its food,  which in consequence
of the  constant  transformations may pass  into  bile,
indicates, as we have just seen, a great difference.
  The carbon of the bile secreted amounts, at least,
to more than five times the quantity of that which
could reach the liver in consequence of the change
of  matter  in  the  body, either  from  the  metamor-
phosed tissues or from the nitrogenised constituents
of the  food ; and we may regard as well founded the
supposition that the non-azotised constituents of the
food take a decided  share in  the production of bile
in the herbivora; for neither experience nor obser-
vation contradicts this opinion.
   58.  We have given, in the foregoing paragraphs,
the analytical proof, that the nitrogenised products
of  the  transformation  of bile, namely, taurine and
ammonia,  may  be formed from all the constituents
of  the urine, with  the exception  of urea—that is,
from hippuric acid,  uric  acid, and allantoine; and
when  we bear in mind that, by the mere  separation
of oxygen and  the elements of water, choloidic acid
may be formed  from starch ;—

        From 6 at. starch = b' (C12Hi0Om) = C72H6tAfl
 Subtract 44 at. oxygen )                   HAu
         4 at. water  )                 ___________
        Remains choloidic acid..........= C72HSA2 >—
 that, finally, choloidic acid,  ammonia, and taurine,
                         14 
 158    RELATION OF STARCH, &C. TO BILE.

if added together,  contain  the elements of choleic
 acid;—

            1 at. choloidic acid = C72 Hj0Oi2
            1 at. taurine......= C4 NH7 OI0
            1 at. ammonia .... =  NH3

            1 at. choleic acid  = C72N2 H6G022;—

 if all this be considered, every doubt as to the possi-
 bility of these changes is removed.
   59.  Chemical analysis and the study of the living
 animal body mutually support each other; and both
 lead to the  conclusion that a certain portion of the
 carbon of the non-azotised constituents  of food (of
 starch, &c, the  elements  of respiration) is secreted
 by the liver in the  form  of bile;  and  further, that
 the  nitrogenised  products  of the  transformation of
 tissues in the herbivora do not, as  in the carnivora,
 reach  the kidneys  immediately or  directly, but that,
 before their expulsion from the body in  the  form of
 urine, they take  a share in certain other processes,
 especially in the  formation  of the bile.
   They are conveyed to  the liver with the non-
 azotised constituents of the food ;  they are returned
 to the  circulation  in the  form of bile,  and are  not
 expelled by the kidneys till  they  have  thus served
for the production of the most important of the sub-
stances employed in respiration.
   60. When the urine is left to itself, the urea which
it contains is converted into carbonate of ammonia ;
the elements of urea are in such proportion, that by 
              ORIGIN  OF THE BILE.          159

the adition of the elements of water, all its carbon is
converted into carbonic  acid, and all  its nitrogen
into ammonia.

    I at. urea C2N2H402 *   I 2 at. carbonic acid C2    O*
    2 at. water    HO* / = \ 2 at. ammonia....  N2H6
           CJN^HeOi                    CsNsHeO*

  61.  Were  we able  directly to  produce  taurine
and ammonia  out  of uric  acid or allantoine, this
might  perhaps be considered as an additional proof
of the  share  which has been ascribed  to these com-
pounds in the production of bile ; it cannot, howev-
er,  be  viewed as any  objection  to  the  views  above
developed  on the subject, that, with the means we
possess,  we  have  not yet  succeeded  in effecting
these  transformations  out of the  body.  Such an
objection loses all its  force, when  we consider that
we cannot admit, as  proved,  the pre-existence of
taurine and ammonia in the bile ; nay, that it is not
even  probable  that these compounds,  which  are
only known  to us as products of the decomposition
of the bile, exist ready formed, as ingredients  of
that fluid.
   By the action of muriatic acid on  bile, we, in  a
manner,  force  its elements to unite in  such  forms
as are  no longer capable of change under the influ-
ence  of  the  same  re-agent;  and when, instead of
the acid, we use potash, we obtain  the same ele-
ments, although arranged in another, and quite  a
different manner.  If taurine  were present, ready 
160
ORIGIN OF THE BILE.
formed, in bile, we should obtain the same products
by the action of acids and of alkalies.  This, how-
ever, is contrary to experience.
  Thus,  even if we  could  convert  allantoine,  or
uric acid  and urea, into taurine and  ammonia, out
of the body, we should  acquire  no  additional in-
sight into the true theory of the  formation of bile,
just because  the pre-existence  of ammonia  and
taurine in the bile must be  doubted, and because
we have  no reason  to believe that urea or  allan-
toine,  as  such,  are employed  by the organism in
the production  of bile.   We  can prove that their
elements  serve  this  purpose,  but we are  utterly
ignorant how these elements enter into these com-
binations,  or what  is  the  chemical character of
the nitrogenised compound  which unites with the
elements  of starch to  form bile, or rather choleic
acid.
   62. Choleic acid may  be formed  from  the ele-
ments of starch with those of uric acid  and urea,
or  of allantoine, or  of  uric  acid, or  of alloxan,
or  of oxalic acid and  ammonia, or of  hippuric
acid.  The possibility  of its being produced from
so  great  a  variety of nitrogenised  compounds  is
sufficient to  show that  all  the  nitrogenised  pro-
ducts of the  metamorphosis of  the  tissues  may
be  employed in the  formation  of bile,  while we
cannot tell  in what precise way they  are so em-
ployed.
   By the action of caustic alkalies allantoine may
be  resolved into oxalic  acid and ammonia; the 
             VITAL METAMORPHOSES.          161

same products are obtained when oxamide is acted
on  by the same  re-agents.   Yet we cannot,  from
the similarity of the products, conclude  that these
two compounds have a similar constitution.   In like
manner the nature of the products  formed by the
action of acids on choleic acid does not entitle us
to draw any  conclusion as to the form in which its
elements are united together.
  63. If the  problem to  be solved by organic che-
mistry be this, namely, to explain the  changes which
the food undergoes in the animal body; then it is
the business  of this science  to ascertain what ele-
ments must be added, what  elements must be  se-
parated, in order  to  effect, or, in general,  to ren-
der possible,  the conversion  of a given  compound
into a second or  a  third ;  but we  cannot expect
from it the synthetic proof of the accuracy of the
views entertained, because every thing in the orga-
nism goes on under the influence  of  the vital force,
an  immaterial  agency,  which  the chemist cannot
employ  at will.
   The  study of the  phenomena which  accompany
the metamorphoses of the food  in the organism, the
discovery of  the share which the  atmosphere or the
elements  of  water take  in these changes,  lead at
once  to  the  conditions  which must be  united in
order to the production of a secretion or of an orga-
nized part.
   64. The presence  of  free  muriatic  acid in the
stomach,  and that  of  soda in  the blood, prove
beyond  all doubt  the necessity of common  salt for
                      14* 
162          USES OF  COMMON SALT

the organic processes; but the quantities of soda re-
quired by animals of different classes, to support the
vital processes, are singularly unequal.
   If we  suppose that a  given  amount of blood,
considered as  a  compound of soda, passes,  in the
body of a carnivorous animal,  in  consequence of
the  change  of matter, into  a  new compound  of
soda,  namely, the  bile,  we  must  assume, that  in
the  normal condition  of  health, the proportion of
soda in  the  blood  is  amply sufficient to form bile
with  the  products of transformation.    The  soda
which has been  used in the vital processes, and any
excess of soda must be expelled in the form of a
salt, after being separated from the blood  by the
 kidneys.
   Now, if it be true, that,  in the  body of an herbivo-
 rous animal, a much larger quantity of bile is pro-
 duced than  corresponds  to  the amount of  blood
 formed or transformed in the  vital  processes ;  if the
 greater part of the  bile, in this  case, proceeds from
 the non-azotised constituents of the food, then the
 soda of the  blood  which  has been formed  into or-
 ganised tissue (assimilated or metamorphosed) can-
 not possibly suffice for the supply of the daily secre-
 tion of bile.   The soda, therefore, of the bile  of the
 herbivora  must  be  supplied directly in the food ;
 their organism must  possess the power of applying
 directly to the formation of bile all the compounds
 of soda present  in  the food, and  decomposable  by
 the organic process.  All the   soda of the animal
 body obviously  proceeds from the  food, but the food 
IN THE ORGANIC PROCESSES.       163
of the carnivora contains, at most, only the amount
of soda necessary to the formation of blood ;  and
in most cases, among animals of this class, we may
assume that only as much soda as corresponds to
the proportion employed to form  the blood is expel-
led in  the urine.
  When the carnivora obtain in  their food as much
soda as suffices for the  production of their blood, an
equal  amount  is excreted  in the urine; when the
food contains less, a part of that which would other-
wise be excreted is retained by the organism.
  All  these statements  are most unequivocally con-
firmed by the composition of the urine in these dif-
ferent  classes of animals.
   65.  As the ultimate product of the changes of all
compounds of soda in  the animal body, we find in
the urine the soda in the form of a salt, and the nitro-
gen in that Of ammonia or  urea.
   The soda in the urine  of the carnivora is found
in combination with sulphuric and phosphoric acids ;
and along with the sulphate and phosphate of soda
we  never fail  to find a certain  quantity of a salt of
ammonia, either muriate or phosphate of ammonia.
There can be  no more decisive evidence in favour
of the opinion,  that  the  soda of  their bile- or of
the  metamorphosed constituents of  their blood  is
very far from sufficing to neutralize the acids which
are  separated, than  the presence  of ammonia  in
their urine.   This urine,  moreover, has an acid re-
 action.
   In contradistinction to this, we find, in the urine 
164
LARGE AMOUNT OF ALKALIES
of the herbivora, soda in predominating quantity;
and that not combined with sulphuric or phosphoric
acids, but with carbonic, benzoic, or hippuric acids.
  65. These well established  facts demonstrate that
the herbivora consume a far larger quantity of soda
than is required  merely for the  supply of the daily
consumption of blood.  In their food are united all
the conditions for  the production  of a second com-
pound of soda, destined for the support of the respi-
ratory process;  and it can only be a very  limited
knowledge of the  vast wisdom  displayed in the ar-
rangements of organized nature which can look on
the presence of so much soda  in the  food and in the
urine of the herbivora as accidental.
  It cannot be  accidental, that the life, the  devel-
opement  of a plant is dependent on the presence of
the alkalies which  it extracts from  the soil.  This
plant serves as food to an extensive class of animals,
and  in   these animals  the  vital  process  is again
most  closely connected with  the  presence  of these
alkalies.   We find the alkalies in  the bile,  and their
presence in the animal body is  the  indispensable
condition for the production of the first food  of the
young animal ;  for  without an  abundant  supply
of potash,  the  production of  milk  becomes  im-
possible.
  67. All observation leads, as appears from the pre-
ceding exposition,  to the opinion,  that  certain non-
azotised  constituents of the  food  of the herbivora
(starch,  sugar,  gum, &c.,)  acquire  the form of a
compound of soda, which, in  their bodies,  serves 
         REQUIRED BY THE  HERBIVORA.      165

for  the  same purpose  as that which we know  cer-
tainly to be served  by  the bile (the most highly  car-
bonized product of the transformation of their tissues)
in the bodies of the carnivora.   These substances
are employed to support  certain vital actions,  and
are finally  consumed  in  the  generation  of animal
heat, and in furnishing means of resistance to the
action   of  the  atmosphere.    In  the carnivora,  the
rapid transformation of their tissues is a condition of
their existence, because it is only as the result of the
change of  matter in the body that those substances
can be formed, which are destined to enter  into
combination with  the oxygen of the air;  and in
this sense we may say that the non-azotised consti-
tuents  of  the  food of the  herbivora  impede  the
change of  matter,.or retard it, and  render unneces-
sary, at all events, so rapid a process as occurs in the
carnivora.
  68. The  quantity of azotised matter, proportion-
ally so small, which the herbivora require  to  sup-
port their vital functions, is closely connected with
the power  possessed  by  the  non-azotized  parts of
their  food  to act as means of supporting  the respi-
ratory process;  and this consideration seems to  ren-
der it not improbable, that the necessity  for more
complex organs of digestion in the herbivora  is
rather  owing to the difficulty of rendering soluble
and available for the vital processes certain non-azo-
tised compounds (gum? amylaceous fibre?) than  to
any thing  in the change or transformation of vege-
table  fibrine,  albumen, and  caseine  into  blood; 
166     STARCH, ETC. ASSIST  IN FORMING

since, for this latter purpose, the less complex di-
gestive  apparatus of  the  carnivora  is amply suffi-
cient.
  69. If, in man, when fed on a mixed  diet, starch
perform a similar part to  that which it plays in the
body of the herbivora;  if it be assumed that the
elements of starch  are equally necessary to the for-
mation of the bile in man as in these animals;  then
it follows that a part  of the azotised products of the
transformation  of  the tissues in the human body,
before they  are expelled through  the bladder, re-
turns into the circulation  from the liver in the shape
of bile, and is  separated by the kidneys from the
blood, as the  ultimate product  of the respiratory
process.
  70. When there is a deficiency  of non-azotised
matter in the food of man, this form of  the produc-
tion of bile is  rendered  impossible.  In that  case,
the  secretions must possess a different composition ;
and the appearance of uric acid in the urine, the de-
position of uric acid in the joints and in the bladder,
as well as the  influence which an excess of animal
food (which must be considered equivalent to a de-
ficiency of starch,  &c.,) exercises on the separation
of uric acid in certain individuals, may be explained
on this principle.   If starch, sugar, &c,  be deficient,
then a part of the azotised  compounds formed du-
ring the change of matter will either remain in the
situation where they have  been formed, in which
case they will be sent  from  the liver  in  the cir-
culation, and  therefore  will not undergo  the  final 
          BILE  IN THE HUMAN BODY.        167

changes  dependent  on the action of oxygen;  or
they will be separated by the kidneys in some form
different from the normal one.
  71. In the preceding paragraphs I have  endea-
voured  to  prove  that the  non-azotised  constitu-
ents of  food  exercise a  most  decided  influence
on  the  nature  and  quality of the  animal secre-
tions.  Whether this occur directly ; whether, that
is to say, their  elements take  an immediate share
in  the act of transformation  of tissues ;  or whe-
ther their  share  in that process be  an indirect
one, is a question  probably  capable of being  re-
solved by  careful  and cautious  experiment and
observation.  It is  possible, that the non-azotised
constituents of food, after undergoing some change,
are  carried from  the  intestinal  canal  directly to
the  liver,  and  that  they  are   converted  into bile
in  this  organ,  where they  meet  with  the  pro-
ducts  of the metamorphosed  tissues,  and  subse-
quently  complete  their course through the circu-
lation.
  This  opinion appears more probable,  when  we
reflect that  as  yet  no trace   of  starch  or sugar
has been detected  in  arterial  blood, not even in
animals  which  had  been  fed  exclusively  with
these  substances.    We  cannot ascribe  to these
substances, since they are wanting in arterial blood,
any share in the nutritive process ; and  the  oc-
currence  of sugar  in  the  urine of those  affected
with diabetes mellitus (which sugar according to
the best  observations, is derived from  the  food) 
168
ORIGIN OF THE NITROGEN
coupled  with  its total  absence in  the blood  of
the same  patients,  obviously proves  that  starch
and  sugar are  not,  as  such, taken into the  cir-
culation.
  72. The writings of physiologists  contain  many
proofs of  the  presence  of certain  constituents of
the bile in the  blood of man in a state of health, al-
though  their quantity can hardly be  determined.
Indeed,  if we suppose 81 lbs.  (58,000 grs.) of blood
to pass through the liver every minute, and if from
this quantity of blood 2 drops of bile  (3 grains to
the drop) are secreted, this would amount to eeVoth
part of the weight of the blood, a proportion far too
small to be quantitatively ascertained by analysis.
  73. The greater part of the bile in  the body of
the herbivora,  and  in  that  of man  fed  on mixed
food, appears from the preceding considerations to
be  derived  from the elements of the  non-azotised
food.  But its  formation is impossible  without the
addition of an  azotised body, for the bile is a com-
pound of nitrogen.   All varieties of bile yet exa-
mined,  yield,  when  subjected  to  dry  distillation,
ammonia and  other nitrogenised products.  Tau-
rine  and ammonia  may easily  be  extracted from
ox bile; and the only reason why we cannot posi-
tively prove that the same products may be obtained
from the bile of other animals is this, that it  is not
easy  to procure, in  the case  of many of these  ani-
mals, a  sufficient quantity of bile  for the experi-
ment.
   Now,  whether the nitrogenised compound  which 
          CONTAINED IN HUMAN BILE.       169

unites with the elements of starch to form bile be de-
rived from the food or from the substance of the me-
tamorphosed tissues, the conclusion that its presence
is an essential condition for the secretion of bile can-
not be considered doubtful.
  Since the herbivora obtain in their food only such
nitrogenised compounds as are identical in composi-
tion with the constituents of their  blood, it is at all
events clear, that the nitrogenised compound which
enters into the composition of bile is derived from a
compound of proteine.  It is either formed in conse-
quence of a change  which the compounds of pro-
teine in the food have undergone, or it is produced
from the blood or from  the substance of the tissues
by  the act of their metamorphosis.
  74.  If the conclusion be accurate, that  nitrogen-
ised compounds, whether derived from the blood or
from the food, take a decided share in the formation
of the secretions, and particularly of the bile, then
it is plain that the organism must possess the power
of causing foreign  matters which are neither parts
nor constituents of the organs in which vital activity
resides, to serve for certain vital processes.  All nitro-
genised substances capable of being rendered soluble,
without  exception, when introduced into the organs
of  circulation  or of digestion, must, if their compo-
sition be  adapted for such purposes, be employed by
the organism in the same manner as the nitrogenised
products which are formed in the act of metamor-
phosis of tissues.
                       15 
 170       CERTAIN REMEDIES  TAKE A

   We are acquainted  with a  multitude  of  sub-
 stances,  which  exercise a most marked  influence
 on the  act of transformation as well as  on  the
 nutritive  process,  while their   elements  take no
 share in  the resulting  changes.   These  are  uni-
 formly substances the  particles of which are  in  a
 certain  state of motion  or  decomposition, which
 state  is communicated  to all such parts of the or-
 ganism as are capable of undergoing a similar trans-
 formation.
   75.  Medicinal and  poisonous  substances  form
 a  second and most extensive class of compounds,
 the elements of which are capable of taking  a direct
 or an indirect  share in  the processes of secretion
 and of transformation.   These  may be subdivided
 into  three great orders;  the first (which includes
 the metallic  poisons) consists of substances which
 enter into chemical combination with certain parts
 or constituents  of  the body, while  the vital force
 is  insufficient to destroy the  compounds thus form-
 ed.  The second division, consisting of the essential
 oils, camphor, empyreumatic substances,  and anti-
 septics, <fcc,  possesses the property  of impeding or
 retarding those kinds of transformation to which cer-
 tain very  complex  organic  molecules are  liable;
 transformations which, when they take place out of
 the body, are usually designated by the  names of
 fermentation and putrefaction.
  The third division of medicinal  substances is
 composed of  bodies,  the elements of which take a
direct share in the  changes going on in the  animal 
SHARE IN  THE  VITAL TRANSFORMATIONS. 171
body.   When introduced into the  system,  they
augment the energy of the vital activity of one or
more organs;  they excite  morbid  phenomena in
the healthy body.  All of them produce a marked
effect in a comparatively small dose, and many are
poisonous  when  administered  in  larger  quantity.
None of the substances in this  class can be said  to
take a  decided share  in the nutritive process, or
to be employed by the organism in the production
of blood ; partly,  because their composition is differ-
ent from that of blood, and, partly, because the pro-
portion in which they must be  given, to exert their
influence, is as nothing, compared with the mass of
the blood.
   These substances,  when  taken into the  circu-
 lation, alter, as is commonly said, the quality of the
 blood,  and in order that they may pass  from the
 stomach  into the circulation with their entire effi-
 cacy, we must assume that their composition  is not
 affected by  the  organic influence of  the stomach.
 If insoluble  when given, they are rendered  soluble
 in that organ, but they are not  decomposed;  other-
 wise, they would be incapable of exerting any influ-
 ence on the blood.
   76.  The blood, in its normal state,  possesses two
 qualities closely related to each other, although  we
 may conceive one of them to be  quite independent
 of the other.
    The blood contains, in the form of the globules,
 the carriers, as it were,  of the oxygen which serves
 for the production of certain tissues, as well as for 
 172      ARTERIAL BLOOD ACTS  BY ITS

 the generation of animal  heat.   The globules  of
 the blood, by means of the property they possess
 of giving off the oxygen  they  have taken  up  in
 the lungs, without  losing  their peculiar character,
 determine  generally the  change  of matter  in the
 body.
   The  second  quality of the  blood, namely, the
 property  which it  possesses  of becoming  part  of
 an organised tissue,  and  its  consequent  adapta-
 tion to promote the formation  and the growth  of
 organs, as  well as to  the reproduction or sup-
 ply of waste  in the tissues,  is owing,  chiefly,  to
 the presence  of disssolved  fibrine and albumen.
 These  two  chief  constituents, which   serve for
 nutrition  and reproduction of  matter,  in passing
 through  the  lungs are   saturated with  oxygen,
 or, at  all events,  absorb  so much from  the at-
 mosphere as entirely to lose  the  power of extract-
 ing oxygen from  the  other substances  present  in
 the blood.
   77. We  know for certain  that  the globules  of
 the venous blood, when they  come in contact with
 air in the  lungs, change their  colour, and that this
 change of colour is accompanied by an absorption  of
 oxygen ; and that all those  constituents of the blood,
 which possess in any degree the power of combining
 with oxygen, absorb it in the lungs, and become sa-
 turated  with it.   Although in  contact with  these
 other  compounds, the globules, when arterialised,
retain their florid, red  colour  in the most  minute
ramifications  of  the arteries; and we observe them 
OXYGEN, FIBRINE, AND ALBUMEN.     173
to change their colour, and to assume the dark red
colour which characterizes venous  blood, only dur-
ing their passage through  the capillaries.  From
these facts we must conclude that the constituents of
arterial blood are altogether destitute of the power
to deprive the arterialised globules of the oxygen
which  they have absorbed  from the air;  and we
can  draw no other conclusion from the change of
colour which occurs in the capillaries, than that the
arterialised  globules,  during their  passage  through
the capillaries, return to the condition  which cha-
racterized them in venous blood ;  that, consequently,
they  give up the oxygen absorbed in the lungs, and
thus  acquire the  power of combining with  that ele-
ment afresh.
   78. We find,  therefore,  in  arterial  blood,  albu-
 men, which, like  all the other constituents of that
 fluid, has  become  saturated  with oxygen  in  its
 passage through the lungs,  and oxygen gas, which
 is conveyed to every  particle  in  the  body in
 chemical combination  with  the   globules of  the
 blood.  As far  as our observations extend (in  the
 developement of the chick  during incubation), all
 the  conditions  seem to be here  united which are
 necessary to the formation  of every kind  of tissue ;
 while that  portion  of oxygen which  is  not  con-
 sumed in the growth or reproduction of organs com-
 bines  with the substance  of the living  parts,  and
  produces, by its union  with their elements, the act
 of transformation which we have called the change
  of matter.
                         15* 
174           MODUS OPERANDI  OF
  79. It  is obvious,  that  all compounds, of what-
ever kind,  which are  present  in  the  capillaries,
whether  separated there,  or introduced by endos-
mosis or  imbibition,  if not altogether  incapable  of
uniting with oxygen, must, when in  contact with
the  arterialised  globules, the  carriers of oxygen,
be  affected  exactly in the same  way  as the  solids
forming part of living organs.   These compounds,
or  their elements,  will  enter  into   combination
with  oxygen,  and in this case  there will  either be
no  change  of matter, or that  change  will exhibit
itself in  another form, yielding products of a  differ-
ent kind.
  80.  The conception, then, of a change in the  two
qualities of the blood above alluded to, by  means of
a foreign body contained in the blood  or introduced
into the circulation (a medicinal agent), presupposes
two kinds of operation.
  Assuming that the remedy cannot enter into  any
such chemical  union with the  constituents  of the
blood  as puts an end to the vital activity; assum-
ing, further, that it is not in  a condition of trans-
formation capable of being communicated to the con-
stituents of the blood or of the organs, and of con-
tinuing in them;  assuming, lastly, that it is incapa-
ble, by its contact with kthe living parts, of putting
a stop to the change of matter,  the transformation
of their  elements;  then, in order to  discover the
modus operandi  of  this class  of medicinal agents,
nothing is  left but to conclude  that  their elements
take a share in  the formation of certain constituents 
          ORGANIC REMEDIAL AGENTS.        175

of the living body, or in the production of certain
secretions.
  81. The  vital process of secretion, in so far as it
is  related to the  chemical  forces, has been sub-
jected  to  examination in the preceding pages.   In
the carnivora we have reason to believe, that with-
out the addition of any foreign  matter in the food,
the  bile  and the  constituents  of the  urine  are
formed  in those parts where  the  change of matter
takes place.   In other classes of animals, on  the
other hand, we  may suppose that  in  the organ of
secretion  itself,  the secreted fluid is produced from
certain  matters  conveyed  to  it;  in the herbivora,
for example, the bile is  formed from  the elements
of starch  along with those of a nitrogenised  pro-
duct of the  metamorphosis  of the tissues.    But
this supposition by no  means excludes the opin-
ion, that  in  the carnivora  the products of the  me-
tamorphosed tissues are resolved into bile, uric acid,
or  urea, only after reaching the secreting organ;
nor  the opinion that the  elements of the non-azo-
tised  food, conveyed directly by the circulation to
every part of the  body,  where change of matter is
going on, may there  unite with the elements  of the
metamorphosed  tissues, to form the constituents of
the bile and of the urine.
   82. If  we  now assume, that certain medicinal
agents  may  become  constituents of secretions,  this
can only  occur in two ways.  Either they enter the
circulation, and take a direct  share in the change of
matter  in  so far as their elements  enter into  the 
176     NITROGENISED  ORGANIC REMEDIES.

composition of the new  products ;  or they are  con-
veyed to the organs of secretion,  where they exert
an influence on the formation or on the quality of a
secretion by the addition of their elements.
  In  either case,  they  must  lose  in the organism
their  chemical character; and we  know with suffi-
cient  certainty, that this class of medicinal bodies
disappears in the body without leaving a trace.   In
fact,  if we ascribe  to them any effect,  they cannot
lose  their peculiar character by  the action of the
stomach :  their disappearance, therefore, presupposes
that   they  have been  applied to  certain purposes,
which cannot be imagined to occur without a change
in their composition.
  83.  Now, however  limited may be  our know-
ledge  of  the  composition  of the  different secre-
tions, with  the exception of  the bile,  this  much is
certain, that  all  the  secretions  contain  nitrogen
chemically  combined.   They pass into  fetid putre-
faction, and yield either in  this change, or in the
dry distillation, ammoniacal products.  Even the  sa-
liva, when acted upon by caustic potash, disengages
ammonia freely.
  84.  Medicinal or remedial agents  may be divided
into  two classes, the nitrogenised  and the non-ni-
trogenised.  The nitrogenised vegetable principles,
whose composition differs from that of the proper
nitrogenised elements of nutrition,  also produced  by
a vegetable  organism, are distinguished, beyond  all
others, for their powerful action on  the animal eco-
nomy. 
            VEGETABLE  ALKALIES, ETC.        177

  The  effects  of these substances  are  singularly
varied;  from the  mildest form  of the  action  of
aloes,  to the most  terrible  poison,  strychnia,  we
observe an endless variety  of different actions.
  With  the  exception of three, all  these  substances
produce  diseased conditions in  the healthy  organ-
ism, and are  poisonous in certain  doses.  Most of
them are, chemically speaking, basic or alkaline.
  No remedy, devoid  of nitrogen possesses a poison-
ous action in a similar dose.*
  85.  The  medicinal or  poisonous action   of  the
nitrogenised vegetable principles has a  fixed rela-
tion to  their  composition; it cannot be supposed
to be  independent  of the  nitrogen  they  contain,
but is certainly not in  direct proportion to the quan-
tity of nitrogen.
  Solanine (38), and  picrotoxine (39), which  con-
tain least nitrogen, are powerful poisons.  Quinine
(40) contains  more  nitrogen  than  morphia (41).
Caffeine  (42), and theobromine  the most  highly
nitrogenised  of  all  vegetable  principles,  are  not
poisonous.
  86.  A nitrogenised body, which exerts, by  means
of its elements,  an influence on  the formation or on
the  quality  of a secretion,  must, in regard to  its

  * This  consideration or comparative view  has led lately  to a
more accurate investigation  of the composition of picrotoxine, the
poisonous principle of cocculus indicus:  and M. Francis  has dis-
covered the existence of nitrogen in it, hitherto overlooked, and haa
also determined its amount. 
178    MODE OF ACTION OF NITROGENISED

chemical character, be  capable  of taking the same
share as the nitrogenised  products  of the animal
body do in the  formation  of the  bile; that is, it
must play the same  part as  a product of the vital
process.  On the other hand, a non-azptised  medi-
cinal agent, in so far as its action affects the  secre-
tions, must be capable  of performing in the animal
body the same part as that which we have ascribed
in the formation of  the  bile, to the non-azotised
elements of food.
  Thus,  if we suppose  that  the elements of hip-
puric or  uric acids are derived from  the  substance
of the organs  in which  vitality resides;  that  as
products  of  the transformation of  these organs
they lose the vital character, without, losing the capa-
city  of undergoing   changes under  the influence
of the inspired  oxygen,  or of the  apparatus  of
secretion;  we  can  hardly doubt that similar  ni-
trogenised compounds,  products  of the vital  pro-
cess  in  plants,  when introduced into  the animal
body, may be  employed by  the organism  exact-
ly in the same  way  as the  nitrogenised  products
of the metamorphosis of the  animal  tissues them-
selves.   If  hippuric  and uric  acids,  or any  of
their  elements,  can  take a share, for example,  in
the  formation and  supply of bile,  we  must allow
the  same power to  other  analogous nitrogenised
compounds.
  We shall never, certainly, be able  to  discover
how  men were led  to  the use  of the hot infusion
of the leaves  of  a certain shrub  (tea)  or of a decoc- 
VEGETABLE PRODUCTS:  CAFFEINE.    179
tion  of certain roasted seeds (coffee.)  Some cause
there must be, which would explain how the prac-
tice  has  become a necessary of life to whole  na-
tions.  But it is surely still more remarkable, that
the beneficial effects  of both  plants on the health
must be ascribed to  one and the  same substance,
the presence of  which in two vegetables, belonging
to different natural  families,  and  the produce of
different quarters of  the globe, could hardly have
presented  itself  to the  boldest  imagination.  Yet
recent researches have shewn, in  such  a  manner
as to  exclude  all doubt,  that caffeine,  the  pecu-
liar  principle of coffee, and theine, that of  tea, are,
in all respects, identical.
   It is not less  worthy of notice, that the American
Indian, living entirely on flesh, discovered  for him-
self,  in  tobacco smoke, a  means of retarding the
change  of matter in the tissues of his  body,  and
thereby  of making hunger more  endurable ;  and
that he cannot withstand the  action  of brandy,
which,  acting  as an element of  respiration, puts
 a stop to  the change of matter by performing the
function which properly belongs  to  the  products
of the metamorphosed tissues.  Tea and coffee were
 originally met  with among  nations whose diet  is
 chiefly vegetable.
   87. Without entering minutely into the medicinal
 action of  caffeine (theine,) it will  surely  appear a
 most  striking fact, even  if we were to deny its in-
 fluence on the  process  of  secretion, that this  sub-
 stance,  with the addition  of oxygen  and the ele- 
180   RELATION OF CAFFEINE, ASPARAGINE.
ments  of water,  can yield taurine, the nitrogenised
compound peculiar to bile :
          1 at. caffeine or theine = C8N2HS O2
          9 at. water...........=     H»09
          9 at. oxygen..........=        O9
                               C8N2Hl4OZ0 =
        = 2 at. taurine..........= 2 (C4NH*0">)
   A similar relation exists  in the case of the pecu-
liar  principle of asparagus and of althaea, aspara-
gine ;  which also, by the  addition of oxygen  and
uie elements of water, yields the elements of tau rine
             1 at. asparagine = C8N2H80<s
             6 at. water.....=    H6Ofl
             8 at. oxygen.... =       O
                             C7N2Hl4020 =
            a= 2 at. taurine = 2 (C4NH7Oio)
   The addition  of the elements of water  and of a
certain quantity  of oxygen  to the elements of theo-
bromime, the characteristic principle of the  cacao
bean,  (theobroma cacao,)  yields  the elements of
taurine  and  urea,  of taurine,  carbonic acid,  and
ammonia, or of taurine and uric acid :
 1 at theobromine C18NeH,0O4 \   f .
22 at. water......      H-O- U J f at taunne C"N«H-0*
16at.oxygen.....        O" j   1l at' ™-C' ^ °'
               C,8N6H32042                C18N6H32042
                        or—
 1 at. theobromine Cl8N6H'0O \    / 4 at. taurine  C16N4H2804°
24 at. water......     H24024 [ = ) 2 at. carb. acid C2     O4
16 at. oxygen.....       O16 j    ( 2 at. ammonia   N2H6
Ci8N6H»40«                 C'sNeH^O44 
AND THEOBROMINE TO BILE AND URINE.  181
                      or—r
1 at. theobromine C18N6H10O4
 8 at water          H8 O8  \ - I 2 at taUrine   C8N2H,40m
,° at;Water......     h"   "   lat. uric acid C'°N4H4 0«
14 at. oxygen.....       O14 J   I
               ON6H18026                C18N6H18026
  88. To see  how the action of caffeine, aspara-
gine,  theobromine, &c,  may  be  explained,  we
must  call to mind  that the chief constituent of the
bile contains  only 3-8  per  cent,  of nitrogen, of
which only the half, or 1-9 per cent., belongs to the
taurine.
  Bile  contains, in  its  natural state,  water  and
solid  matter,  in  the  proportion  of 90 parts  by
weight of the former  to 10  of the  latter.  If we
suppose these 10 parts by weight of solid matter
to be choleic acid,  with 3-87 per cent,  of nitrogen,
then  100  parts  of fresh bile  will contain  0171
parts of nitrogen  in the  shape of taurine.   Now
this quantity is contained in  0-6 parts  of caffeine :
or 2T\ths grains of caffeine can  give to an ounce of
bile the  nitrogen it contains in the form of taurine.
If an infusion of  tea  contain  no more  than the
^th  of a grain of  caffeine,  still, if it  contribute
in  point of fact  to  the  formation  of bile,  the
action,  even  of such a quantity, cannot be looked
upon as a  nullity.  Neither can it be denied  that
in  the  case of an  excess of non-azotised food and
a deficiency of motion, which is required to cause
the change of matter  in the tissues, and thus  to
yield the nitrogenised product  which  enters  into
the composition of the  bile; that in such a  con-
                     16 
182    MODE  OF ACTION OF VEGETABLES.

dition, the health  may be benefited by  the  use of
compounds which are  capable  of supplying  the
place of the nitrogenised product produced  in the
healthy state of the body, and  essential  to the pro-
duction of an important element of respiration.   In
a chemical sense -— and it is this alone which the
preceding  remarks are  intended  to show — caffeine
or theine, asparagine, and theobromine,  are, in vir-
tue  of their  composition, better adapted  to  this
purpose  than  all other nitrogenised vegetable  prin-
ciples.   The action of these  substances,  in ordinary
circumstances, is not obvious, but it unquestionably
exists.
   89. With  respect  to the action  of the  other ni-
trogenised  vegetable  principles, such  as quinine,
or  the  alkaloids  of opium, &c, which  manifests
itself, not  in  the processes  of secretion,  but in
phenomena of another  kind, physiologists and pa-
thologists  entertain no  doubt  that  it is  exerted
chiefly on  the brain  and nerves.   This  action is
commonly said to be  dynamic — that is,  it accele-
rates,  or retards,  or  alters in some way the  phe-
nomena  of motion  in  animal life.   If we  reflect
that this action is exerted by  substances which are
material, tangible and ponderable ;  that  they dis-
appear in the organism; that a double  dose acts
more powerfully  than a single  one ; that,  after a
time, a  fresh dose must be given, if we wish  to
produce  the action a  second  time ;  all these  con-
siderations, viewed  chemically, permit only  one
form of  explanation ; the supposition, namely, that 
      ALKALIES ON THE  NERVOUS SYSTEM.   183

these compounds, by  means  of their elements, take
a share in the formation of new, or the transforma-
tion of existing brain  and nervous matter.
  However  strange the idea  may, at first sight, ap-
pear, that the  alkaloids of opium  or of cinchona
bark, the elements of codeine,  morphia, quinine,
&c,  may  be converted into  constituents of brain
and  nervous matter, into organs  of vital ener-
gy,  from which  the  organic  motions  of the body
derive  their origin;  that  these substances form
a  constituent  of that  matter, by  the removal of
which  the  seat  of intellectual  life,  of  sensation,
and of consciousness, is  annihilated ;  it is, never-
theless,  certain,  that  all these  forms  of power
and activity are  most closely dependent, not  only
on   the  existence,  but also  on a  certain   quality
of  the  substance  of  the  brain,  spinal  marrow,
and  nerves;  insomuch,  that  all  the  manifesta-
tions of the life or  vital energy  of these modi-
fications of nervous  matter,  which are recognised
as  the  phenomena of motion,  sensation,  or feel-
ing,  assume another  form as soon as their com-
position is  altered.   The animal organism  has  pro-
duced  the  brain and nerves  out of  compounds
furnished to it by vegetables ; it is the constituents
of  the  food of the animal,  which, in consequence
of  a series  of changes, have assumed  the properties
and the structure which we  find in the brain  and
nerves.
   90. If it must  be  admitted  as an  undeniable
truth, that  the substance  of the brain  and nerves  is 
184        COMPOSITION AND ORIGIN
produced from the  elements  of vegetable albumen,
fibrine and caseine, either alone, or with the aid of
the elements  of non-azotized food,  or  of the fat
formed from the latter, there is nothing absurd in
the opinion, that other constituents  of  vegetables,
intermediate  in composition  between the  fats  and
the compounds  of proteine, may be applied in the
organism to the same purpose.
   91. According to the researches  of Fremy, the
chief constituent of the fat found in the brain is a
compound of soda with a peculiar acid, the cerebric
acid, which contains, in 100 parts,
       Carbon...........667
       Hydrogen........;  .  10-6
       Nitrogen..........2-3
       Phosphorus..........0-9
       Oxygen...........19-5
   It is easy to  see that the composition of cerebric
acid differs entirely, both  from that of ordinary fats
and of the compounds of proteine.  Common fats
contain no nitrogen, while  the  compounds of pro-
teine contain nearly 17 per cent.  Leaving  the phos-
phorus out of view, the composition of this acid ap-
proaches  most  nearly to that of choleic  acid,  al-
though these two compounds are quite distinct.
   92. Brain  and nervous matter  is, at  all events,
formed in  a manner similar to  that  in  which bile
is produced ;  either by the  separation  of a  high-
ly  nitrogenised compound  from  the elements  of
blood, or  by the  combination of  a nitrogenised 
            OF THE NERVOUS MATTER.        1S5

product  of the vital  process with a  non-azotised
compound (probably,  a fatty body).   All that has
been  said in the preceding pages  on the various
possible  ways by  which  the  bile  might be  sup-
posed  to be  formed,  all  the  conclusions  which
we attained  in  regard to  the co-operation of azo-
tised  and non-azotised elements of food, may  be
applied  with equal justice  and equal probability
to the formation  and production  of  the nervous
substance.
   We must  not  forget that, in whatever light we
may  view the vital  operations, the production of
nervous  matter from  blood  pre-supposes a change
in the composition  and qualities of the constituents
of blood.  That such  a change  occurs  is as certain
as that the existence of the  nervous  matter cannot
be denied.  In  this sense,  we  must  assume,  that
from  a  compound  of  proteine  may be  formed  a
first,  second,  third,  &c., product, before a certain
number  of its  elements can  become constituents of
the nervous  matter;  and it  must be considered as
quite certain, that  a  product of the  vital process
in a  plant, introduced into  the blood, will,  if its
composition be adapted to  this purpose, supply the
place of the first, second, or third product  of the
alteration of  the compound of proteine.  Indeed
it cannot be  considered merely  accidental, that the
composition of the most active remedies, namely,
the vegetable  alkaloids, cannot  be shown to  be re-
lated  to that of any constituent  of the body, except
only  the substance of the nerves and  brain.   All
                       16* 
186    RELATION OF VEGETABLE ALKALIES

of these contain a certain quantity of nitrogen, and,
in regard to their  composition, they  are  interme-
diate  between  the  compounds of proteine and the
fats.
   93.  In contradistinction to their chemical charac-
ter, we find that the substance of the brain exhibits
the characters  of  an  acid.   It contains far more
oxygen than the organic bases or  alkaloids.   We
observe, that quinine and cinchonine, morphia  and
codeine, strychnia and brucia, which are, respective-
ly, so  nearly alike in composition,  if they  do not
produce  absolutely the  same effect,  yet  resemble
each other in  their action more than those which
differ more  widely in composition.   We find that
their energy of action diminishes, as the amount of
oxygen they contain increases (as in  the case of nar-
cotine,) and that, strictly speaking, no one of them
can be entirely replaced by another.  There can-
not be a more decisive proof of the  nature  of their
action  than this last fact;  it  must  stand  in the
closest relation to their composition.   If these com-
pounds,  in  point of fact, are capable of  taking a
share in the formation  or in the alteration of the
qualities of brain and nervous matter, their action
on the healthy as well as  the  diseased organism
admits of a surprisingly simple explanation.   If we
are not tempted to deny, that the chief constituent
of soup may be applied  to a  purpose corresponding
to its composition in the human body, or that the
organic constituent of bones may be so employed
in the body of the dog, although  that  substance 
           TO THE NERVOUS MATTER.        187

(gelantine in both cases) is absolutely incapable of
yielding blood; if, therefore, nitrogenised compounds,
totally different from  the  compounds of proteine,
may be  employed  for  purposes  corresponding to
their composition ; we  may thence  conclude that a
product of vegetable life, also different from proteine,
but similar to a constituent of the animal body, may
be employed by  the organism in the same way and
for the same  purpose as the natural product,  ori-
ginally formed by the vital energy of the  animal
organs, and  that, indeed,  from  a  vegetable sub-
stance.
   The time  is  not  long gone by,  when  we  had
not the  very  slightest conception of the cause of
the various effects of opium, and when the action
of cinchona bark  was shrouded  in  incomprehensi-
ble obscurity.   Now that we know that these effects
are caused by crystallizable compounds, which differ
as much  in composition as in  their action on the
system ;  now that we know the substances to which
the medicinal or poisonous energy must be ascribed,
it would  argue  only want of sense to consider the
action of these substances inex'plicable; and to do
so, as many  have done, because  they act  in very
minute doses, is as unreasonable as it would be to
judge of the sharpness of a razor  by its weight.
   94.  It would serve no  purpose to give  these
considerations a greater extension at present.  How-
ever hypothetical  they may appear, they  only de-
serve  attention  in so  far as  they point  out the
way which chemistry pursues, and which she ought 
188       THEORY OF  THE  ACTION OF

not to quit,  if she  would really be of service  to
physiology and  pathology.   The combinations  of
the chemist  relate to the change of  matter, for-
wards  and  backwards, to the conversion  of food
into the various tissues and secretions,  and to their
metamorphosis into  lifeless compounds ;  his inves-
tigations ought to tell us what has taken place and
what  can take place in the  body.  It  is  singular
that we find medicinal agencies all dependant on
certain matters,  which  differ  in  composition ; and
if, by  the introduction  of a  substance, certain ab-
normal  conditions are rendered normal, it  will be
impossible  to reject  the  opinion, that  this pheno-
menon  depends  on  a  change  in the  composition
of the  constituents   of the  diseased  organism,  a
change in  which the elements of the  remedy take
a share; a  share similar to that which the veget-
able  elements of food have taken in the formation
of fat,  of membranes, of the  saliva,  of the  seminal
fluid,  &c.   Their carbon, hydrogen,   or nitrogen,
or whatever  else belongs  to their composition, are
derived from the vegetable   organism ; and,  after
all, the  action  and  effects  of  quinine,  morphia,
and the vegetable poisons in  general,  are  no hy-
potheses.
  95. Thus, as  we  may say, in  a certain sense,  of
caffeine or theine and  asparagine, &c, as  well as
of the  non-azotised elements of food, that they are
food for the liver, since  they  contain the  elements,
by the presence of which  that organ is enabled  to
perform its  functions, so we  may  consider  these 
     NITROGENISED VEGETABLE PRODUCTS.   189

nitrogenised  compounds, so  remarkable  for  their
action  on the brain and on the substance of the
organs of motion, as elements  of food  for the or-
gans as  yet  unknown,  which are destined  for the
metamorphosis of the constituents of the blood into
nervous  substance and brain.  Such organs  there
must be in  the  animal body, and if, in the diseased
state, an abnormal process of production or trans-
formation of the constituents of cerebral and nervous
matter has been established ; if, in the organs intended
for this purpose, the power of forming that matter out
of the constituents of blood, or the power of resisting
an abnormal degree of activity in its decomposition
or transformation, has been diminished; then, in  a
chemical sense, there is no objection to the opinion,
that substances of a composition  analogous to that
of nervous  or cerebral  matter, and,  consequently,
adapted  to form  that matter, may be  employed, in-
stead of the substances produced from the  blood,
either to furnish the necessary resistance, or to re-
store the normal  condition.
   96.  Some  physiologists and chemists  have ex-
pressed doubts of the peculiar and distinct character
of cerebric acid, a substance which, from its amount
of carbon and hydrogen,  and from its external cha-
racters, resembles a nitrogenised  fatty acid.   But a
nitrogenised fat, having an acid character, is, in fact,
no anomaly.  Hippuric acid  is  in many of its cha-
racters very  similar to  the fatty acids, but is essen-
tially distinguished from them by containing nitro-
gen.  The organic constituents of bile resemble the 
190       PHOSPHORUS SEEMS ESSENTIAL

acid resins in  physical  characters, and yet contain
nitrogen.   The organic alkalies  are intermediate in
their physical characters between the fats and resins,
and they all contain nitrogen.   A nitrogenised fatty
acid is as  little improbable as the existence of a ni-
trogenised resin with the characters of a base.
  97. An accurate investigation would probaly dis-
cover differences in the composition  of the  brain,
spinal marrow,  and nerves.   According to the ob-
servations  of  Valentin, the quality of the  cerebral
and nervous  substance is very rapidly altered  from
the period of death, and very uncommon precautions
would be required for the separation of foreign mat-
ters not properly belonging to the  substance of the
spinal marrow or  brain.   But,  however  difficult it
may appear, the investigation seems  yet to be prac-
ticable.   We know, in the meantime,  that all expe-
rience is against the notion of a  large amount of
carbon and hydrogen in the substance of the  brain.
The absence of nitrogen as an  element of the cere-
bral  and nervous  matter, appears, at  all events, im-
probable.   This  substance,  moreover,  cannot be
classed with ordinary fats, because we find the cere-
bric  acid  combined  with soda,  whereas,  all  fats
are compounds of fatty acids with oxide of glycerule.
In regard to the phosphorus of the brain, we can only
guess as to the form in which the phosphorus exists.
Walchner observed recently that bubbles of sponta-
neously inflammable phosphuretted hydrogen were
disengaged from  the  trough of a spring in Carls-
ruhe, on the bottom of which  fish had putrefied ; 
TO THE NERVOUS  MATTER.         191
and  gases  containing  phosphorus  have  also  been
observed among the  products  of the putrefaction  of
the brain.*

  * The curator  of the museum at Geneva  gave to M. Leroyer,
apothecary, a large quantity of spirit of wine,  which had been used
for the preservation of fishes, and which he undertook to purify.  He
distilled it from a  mixture  of chloride of calcium and quicklime, and
evaporated the residue in the air, over  a fire.  As soon as the mass
had acquired a certain consistence, and a higher temperature, a pro-
digious quantity of spontaneously inflammable  phosphuretted hydro-
gen was disengaged.  (Dumas, V. 267.) 
 
PART III.
          THE
PHENOMENA OF MOTION
          IN THE
   ANIMAL ORGANISM.
17 
1 
THE
PHENOMENA  OF  MOTION
ANIMAL  ORGANISM.
                       1.
  It might appear an unprofitable task to add one
more  to the  innumerable  forms under which the
human intellect has viewed the  nature and essence
of that peculiar cause which must be considered as
the ultimate source of the phenomena which charac-
terize vegetable and animal life, were it not that cer-
tain conceptions  present  themselves  as  necessary
deductions from the views on this subject develop-
ed in  the  introduction  to the first part of this work.
The following pages will be  devoted to  a  more
detailed examination  of these deductions.  It must
be  admitted here,  that all these  conclusions  will
lose their  force and significance, if it can be proved
that the cause of vital activity has  in its manifes-
tations nothing in common with other known causes
which produce motion  or change of form and struc-
ture in  matter.
   But  a  comparison of its  peculiarities  with the 
196       THE PHENOMENA OF MOTION

modus operandi  of these other  causes, cannot, at
all  events, fail  to be advantageous,  inasmuch as
the nature and essence  of natural phenomena are
recognizable, not by abstraction, but only by  com-
parative observations.
  If the  vital  phenomena be considered as mani-
festations of a peculiar  force,  then  the effects of
this force must be regulated by  certain laws, which
laws may be investigated ; and  these laws must be
in harmony  with the universal laws of resistance
and motion, which   preserve in their  courses the
worlds of our own and  other systems, and which
also determine changes of form and structure in ma-
terial bodies ;  altogether independently of the mat-
ter in which  vital activity appears to reside, or of the
form in which vitality is manifested.
   The vital  force in  a living animal tissue appears
as a cause of growth  in the  mass, and  of resistance
to those  external agencies which tend to alter the
form, structure, and composition of the substance of
the tissue in which the vital energy resides.
  This force further  manifests  itself as a cause of
motion and of change in the form  and structure of
material  substances, by the disturbance and abolition
of the state  of rest in which those chemical forces
exist, by which the elements of the compounds con-
veyed to the living tissues, in the form  of food, and
held together.
  The vital  force causes a  decomposition  of the
constituents  of food, and  destroys  the  force of at-
traction which is continually exerted between  their 
           IN THE ANIMAL ORGANISM.        197

molecules; it alters the direction of the chemical
forces  in  such wise, that the elements  of the con-
stituents of food arrange themselves in another form,
and  combine  to  produce  new  compounds, either
identical in composition with  the  living tissues, or
differing from them; it further  changes the direc-
tion  and  force of the  attraction  of cohesion, de-
stroys the cohesion of the nutritious compounds, and
forces the new compounds to  assume forms altoge-
ther  different from those which are the result of the
attraction of cohesion  when  acting freely,  that is,
without resistance.
   The  vital force is also  manifested as a force of
attraction, inasmuch as the new compound produced
by the  change of form and  structure in the food,
when it has a composition identical with that of the
living tissue,  becomes a part of that tissue.
   Those  newly-formed compounds, whose compo-
sition differs  from that  of the living tissue, are re-
moved from the situation in which they are  formed,
and, in the shape of certain secretions, being carried
to other parts of the body,  undergo in contact with
these a series of analogous changes.
   The vital force is manifested in the form of resist-
ance,  inasmuch as by its presence in the living tis-
sues, their elements acquire the  power of withstand-
ing  the disturbance and change in their form and
composition,  which external  agencies tend to pro-
duce ;  a power   which, simply as chemical com-
pounds, they do not possess.
   As in the case  of other forces,  the conception of
                       17* 
198       THE  PHENOMENA 05'  MOTION
an unequal  intensity of the vital force comprehends
not  only an unequal  capacity  for  growth in  the
mass and  an unequal power of overcoming  che-
mical  resistance,  but also  an  inequality in  the
amount  of that  resistance  which  the parts or  con-
stituents of the  living  tissue  oppose  to a change in
their form and composition, from  the action of new
external active causes  of change ;  just as  the force
of cohesion or  of affinity  is in direct proportion to
the resistance which these forces oppose to any ex-
ternal cause, mechanical or chemical, tending to se-
parate the  molecules,  or the elements of an existing
compound.
   The manifestations of the vital force are dependent
on a certain form of the tissue in which it resides,
as well as on a fixed composition in the substance of
the living tissue.
   The capacity  of growth in a  living tissue is de-
termined  by the  immediate contact with matters
adapted to a certain decomposition, or the  elements
of which are capable of becoming component parts of
the tissue in which vitality resides.
  The phenomenon of growth,  or increase in  the
mass, presupposes that  the  acting vital force is more
powerful  than  the resistance which the  chemical
force opposes to  the decomposition or transformation
of the elements  of the  food.
  The  manifestations  of the vital force  are depen-
dent on a certain temperature.   Neither  in a plant
nor in an animal  do vital phenomena  occur when the
temperature is lowered  to a certain extent. 
           IN THE ANIMAL ORGANISM.       199

  The phenomena of vitality in a living organism
diminish  in  intensity  when  heat  is  abstracted,
provided  the  lost heat  be not  restored by  other
causes.
  Deprivation of food soon  puts a  stop to all mani-
festations  of vitality.
  The contact of the living tissues with the ele-
ments of nutrition is determined in the animal body
by a  mechanical force  produced  within  the body,
which gives to certain organs the power of causing
change of place, of producing motion, and of over-
coming  mechanical resistance.
  We may communicate motion  to a body  at rest
by means of a number of forces, very different  in
their  manifestations.   Thus, a time-piece may  be
set in motion by  a falling  weight (gravitation),  or
by a bent spring (elasticity).  Every kind of motion
may be produced by the electric  or magnetic  force,
as well  as by chemical attraction ;  while  we cannot
say, as long as we only consider the manifestation of
these forces in  the phenomenon or result produced,
which of these various causes of change of place has
set the body in motion.
   In  the  animal  organism  we are acquainted  with
only  one cause  of  motion ;  and this  is the same
cause which determines the growth of living tissues,
and o-ives them the power  of resistance to external
agencies ; it is the vital force.
   In  order to attain a clear conception of these
manifestations  of the vital force,  so  different  in
form, we must  bear in mind, that every known 
 200      THE  PHENOMENA OF  MOTION

 force is  recognized  by two  conditions  of activity,
 entirely different in  the phenomena they offer to the
 attention of the  observer.
   The force of gravitation inherent in the particles
 of a stone,  gives  to them a continual tendency to
 move towards the  centre of the earth.
   This effect of gravitation  becomes  inappreciable
 to the senses when the stone,  for  example,  rests
 upon a table, the particles  of which oppose a resist-
 ance to the manifestation  of its  gravitation.    The
 force of gravity, however, is  constantly present, and
 manifests itself as a  pressure on  the supporting
 body ;  but the stone remains at rest;  it has no mo-
 tion.   The  manifestation of gravity  in the state of
 rest we call its weight.
   That which  prevents the  stone from falling is a
resistance produced  by  the  force of  attraction, by
 which the particles  of the wood cohere together ;
 a  mass of water would  not  prevent the fall of the
 stone.
   If the force which impelled the mass of the  stone
 towards the centre  of the  earth  were greater than
 the force  of cohesion in  the  particles  of the  wood,
the latter  would be  overcome; it would be unable
to prevent the fall  of the stone.
   When we remove the support, and with  it  the
force which has prevented  the  manifestation of the
force of gravity, the latter at once  appears as  the
cause of change of  place  in  the stone, which  ac-
quires motion, or falls.  Resistance is invariably the
result of a force in action. 
IN THE ANIMAL ORGANISM.       201
  According as the stone is allowed to fall during a
longer or shorter time, it acquires properties which
it had not while at rest ;  it acquires, for example,
the power of overcoming more feeble or more pow-
erful obstacles, or that of communicating motion to
bodies in a state of rest.
  If it fall from  a  certain height  it makes a  perma-
nent  impression on  the  spot on  which it falls ;  if
it fall  from a still greater height (during a longer
time) it  perforates the  table ;  its own  motion  is
communicated to a certain number of the particles
of the wood which  now fall along with the stone
itself.  The  stone, while at rest, possessed none of
these properties.
  The velocity  of the falling  body  is  always  the
effect of the moving  force, and is, ceteris  paribus,
proportional  to the force of gravitation.
  A body, falling  freely, acquires at the end of  one
second  a velocity of 30 feet.  The  same body,  if
falling on the moon, would acquire  in one second
only a velocity of  gWlhs of a foot = l  inch, because,
in the moon, the intensity of gravitation (the pressure
acting on the body, the  moving power) is 360 times
smaller.
  If the pressure continue uniform, the velocity  is
directly  porportional to it;  so that,  for example,
the body falling 360  times slower, will, after  360
seconds,  have the same  velocity as the other body
after one second.
  Consequently, the effect is  proportional, not to
the moving  force alone, nor to the time alone, but 
202       THE PHENOMENA OF MOTION

to the  pressure multiplied into the  time, which is
called the momentum of force.
   In two equal  masses the  velocity  expresses the
momemtum of force.   But under the same  pressure
a body moves more slowly as its mass is  greater; a
mass twice as great  requires,  in order to attain in
the same time an equal velocity, twice the pressure;
or, under the single pressure,  it must continue in
motion twice as  long.
   In order, therefore, to have  an expression for the
whole  effect  produced, we must multiply the mass
into the velocity.  This product is called the amount
of motion.
   The amount of motion in a  given  body  must in
all cases  correspond exactly to the momentum of
force.
   These two,  the  amount  of motion   and  the
momentum of force, are also called simply force ;
because we  suppose  that  a less pressure acting,
for example,  during 10 seconds,  is equal  to a pres-
sure ten  times greater, acting only during one se-
cond.
   The momentum of motion in mechanics  signifies
the effect  of  a moving  force,  without reference  to
the time (velocity) in which it  was  manifested.  If
one man,  for example,  raises 30 lbs. to a height of
100 feet,  and a  second one 30 lbs. to a height  of
200 feet,  then the  latter has  expended twice  as
much force  as the  former.   A third who  raises
60 lbs.  to a height of 50 feet, expends no more force
than the first  did  in raising 30 lbs.  to the height of 
IN THE AN'MAL  ORGANISM.       203
100  feet.   The  momentum of motion  of the  first
(30x100)  is equal  to  that of the  third  (60x50)
while  that  of  the second  (30x200)  is twice  as
great.
  Momentum of force  and momentum  of motion
in mechanics are therefore expressions or measures
for effects of force, having reference to the velocity
attained in a given time,  or  to a  given  space; and
in this sense may be  applied to  the effects of  all
other causes  of motion, or of change  in form and
structure, however great or however small may be
the space or the time in which their  effects are dis-
played to the senses.
   Every  force,  therefore,  exhibits itself in  mat-
ter  either  in  the form  of resistance  to external
causes of motion, or of change in form and struc-
ture;  or  as a  moving force  when no resistance
is opposed to  it;  or  finally,  in overcoming  re-
sistance.
   One and  the  same  force  communicates  motion
and destroys motion ;  the  former  when its manifes-
tations are  opposed by  no  resistance; the latter,
when it puts a stop to the manifestation of  some
other  cause  of motion, or of change  in form  and
structure.   Equilibrium  or rest  is  that state of
activity in which one force or momentum of motion
is destroyed  by an opposite force or momentum of
motion.
   We obsesve both  these manifestations of  activity
 in that force which  gives to the living  tissues their
 peculiar properties. 
204      THE PHENOMENA ON MOTION

   The  vital force appears as a  moving  force  or
cause of  motion  when it  overcomes the chemical
forces (cohesion and affinity) which act between the
constituents of food, and when it changes the posi-
tion or  place  in  which  their elements occur; it is
manifested as a cause of motion in overcoming the
chemical  attraction  of  the  constituents  of food,
and is,  further, the cause  which  compels  them  to
combine in  a new arrangement, and to assume new
forms.
   It is plain  that a  part of the  animal body pos-
sessed of vitality,  which  has therefore the power of
overcoming  resistance, and of giving motion  to the
elementary  particles of the food, by  means of  the
vital  force  manifested in  itself must  have a mo-
mentum  of motion, which is  nothing else than  the
measure of the resulting motion or change  in form
and structure.
   We know that  this momentum  of  motion in  the
vital  force,  residing in a  living part, may  be em-
ployed  in giving  motion to bodies at rest,  (that is,
in  causing decomposition,  or  overcoming resist-
ance,) and  if  the vital  force is  analogous in its
manifestations  to  other  forces, this momentum  of
motion  must be capable of being conveyed or com-
municated by matters, which  in themselves do not
destroy  its effect   by  an opposite  manifestation of
force.
  Motion, by whatever cause produced, cannot in
itself be annihilated ; it  may indeed  become  inap-
preciable  to the senses, but even when arrested by 
               IN THE ANIMAL ORGANISM.         205

resistance  (by  the  manifestation  of  an  opposite
force),  its  effect  is  not  annihilated.  The  falling
stone, by means of the amount of motion acquired
in  its  descent, produces  an effect when it reaches
the table.   The impression  made on the wood, the
velocity communicated  by its  parts to those  of the
wood,—all this is its effect.
   If we transfer  the  conceptions  of motion,  equi-
librium,  and  resistance,  to  the  chemical  forces,
which,  in  their  modus operandi, approach  to the
vital  force  infinitely nearer  than  gravitation  does,
we know with  the  utmost  certainty,  that they are
active only in  the  case of immediate contact.  We
know  also,  that  the unequal capacity  of  chemical
compounds to offer  resistance to  external disturbing
influences, to  those  of heat,  or  of electricity,  which
tend  to  separate their  particles, as  well  as  their
power of overcoming  resistance in other compounds
(of causing  decomposition)  ; that,  in  a word, the
active force in a  compound  depends  on a certain
order or arrangement,  in which its elementary par-
ticles touch each other.
   The  same  elements, united  in a different  order,
when  in contact with other  compounds,  exert  a
most  unequal  power of offering  or overcoming re-
sistance.  In   one  form  the  force  manifested  is
available (the body is active,  an  acid, for example) ;
in another not  (the  body is  indifferent, neutral); in
a third form, the momentum  of force is opposed to
that of the first (the body is active, but a base).
                        18 
206
THE PHENOMENA OF  MOTION
  If we alter the arrangement of the elements, we are
able to separate the constituents  of a compound by
means of another active body; while the  same ele-
ments, united in their original  order, would have
opposed  an invincible resistance to the action of the
decomposing agent.
  In  the same way as two equal inelastic  masses,
impelled  with  equal  velocity from  opposite  points,
on coming into contact are  brought to  rest; in the
same way, therefore, as two  equal and opposite mo-
menta  of motion  mutually  destroy  each  other;  so
may  the momentum of  force in  a chemical com-
pound be destroyed in whole or in part by an equal
or  unequal,  and opposite  momentum of  force in a
second  compound.  But  it cannot  be  annihilated
as  long as  the   arrangement   of   the  elementary
particles, by which its inherent force was  manifested,
is not changed.
  The chemical  force of sulphuric  acid  is  present
in  sulphate of lime as entire as  in oil of  vitriol.   It
is not appreciable  by the senses ; but if  the cause
be  removed which prevented  its  manifestation,  it
appears  in its full force  in the compound in which it
properly resides.
  Thus  the force of cohesion in  a solid may disap-
pear,  to  the senses, from the action of a chemical
force  (in solution),  or of heat   (in fusion),  without
being in  reality annihilated or  even weakened.   If
we remove the opposing force or resistance, the force
of cohesion appears unchanged in crystallization. 
              IN THE ANIMAL ORGANISM.          207

  By means of the electrical  force, or that of heat,
we can give the  most varied  directions to the mani-
festations  of  chemical force.   By these  means we
can fix, as it were, the order in which the elemen-
tary particles shall  unite.   Let us remove the cause
(heat  or  electricity)  which has turned the balance
in favour of the weaker attraction in  one direction,
and the stronger  attraction  will  shew  itself continu-
ally active in another direction ;  and  if this stronger
attraction can overcome the vis inertias  of the ele-
mentary particles,  they will  unite in  a  new  form,
and  a  new compound of different  properties  must
be the result.
  In  compounds  of this  kind, in  which,  therefore,
the free manifestation  of the  chemical  force has
been impeded by other  forces,  a  blow, or mechanical
friction, or the  contact  of a substance, the  particles
of  which are in a state  of motion  (decomposition,
transformation), or any  external cause,  whose  ac-
tivity is added to  the  stronger attraction  of the ele-
mentary  particles  in  another  direction,  may suffice
to give  the preponderance  to this  stronger attrac-
tion,  to overcome the vis inertias, to  alter the form
and  structure  of the  compound,  which  are  the
result of foreign  causes, and to produce the resolu-
tion  of the compound into one or  more  new com-
pounds with altered properties.
   Transformations, or as they may be  called, phe-
nomena of motion, in compounds of this class, may
be effected by  means of the  free  and  available 
 208        THE  PHENOMENA OF MOTION

 chemical force of another chemical componnd, and
 that  without its  manifestation   being  enfeebled  or
 arrested by resistance.   Thus the  equilibrium in the
 attraction  between the  elements  of  cane-sugar  is
 destroyed  by  contact with a very small  quantity of
 sulphuric acid, and it  is  converted into grape-sugar.
 In the same  way  we  see  the elements of  starch,
 under the same  influence, arrange themselves  with
 those  of water  in a new form, while the sulphuric
 acid, which has  served  to produce these transforma-
 tions,  loses  nothing of  its  chemical character.  In
 regard to other  substances  on which   it  acts,  it
 remains as  active as  before,  exactly as if it had
 exerted no  sort  of influence  on the  cane-sugar  or
 starch.
   In  contradistinction  to the  manifestations of the
 so-called mechanical forces, we have  recognized in
 the chemical forces causes  of motion and of change
 in form and structure,  without  any observable ex-
 haustion of  the  force  by which  these  phenomena
 are  produced;  but the  origin  of  the  continued
 manifestation of  activity remains  still  the same; it
 is the   absence of an  opposite  force  (a  resistance)
 capable  of neutralizing it or bringing it into the state
 of equilibrium.
  As  the  manifestations  of chemical  forces  (the
momentum of force in a  chemical  compound)  seem
to depend  on a certain  order in which the elemen-
tary particles  are united together, so   experience
tells  us, that the vital  phenomena are  inseparable 
            IN THE ANIMAL ORGANISM.        209

from  matter;  that  the manifestations  of the  vital
force in a living  part  are determined  by a certain
form  of that part, and  by a certain arrangement  of
its elementary particles.  If  we destroy the form,  or
alter  the  composition  of the organ, all manifesta-
tions  of vitality disappear.
  There is nothing to prevent us  from considering
the vital force as a peculiar property, which  is pos-
sessed by certain material bodies, and becomes sen-
sible  when their  elementary particles are  combined
in a certain arrangement or form.
  This supposition takes  from the  vital  phenomena
nothing  of  their  wonderful peculiarity;  it  may
therefore  be  considered  as a resting  point,  from
which an  investigation into these  phenomena, and
the laws which regulate  them, may be  commenced;
exactly as we consider the  properties  and laws  of
light  to be  dependant  on   a  certain   luminiferous
matter, or other, which  has  no  further connection
with  the laws ascertained by investigation.
  Considered under this  form, the  vital force unites
in its manifestations all the  peculiarities of chemical
forces, and of the not less  wonderful  cause, which
we regard as the ultimate  origin  of electrical  phe-
nomena.
   The vital force does not  act, like the force of gra-
vitation or  the magnetic  force, at  infinite distances,
but,  like  chemical  forces, it is active  only  in the
case  of immediate contact.   It becomes sensible  by
means of an aggregation of  material particles.
              18* 
210       THE PHENOMENA OF MOTION

   A living part  acquires, on the  above  supposition,
the  capacity  of   offering and of  overcoming  re-
sistance, by the  combination of its elementary par-
ticles  in  a certain form;  and  as long  as  its form
and composition   are  not  destroyed  by   opposing
forces, it  must retain  its energy uninterrupted and
unimpaired.
   When,  by  the  act of  manifestation of this energy
in a living part,  the elements of the food are  made
to  unite  in  the   same form  and  structure as  the
living  organ  possesses, then these elements acquire
the  same  powers.  By  this combination,  the  vital
force  inherent in  them is enabled to manifest itself
freely, and may be applied in the same way as that
of the previously existing tissue.
   If,  now,  we   bear  in  mind,  that   all   matters
which  serve  as  food  to  living organisms are  com-
pounds of two or  more  elements,  which  are kept
together  by certain chemical forces ; if we reflect
that in the act  of manifestation  of force in a liv-
ing  tissue, the elements  of  the food are  made  to
combine in a  new order;—it  is  quite  certain  that
the momentum of  force or of  motion  in  the vital
force was more  powerful than  the  chemical attrac-
tion existing between the  elements of the food.*

  * The hands of a  man, who raises with a rope and simple
pulley, 301bs. to  the height of 100 feet, pass over a space of
100 feet, while his muscular energy furnishes the equilibrium to a
pressure of  301bs.  Were the force which the man could exert
not greater than would suffice to keep in equilibrium a pressure of 
            IN THE ANIMAL ORGANISM.         211

  The chemical force which kept  the elements to-
gether acted  as  a resistance, which was overcome
by the active vital force.
  Had  both forces been equal, no  kind  of sensible
effect would have  ensued.  Had the chemical force
been the stronger,  the living part would have under-
gone a change.
  If we now suppose that a certain amount of vital
force  must  have  been expended in bringing to an
equilibrium  the chemical  force,  there  must  still re-
main  an excess  of force, by  which  the decompo-
sition  was  effected.  This  excess constitutes  the
momentum  of force in the living part, by means of
which the  change was produced ;  by means of this
excess the  part   acquires a  permanent   power  of
causing further decompositions, and of retaining its
condition, form, and structure, in opposition to exter-
nal agencies.
  We may imagine this excess  to be  removed,  and
employed in some other  form.   This  would not of
itself  endanger  the  existence  of the  living  part,
because  the opposing forces would be left  in equi-
librio ; but, by the removal of the excess of force, the
part would  lose its  capacity of growth, its power to
cause further decompositions, and  its ability to re-
sist external causes  of change.  If, in this state of
equilibrium, oxygen  (a chemical  agent)  should be
brought  in  contact with  it, then there would be no
30 lbs., he would be unable to raise the weight to the height men-
tioned. 
212        THE PHENOMENA OF MOTION

resistance to the tendency of the oxygen to combine
with some element of  the  living part,  because  its
power of resistance has been taken away by some
other  application of its  excess  of vital  force.  Ac-
cording to the amount of  oxygen  brought  to it, a
certain proportion of the living part would  lose  its
condition of  vitality,  and take the form of  a  che-
mical  combination,  having  a composition different
from  that  of the living tissue.   In a  word, there
would occur  a change in the properties  of the living
compound, or  what  we  have  called a change  of
matter.
   If we reflect  that the  capacity  of  growth  or
increase of mass in plants  is  almost unlimited; that
a hundred twigs  from a willow tree, if placed in the
soil, become a hundred  trees ; we can hardly  enter-
tain a doubt, that with the  combination of  the ele-
ments  of the food of the plant  so as to form a part
of  it,  a fresh momentum  of force  is added  in the
newly formed  part  to the previously existing mo-
mentum in the plant;  insomuch,  that  with  the  in-
crease of mass, the sum of vital force is augmented.
  According to  the amount of available vital  force,
the products formed  by its  activity from the food
are varied.   The composition of the buds,  of the
radical fibres, of  the leaf, of the  flower, and of the
fruit,  are  very different one  from  the  other; and
the chemical force by which their elements are held
together is very different in each of these  cases.
  Of  the  non-azotised  constituents  of  plants  we 
IN THE ANIMAL ORGANISM.        213
may assert, that no part of the momentum of force
is  expended in maintaining  their form and structure,
when their elements have once combined in that or-
der in which they become parts of organs endued with
vitality.
   Very  different is the  character of  the  azotised
vegetable principles ;  for, when separated from the
plant, they pass, as is  commonly said, spontaneously,
into fermentation and  putrefaction.   The cause of
this decomposition or transformation of their elements
is  the chemical action  which the oxygen of the atmo-
sphere exercises on one of their constituents.  Now
we  know, that as  long as the plant exhibits the  phe-
nomena  of life, oxygen gas is given off from its sur-
face ;  that this oxygen is altogether  without  action
on the constituents of the living plant,  for which, in
other circumstances, it  has the strongest attraction.
It is obvious,  therefore, that a certain  amount of
vital force must be expended, partly to  retain the
elements of  the  complex azotised  principles  in the
form,  order,  and  structure which belong to  them ;
and partly as a means of resistance against  the in-
cessant  tendency of the oxygen of the  atmosphere
to act on their elements, as well as against that of the
oxygen  separated in the organism of the plant by the
vital process.
   With the  increase  of these easily altered   com-
pounds,  in the flower and in the fruit, for example,
the sum of chemical  force  (the  free  manifestation
of which, counteracted by an  equal  measure of vital 
214        THE PHENOMENA OF  MOTION
force,  is  employed  to furnish  resistance)  also  in-
creases.
  The plant  increases  in  mass until  the vital force
inherent in it comes into equilibrium with all the other
causes  opposed  to  its  manifestation.   From  this
period, every  new  cause  of disturbance, added to
those  previously existing  (a  change  of  temperature,
for example),  deprives it of the power of offering re-
sistance, and it dies down.
  In perennial  plants (in trees, for example), the mass
of  the easily  decomposable  * (azotised)   compounds,
compared with that of the  non-azotised, is so small,
that of the whole  sum of force,  only a minimum is
expended as resistance.   In  animals, this proportion
is reversed.
   During every period of the life of a plant, the avail-
able vital force (that which is not neutralized by resis-
tance) is expended only in one form of vital manifes-
tation, that  of growth or increase of  mass, or the
overcoming of resistance.   No part of this force is ap-
plied to other  purposes.
   In the animal organism, the vital force exhibits it-
self, as in the  plant,  in the form  of the capacity of
growth, and as  the means  of  resistance to external
agencies ;  but both of these manifestations are con-
fined within  certain limits.
   We observe in  animals,  that  the conversion  of
food  into  blood, and the contact of the blood  with
the living tissues, are determined by a mechanical
force, whose  manifestation proceeds from  distinct 
IN THE ANIMAL  ORGANISM.         215
organs, and is  effected by a  distinct system  of or-
gans, possessing the property of communicating and
extending the motion which they receive.  We find
the power of the animal to change its  place  and to
produce  mechanical effects by means  of its limbs,
dependant on a second similar  system  of organs  or
apparatus.   Both of these  systems of  apparatus,  as
well as the phenomena of motion proceeding from
them, are wanting in plants.
  In order to form a clear conception  of the origin
and  source of the mechanical motions in the  animal
body, it may be advantageous to reflect on the mo-
dus  operandi of other forces,  which in their mani-
festations are most closely allied to the vital force.
  When a  number of plates  of zinc  and  copper,
arranged in a certain  order, are brought  into  con-
tact with an acid,  and when the  extremities  of the
apparatus are joined by means  of a metallic wire, a
chemical action begins at the surface  of  the plates
of zinc, and  the wire, in consequence of this  action,
acquires the most singular and wonderful  properties.
  The wire appears as the carrier or conductor of a
force,  which may be conducted and communicated
through  it in every direction  with amazing velocity.
It is the conductor  or propagator of an  uninterrupted
series  of manifestations of activity.
  Such a propagation of motion is  inconceivable, if
in the wire there were  a  resistance to be overcome;
for every resistance  would  convert a part  of the
moving force into  a force at rest. 
216      THE  PHENOMENA OF  MOTION

   When  the  wire  is  divided in the  middle,  and
its continuity  interrupted,  the  propagation of  force
ceases, and we observe, that  in this case the action
between  the  zinc  and  the  acid is  immediately
stopped.
   If  the  communication  be  restored, the  action
which had disappeared reappears  with all its origi-
nal energy.
   By  means of the  force  present in  the wire,  we
can produce the most varied  effects;  we can  over-
come all kinds of resistance, raise weights, set ships
in motion, &c.  And, what is  still more remarkable,
the wire  acts as a hollow  tube, in which a  current
of chemical force circulates freely and without hin-
drance.
   Those properties  which, when firmly attached to
certain bodies, we call  the  strongest and  most ener-
getic affinities, we find,  to  all  appearance, free and
uncombined in  the wire.   We  can transport  them
from the wire to  other bodies, and thereby  give to
them an affinity (a power of entering  into combina-
tion) which in themselves they do not  possess.   Ac-
cording  to  the  amount of  force  circulating in the
wire, we are able by means of it to decompose com-
pounds, the  elements of which  have  the  strongest
attraction for each other.   Yet the substance of the
wire takes not the smallest share  in all these mani-
festations  of force ; it  is  merely  the  conductor of
force.
  We  observe,  further, in this wire, phenomena of 
IN THE ANIMAL ORGANISM.         217
attraction and  repulsion, which we must  ascribe to
the  disturbance of  the  equilibrium  in  the electric
or  magnetic force;  and  when  this equilibrium  is
restored, the restoration is accompanied by the de-
velopement  of  light and  heat,  its  never-failing  com-
panions.
  All these remarkable phenomena are produced  by
the chemical action which the  zinc and the acid  exert
on each other;  they are  accompanied by a change in
form and structure, which both undergo.
   The acid loses  its chemical character;  the  zinc
enters into combination with  it.   The manifestations
of  force  produced  in the wire  are the  immediate
consequence of the  change in the properties of  the
acid and the metal.
   One particle of acid after  another loses its  pecu-
liar chemical character;  and  we  perceive that  in
the  same proportion the  wire acquires a  chemical,
mechanical,  galvanic, or  magnetic force,  whatever
name be  given to it.  According to  the  number of
acid particles  which in a given  time undergo this
change, that is, according to  the surface of the zinc,
the wire  receives a greater or less amount of these
forces.
   The  continuance of the current  of force depends
on the duration of the chemical action ; and the dura-
tion of  the  latter  is most  closely connected with  the
carrying  away, by conduction, of the force.
   If we  check  the propagation of the  current of
force, the  acid  retains its  chemical  character.  If
                        19 
218         THE PHENOMENA OF MOTION

we employ it to overcome chemical  or mechanical
resistance,  to decompose chemical  compounds, or
to produce motion, the  chemical  action  continues;
that  is  to  say,  one  particle  of acid after  another
changes its properties.
   In the preceding paragraphs  we have  considered
these remarkable  phenomena in  a  form  which  is
independent  of  the explanations of the schools.  Is
the force which circulates in the wire  the electrical
force ?  Is  it chemical  affinity ?  Is  it propagated
in the conductor  like a  fluid set in motion, or  in
the form  of a  series of momenta  of motion, like
light  and  sound, from one particle of the  conductor
to another?  All  this we know not, and  we  shall
never  know.  All  the  suppositions  which may be
employed  as  explanations of the phenomena  have
not the slightest influence  on  the  truth  of  these
phenomena;  for they refer  merely  to the  form in
which they are manifested.
   On some  points,  however,  there  is no  doubt;
namely, that  all  the effects which  may  be  produced
by the wire are  determined  by  the   change of pro-
perties in  the zinc  and  in the  acid;  for  the term
" chemical  action" signifies  neither  mure nor less
than the act  of change in them ;  thnt  these  effects
depend  on  the  presence  of  a conductor, of a  sub-
stance which propagates in  all  directions, where it
is not neutralized  by resistance,  the  force or mo-
mentum produced; that  this force becomes a  mo-
mentum of motion, by means of which we can  pro- 
            IN THE ANIMAL ORGANISM.        219

duce mechanical effects, and which, when transferred to
other bodies, communicates to them all those proper-
ties, the ultimate cause of which is the chemical force
itself;  for these  bodies acquire  the power of causing
decompositions and combinations, such  as, without a
supply of force through the conductor, they could not
effect.
  If we  employ these well-known facts  as means to
assist us in  investigating the ultimate cause of the me-
chanical  effects  in the  animal  organism, observation
teaches us, that the motion of  the blood  and of the
other animal  fluids  proceeds  from distinct organs,
which, as in the case of the heart and intestines, do not
generate the moving power in themselves, but receive
it from other quarters.
  We know with certainty that the nerves are  the
conductors  and  propagators of  mechanical effects ;
we know, that by means of them motion is propa-
gated in all directions.  For each motion we recog-
nize  a separate nerve, a  peculiar  conductor, with
the conducting power of which, or with  its  interrup-
tion, the propagation  of  motion is affected or  de-
stroyed.
  By  means  of the  nerves all  parts of the  body,
all the  limbs, receive  the  moving force which is in-
dispensable to their functions, to  change  of  place,
to the  production  of  mechanical  effects.   Where
nerves are  not  found, motion does not occur.  The
excess of force  generated in one place is conducted
to other parts by the nerves.   The force which one 
220        THE PHENOMENA OF MOTION
organ cannot produce in itself is conveyed to it from
other quarters ; and the vital force which is wanting
to it, in order to furnish resistance to  external  causes
of disturbance, it receives in the form of excess from
another organ, an excess which that organ cannot con-
sume in itself.
   We  observe  further, that the voluntary and  in-
voluntary motions, in other words, all  mechanical ef-
fects  in  the animal organism, are accompanied  by,
nay, are dependant on, a peculiar change of form and
structure in the substance of certain living parts, the
increase or diminution  of which  change stands  in
the very closest relation to the measure of motion, or
the amount of force consumed  in the  motions  per-
formed.
   As  an immediate effect of  the manifestation  of
mechanical  force, we  see, that  a part of the mus-
cular  substance  loses  its  vital  properties,  its cha-
racter  of life ; that this portion  separates from  the
living  part,  and  loses  its capacity of  growth and its
power of resistance.  We find  that  this change of
properties  is  accompanied  by  the   entrance of a
foreign body  (oxygen) into  the  composition of  the
muscular fibre  (just as the acid lost  its chemical
character by  combining with zinc ;)  and  all experi-
ence proves, that this conversion  of living muscular
fibre into compounds  destitute  of vitality is accele-
rated  or retarded according to the amount  of force
employed to produce  motion.   Nay,  it may  safely
be  affirmed,  that they  are  mutually  proportional ; 
           IN  THE ANIMAL ORGANISM.        221

that  a rapid  transformation of muscular fibre, or,  as
it  may  be called, a rapid  change of matter, deter-
mines a  greater amount of mechanical force;  and
conversely,  that  a greater amount of mechanical
motion  (of  mechanical force expended in  motion)
determines a more rapid change of matter.
   From  this decided  relation  between the  change
of matter  in the  animal  body and the force  con-
sumed in mechanical  motion, no  other  conclusion
can  be  drawn  but this, that the active or available
vital  force in certain living parts is the cause of the
mechanical phenomena in the animal organism.
   The moving force certainly proceeds from living
parts; these  parts  possessed  a  momentum of force
or of motion, which they lost  in  proportion as other
parts acquired  a momentum of force  or of  motion;
they  lose their capacity of growth, and their power
to resist external  causes  of change.  It  is  obvious
that the  ultimate cause, the vital force, from which
they  acquired  these properties,  has served  for the
production of  mechanical force, that  is,  has   been
expended in the shape of motion.
   How, indeed, could  we conceive that a living part
should  lose the condition  of life, should become  in-
capable  of  resisting the action of  the oxygen  con-
veyed to it  by  the arterial  blood, and  should  be
deprived of  the power to overcome chemical  re-
sistance,  unless the  momentum of the vital  force,
which had given to it all  these properties, had  been
expended for other purposes?
              19* 
222       THE PHENOMENA OF MOTION

  By the power of the  conductors, the nerves, to
propagate the momentum of force in  a living part,
or the  effect which the active  vital force inherent in
the part produces  on  all the  surrounding parts, in
all  directions where  the force,  or rather its  mo-
mentum  of  motion, is  consumed  without  resistance
(for  without motion  no  change  of matter occurs,
and  when motion has begun, there is no longer re-
sistance), an equilibrium  is obviously established in
the  living  part,  between  the  chemical forces  and
the remaining vital force; which  equilibrium would
not have occurred had not vital force been expended
in producing mechanical motion.
  In this state,  any external cause capable of ex-
erting  an influence on the form, structure, and  com-
position  of   the  organ meets  with  no further  re-
sistance.  If oxygen were not conveyed to it, the
organ  would maintain its  condition, but without any
manifestation of  vitality.   It is only with the  com-
mencement  of chemical action that the change of
matter, that  is, the separation of a part of the organ
in the form of lifeless compounds, begins.
  The change  of matter, the  manifestation of  me-
chanical force, and  the absorption of oxygen, are, in
the  animal  body, so  closely connected  with  each
other, that we may consider the amount of motion,
and  the  quantity of  living  tissue  transformed, as
proportional  to the quantity of oxygen inspired  and
consumed in a  given  time  by the  animal.  For a
certain amount of  motion, for a  certain proportion 
IN THE ANIMAL ORGANISM.         223
of vital  force consumed  as  mechanical force,  an
equivalent  of chemical force is manifested ;  that is,
an equivalent  of oxygen  enters  into  combination
with the substance of the organ which has lost the
vital force ;  and a corresponding  proportion  of the
substance of the  organ is separated from the living
tissue in the shape of  an oxidised compound.
  All  those  parts  of  the  body which  nature  has
destined  to effect the  change of matter, that is, to
the production of mechanical  force, are  penetrated
in all  directions  by a multitude of  the  most minute
tubes or vessels, in which a current of oxygen con-
tinually circulates,  in  the  form  of arterial  blood.
To the above-mentioned  separation  of  part  of the
elements of these parts, in other  words,  to the dis-
turbance  of their equilibrium, this  oxygen is abso-
lutely essential.
  As long as the vital force of these  parts  is not
conducted away and applied to other  purposes, the
oxygen of  the  arterial blood  has  not  the  slightest
effect on the  substance of the organized  parts; and
in all  cases, only so much  oxygen is  taken up as
corresponds  to  the   conducting  power, and, con-
sequently, to the mechanical effects  produced.
  The oxygen  of the  atmosphere  is the proper, ac-
tive, external cause of the  waste  of matter  in the
animal  body; it acts  like  a  force which disturbs
and  tends  to destroy the manifestation  of the vital
force  at  every  moment.   But its  effect  as  a che^
mical  agent,  the disturbance proceeding  from it,  is 
 224       THE PHENOMENA OF MOTION

 held  in  equilibrium by the vital force, which is free
 and available in the living tissue,  or  is  annihilated
 by a chemical  agency opposed to that  of  oxygen,
 the manifestation  of which must  be  considered  as
 dependant on the vital force.
   In  chemical  language,  to annihilate  the  chemical
 action of oxygen, means, to present to it substances,
 or parts of organs, which are capable  of combining
 with it.
   The  action of oxygen (affinity)  is  either neutra-
 lized  by means of the elements  of organized  parts,
 which combine with  it (after the free vital force has
 been conducted away), or else  the  organ  presents to
 it the products of other organs, or certain  matters
 formed from the  elements of the food, by  the vital
 activity of certain systems of apparatus.
   It  is  only the  muscular system which,  in this
 sense,  produces in itself  a resistance  to the  che-
 mical  action of oxygen, and  neutralizes  it  com-
 pletely.
   The substance of  cellular tissue, of membranes,
 and of the skin, the minutest particles  of which are
 not in immediate  contact with arterial blood  (with
 oxygen), are not destined to undergo this  change  of
matter.   Whatever changes they may undergo  in
the vital  process,  affect,  in  all  cases,  only their
surface.
   The gelatinous  tissues,  mucous membranes,  ten-
dons,  &c,  are not  designed to produce mechanical
force;  they  contain   in  their  substance  no  con- 
            IN THE ANIMAL  ORGANISM.        225

ductors of  mechanical effects.   But the muscular
system is interwoven with innumerable nerves.   The
substance  of  the  uterus  is in  no  respect different
in chemical  composition  from  the  other muscles ;
but it  is not  adapted  to the change of matter,  to
the production of force, and  contains no organs for
conducting away  the  moving power.  Cellular tis-
sue, gelatinous membranes, and  mucous  membranes,
are far from being  destitute of the power of com-
bining with oxygen, when moisture is present;  we
know that, when  moist, they cannot  be  brought in
contact with oxygen without  undergoing  a progres-
sive  alteration.   But  one  surface  of the intestines
and the cells of the  lungs are constantly in contact
with oxygen ;  and  it  is obvious that they must  be
as rapidly altered  by the  chemical  action of  the
oxygen in  the body as out  of  it,  were  it not that
there  exists in the organism  itself a source of resist-
ance,  which completely neutralizes  the action of the
oxygen.  Among  the means  by which this resistance
is furnished  we  may  include all substances which
are capable  of combining with oxygen, or acquire
that   property under   the  influence of  the  vital
force,  and  which  surpass  the  tissues  above  men-
tioned in their power of neutralizing  its chemical ac-
tion.
   All those constituents of the body  which, in them-
selves, do not possess,  in the form of vital force, the
power of resisting the  action of oxygen, must be far
better adapted for the  purpose of combining with, and 
226        THE PHENOMENA OF MOTION

neutralizing it, than those tissues which are under the
influence of the vital force, although only through the
nerves.   In this point of view, we cannot fail to per-
ceive the importance of the bile  in regard to the sub-
stance of the intestines, and that of the pulmonary cells,
as well as that of  fat, of mucus, and of the secretions
generally.
   When the membranes are compelled from their own
substance to furnish  resistance  to the action  of the
oxygen, that is, when there is a  deficiency of the sub-
stances  destined by nature for  their protection, they
must, since  their renewal  is  confined within  narrow
limits, yield to  the chemical action.  The lungs and
intestines will  always simultaneously suffer abnormal
changes.
   From  the change of matter itself, from the meta-
morphosis of the living  muscular tissue, these organs
receive  the means of resistance to the action of  oxy-
gen  which  are indispensable to  their preservation.
According to the rapidity of this process, the quanti-
ty of bile secreted increases ;  while  that of the fat
present in the  body diminishes in the same propor-
tion.
   For carrying on  the involuntary motions  in the
animal body,  a certain  amount of vital force is ex-
pended  at every moment  of its existence; and, con-
sequently,  an  incessant  change of matter  goes on ;
but  the  amount of living tissue, which,  in  conse-
quence  of this  form of consumption of vital  force,
loses its condition of life and its capacity of growth, 
            IN THE ANIMAL  ORGANISM.        227

is confined within narrow limits.  It is directly  pro-
portional to the force required for these involuntary
motions.
  Now, although we may suppose that the living mus-
cular tissue,  with a sufficient supply of food, never
loses its capacity of growth; that this  form of  vital
manifestation  is continually effective ; this cannot ap-
ply  to  those  parts of the body whose available  vital
force has been expended in producing mechanical ef-
fects.   For  the  waste of matter, in consequence of
motion  and laborious exertion, is  extremely various in
different individuals.
   If we reflect, that the  slightest motion  of a finger
consumes  force ; that in consequence  of the  force
expended, a  corresponding  portion  of muscle  dimi-
nishes in volume; it is obvious,   that an  equilibrium
between supply and waste of matter (in living tissues)
can only occur  when the portion separated or  ex-
pelled  in  a  lifeless  form  is, at the  same  instant in
which  it loses its vital condition,  restored in another
 part.
   The capacity of growth  or increase  in  mass de-
 pends  on the momentum  of force belonging to  each
 part;  and must be capable of continued manifesta-
 tion (if there be a sufficient  supply  of  nourishment),
 as long as it does not lose this momentum, by expend-
 ing it,  for example, in  producing  motion.
   In all circumstances, the growth itself is  restricted
 to the  time :  that is to say, it cannot be unlimited in a
 limited time. 
228        THE  PHENOMENA OF  MOTION

  A living part cannot  increase in volume at the
same moment  in  which  a portion of  it loses the
vital condition,  and  is  expelled  from  the  organ in
the form  of  a  lifeless compound;  on the  contrary,
its volume must diminish.
  The  continued  application  of  the  momentum of
force in living  tissues  to mechanical effects  deter-
mines, therefore, a  continued  separation of matter;
and  only  from  the  period at which the  cause of
waste  ceases to operate,  can  the capacity of growth
be manifested.
  Now, since,  in  different individuals, according to
the  amount  of force consumed in producing  volun-
tary mechanical effects,  unequal  quantities  of  living
tissue  are wasted, there  must occur, in every indi-
vidual, unless the  phenomena of motion are to cease
entirely,  a condition  in  which  all  voluntary mo-
tions are  completely  checked, in which,  therefore,
these  occasion  no waste.  This  condition is  called
sleep.
   The growth of  one part, which is  not deprived  of
its  vital  force,  cannot be in the  slightest degree
affected by  the consumption of the vital  force  of
another  part in producing  motion.   The one may
increase in volume, while the other  diminishes; and
the waste  in one  can  neither increase  nor diminish
the supply in the other.
   Now, since  the consumption  of force for the in-
voluntary  motions continues in sleep, it is  plain that
a waste of matter also continues in  that state; and 
IN THE ANIMAL ORGANISM.         229
if the original equilibrium  is to be restored, we must
suppose  that, during sleep,  an amount of  force is
accumulated in  the form  of  living  tissue,  exactly
equal to that which was consumed in voluntary and
involuntary  motion during the  preceding  waking
period.
  If the equilibrium between  waste  and  supply  of
matter  be  in the  least degree disturbed,  this is in-
stantly seen in the  different amount of force available
for  mechanical purposes.
  It is further obvious, that if there  should  occur  a
disproportion between the conducting power  of the
nerves  of  voluntary and  involuntary motion,  a  dif-
ference  in  the  phenomena  of  motion  themselves
will be  perceptible, in the same proportion as  the
one or  the other  is  capable of propagating  the
momentum of force,  generated  by  the  change of
matter.  As the  motions of  the circulating  system
and of  the intestines  increase,  the  power  of pro-
ducing mechanical effects in the  limbs must dimi-
nish in the  same   proportion  (as in wasting fevers) ;
and if, in a given time, more vital  force has been
consumed  for mechanical purposes (labour, running,
dancing, &c.) than is  properly available for  the vo-
luntary and involuntary  motions;   if  force be ex-
pended more rapidly than  the change of matter can
be  effected  in the same time; then  a  part of that
force  which is necessary  for the involuntary  mo-
tions must be expended  in restoring the excess  of
 force  consumed in voluntary  motion.   The  motions
                20 
230         THE PHENOMENA OF MOTION
of the heart and of the intestines, in this case, will  be
retarded, or will entirely cease.
  From  the unequal degree  of conducting power in
the nerves, we must deduce those conditions which
are termed  paralysis,  syncope, and  spasm.   Para-
lysis  of  the  nerves  of voluntary  motion may exist
without  emaciation ;  but frequently  recurring  at-
tacks  of epilepsy (in  which  vital force is  rapidly
wasted in producing  mechanical effects) are  always
accompanied by remarkably rapid emaciation.
  It  ought  to  excite the highest admiration  when
we consider with  what infinite wisdom the  Creator
has divided the means by  which animals and plants
are qualified for their functions, for  their peculiar vital
manifestations.
   The living part of a plant acquires the whole force
and direction of its vital energy from the absence  of
all  conductors of  force.   By  this  means the leaf is
enabled to  overcome  the  strongest  chemical  attrac-
tions,  to decompose  carbonic acid,  and to assimilate
the elements of its nourishment.
  In  the flower alone does a process  similar to the
change  of  matter in the  animal body occur.   There,
phenomena of motion  appear ;  but the  mechanical
effects are not propagated  to a distance, owing to the
absence of conductors of force.
   The same  vital force which  we recognize in  the
plant  as an  almost  unlimited capacity of  growth,
is  converted  in  the  animal  body  into  moving
power (into  a  current of vital force); and a most 
            IN THE ANIMAL  ORGANISM.        231

wonderful  and wise economy has destined for  the
nourishment of the animal only such compounds as
have a composition identical with that of  the organs
which  generate force,  that is, with the  muscular tis-
sue.   The expenditure  of force which the living parts
of animals require, in order to reproduce  themselves
from the blood ; the resistance of the chemical force
which has to be overcome in the azotised constituents
of food  by the vital agency of the organs destined to
convert them into blood ; these are as nothing com-
pared to the  force with which the elements of car-
bonic acid  are  held  together.   A certain amount
of force would  necessarily be prevented  from as-
suming the form of moving power, if it were to be
expended in  overcoming  chemical resistance ;  for
the momentum of motion of the vital force  is diminish-
ed by all obstacles.  But the  conversion  of the con-
stituents of blood into muscular fibre (into an organ
which generates  force)  is  only  a change of form.
Both have the  same composition ;  blood is fluid, mus-
cular fibre is solid blood.   We may even suppose that
this  change  takes place  without  any expenditure of
vital force ; for the mere passage of a fluid  body into
the solid state requires no manifestation of force, but
only the removal of obstacles, which oppose that force
(cohesion.) which determines the form of matter, in its
manifestations.
   In what form or in what  manner the  vital force
produces mechanical  effects  in the  animal body is
altogether  unknown,  and is  as  little  to  be  ascer- 
232         THE PHENOMENA  OF MOTION

tained by experiment as the connection  of  chemical
action with the phenomena  of motion which we can
produce with the galvanic battery.   All  the explana-
tions which  have been  attempted are only represen-
tations of the phenomenon ; they are, more  or  less,
exact  descriptions and  comparisons of  known  phe-
nomena with  these,  whose  cause  is unknown.    In
this respect we  are  like an ignorant man,  to whom
the rise and fall of an iron rod in a cylinder,  in which
the eye can perceive nothing, and its connection with
the turning and motion  of  a thousand  wheels at a
distance  from the piston-rod, appear  incomprehensi-
ble.
  We know not how a certain  something, invisible
and imponderable in itself  (heat),  gives to certain
bodies the power of exerting an enormous pressure
on  surrounding objects;  we know not even  how this
something itself is produced when we  burn wood  or
coals.
  So  is it with the  vital force, and with the pheno-
mena exhibited by living bodies.   The cause of these
phenomena  is not chemical force; it is not electri-
city, nor magnetism ; it is a  force which  has certain
properties  in  common  with all  causes  of motion
and of change in form and  structure in material  sub-
stances.  It is a  peculiar force,  because it  exhibits
manifestations which  are found  in  no other known
force. 
           IN THE  ANIMAL  ORGANISM.        233


                        II.
  In the living  plant, the intensity of the  vital  force
far exceeds that of the chemical action of oxygen.
  We  know, with  the  utmost  certainty, that,  by
the influence of the  vital force, oxygen is separated
from elements to which  it  has the  strongest affinity ;
that  it is given  out in  the  gaseous form,  without
exerting  the slightest action  on  the juices  of the
plant.
  How  powerful, indeed,  must  the resistance ap-
pear which the vital  force  supplies to leaves charged
with oil of turpentine  or tannic acid, when we con-
sider the affinity of oxygen for these compounds !
  This intensity of action or  of  resistance the  plant
obtains by means of the  sun's light;  the effect  of
which  in chemical  actions  may  be,  and is,  com-
pared to that of  a  very high temperature (a mode-
rate red  heat.)
  During the night  an opposite  process goes on  in
the plant;  we  see then that the constituents of the
leaves and  green parts  combine with  the oxygen of
the air,  a  property  which in  daylight  they  did not
possess.
  From  these  facts we  can  draw  no  other  conclu-
sion but this:  that  the intensity  of the  vital  force
diminishes  with  the  abstraction  of light; that with
the approach of night a state of equilibrium  is esta-
blished,  and that in  complete darkness  all those con-
              20* 
234        THE PHENOMENA OF MOTION

stituents of plants  which, during the day,  possessed
the power of separating oxygen from chemical com-
binations, and  of resisting its action,  lose this  power
completely.
   A  precisely similar  phenomenon  is  observed  in
animals.
   The living  animal  body exhibits its peculiar mani-
festations of vitality only  at  certain  temperatures.
When exposed  to  a certain  degree of cold, these
vital phenomena entirely cease.
   The abstraction of heat must, therefore, be viewed
as quite equivalent  to  a  diminution  of  the vital
energy ; the  resistance opposed by the  vital force to
external causes of  disturbance   must  diminish,  in
certain temperatures, in the same* ratio  in which the
tendency of  the elements of the body  to  combine
with the oxygen of the air increases.
   By the  combination of oxygen  with  the  consti-
tuents of the metamorphosed  tissues, the  tempera-
ture  necessary  to  the  manifestations of  vitality  is
produced in the  carnivora.  In the herbivora,  again,
a certain amount of heat is developed by  means  of
those elements  of  their non-azotised  food  which
have the property of combining with oxygen.
   It  is  obvious  that  the  temperature of an animal
body cannot change, if the  amount of inspired oxy-
gen increases in the same ratio as the  loss of heat
by external coolings
  Two  individuals, carnivora, of  equal  weight, ex-
posed to unequal  degrees of cold, lose, in a  given 
            IN THE ANIMAL ORGANISM.         235

time,  by  external  cooling,  unequal  quantities  of
heat.   Experience teaches, that if their peculiar tem-
perature and their original weight are to remain unal-
tered, they require unequal quantities of food; more in
the lower temperature than in the higher.
  The circumstance that the original weight remains
the same, with  unequal  quantities of  food, obviously
presupposes, that in the  same  time  a  quantity  of
oxygen proportioned to the temperature  has  been
absorbed;  more  in the  lower  than in  the  higher
temperature.
  We find that  the  weight of  both individuals, at
the end of 24  hours, is equal to  the  original weight.
But we have  assumed  that their food is converted
into  blood ; that the blood has  served for nutrition;
and  it is plain,  that when the  original  weight has
been  restored,  a quantity of the constituents  of the
body,  equal in weight to those of the food,  has lost
its condition of life, and has been expelled in combi-
nation with oxygen.
   The one individual, which, being  exposed  to the
lower temperature, consumed more food, has also ab-
sorbed more oxygen ;  a greater quantity of the con-
stituents of its  body has been  separated  in combina-
tion with  oxygen ; and, in  consequence  of this com-
bination with oxygen, a greater amount of heat has
been  liberated, by which means the heat abstracted
has been restored,  and  the  proper temperature of the
body kept up.
   Consequently, by the abstraction of heat, provided 
 236        THE  PHENOMENA OF MOTION

 there  be a  full  supply  of food  and  free  access  of
 oxygen, the change  of matter must  be accelerated;
 and,  along  with  the  augmented  transformation, in a
 given time, of  living  tissues, a  greater  amount  of
 vital  force  must be  rendered available  for  mecha-
 nical purposes.
   With  the external  cooling,  the respiratory mo-
 tions become stronger;  in  a lower temperature more
 oxygen  is  conveyed  to the blood ; the waste of mat-
 ter increases, and if  the supply be not kept in equili-
 brium with  this waste, by means of food, the tempera-
 ture of the body gradually  sinks.
   But, in  a  given  time,   an unlimited  supply of
 oxygen cannot be introduced  into the  body; only a
 certain amount of living tissue can lose the state of
 life, and only a limited amount of vital force can be
 manifested  in mechanical   phenomena.   It is  only,
 therefore, when the cooling, the generation of force,
 and the absorption of oxygen are in equilibrium toge-
 ther,  that the  temperature of the  body can remain
 unchanged.   If the loss of heat by cooling go beyond
 a  certain point, the vital phenomena diminish in the
 same ratio;  for the temperature falls, and the tempe-
 rature must  be considered  as  a uniform condition of
 their manifestation.
   Now experience teaches, that  when the  tempera-
 ture of the  body sinks, the power of  the  limbs to
produce mechanical effects (or the  force  necessary
to  the voluntary  motions)  is  also diminished.  The
condition of sleep ensues, and at last  even  the invo- 
            IN THE ANIMAL ORGANISM.         237

Iuntary motions (those of the  heart and intestines,
for  example) cease, and apparent death  or  syncope
supervenes.
  It is obvious  that the cause of the generation of
force, namely the change of matter, is diminished, be-
cause, with  the abstraction of heat, as in the plant by
abstraction of light, the intensity of the vital  force di-
minishes.  It is  also obvious that the momentum of
force  in a living part  depends on its proper tempera-
ture ;  exactly as the effect of a  falling body stands in
a fixed relation to certain other conditions ; for exam-
ple, to the velocity attained in falling.
  When the  temperature sinks,  the vital  energy
diminishes;  when it  again  rises,  the momentum of
force  in the  living parts appears once more  in all its
original intensity.
  The production  of  force for  mechanical  purposes,
and the temperature of the body, must, consequently,
bear a fixed  relation to the amount of oxygen which
can be absorbed in a given time by the animal body.
  The quantities of oxygen which a whale and a car-
rier's  horse  can inspire in a given time  are  very un-
equal.  The temperature, as well as the quantity of
oxygen, is much greater in the horse.
  The force exerted  by a whale, when  struck with
the harpoon, his body being supported  by  the  sur-
rounding  medium, and the  force  exerted by a  car-
rier's horse, which carries its  own weight and a
heavy burden for eight or ten  hours, must both  bear
the  same ratio to the oxygen consumed.   If  we 
238        THE  PHENOMENA OF  MOTION

take into  consideration the time  during  which  the
force  is manifested, it is obvious that the amount of
force developed  by the horse  is  far greater than in
the case of the whale.
  In  climbing  high   mountains,  where,  in  conse-
quence  of the respiration of a highly rarefied  atmo-
sphere, much  less oxygen is conveyed to the  blood,
in equal times, than in valleys or at the level  of the
sea,  the change of matter diminishes in the same
ratio, and with  it the amount  of force available for
mechanical  purposes.  For the most part, drowsiness
and  want  of  force  for  mechanical  exertions  come
on;  after twenty or  thirty steps, fatigue  compels us
to a  fresh  accumulation  of  force by means of rest
(absorption of  oxygen  without waste  of  force in
voluntary motions).
   By the  absorption of oxygen into  the substance
of living tissues, these lose  their  condition of  life,
and  are  separated  as   lifeless,  unorganised  com-
pounds ;  but the whole of the  inspired oxygen is not
applied  to  these transformations:  the greater part
serves to convert into gas and  vapour  all matters
which no longer belong  to the  organism ;  and, as
formerly  mentioned,  the   combination of  the  ele-
ments of such compounds with the oxygen  produces
the temperature  proper to the animal organism.
  The production of heat and  the change of malter
are closely related to each other : but although heat
can be produced in the body without  any change of
matter in living tissues,  yet  the change of  matter 
IN THE ANIMAL  ORGANISM.        239
cannot be supposed to take place without the co-opera-
tion of oxygen.
  According to all the observations  hitherto made,
neither the  expired  air, nor  the  perspiration, nor  the
urine, contains  any  trace of alcohol, after  indulgence
in spirituous liquors ;  and there  can be no doubt that
the elements of alcohol combine with  oxygen in the
body; that its carbon  and hydrogen are given off as
carbonic acid and water.
  The oxygen  which  has accomplished this change
must have been taken from the arterial blood; for we
know of no channel, save the circulation of the blood,
by which oxygen can penetrate into the interior of the
body.
  Owing to its volatility, and  the  ease with which
its vapour  permeates animal membranes  and tissues,
alcohol  can spread  throughout the  body in all direc-
tions.
   If the power of  the elements of alcohol  to com-
bine with oxygen were not greater than that of the
compounds  formed by the change  of  matter, or that
of the substance of living tissues, they (the elements
of  alcohol) could  not combine with  oxygen in the
body.
   It is, consequently, obvious,  that  by  the use of
alcohol a limit must  rapidly be put  to  the change
of malter in certain parts of  the  body. The oxygen
of the  arterial blood, which, in the absence of alco-
 hol, would  have combined  with the matter of the
tissues, or with that  formed by the  metamorphosis 
240        THE PHENOMENA OF  MOTION
of these  tissues, now combines with the elements of
alcohol.  The arterial blood becomes venous, without
the substance of the muscles having taken any share
in the transformation.
  Now we observe, that the developement of heat in
the body, after the use  of wine, increases rather than
diminishes, without the manifestation of a correspond-
ing amount of mechanical force.
  A moderate quantity  of wine, in women and chil-
dren unaccustomed to its use,  produces,  on the con-
trary, a diminution of the  force  necessary for volun-
tary motions.  Weariness,  feebleness in the  limbs,
and drowsiness, plainly  shew that the force  available
for mechanical purposes, in other words, the change
of matter, has been diminished.
  A diminution  of the  conducting power of  the
nerves of  voluntary motion may   doubtless take  a
certain share in producing these symptoms; but this
must be  altogether without  influence  on  the sum of
available force.
  What the  conductors of  voluntary  motion cannot
carry away for effects of force, must be taken up by
the nerves  of involuntary motion,  and conveyed to
the heart,  lungs,  and  intestines.   In  this  case, the
circulation  will appear accelerated  at the expense of
the force available for voluntary  motion;  but,  as
was before remarked, without  the production   of  a
greater amount  of mechanical force by  the process
of oxidation of the alcohol.
  Finally, we observe,  in  hybernating  animals,  that, 
IN THE ANIMAL ORGANISM.
241
during their winter sleep, the  capacity of increase in
mass  (one of the  chief manifestations of  the  vital
force), owing to the absence of food, is entirely sup-
pressed.   In  several, apparent death occurs in con-
sequence  of the low temperature and of the diminu-
tion  of vital  energy thus  produced ;  in  others, the
involuntary  motions continue, and  the  animal pre-
serves a temperature  independent  of the surround-
ing temperature.  The respirations go on;  oxygen,
the condition which determines the  production  of
heat  and  force, is  absorbed now as well as in the
former state of the animal;  and  previous  to the
winter sleep, we find  all those parts of their body,
which in  themselves are unable to furnish resistance
to the  action  of the  oxygen, and which, like the
intestines  and  membranes, are  not destined for the
change of matter,  covered with  fat; that is,  sur-
rounded by a substance which  supplies the want of
resistance.
   If  we  now  suppose,  that  the  oxygen absorbed
during the winter  sleep combines, not with the ele-
ments of living tissues,  but  with  those  of the fat,
then  the  living part,  although  a certain  momentum
of motion be  expended in keeping up  the circula-
tion,  will  not  be  separated  and  expelled from the
 body.                                          .
   With the return of  the higher  temperature,  the
 capacity  of growth increases in the same ratio and
 the motion  of  the blood  increases with the absorp-
 tion  of  oxygen.  Many  of  these  animals become
              21 
242         THE PHENOMENA OF MOTION
emaciated during  the  winter sleep,  others  not till
after awaking from it.
  In  hybernating  animals the active force of the
living parts is exclusively devoted, during  hyberna-
tion, to  the support of the involuntary motions.   The
expenditure  of force in voluntary motion is entirely
suppressed.
  In  contradistinction  to  these  phenomena,  we
know that,  in  the  case  of  excess of  motion  and
exertion, the  active force in living  parts  may be
exclusively  and  entirely  consumed  in  producing
voluntary mechanical effects; in suchwise  that  no
force shall remain  available  for  the involuntary mo-
tions.  A stag may be  hunted  to  death;  but  this
cannot occur  without  the metamorphosis  of all the
living parts  of its muscular system, and  its flesh be-
comes uneatable.  The condition of  metamorphosis
into which  it has  been  brought by an  enormous
consumption  both of force and of oxygen  continues
when all phenomena of motion have ceased.  In the
living tissues, all the resistance  offered  by the vital
force to external agencies of change is entirely de-
stroyed.
  But however closely the conditions of the produc-
tion of heat and of force  may seem to be  connected
together, with  reference  to  mechanical  effects, yet
the disengagement  of heat can' in no way be  consi-
dered as in itself the only  cause of these  effects.
  All experience proves, that there is, in the organ-
ism, only one source of mechanical power;  and this 
IN THE  ANIMAL ORGANISM.        243
source is the conversion of living parts  into lifeless,
amorphous compounds.
  Proceeding from  this truth, which is  independent
of all  theory, animal  life  may be viewed as deter-
mined by  the  mutual  action of opposed forces ;  of
which one  class must  be considered as causes of in-
crease (of supply of matter), and the other as causes
of diminution (of waste of matter).
  The increase of mass is  effected in living parts by
the vital force ;  the manifestation of  this power is
dependant  on heat;  that  is, on a  certain tempera-
ture peculiar to each specific organism.
  The  cause of  waste  of  matter  is  the chemi-
cal action  of oxygen;  and its  manifestation is  de-
pendent  on  the  abstraction  of  heat as well as  on
the expenditure  of the  vital force for mechanical
purposes.
   The act of waste of  matter is  called the change of
matter; it  occurs  in consequence of the absorption of
oxygen into the  substance of living parts.  This ab-
sorption of oxygen occurs only when the  resistance
which the vital force of living parts opposes  to  the
chemical action of the  oxygen is weaker than that che-
mical action; and this weaker resistance is determined
by  the abstraction of heat, or by the expenditure in
mechanical motions of the  available force of  living
parts.
   By the  combination of  the oxygen introduced in
the arterial blood with such constituents of the body
as offer  no resistance  to its  action, the temperature 
 244       THE PHENOMENA OF MOTION

 necessary for the  manifestation of vital  activity is
 produced.
   From the  relations  between  the  consumption  of
 oxygen on the one hand, and the change of matter
 and developement of heat on the other, the follow-
 ing general rules may be deduced.
   For  every  proportion of oxygen which  enters into
 combination  in  the  body, a corresponding proportion
 of heat must be generated.
   The  sum  of force  available for  mechanical pur-
 poses must be equal to the sum of the vital forces
 of all tissues adapted to the change of matter.
   If,  in equal times,  unequal  quantities  of  oxygen
 are consumed,  the  result is obvious,  in an unequal
 amount of heat  liberated,  and of mechanical force.
   When unequal  amounts of mechanical  force are
 expended, this  determines the  absorption of corre-
 sponding and  unequal quantities of oxygen.
   For  the conversion of  living  tissues into  lifeless
 compounds, and for the combination of oxygen with
 such constituents of the body as have  an affinity for
 it, time is required.
   In a  given time, only  a limited amount  of me-
 chanical force can  be  manifested, and  only a  limited
 amount  of heat can be liberated.
   That  which is expended, in  mechanical  effects, in
the shape of velocity, is lost in time;  that is to  say,
the more rapid  the motions are, the sooner  or the
more quickly is the force exhausted.
   The  sum of the  mechanical foree  produced  in a 
            IN THE ANIMAL  ORGANISM.         245

given  time  is equal to the sum of force necessary,
during the same  time, to produce the  voluntary  and
involuntary  motions;  that is, all the  force which the
heart, intestines, &c, require  for  their  motions is lost
to the voluntary motions.
  The amount of azotised food  necessary to  restore
the equilibrium between waste and supply is  directly
proportional  to  the  amount  of tissues  metamor-
phosed.
  The amount  of living matter, which in  the body
loses the condition of life, is, in equal temperatures,
directly proportional  to the  mechanical effects  pro-
duced in a given time.
  The amount of tissue metamorphosed in  a given
time may be measured by the quantity  of nitrogen in
the urine.
  The sum of the mechanical  effects produced  in
two individuals,  in  the same  temperature, is  propor-
tional to the amount  of  nitrogen  in  their   urine;
whether the mechanical force  has been employed in
voluntary or involuntary motions, whether it has been
consumed  by the  limbs or by the  heart  and other
viscera.
  That condition of the body which is called health
includes the conception of an equilibrium among all
the causes of waste and of supply;  and thus animal
life is  recognized  as the mutual action of both;  and
appears as an alternating destruction and  restoration
of the state of equilibrium.
  In regard to  its absolute  amount,  the waste  and
           21* 
 246        THE  PHENOMENA OF  MOTION

 supply  of matter is, in  the  different  periods of life,
 unequal;  but,  in the state  of health, the available
 vital force must always be considered  as a constant
 quantity,  corresponding  to the sum  of  living  par-
 ticles.
   Growth, or  the increase of mass, stands, at every
 age, in a  fixed relation to the amount of vital  force
 consumed as moving power.
   The vital force, which is expended for mechanical
 purposes,  is subtracted  from the  sum of the force
 available  for the purpose of increase of mass.
   The active force, which is consumed  in the  body
 in overcoming resistance (in  causing  increase  of
 mass), cannot,  at the same time, be employed to  pro-
 duce mechanical  effects.
   Hence  it  follows  necessarily,  that  when,  as  in
 childhood, the supply exceeds  the waste of matter, the
 mechanical effects produced  must be less in the same
 proportion.
   With the increase of mechanical effects produced,
 the capacity of increase of mass or of the  supply  of
 waste  in   living  tissues  must diminish in the same
 proportion.
   A perfect balance  between  the  consumption  of
 vital force  for supply  of matter and that for  me-
 chanical effects occurs, therefore,  only in the adult
 state.    It is  at  once  recognized  in   the  complete
 supply of the  matter consumed.  In  old  age more
is  wasted; in   childhood  more  is  supplied  than.
 wasted. 
            IN THE ANIMAL ORGANISM.         247

   The force available for mechanical purposes in an
 adult  man  is reckoned, in mechanics, equal to ith of
 his own weight, which he can move during eight hours,
 with a velocity of five feet in two seconds.
   If the weight  of a  man be  150 lbs.,  his  force is
 equal  to a  weight of  30 lbs.  carried by him  to  a
 distance   of 72,000  feet.  For  every  second  his
 momentum  of force is = 30x2'5 = 75 lbs.;  and for
 the whole  day's  work,  his  momentum  of motion is
 = 30X72,000 =216,000.
   By  the  restoration  of  the original weight of his
 body, the man  collects  again a sum of force which
 allows him, next day, to  produce, without exhaustion,
 the same amount, of mechanical effects.
   This supply of force is furnished in  a seven hours'
 sleep.
   In  manufactories of  rolled iron it frequently  hap-
 pens, that the pressure of the engine, going at its ordi-
 nary rate, is  not sufficient  to force a rod of iron  of a
 certain thickness to pass below the  cylinders.   The
 workman, in this  case,  allows the whole force of the
 steam  to  act on the revolving wheel, and not  until
 this has acquired a great velocity does he  bring  the
 rod  under the rollers; when  it is instantly flattened
 with great ease  into a  plate, while the wheel  gra-
 dually loses the velocity  it had acquired.  What the
 wheel  gained in velocity, the roller gained in force ;
 by this process force was obviously collected, accu-
mulated in the velocity; but in this  sense  force  does
not accumulate in the living organism. 
248       THE PHENOMENA OF MOTION

   The restoration of force is  effected, in the animal
body, by the transformation of the separated parts,
destined  for the production  of  force,  and  by the  ex-
penditure of the active vital force in causing formation
of new parts ; and, with the restoration of the  sepa-
rated or  effete  parts, the organism recovers a  force
equal to  that which has been expended.
   It is plain, that  the  vital force  manifested, during
sleep, in the formation  of new parts, must  be equal
to the whole sum  of the moving power expended in
the walking state in all  mechanical effects whatever,
plus a certain amount of force, which is required  for
carrying on those involuntary motions which continue
during sleep.
   From  day to day, the labouring man,  with  suffi-
cient food, recovers, in seven hours' sleep, the whole
sum of force; and without reckoning  the force neces-
sary for  the involuntary motions which  may be consi-
dered equal in all men, we may assume, that the me-
chanical  force available  for work is directly propor-
tional to the number of hours of sleep.
   The adult man sleeps 7 hours, and wakes 17 hours ;
consequently, if the equilibrium be restored in 24 hours,
the mechanical effects produced in  17 hours must be
equal to  the effects produced during  7 hours in  the
shape of  formation of new parts.
  An old man sleeps only  3^ hours;  and  if every
thing else  be supposed  the  same as in the case  of
the adult, he  will be  able, at all events,  to  produce
half of the mechanical  effects  produced by an adult 
IN THE ANIMAL ORGANISM.        249
of equal weight;  that is, he will be able to carry only
15 lbs. instead  of 30 to the same distance.
  The  infant at the breast sleeps 20 hours and wakes
only four;  the  active force consumed in formation of
new parts is, in this case, to that consumed in mechan-
ical effects (in  motion  of the  limbs), as 20 to 4 ;  but
his limbs possess no momentum of force, for he cannot
yet support  his own  body.   If we assume, that the
aged  man  and  infant consume in mechanical effects a
quantity of force corresponding to the proportion avail-
able in the  adult, then the mechanical effects  are pro-
portional to the number of waking hours, the forma-
tion of new parts to the number of hours of sleep, and
we shall have:
        Force expended in         Force expended in
        mechanical effects.       formation of new parts.
      In the adult.....17        :        7
      In the infant.....   4        :       20
      In the old man ... 20        :        4
  In the adult,  a perfect equilibrium takes  place be-
tween waste and  supply ; in the old man and in the
infant, waste and supply are not in equilibrium.  If we
make the consumption of force in the 17 waking hours
equal to that required for the restoration of the equili-
brium during sleep =  100 = 17 waking hours, = 7
hours of sleep, we obtain the following proportions.
The  mechanical effects  are  to  those in the shape of
formation of new parts :
             In the adult man = 100 : 100
             In the infant . . . =  25 : 250
             In the old  man. . = 125 :  50. 
250        THE PHENOMENA OF MOTION

  Or the increase of  mass  to the  diminution  by
waste:
             In the adult man = 100 : 100
             In the infant . . . = 100 :  10
             In the old man . . = 100 : 250
  It is consequently clear, that if the old man performs
an amount of work proportional to the sleeping hours
of the adult, the waste will be  greater than the supply ;
that is, his body will rapidly decrease  in weight, if he
carry 15  lbs. to the distance of 72,000 feet with a
velocity  of  2^  feet in  the  second;  but he  will be
able, without injury, to  carry 6 lbs. to the same dis-
tance.
  In the infant  the increase  is to the decrease as 10
to 1, and consequently, if we in his  case increase the
expenditure of force in mechanical effects to ten times
its  proper amount, there will thus be established only
an   equilibrium  between waste and supply.   The
child, indeed, will not grow ;  but neither will it  lose
weight.
  If, in  the  adult  man, the consumption  of force
for  mechanical  purposes in 24 hours be augmented
beyond the  amount  restorable  in  seven  hours  of
sleep, then, if the  equilibrium  is to be  restored, less
force, in  the  same proportion, must  be expended in
mechanical effects  in the next 24 hours.  If this be not
done, the  mass of  the body decreases, and  the state
characteristic of old age more or less decidedly super-
venes.
  With every hour of sleep the sum of available force 
            IN THE  ANIMAL ORGANISM.        251

increases in the old man, or  approaches the state of
equilibrium between waste and supply which exists in
the adult.
  It  is further evident, that if a part  of  the  force
which is  available for mechanical purposes, without
disturbing the equilibrium, should not be consumed in
moving the limbs, in raising weights, or in other la-
bour, it will be available for involuntary motions.  If
the motion of the heart, of the fluids, and of the intes-
tines (the circulation of the blood and digestion), are
accelerated in proportion to the amount of force not
consumed in voluntary motions, the weight of the body
will  neither  increase or diminish in 24 hours.   The
body, therefore, can only increase in mass, if the force
accumulated during sleep, and  available for mechani-
cal purposes, is  employed neither  for voluntary nor
for involuntary motions.
   The numerical values above given for the  expen-
diture of force in the human body refer, as has  been
expressly  stated, only  to  a given,  uniform  tempe-
rature.  In  a different  temperature, and  with  defi-
cient  nourishment,  all  these  proportions  must be
changed.
   If we surround a part of the body with ice or snow,
while other parts are left in the natural  state, there
occurs, more or less quickly, in  consequence of the
loss of heat, an accelerated change of matter  in the
 cooled part.
   The resistance of the living tissues to the action of
 oxygen is weaker at the cooled part than in the other 
 252        THE  PHENOMENA  OF MOTION

 parts ;  and this, in its effects,  is equivalent  to  an in-
 crease of resistance in these other parts.
   The momentum of force of  the vitality in the parts
 which  are  not cooled  is  expended, as before, in me-
 chanical motion ;  but the whole  action of the inspired
 oxygen is exerted on the cooled part.
   If  we imagine an iron  cylinder,  into which we ad-
 mit  steam  under a  certain pressure, then if the force
 with  which the particles of the iron cohere be equal
 to the force which tends to  separate  them, an equili-
 brium will  result; that is,  the whole effect of the
 steam will  be  neutralized  by  the resistance.   But if
 one of the sides of the cylinder be moveable, a piston-
 rod,  for example, and offer to  the pressure  of the
 steam a less resistance  than  other parts, the  whole
 force will be expended in moving this  one side—that
 is, in  raising the  piston-rod.  If we do not  introduce
 fresh steam (fresh force), an equilibrium will soon be
 established.   The piston-rod resists a certain force
 without moving, but is  raised by an increased pres-
 sure.   When this excess of force  has been consumed
 in motion, it cannot be raised higher ; but if new va-
 pour be continually admitted, the  rod will  continue to
 move.
  In the cooled part  of the body, the living  tissues
offer  a  less  resistance to the chemical action of  the
inspired oxygen ; the power  of the  oxygen to unite
with the elements of the  tissues  is, at this  part, ex-
alted.  When the part has once lost its condition of
life, resistance entirely ceases;  and in consequence of 
IN THE ANIMAL ORGANISM.        253
the combination of the oxygen with the elements of
the metamorphosed tissues, a greater amount of heat
is liberated.
  For  a given  amount of oxygen, the heat produced
is, in all cases, exactly the same.  In the cooled part,
the change  of matter, and with  it the  disengage-
ment of heat, increases ;  while  in  the other  parts
the change of matter and liberation of heat decrease.
But when the  cooled  part, by the  union of oxygen
with the  elements of  the  metamorphosed  tissues,
has recovered  its original  temperature,  the  resist-
ance of its living  particles  to the oxygen conveyed
to them again  increases, and, as  the   resistance  of
other  parts is now diminished, a  more  rapid change
of  matter  now occurs in  them,  their temperature
rises, and along with  this, if  the cause of the change
of  matter  continues to  operate,  a larger amount
of vital force becomes  available for mechanical  pur-
poses.
  Let us now suppose that heat is abstracted from the
whole surface of ihe  body ; in  this case the whole ac-
tion of the oxygen will be directed to the skin, and in
a short time the  change of  matter must  increase
throughout the  body.  Fat, and all  such  matters  as
are capable of combining with the  oxygen which is
brought to them in larger quantity than  usual, will be
expelled from the body in the  form of  oxidised com-
pounds.
             22 
254
                       III.

            THEORY OF DISEASE.
  Every substance or  matter, every chemical or me-
chanical agency, which changes or disturbs the resto-
ration of the equilibrium between the manifestations of
the causes of waste and supply, in such a way as to
add its action to the causes of waste, is called a cause
of  disease.  Disease  occurs when  the  sum of vital
force, which tends to  neutralize all  causes of  distur-
bance (in other words, when the resistance offered by
the vital force), is weaker than the acting cause of dis-
turbance.
  Death is that condition in which all resistance on the
part of the vital force  entirely ceases.  So long as this
condition is not established, the living tissues  continue
to offer  resistance.
  To the observer, the action of a  cause  of disease
exhibits itself in the disturbance of the proportion  be-
tween waste and supply which is  proper to  each  pe-
riod of life.  In medicine, every abnormal condition of
supply or of waste, in all parts or in a single part of
the body, is called disease.
  It is  evident that one and the same  cause of dis-
ease will produce in the  organism  very  different
effects,  according  to  the  period of  life ; and  that a
certain  amount  of disturbance, which  produces dis-
ease in  the adult state, may be without influence in 
THEORY OF DISEASE.
255
childhood or in old  age.   A cause  of disease may,
when it  is added  to  the  cause  of waste in old' age,
produce  death (annihilate all resistance on the  part
of the vital  force); while  in the  adult state it  may
produce  only a  disproportion  between supply  and
waste; and  in infancy, only an equilibrium between
supply and waste (the abstract state of health).
  A cause of disease  which strengthens the causes of
supply, either directly or indirectly by weakening the
action of the causes of waste, destroys, in the child
and in the adult, the relative normal state of health;
while in  old age it merely brings the waste and supply
into equilibrium.
  A child, lightly clothed, can bear cooling by a low
external  temperature  without injury  to  health; the
force available for mechanical purposes and the tem-
perature of its body increase with the change of mat-
ter which follows  the  cooling ; while a high tempera-
ture, which impedes the change of matter, is followed
by disease.
  On the other hand, we see, in hospitals and charita-
ble institutions (in Brussels, for example) in which old
people spend the last years of life, when the temper-
ature  of the  dormitory,  in   winter,  sinks 2  or 3
degrees  below the  usual  point, that by  this  slight
degree of cooling the death of the oldest and weakest
males as well  as  females, is brought about.  They
are found lying tranquilly in bed, without the slightest
symptoms  of  disease, or  of the  usual recognizable
causes of death, 
256
THEORY OF DISEASE.
   A  deficiency of resistance,  in a  living part, to the
 causes of waste is, obviously, a  deficiency of resistance
 to the action of the oxygen of the atmosphere.
   When, from  any cause whatever,  this resistance di-
 minishes in a living part, the change of matter increases
 in an equal degree.
   Now, since the phenomena of motion in  the  animal
 body are dependant on the change  of matter,  the in-
 crease of the change of matter in any part is followed
 by an increase  of all motions.  According to the con-
 ducting  power of the nerves,  the available force is
 carried  away by  the  nerves  of involuntary  motion
 alone, or by all the nerves together.
   Consequently, if, in consequence of a diseased trans-
 formation of living  tissues, a greater amount of force
 be generated than  is required for the  production of the
 normal  motions, it  is seen  in  an acceleration of all or
 some of the involuntary motions, as well as in a higher
 temperature of the diseased part.
   This  condition is called fever.
  When a great excess of force is produced by change
 of matter, the force, since it can only be consumed by
 motion,  extends itself to the apparatus of voluntary
 motion.
  This  state is  called a febrile paroxysm.
  In  consequence  of the   acceleration  of the  circu-
lation  in the state of fever,  a greater  amount of
arterial  blood, and, consequently, of oxygen,  is  con-
veyed to the diseased part, as  well  as to all other
parts; and  if the   active  force in the  healthy part? 
THEORY OF DISEASE.
257
continue uniform, the whole action of the excess of
oxygen must be exerted on the diseased part alone.
  According as a single organ, or a system of organs,
is affected, the change of matter extends  to one part
alone, or to the whole affected system.
  Should there  be formed, in the diseased parts, in
consequence of the change of matter, from  the ele-
ments  of the blood or of the  tissue, new products,
which the neighbouring parts cannot employ for their
own vital functions ;—should the surrounding parts,
moreover, be unable to convey these products to other
parts, where they may undergo transformation, then
these new products will suffer, at the place where they
have been formed, a process of decomposition analo-
gous to fermentation or putrefaction.
  In certain cases, medicine removes these diseased
conditions, by exciting in  the  vicinity of the diseased
part, or in  any convenient  situation, an artificial dis-
eased  state  (as by blisters, sinapisms, or  setons) ;
thus diminishing, by  means of artificial disturbance,
the  resistance  offered to  the  external  causes  of
change in these parts by the vital force.   The physi-
cian succeeds in putting an end to the original dis-
eased condition, when the disturbance artificially ex-
cited  (or  the diminution  of  resistance  in  another
part) exceeds in amount the diseased  state  to be over-
come.
  The accelerated change of matter  and the elevated
temperature in the diseased part shew, that the resist-
ance offered by the vital force to the  action of oxygen
                        22* 
258
THEORY OF DISEASE.
is  feebler than in the healthy state.   But this resist-
ance  only  ceases  entirely when  death takes place.
By the artificial diminution of resistance  in  another
part, the resistance in the diseased organ is not indeed
directly strengthened ;  but the chemical action (the
cause of the change of matter) is diminished in the
diseased  part, being directed  to another part, where
the physician has succeeded in producing a still more
feeble resistance to the change of matter (to the action
of oxygen).
   A complete cure of the original disease occurs, when
external action and resistance, in the diseased part, are
brought into equilibrium.  Health and  the restoration
of the diseased tissue to its original  condition follow,
when we are able so far to weaken the disturbing ac-
tion of oxygen, by any means, that it  becomes inferior
to the resistance offered by the vital force, which, al-
though  enfeebled, has never  ceased to act; for this
proportion between these causes of change is  the uni-
form and necessary condition of increase of mass in the
living organism.
   In cases of a  different  kind,  where artificial ex-
ternal disturbance produces no effect, the physician
adopts  other indirect methods to  exalt  the resist-
ance offered by the vital force.   These methods, the
result of ages  of  experience,  are  such, that the  most
perfect  theory could hardly have pointed them out
more  acutely  or more justly than  has  been  done
by the  observation  of  sagacious  practitioners.   He
diminishes,  by  blood-letting,  the  number  of  the 
THEORY OF DISEASE.
259
carriers of oxygen (the globules), and  by this  means
the conditions of change of matter ; he excludes from
the food all such matters as are capable of conversion
into blood ; he gives  chiefly or entirely non-azotised
food, which supports the respiratory process, as well
as fruit and vegetables, which contain the alkalies ne-
cessary for the secretions.
  If he succeed,  by these means, in  diminishing the
action of the oxygen in the blood on the diseased part,
so far that the vital  force of the  latter, its resistance,
in the smallest degree overcomes the chemical action;
and if he accomplish this,  without arresting  the func-
tions of the other organs, then restoration to  health  is
certain.
   To the method of cure adopted in  such  cases, if
employed with sagacity and acute observation, there
is added, as we  may call it,  an ally on the side of
the diseased organ, and this is the vital  force  of the
healthy parts.   For,  when  blood is  abstracted, the
external  causes  of change are  diminished also  in
them, and their vital  force, formerly neutralized  by
these causes, now obtains the preponderance.  The
change of  matter,  indeed, is  diminished throughout
the body,  and  with it  the phenomena  of motion:
but the  sum  of  all resisting powers, taken together,
increases in proportion as the  amount  of the oxygen
acting on them  in the blood  is  diminished.   In the
sensation  of  hunger, this  resistance,  in  a  certain
sense, makes  itself  known;  and  the   preponderat-
ing vital  force  exhibits   itself, in  many patients 
260           THEORY OF DISEASE.

when hunger is felt, in the  form  of an  abnormal
growth, or  an abnormal metamorphosis of certain
parts of organs.   Sympathy  is the  transference  of
diminished resistance from  one part,  not exactly  to
the next, but to more distant organs,  when the func-
tions  of both mutually  influence  each other.  When
the  action of the  diseased  organ is connected with
that   of   another—when, for  example, the  one  no
longer produces the  matters  necessary to  the  per-
formance  of the functions of the other—then the dis-
eased condition is  transferred, but only apparently, to
the latter.
   In  regard to the nature and essence  of  the vital
force, we  can hardly deceive  ourselves, when we re-
flect, that it behaves, in all its  manifestations, exactly
like  other natural  forces;  that it  is devoid  of con-
sciousness or of volition, and is subject to the action of
a blister.
   The nerves, which accomplish the  voluntary and
involuntary motions  in  the  body, are, according  to
the  preceding  exposition, not  the producers, but
only the conductors of  the  vital  force ; they propa-
gate  motion,  and  behave  towards other causes  of
motion, which  in  their manifestations  are analogous
to the vital force,  towards  a current  of electricity,
for example, in a precisely analogous manner.  They
permit the  current to traverse them, and present,  as
conductors  of electricity,  all the phenomena which
they  exhibit as conductors  of the  vital force.   In
the present state of our  knowledge,  no  one, proba- 
THEORY OF DISEASE.
261
bly,  will imagine that electricity is  to be  considered
as the  cause of  the  phenomena  of motion in  the
body ;  but still, the medicinal action of  electricity,
as well as that  of a magnet, which, when placed in
contact with the body, produces  a current of elec-
tricity, cannot  be denied.   For to the existing force
of motion or of disturbance there is added, in  the
electrical  current,  a new cause of motion  and  of
change  in form and structure, which cannot be consi-
dered as altogether inefficient.
  Practical  medicine,  in  many diseases,  makes  use
of cold  in a highly rational manner, as a means of
exalting and accelerating, in an unwonted degree,  the
change of matter.   This occurs especially in  certain
morbid  conditions in the  substance of the centre of
the apparatus of motion ; when a glowing  heat and a
rapid current of blood towards the head point out an
abnormal  metamorphosis of  the  brain.    When this
condition  continues beyond a certain time,  experi-
ence teaches that all motions in the body  cease.   If
the  change   of  matter  be  chiefly  confined  to  the
brain, then the change of matter, the generation of
force, diminishes in  all other parts. . By surrounding
the head with ice,  the  temperature  is  lowered,  but
the cause of the liberation of heat continues;  the
metamorphosis, which decides the  issue of the dis-
ease,  is  limited to  a short  period.  We must  not
forget, that the ice  melts and  absorbs heat from  the
diseased  part; that  if the  ice be removed  before  the
completion- of  the  metamorphosis,  the  temperature 
262
THEORY  OF DISEASE.
again rises;  that far more  heat  is removed by means
of ice than if we were  to surround the head with a
bad  conductor  of heat.   There has obviously  been
liberated in an  equal time  a  far larger  amount of
heat than in the state  of health;  and this  is only
rendered possible by an  increased supply of oxygen,
which must have determined a more rapid  change
of matter.
  The  self regulating steam engines, in  which, to
produce a uniform  motion,  the human intellect has
shewn the  most  admirable  acuteness  and sagacity,
furnish no unapt image  of what occurs in the animal
body.
  Every one knows, that  in the tube  which conveys
the ^team  to  the cylinder  where the piston-rod is
to be raised, a stop-cock  of  peculiar construction
is  placed, through which  all  the steam  must  pass.
By an arrangement  connected with  the  regulating
wheel, this stop-cock opens when the wheel moves
slower,  and closes more  or less completely when
the  wheel  moves  faster  than  is required for  a
uniform. motion.  When  it  opens, more  steam is
admitted (more-force),  and the  motion  of the  ma-
chine is  accelerated.  When  it shuts, the steam is
more or less cut off, the  force acting on  the piston-
rod  diminishes,  the tension  of the steam increases,
and  this tension is accumulated for subsequent use.
The tension of the vapour, or the  force, so to speak,
is  produced by  change  of matter, by  the combustion
of coals in  the  fire-place.   The force increases  (the 
THEORY OF DISEASE.
263
amount of steam generated and its  tension increase)
with the temperature  in  the  fire-place,  which  de-
pends on the supply of coals and of air.  There are
in these  engines other  arrangements, all  intended
for regulation.  When the tension  of steam in the
boiler  rises  beyond  a  certain point, the passages for
admission of  air close themselves ;  the  combustion
is retarded,  the  supply of  force (of  steam)  is dimin-
ished.  When the  engine  goes slower, more  steam
is admitted  to  the  cylinder, its  tension  diminishes,
the air passages are opened, and the  cause  of dis-
engagement  of  heat  (or  production  of  force)  in-
creases.  Another arrangement supplies the fire-place
incessantly  with  coals  in  proportion as  they are
wanted.
   If we  now lower the temperature  at  any part of
the boiler, the tension within  is diminished ; this is
immediately  seen in the  regulators of force, which
act precisely as if we had removed from the boiler
a certain quantity of steam  (force).   The  regulator
and the air-passages open, and the  machine supplies
itself with more coals.
   The body, in  regard to the production of heat and
of force, acts just like one of these  machines.  With
the lowering of the external temperature, the respi-
rations become deeper and more frequent;  oxygen
is supplied  in greater  quantity and of greater  den-
sity ;  the change of matter is increased,  and  more
food  must  be  supplied,  if  the  temperature of  the
body is to remain unchanged. 
264
THEORY OF DISEASE.
  It is hardly necessary to mention, that in  the body,
the tension of vapour cannot, any more than an electri-
cal current, be considered the cause of the production
of force.
  From the theory of disease developed in the prece-
ding pages, it follows obviously, that a deceased  con-
dition once established, in any part of the body, cannot
be made to disappear by the chemical action of a re-
medy.  A limit may be put by a remedy to  an abnor-
mal process of transformation ; that process  may be
accelerated or retarded ; but this  alone  does not re-
store the normal (healthy) condition.
  The art of the physician consists in the knowledge
of the means which  enable  him  to  exercise an in-
fluence on the duration of the disease; and in the
removal  of all disturbing causes, the action  of which
strengthens or increases  that of the  actual  cause of
disease.
  It is only  by  a just application of  its  principles
that any theory  can produce really beneficial results.
The very same  method of cure  may restore health
in one individual, which, if applied to  another,  may
prove fatal in its  effects.  Thus in certain  inflamma-
tory diseases, and in  highly  muscular  subjects, the
antiphlogistic  treatment has   a  very  high  value ;
while in other cases blood-letting  produces  unfavour-
able results.   The vivifying  agency  of the blood
must  ever continue to  be  the  most important condi-
tion in the  restoration of  a  disturbed  equilibrium,
which result  is  always dependant on  the  saving of 
THEORY OF RESPIRATION.         265
time; and the  blood must, therefore, be  considered
and  constantly kept in  view,  as  the  ultimate and
most powerful  cause of a lasting vital  resistance, as
well in the diseased  as in the unaffected parts of the
body.
  It is obvious, moreover, that in all diseases where
the formation of contagious matter and of exanthema-
ta is accompanied by  fever, two diseased conditions
simultaneously exist,  and two processes are simulta-
neously  completed ; and that the blood, as it were by
re-action (i. e. fever), becomes a means of cure, as be-
ing the carrier of  that substance  (oxygen) without the
aid of which the diseased  products cannot be rendered
harmless,  destroyed, or expelled from  the body ; a
means of  cure  by which, in short, neutralization  or
equilibrium is effected.


                       IV.

        THEORY  OF  RESPIRATION.
  During  the passage of the venous blood through the
lungs, the  globules  change their colour; and with
this change of colour, oxygen is absorbed from the at-
mosphere.  Further, for every volume of oxygen ab-
sorbed, an equal volume  of carbonic acid  is, in most
cases, given out.
  The red globules contain a compound of iron ; and
no other constituent of the body contains iron.
   Whatever change the other  constituents of  the
               23 
266         THEORY OF RESPIRATION.
blood undergo in the lungs, thus much is certain, that
the globules of venous blood experience a change of
colour, and that  this change depends on the action of
oxygen.
  Now we observe  that  the globules  of arterial
blood retain their  colour  in the larger vessels, and
lose  it  only during their  passage  through the  ca-
pillaries.  All  those constituents  of  venous  blood,
which are  capable of combining with oxygen, take
up a corresponding quantity of it  in the lungs.  Ex-
periments made  with arterial serum have shewn, that
when in contact with oxygen it  does not  diminish
the volume of that gas.   Venous  blood, in contact
with  oxygen, is reddened, while oxygen is absorbed;
and  a corresponding  quantity of carbonic acid  is
formed.
  It is evident that the change of colour in the venous
globules depends on the combination of some  one of
their  elements with oxygen; and that this absorption
of oxygen is attended  with the separation of a certain
quantity of carbonic acid gas.
  This carbonic acid is not separated from the serum ;
for the serum  does not possess the property, when in
Contact with oxygen, of giving off carbonic acid.  On
the contrary, when  separated from the globules, it ab-
sorbs from half its volume to an equal  volume of car-
bonic acid, and,  at  ordinary temperatures, is not satu-
rated with that  gas.   (See the article " Blut" in the
" Handworterbuch  der  Chemie   von Poggendorff,
Wohler, and Liebig, p. 877.) 
THEORY OF RESPIRATION.
267
  Arterial  blood, when  drawn  from  the  body, is
soon altered;  its  florid  colour becomes dark red.
The florid  blood, which  owes  its colour to the glo-
bules, becomes dark  by the  action of carbonic acid,
and  this change  of  colour  affects  the  globules, for
florid blood absorbs a number of gases  which do not
dissolve  in the fluid  part of the blood  when sepa-
rated from the globules.  It is evident,  therefore, that
the globules have the power of combining with gases.
   The globules of the  blood change their  colour in
different gases ; and this change may be owing either
to a combination or to a decomposition.
   Sulphuretted hydrogen turns them blackish green
and finally black; and  the  original red colour can-
not, in this case, be restored by contact  with oxygen.
Here a decomposition has obviously taken place.
   The  globules darkened by carbonic  acid become
again florid in oxygen, with disengagement of car-
bonic acid.  The same  thing  takes place in nitrous
oxide.   It  is clear that they  have here undergone
no  decomposition, and,  consequently,  they  possess
the  power of combining with  gases, while the com-
pound they form  with carbonic acid is destroyed by
oxygen.  When  left  to  themselves, out of the body,
the compound formed  with oxygen again  becomes
 dark, but does not recover  its florid colour a second
 time by the action of oxygen.
   The globules  of the blood  contain a compound of
 iron.  From  the never-failing presence of  iron  in
 red blood, we must conclude, that it  is unquestion- 
268         THEORY  OF RESPIRATION.
 ably necessary to animal life; and, since physiology
 has proved, that the  globules take no  share  in  the
 process of nutrition, it cannot be  doubted  that they
 play a part in the process of respiration.
   The compound of iron in the  globules has  the
 characters of an oxidised  compound;  for it  is  de-
 composed by sulphuretted  hydrogen,  exactly  in  the
 same way  as the oxides  or other analogous com-
 pounds of iron.   By means of diluted mineral acids,
 peroxide  (sesquioxide) of iron may be  extracted, at
 the ordinary temperature,  from  the  fresh or  dried
 red colouring matter of the blood.
   The characters of the  compounds  of iron may,
 perhaps,  assist  us  to  explain the  share which that
 metal  takes in  the  respiratory process.   No other
 metal  can be compared with iron, for the remark-
 able properties  of its  compounds.
   The compounds of protoxide of iron possess  the
 property  of depriving other oxidised compounds of
 oxygen ;  while  the compounds of  peroxide of iron,
 under other circumstances, give up oxygen with  the
 utmost  facility.
   Hydrated peroxide of iron, in contact  with organic
 matters destitute  of sulphur, is converted  into car-
 bonate  of the  protoxide.
   Carbonate of  protoxide  of iron, in  contact with
water and oxygen, is  decomposed; all the  carbonic
acid is  given  off, and, by  absorption  of oxygen, it
passes into the hydrated peroxide,  which may  again
be converted into a compound of the  protoxide. 
THEORY OF RESPIRATION.         269
  Not only the oxides of iron, but also the cyanides
of that metal,  exhibit  similar  properties.  Prussian
blue  contains iron in combination with  all  the  or-
ganic elements of the body;  hydrogen and  oxygen
(water), carbon and nitrogen (cyanogen).
   When it is  exposed to light, cyanogen is given
off, and  it  becomes  white ;  in  the  dark it  attracts
oxygen, and recovers its blue  colour.
   All these observations, taken  together, lead to  the
opinion that the globules  of  arterial blood  contain
a compound of iron saturated  with  oxygen,  which,
in the living blood, loses its  oxygen  during  its  pas-
sage  through the capillaries.  The same thing occurs
when it is separated from the body, and begins to
undergo decomposition  (to putrefy).  The compound,
rich  in oxygen, passes, therefore, by  the  loss of oxy-
 gen (reduction), into  one  far  less charged with that
 element.   One  of the products  of oxidation  formed
 in this process is carbonic acid. The compound of
 iron  in  the venous  blood possesses  the  property of
 combining with  carbonic  acid; and  it  is  obvious,
 that  the globules of the arterial blood, after  losing a
 part of their  oxygen,  will, if  they  meet with  car-
 bonic acid, combine with that substance.
   When they  reach the  lungs,  they will again  take
 up the  oxygen they have lost;  for every volume of
 oxygen absorbed,  a corresponding  volume   of  car-
 bonic  acid will  be separated ;  they will return  to
 their former state;  that  is,  they will again acquire
 the power of giving off oxygen.
               23* 
270         THEORY  OF RESPIRATION.
  For every  volume of oxygen  which  the  globules
can give off, there will be  formed (as carbonic  acid
contains its own volume of oxygen, without conden-
sation) neither more nor less  than  an equal volume
of  carbonic  acid.  For every  volume  of  oxygen
which  the  globules  are capable of absorbing, no
more  carbonic acid  can possibly be separated  than
that volume of oxygen can  produce.
  When carbonate  of  protoxide of iron,  by  the
absorption of oxygen,  passes  into  the   hydrated
peroxide, there  are given  off, for every  volume  of
oxygen  necessary to the change from protoxide to
peroxide, four volumes of carbonic acid gas.
  But from  one volume of oxygen only one volume
of carbonic acid can be produced; and the absorption
of one volume of oxygen  can only cause, directly,
the separation of an equal  volume of carbonic  acid
Consequently, the substance or compound which has
lost its oxygen, during the  passage  of  arterial  into
venous blood, must have been capable of absorbing or
combining with carbonic  acid ; and we find, in point
of fact,  that  the living blood  is  never, in any  state,
saturated with  carbonic  acid; that  it is  capable of
taking up an additional quantity, without any appa-
rent disturbance  of  the  function  of the  globules.
Thus, for example, after drinking effervescing  wines.
beer,  or mineral waters,  more  carbonic acid  must
necessarily be  expired  than at  other times.  In all
cases, where the oxygen of the arterial globules  has
been partly expended, otherwise  than in  the forma- 
THEORY OF RESPIRATION.         271
tion  of carbonic  acid, the amount of this  latter gas
expired will correspond exactly with that  which has
been formed; less, however, will be given out after
the use of fat and of still  wines,  than after  cham-
pagne.
  According to the  views now developed, the glo-
bules of arterial blood, in their passage through the
capillaries, yield  oxygen to  certain constituents of
the body.   A small portion of this  oxygen  serves to
produce the  change  of matter, and determines the
separation of living parts and  their conversion into
lifeless compounds, as well as  the formation of the
secretions and  excretions.  The greater part,  how-
ever, of the oxygen  is employed  in  converting into
oxidised  compounds  the  newly formed substances,
which  no longer form part of the living tissues.
  In their return  towards the  heart,  the globules
which  have lost their  oxygen combine with carbonic
acid, producing venous blood ;  and, when they reach
the lungs, an exchange takes place betwreen this car-
bonic acid and the oxygen of the atmosphere.
  The organic compound of iron,  which  exists in
venous blood,   recovers in the  lungs the  oxygen  it
has lost,  and,  in consequence  of this  absorption of
oxygen, the carbonic acid in combination with it  is
separated.
  All  the compounds present in venous blood,  which
have an attraction for oxygen,  are converted,  in the
luno-s,  like the globules,  into  more highly  oxidised
compounds; a certain  amount of carbonic acid  is 
272       THEORY OF  RESPIRATION.

formed, of which a part always remains dissolved in
the serum of the blood.
   The quantity of carbonic acid dissolved,  or of that
combined with soda, must  be  equal  in venous and
arterial blood,  since  both have  the  same tempera-
ture ; but arterial blood, when drawn, must, after a
short time, contain a larger quantity  of carbonic  acid
than venous blood, because the oxygen of the globules
is expended in producing that compound.
   Hence, in the  animal  organism, two processes of
oxidation are going on ;  one  in  the  lungs,  the  other
in the capillaries.  By means  of  the former, in spite
of the degree of cooling, and of  the increased evapo-
ration which  takes  place there,  the constant tempe-
rature of the lungs is kept up ;  while  the heat of the
rest of the body is supplied by the latter.
   A man, who expires daily 13'9 oz. of carbon, in the
form of carbonic acid, consumes, in 24 hours, 37 oz. of
oxygen,  which  occupy a space  equal to  807  litres
= 51,648 cubic inches (hessian).
  If we reckon 18 respirations to a minute, we have,
in 24 hours, 25,920 respirations ;  and, consequently, in
each respiration,  there  are   taken  into   the  blood
Is ft o = 199 cubic inch of oxygen.
   In one minute, therefore, there are  added to  the
constituents of the blood  18 x  1'99 = 35-8 cubic inch-
es of oxygen,  which, at the  ordinary temperature,
weigh rather less than 12 grains.
  If we now assume, that in  one minute  10 lbs. of
blood pass through the  lungs (Muller, Physiologie, 
            THEORY OF  RESPIRATION.         273
vol. i. p. 345), and that this quantity of blood measures
320 cubic inches, then 1 cubic inch of oxygen unites
with 9 cubic inches of blood, very nearly.
  According to the researches of Denis, Richardson,
and Nasse (Handworterbuch  der Physiologie, vol. i.
p. 138), 10,000 parts of  blood contain 8 parts of per-
oxide of iron.  Consequently, 76,800 grains (10 lbs.
hessian) of blood contain 61*54 grains of peroxide of
iron in arterial blood, = 55*14 of protoxide in venous
blood.
  Let  us now assume that  the  iron of the  globules
of venous  blood is  in the  state of  protoxide.  It
follows, that  55*14  grains of protoxide  of iron, in
passing through  the lungs, take  up, in one  minute,
6*40 grains of oxygen  (the  quantity  necessary to
convert it into  peroxide).  But  since, in the  same
time,  the 10 lbs.  of  blood have  taken up  12 grains
of oxygen,  there remain  5*60  grains  of  oxygen,
which  combine  with the other constituents  of the
blood.
  Now, 55*14 grains of protoxide of iron combine with
34*8 grains of carbonic acid, which occupy the volume
of 73 cubic inches.  It  is obvious, therefore, that the
amount of  iron present  in the blood, if in the state of
protoxide, is sufficient to furnish  the means of carry-
ing or transporting  twice  as much carbonic  acid as
can possibly be formed by the oxygen absorbed  in the
lungs.
  The hypothesis just developed rests on well-known
observations, and, indeed, explains completely the pro- 
274          THEORY OF  RESPIRATION.
cess of respiration, as far as it depends on the globules
of the blood.   It does not exclude the opinion that car-
bonic acid may reach the lungs in other ways; that
certain other constituents of  the blood  may give rise
to the  formation of carbonic acid in the lungs.  But
all  this has no connection with that vital process by
which the heat necessary for the  support  of life is
generated in every part of the  body.  Now it is this
alone which, for the present, can be considered as the
object truly worthy of  investigation.   It  is  not, in-
deed, uninteresting to inquire, why dark blood becomes
florid  by the  action of nitre, common salt, &c.;  but
this question has no relation to the natural respiratory
process.
  The frightful effects  of sulphuretted hydrogen, and
of prussic acid, which, when inspired, put a stop to all
the phenomena  of motion in a few seconds, are  ex-
plained in a  natural manner by the well-known  ac-
tion of these  compounds on those of iron, when alka-
lies are present; and free alkali  is never absent in the
blood.
  Let us suppose that the globules lose their property
of absorbing oxygen, and of afterwards giving up this
oxygen and carrying off the resulting carbonic acid ;
such a hypothetical state of disease must instantly be-
come perceptible in  the  temperature and  other vital
phenomena of the  body.   The change of matter will
be arrested, while yet the vital motions will  not be in-
stantly stopped.
  The conductors of force, the nerves, will convey, 
             THEORY  OF RESPIRATION.         275

as before, to the heart and intestines the power neces-
sary for their  functions.  This  power they will  re-
ceive from the  muscular system, while, as no  change
of matter takes place  in the  latter, the supply must
soon fail.  As no change of matter occurs, no lifeless
compounds are  separated, neither bile nor urine can
be formed ; and the temperature of the body must sink.
   This  state of matters soon puts a stop to the pro-
cess of nutrition,  and,  sooner or  later, death  must
follow, but unaccompanied by febrile symptoms, which,
in this case, is a very important fact.
   This example has been selected in  order to  shew
the importance and  probable advantage of an exami-
nation  of the  blood in  analogous diseased conditions.
It cannot be, in the slightest degree, doubtful that  the
function  ascribed  to the blood globules  may  be con-
sidered  as fully explained and cleared up, if, in such
morbid conditions, we shall discover a change  in their
form, structure, or  chemical characters,  a  change
which must be recognizable by the use of appropriate
re-agents.
   If we consider the force which determines the vital
phenomena as a property of certain substances, this
view leads of itself to  a new and  more rigorous con-
sideration of certain singular phenomena, which  these
very substances exhibit,  in  circumstances  in which
they no longer make a part of living organisms. 
 
           APPENDIX  ;

                     CONTAINING

      THE ANALYTICAL EVIDENCE

REFERRED TO IN THE SECTIONS IN WHICH ARE DESCRIBED

                       THE

  CHEMICAL  PROCESSES  OF  RESPIRATION,

                OF  NUTRITION,

                     AND OF THE              rf

        METAMORPHOSIS OF TISSUES.
  *** The Notes correspond with the numbers in parentheses in the text.
All the Analyses quoted, which have the mark * attached, have been made
in the ctemical laboratory of the University of Giessen.- ,
24 
 
APPENDIX.
     INTRODUCTION TO THE ANALYSES.

  The method formerly  employed to exhibit the differ-
ences in composition of different substances, that, namely,
of giving the proportions of the  various elements in 100
parts,  has been long abandoned by  chemists; because it
affords  no insight into the  relations which exist  between
two or more  compounds.   In order to give some proofs of
this statement, we shall here state, in that form, the com-'
position of aldehyde and acetic acid, of oil of bitter almonds
and benzoic acid.
               • j    ,,. t. j   -d    •   -a  Oil of bitter
        Acetic acid.  Aldehyde. Benzoic acid.   aimond3.
Carbon    40-00      55-024        69-25       79-56
Hydrogen   6-67       8-983         4-86        5-56
Oxygen    53-33      35-993        25-69        14-88

  Now aldehyde is  converted into acetic  acid, and oil of
bitter almonds into benzoic acid, simply by the addition of
oxygen, without any change in regard to the other elements.
This important relation cannot be traced in the  mere nu-
merical results of analysis as above given ; but if the com- 
280
APPENDIX.
position of the related compounds be expressed in formulae,
according to  equivalents, the connection in each case be-
comes obvious, even to him who knows no more of chem-
istry than that C represents an equivalent or combining por-
tion  of carbon, H an equivalent of hydrogen,  and O  an
equivalent of oxygen.

       Formula                       Formula
of acetic acid.    of aldehyde.    of benzoic acid.    of oil of bitter almonds.
 C4H404.    C4H402.     C14H604.        C14H6Oa.

  These formulae are exact expressions of the results of
analysis, which, in each of the two cases quoted, refer to a
fixed quantity of carbon;  in one to 4  equivalents, in the
other to 14.  They shew, that acetic acid differs  from  aide-
hyde, and benzoic  acid from oil of bitter almonds,  only in
the proportion of oxygen.
  Nor is it more difficult to understand  the signification of
the following formulae.

   Cyamelide.     1 eq. cyanuric acid.     3 eq. hydrated cyanic acid.
  C6N3H306 = Cy3(=C6N3)03 + 3HO = 3(CyO + HO)=
                  = C6N3H306         = C6N3H306.

  (In these formulae, N represents an equivalent of nitro-
gen, and Cy  an equivalent of cyanogen.   This  latter sub-
stance being  composed of 2 equivalents of carbon and 1 eq.
of nitrogen, Cy = C2N.)
  The first formula (that of Cyamelide) is what is called an
empirical formula,  in which the relative proportions of the
elements are, indeed, exactly known, but where we have not
even  a theory, far less any actual  knowledge, of  the or-
der in which they are arranged.   The  second formula is
intended to express  the opinion  that  3 eq. of cyanogen
(= 6 eq.  of carbon + 3 eq. of  nitrogen)  having  united 
               ANALYTICAL EVIDENCE.           281

to form  a compound  atom  or  molecule,  have combined
with 3 eq.  of oxygen  and 3 eq. of water, to form 1 eq.
of hydrated cyanuric acid.   The third expresses the order
in which the elements  are supposed to be arranged in hy-
drated cyanic acid, the whole multiplied by 3.   Each equi-
valent of cyanic acid  is  formed of 1 eq. of  cyanogen, 1
eq. of oxygen, and 1 eq. of water  ; and hence the same num.
ber of atoms of each element, which together formed  1
eq. of cyanuric acid, is here so divided as to yield  3 eq. of
cyanic acid.
   We have  here, therefore, the same absolute and relative
amount  of atoms of each element, arranged in three diffe-
rent ways;  yet in  each of  these the proportions of the
elements, calculated for 100  parts, must  of course be the
same.  It is easy, therefore, to see the advantage  we pos-
sess  by   the use of  formulae ; thaty namely, of exhibiting
the relations existing between compounds of different com-
position ; and  that also  of expressing the  actual, probable,
or possible differences between substances whose composi-
tion, in 100 parts, is  the same, while  their properties, as in
the case  above quoted, are perfectly distinct.
   It does not come within our province, here to explain the
method or rule by which the  composition of a  substance,
in 100 parts (as it is always obtained in analysis), is  express-
ed in a formula ; we shall only describe the rule for calcu-
lating, from a  given formula, the composition  in 100 parts.
For this purpose it must be noted that C, in a chemical for-
mula, signifies a weight of carbon expressed by the number
76-437 (according to the most recent determinations 75-8 or
75-0, a variation which has no effect whatever on the for-
mulae here  adduced, all  of  which are calculated on the
number  76-437) ;  that  H  signifies a weight  of hydrogen
= 12*478 ;  N a weight of nitrogen = 177-04 ; and lastly,
O a weight  of oxygen = 100.
                24* 
282
APPENDIX.
  The formula  of proteine, C48N6H360,4, expresses, there-
fore,

          48 times 76-437 = 3668-88 carbon,
           6 times 177-040 = 1062-24 nitrogen,
          36 times 12-478 =  449-26 hydrogen,
          14 times 100-000 = 1400-00 oxygen.
    The sum gives a weight of 6580-38 proteine.

Therefore—
                                             In ]00 parts.
In 6580-38 parts of proteine are contained 3668-88 carbon   55-742
In 6580-38          ditto            1062-24 nitrogen 16-143
In 6580-38          ditto              449-26 hydrogen 6-827
In 6580-38          ditto            1400-00 oxygen  21-288
                                                  100-000

  The  actual  results  of analysis,  reduced to  100  parts,
when compared with the  above numbers, will shew how far
the assumed formula is correct; or, supposing the formula
ascertained, they will shew the degree  of accuracy display.
ed by the experimenter.   Thus the proportions in 100 parts,
calculated from the formula, furnish an  important check to
the  operator, and,  conversely, the formula  calculated from
his results, when compared with other  known formulae, sup-
plies  a  test of his accuracy, or of  the  purity of the sub-
stance analyzed. 
ANALYTICAL  EVIDENCE.
283
                NOTE (1), p. 12.
CONSUMPTION OF OXYGEN BY AN ADULT.
                  An adult man
           >--------------—-*----------------^  Carbon contained
           consumes of oxygen produces of carbonic     in the
in 24 hours.
According to     ,------^-
                 cubic in.  grains.
Lavoisier & Seguin 46,037  15,661
Menzies    .     . 51,480  17,625
Davy   .    .     . 45,504  15,751
Allen and Pepys  . 39,600  13,464
acid in 24 hours.   carbonic acid.
cubic in.  grains.    grains.
14,930   8,584   2,820 French.
                    English.
31,680  17,811   4,853  do.
39,600  18,612  5,148  do.
               NOTE (2), p. 13.
COMPOSITION OF DRY BLOOD (see note 28).
	In 100 parts. In 48 lbs. Hessian = 3	
Carbon .	. 51-96 .	. 19154-5
Hydrogen	. 7-25 .	. 2672-7
Nitrogen	. 15-07 .	. 5555-4
Oxygen	. 21-30 .	. 7852-0
Ashes .	. 4-42 .	. 1629-4
                     100-00               36864-0
   Grains.                    Grains.
  19154-5 carbon form, with 50539-5 oxygen, carbonic acid.
   2672-7 hydrogen    do.   21415-8   do.    water.

                    Sum = 71955-3   do.
Deduct  oxygen present ? _  7353.0
  in blood  .     .     . )

                  Remain   64103-3 grains of oxygen, required
for the complete combustion of 4-8 lbs. of dry blood.
  It is assumed, in this  calculation, that 24 lbs. of blood
yield 4*8 lbs. (20 per cent.) of dry  residue.   The remain-
der, 80 per cent., is water. 
284
APPENDIX.
                      NOTE  (3), p. 14.

   DETERMINATION  OF THE AMOUNT OP CARBON
                         EXPIRED.

                       1. Analysis of

                           Fceces.

   2-356 dry faeces left 0-320 ashes (13-58 per cent.)
   0-352 dry fasces yielded 0-576 carbonic acid, and 0-218 water.

                           Lentils.

   0-566 lentils, dried  at 212°, yielded 0-910 carbonic acid, and
 0-366 water.

                           Pease.

   1-060 pease, dried at 212°, left 0-037 ashes.
   0-416  do.       do.      yielded 0-642 carbonic acid,  and
 0-241 water.

                         Potatoes.

   0-443 dried potatoes yielded  0-704 carbonic acid, and  0-248
water.

                Black Bread (Schwarzbrod).

   0-302 dried black bread yielded 0-496 carbonic acid, and 0-175
water.
   0-241           do.           0-393        do.        0-142
water.

   From the above, which  are the direct results  of experi-
ment, the composition in 100 parts is calculated as in the
following table. 
ANALYTICAL EVIDENCE.            285
           2. Composition
Of Faeces. Of Black Bread.    Of Potatoes.  Of Flesh.
	Play fair.*	Boeckmann.*	Boussingault. Boeckmann. *	
Carbon	45-24	45-09 45-41	44-1 43-944 (See note	
Hydrogen	6-88	6-54 6-45	5-8 1	3-222 28.)
Nitrogen )	34-73	45-12 44-89	45-1 44-919	
Oxygen )				
Ashes	13-15	3-25 3-25	5-0	1-915
	100-00	100-00 100-00	100-0 100-000	
Water	300-00			
	400-00			
		Of Pease.	Of Lentils	Of Beans.
		Play fair.*	Play fair.*	Play fair."
Carbon	.	. . 35-743	37-38	38-24
Hydrogen		. . 5-401	5-54	5-84
Nitrogen i Oxygen \		. . 39-366	37-98	38-10
				
Ashes			3-20	3-71
Water		16-000	15-90 100-00	14-11
				
		100-000		100-00
	Fresh Meat.		Potatoes.	Black Bread.
	Baeckmann.* Bou . . 75 74-JT		ssingault.	Boeckmann.*
Water . .			72-2 73-2	33 31-418
Dry Matter		25 25-2	27-8 26-8	67 68-592
				
	100 100-0 100-0 100-0			J00 100-000
                   3.  Calculation,
with the help of  the  preceding data,  of the  amount of
carbon expired by an  adult man.  The following results
are deduced  from observations made (see table)  on the
average  daily consumption of food, by from  27 to  30
soldiers in barracks for a month, or by 855 men for one 
286
APPENDIX.
day.   The food, consisting of bread, potatoes,  meat, len-
tils, pease, beans, &c, was weighed, with the utmost exact-
ness,  every day during a  month  (including even  pepper,
salt, and butter ;) and each article of food was separately
subjected to ultimate  analysis.   The  only  exceptions,
among the men, to the uniform  allowance  of  food, were
three  soldiers of the  guard, who,  in addition to the daily
allowance  of 2 lbs.  of bread, received, during  each of
the periods allotted  for  the  pay  of  the  troops,  2\ lbs.
extra  ;  and  one  drummer  who,  in  the   same  period,
left 2\ lbs. unconsumed.   According to an  approximative
report by the sergeant-major, each soldier consumes daily,
on  an average, out of barracks,  3  oz.  of sausage, f oz.
of butter, \  pint of beer, and T\ pint of brandy ; the car-
bon of which articles amounts to more than double  that
of the faeces and urine  taken together.  In  the  soldier,
the faeces amount daily, on an average, to  5^  oz.; they
contain 75 per cent, of water, and the dry residue contains
45-24 per cent,  of carbon, and 13-15 per cent, of ashes.
100 parts of fresh faeces consequently  contain 11*31 per
cent,  of  carbon, very nearly  the  same proportion as in
fresh  meat.   In the calculation, the carbon  of the fseces
and of the urine has been assumed as equal to that of green
vegetables, and  of the food (sausages,  butter,  beer, &c.)
consumed in  the alehouse.
  From the observations, as recorded in the  table,  the fol-
lowing conclusions are deduced.
  Flesh.—Meat devoid  of fat, if reckoned at 74 per cent.
water, and 26 per cent, dry matter, contains in 100 parts
very nearly 13*6 parts of carbon.  Ordinary  meat contains
both fat and cellular tissue, which  together amount to |th
of the weight of the meat as bought from  the butcher. The
number of ounces consumed (by 855 men) was 4,448, con-
sisting, therefore, of 
ANALYTICAL  EVIDENCE.
287
3812-5 oz. of flesh, free from fat, containing of carbon 518-5 oz.
 635-5 oz. of fat and cellular tissue,      ditto       449-0 oz.
4448-0 oz.                           In ant carbon 967-6 oz.
  With the bones, the meat, as purchased, contains 29 per
cent,  of  fixed matter, including  bones; 4,448 oz. of flesh
therefore contain 448 oz. of dry bones.  These have not
been included in the calculation, although, when boiled, they
yield  from 8 to 10 per cent, of gelatine, which is taken as
food in the soup.
  Fat.—The amount of fat consumed was 56  oz. ;  which,
the carbon being calculated at 80 per cent., contain in all
44-8 oz. of carbon.
  Lentils, pease,  and beans.—There were  consumed 53*5
oz.  of lentils, 185*5 oz. of pease, and 218 oz. of beans.  As-
suming the average amount of carbon in these vegetables to
be 37 per cent., the total quantity of carbon consumed in
this form was 169-1 oz.
  Potatoes.—100 parts of fresh potatoes contain 12*2 parts
of carbon.   In the 15*876 oz. of potatoes consumed, there-
fore, the amount of carbon was  1936-85 oz.
  Bread.—855 men  eat daily 855 times  32  oz., besides
36 lbs. of bread in the soup,  which in all amounts to 27,936
oz.   100 oz. of fresh  bread contain, on an average, 30*15
oz.  of carbon • consequently, the carbon consumed in the
bread amounts to 8771-5 oz.
  The total consumption, therefore, was,
  In the meat     ....     967-50 oz. of carbon
  In the fat  .
  In the lentils, pease, and beans
  In the potatoes
  In the bread
    Consumed by 855 men

Consumed by 1 man  .
  44-80    ditto
 16910    ditto
1936-85    ditto
8771-50    ditto
11889-75     ditto
13-9      ditto 
288
APPENDIX.
  The faeces of a soldier weigh 5*5 oz., and contain, in the
fresh state, 11 per cent, of carbon.   For 86 kreutzer (about
2s. 5d. sterling) there may be bought, on  an  average, 172
lbs. of  vegetables,,such as cabbages, greens, turnips, &c.:
25 maas of sour krout weigh 100 lbs.;  and for 481 kreutzer
(Is. 5d.  sterling) there are bought, on an average, 24£ lbs.
of onions, leeks, celery, &c*   855 men consumed
      Of green vegetables     .     .     .    2,802 oz.
       Of sour krout .    .    .     .     .    1,600
      Of onions,  &c.    ....      388
             In all.....4,790
         And one man   ....      5-6 oz.

   For this reason, the carbon of the last mentioned articles
 of food has been assumed as equal to that of the faeces and
 urine.   Sausages, brandy, beer, in short, the small quantity
 of food taken irregularly in the alehouse,.has riot been in-
 cluded in  the calculation.
   The daily allowance of bread, being uniformly 2 lbs. per
 man, with the exceptions formerly mentioned, has not been
 inserted in the table, which includes only those matters of
 which, from the  daily allowance being variable, an  average
 was required. The small quantity of bread in the table is
 that given in the soup, which  is over and  above the daily
 supply.

   * In the original table, the quantities of these vegetables are  entered
 according to  their value in kreutzers, but  they are here calculated by
 weight from the above data, as this appeared better adapted for com-
 parison in this country than the prices would have been.—Ed. 
                                                   TABLE  I. (to Note  3.)
Containing a Summary of the Victuals consumed during November, 1840, by a Company of the Body Guard of the Grand Duke of Hesse Darmstadt.
1840. Novemb'r, in the period from the	No. of men supplied with food.	Beef.	Pork.	Potatoes.	Peas.	Beans.	Lentils.	Sour-krout.	Green veget-ables.	Bread in Soup.	Salt.	Onions, Leeks, &c.	Pepper. Price in Kreutzers. 3kr.=ld.	Fat or Lard.	Vinegar.
1st to 5th 6th to 10th 11th to 15th 16th to 20lh 21st to 25th 26th to 30th	139 145 136 136 147 152	lbs. 36 37 36 37 39 30	lbs. 9 9 9 9 Sau-sages. 7£ 19|	lbs. oz. 147 0 165 6 153 2 177 10 171 8 177 10	lbs. oz. 4 151 3 5 3 5	lbs. oz. 3 7| 3 74 3 7| 3 7\	lbs. oz. 3 51	lbs. 20 16 16 16 32	lbs. 12 70 42 12 36	lbs. 5 74 6" H 2\	lbs. 4J-5 41 4	lbs. 4 34 4 3|	kr. 24 24 2 3i ~h ol	oz. 131 lOf 8	pints. 14
Total,	855	215	63	992 4	11 94	13 14	3 54	100	172	36	28	20i	1S4	56	14
The average No. of men daily fed is 856=28^, 30 --*U2' therefore ea man had	i Monthly < j Daily I	lbs. 731 ' 51	lbs. 012 A~5l	lbs. oz. 34 13	oz. 6-37-"171	OZ. 7135 '171	OZ. 1150 L\ 71	lbs.oz. Oil91	lbs. 6-S-"l 7 1	lb. 115	lb. 56 57	oz. II-7-	31 kr Si Kr'	Iff oz.	pint. 3 3T
		OZ. 4-4-*17 1	l 153 LS1SS OZ.	lb. oz i m	OZ. 3T1 rrnr	OZ. 222	OZ. 107 1 7 TO	oz. 7 149 iTTT	oz. ol 87 ^stt	lb. 36	lb. •2 8 ■8TJ	oz. 324	-3-1 kr 1 7 To Kr"	At oz-	pint. 3 niTT
N  r —A"! all the weishts mentioned in the text of this work are Hessian pounds and ounces, the different articles in this table have been reduced to
7712  or as 1:11017 ; and 1 oz. Hessian = 482 grains Troy (1 oz. Troy is = 480 grains), while 1 oz. avoirdupois is = 4375 grains Troy 
290                    APPENDIX.


               TABLE  II.—Note (4), p. 14. a
FOOD CONSUMED BY A HORSE IN TWENTY-FOUR HOURS.
Articles of food.	Weight in the fresh state.	Weight in the dry state.	Carbon.	Hydro-gen.	Oxy-gen.	Nitro-gen.	Salts & earthy mat-ters.
Hay Oats Water	7500 2270 16000	6465 1927	2961-0 977-0	323-2 123-3	2502-0 707-2	97-0 42-4	581-8 77-1 13-3
Total	25770	8392	3938-0	446-5	3209-2	139-4	672-2
EXCRETIONS OF A HORSE IN TWENTY-FOUR HOURS.
Excretions.	Weight in the fresh state.	Weight in the dry state.	Carbon.	Hydro-gen.	Oxy-gen.	Nitro-gen.	Salts Ac earthy mat-ters.
Urine Excrements	1330 14250	302 3525	108-7 1364-4	11-5 179-8	34-1 1328-9	37-8 77-6	109-9 574-6
Total	15580	3827	1472-9	191-3	1363-0	115-4	684-5
Total from the previous part of this Table.	25770	8392	3938-0	446-5	3209-2	139-4	672-2
Difference	10190	4565	2465-1	255-2	1846-2	24-0	12-3
+ or —							+
  a Boussingault, Ann. de Ch. et de Phys., LXX., 136.  The weights
in this table are given in grammes.  1 gramme = 1544 grains Troy
very nearly. 
ANALYTICAL EVIDENCE.
291
       TABLE  II.—Note (4), p. 14 (concluded.)





FOOD CONSUMED BY A COW IN  TWENTY-FOUR HOURS.
Articles of food.	Weight in the fresh state.	Weight in the dry state.	Carbon	Hydro-gen.	Oxygen	Nitro-gen.	Salts and earthy matters.
Potatoes After Grass Water	15000 7500 60000	4170 6315	1839-0 2974-4	241-9 353-6	1830-6 2204-0	50-0 151-5	208-5 631-5 50-0
Total	82500	10485	4813-4	595-5	4034-6	201-5	889-0
EXCRETIONS  OF A  COW IN TWENTY-FOUR HOURS.
Excretions.	Weight in the fresh state	Weight in the dry state	Carbon	Hydro-gen.	Oxygen	Nitro-gen.	Salts and earthy matters
Excrements Urine Milk	28413 8200 8539	4000-0 960-8 1150-6	1712-0 261-4 628-2	208-0 25-0 99-0	1508-0 253-7 321-0	92-0 36-5 46-0	480-0 384-2 56-4
Total	45152	6111-4	2601-6	332-0	2082-7	174-5	920-6
Total of first part of this Table	82500	10485-0	4813-4	595-5	4034-6	201-5	889-0
Difference	37348	4374-6	2211-8	263-5	1951-9	27-0	31-6
					- ~		+ 1
 
292
APPENDIX.
                   NOTE (5), p. 19.

TEMPERATURE OF THE BLOOD AND FREQUENCY OF
                     THE PULSE.
                     According

                    The mean
                  temperature is
                      F.
In the Pigeon .  .  .   107-6°
Common Fowl  .  .   106-7°
Duck.....108-5°
Raven.....108-5°
Lark.....117-2°
Simia Callitriche .  .    95-9°
Guinea Pig   .  .  .   100-4°
Dog......99-3°
Cat......101-3°
Goat......102-5°
Hare......   100-4°
Horse.....98-2°
Man......98-6°

Man (Liebig) .  .   .   97-7°
Woman (Liebig) .   .   98-2°
  The temperature of a child is 102-2°.
  The temperature of the human body, in the mouth or in
the rectum, for example, is from  97*7° to 98*6°.   That of
the blood (Majendie) is from 100-6° to 101-6°.   As a mean
temperature, 99*5° has been adopted in this work, page 19.
to Prevost and Dumas,		
The frequency		
of the pulse	of the respiration	
in the minute.	in the minute.	
136		34
140		30
170		21
110		21
200		22
90		30
140		36
90		28
100		24
84		24
120		36
56		16
72		18
65		17
60		15
 
                ANALYTICAL  EVIDENCE.            293

                      NOTE (6), p. 36.

  The  prisoners in the house  of  arrest of Giessen receive
daily l\ lb. of bread  (24 oz.), which contain 7± oz. of car-
bon.   They  receive,  besides, 1 lb. of soup  daily,  and  on
each alternate day, 1 lb. of potatoes.

     14 lb. of bread contains   .     .     7-25 oz. of carbon.
     1  lb. of soup contains    .     .     0-75     ditto
     4 lb., of potatoes contains .     .     1-00     ditto

             Total      .     .     .     9-00     ditto, f
                     NOTE (7), p. 43.

COMPOSITION OF THE  FIBRINE AND ALBUMEN OF
                         BLOOD, a

               Albumen from Serum of Blood.      Fibrine.
                         Scherer.*            Scherer.*   Mulder.
                     I.     II.      in.     I.      II.      III.
Carbon.....53850 55461  56097  53671  54454  5456
Hydrogen ....   6983   7201   6880   6878   7069   690
Nitrogen  ....  15673  15673  15681  15763  15762  1572
Oxygen     ■]
Sulphur     >   .   .  23-494  21655 22342  23688  22715  2282
Phosphorus J
 a Annalen der Chem. und Pharm., XXVIII., 74, and XL., 33, 36.

  For additional analyses of animal fibrine and  albumen,
see Note (27),  which  also contains analyses of the various
animal tissues.

  t At page 36 the carbon contained in the daily food of these prisoners
is calculated at 8£ oz., and the appendix in the original makes the num-
ber also 8-5, apparently by an error in adding up  the above numbers,
which yield the sum of 9 oz.  Possibly there may be an error in excess
in the proportion of carbon calculated for the soup, which, in that case,.
ought to be 025 oz.—Editor.
                25* 
294
APPENDIX.
                     NOTE (8), p. 48.

COMPOSITION  OF VEGETABLE FIBRINE, VEGETABLE
  ALBUMEN,  VEGETABLE   CASEINE, AND  VEGETA-
  BLE GLUTEN.
Vegetable Fibrine.
Gluten,
Sherer. 'a
Carbon  .  .
Hydrogen  .
Nitrogen
Oxygen
Sulphur
Phosphorus
                         As obtained from
                             wheat flour.
                     Jones.'b Marcet.c Boussin-
r-------------------v              gault.
  I.      II.      III.     IV.     I.    II.
 53064  54-603  54617 53-83  557  535
  7132   7302   7-491  702  145  150
 15-359  15-809  15809 1558   78   70

 24-445  22285  22083 2356  220  245
a Ann. der Chem. und Pharm., XL., 7.
b Ibid., XL., 65.
c L. Gmelin's Theor. Chemie, II., 1092.
Carbon
 Vegetable  Albumen, a

From Rye.   Wheat.     Gluten.
Almonds.
Jones.*
 54-74
Jones.*  Varrentrapp <fc Will.* Jones.'
55-01
Hydrogen . . . 7-77	7-23
Nitrogen . . . 15-85	15-92
Oxygen \	
Sulphur i . 21-64	21-84
Phosphorus J	
	i Boussingault.
Carbon . . .	. 52-7
Hydrogen . .	. 6-9
. Nitrogen . . .	. 18-4
Oxygen, &c.	. 22-0
 54-85      57-03
  6-98       7-53
 15-88      13-48

 22-39      21-96

Varrentrapp arid Will.*


      15-70
a Ann. der Chem. und Pharm., XL., 66, and XXXIX., 291. 
ANALYTICAL EVIDENCE.           295
Vegetable  Caseine. a
			Sulphate of Caseine
			and Potash.
	Scherer.*	Jones.*	Varrentrapp and Will.
Carbon . .	54-138	55-05	51-41 51-24
Hydrogen	7-156	7-59	7-83 6-77
Nitrogen . .	. 15-672	15-89	14-48 13-23
Oxygen, &c.	23-034	21-47	--- ---
a Ann. der Chem. und Pharm., XXXIX., 291, and XL., 8 and 67.

                Vegetable Gluten.
                        Jones. *a        Boussingault.
Carbon   ....   55-22
Hydrogen   .   .  .    7-42
Nitrogen ....   15-98
Oxygen, &c.    .  •   21-38
      a Ann. der Chem. und Pharm
54-2
 7-5
13-9
24-4
, XL.
52.3
 6-5
18-9
22-3
66,
  The pure gluten, analyzed by Jones, was that portion of
the raw gluten from wheat flour which is soluble in hot al-
cohol.   The insoluble portion is vegetable fibrine, the analy-
sis of which has been already given.
             NOTE (9), p. 51.
COMPOSITION OF ANIMAL CASEINE. a
                           Scherer."
From fresh From sour From milk milk.,, j milk. by acetic acid		Albuminous sub-stance in milk. 6.
I. n. 54-825 54-721 7-153 7-239 15-628 15-724	III. IV. 54-665 54-580 7-465 7-352 15-724 15-696	v. 54-507 6-913 15-670
22-394  22-316   22-146  22-372     22-910
Carbon  .
Hydrogen
Nitrogen .
Oxygen )
Sulphur >
  a Ann. der Chem. und Pharm., XL., 40 et seq.
  b This substance, called, in German, zieger, is contained in the whey
of milk after coagulation by an acid.  It is coagulated by heat, and
very much resembles albumen. 
296
APPENDIX.
	Mulder, a
Carbon .	54-96
Hydrogen Nitrogen Oxygen . Sulphur . . .	7-15 15-89 21-73 0-36
a For the analysis of vegetable caseine, see the preceding note.
                   NOTE (10), p. 64.

AMOUNT OF MATTER SOLUBLE IN ALCOHOL IN THE
  SOLID EXCREMENTS OF THE HORSE  AND  COW.
  (WILL.*)

   18-3 grammes of dried horse-dung lost, by the action of
alcohol, 0-995 gramme.   The residue, when  dry, had the
appearance of saw-dust, after it has been deprived, by boil-
ing, of all soluble matter.
   14-98 grammes of dry cow-dung lost, by the same treat-
ment, 0*625 gramme.
	NOTE (11)		p. 70.	
	COMPOSITION OF STARCH, a			
	Calculated		Strecker."	
		From	From From	From
	C12H10O10.	Peas.	Lentils. Beans.	Buckwheat
Carbon	. 44-91	44-33	44-46 44-16	44-23
Hydrogen	. 6-11	6-57	6-54 6-69	6-40
Oxygen .	. 48-98	49-09	49-00 49-15	49-37
 
analytical evidence.            297
          From maize.
Carbon     44-27
Hydrogen    6-67
Oxygen     49-06
From horse-chesnuts.
     44-44
      6-47
     49-08
From wheat.
 44-26
  6-70
 49-04
From rye.
 44-16
  6-64
 49-20
Strecker.*
          From rice.
Carbon      44-69
Hydrogen    6-36
Oxygen     48-95
   From
dahlia roots.
   44-13
    6-56
   49-31
   From
unripe apples.
   44-10
    6-57
   49-33
   From
unripe pears.
   44-14
     6-75
   49-11
From potatoes.
From arrow-root. From yams, a
          Berzelius.
Carbon     44-250
Hydrogen    6-674
Oxygen    49-076
Gay Lussac & Thenard.
      43-55
       6-77
      49-68
Prout.
44-40
 6-18
49-42
Ortigosa.
  44-2
   6-5
  49-3
  a The starch employed for the analyses, made by Strecker and Orti-
gosa, was prepared from the chemical laboratory at Giessen, from the
respective seeds, bulbs, and fruits.
                     NOTE (12), p. 71.

COMPOSITION OF GRAPE SUGAR.  (STARCH SUGAR.)

        Fromgrapes.a  From starch.* From honey.c    Calculated.
                 De Saussure.              Prout-        CuHmOm.
37-29
 6-84
55-87
36-36
 7-09
56-55
Carbon      36-71
Hydrogen    6-78
Oxygen     56-51
                a Ann. de Chimie, XI., 381.
                b  Ann. of Philosophy, VI., 426.
                c  Philosioph. Trans. 1827, 373.
36-80
 7-01
56-19 
298
appendix.
           NOTE (13), p. 72.
COMPOSITION  OF SUGAR OF MILK.
Gay Lussac					Calculated
and Thenard.	Prout.	Brunn,	Berzelius.	Liebig.'	Cl2ll"l20ia
Carbon 38825	4000	40-437	39-474	4000	4046
Hydrogen 7341	666	6-711	7167	6-73	6-61
Oxygen 53831	53-34	52-852	53-359	53-27	5293
    NOTE (14), p. 72.
COMPOSITION OF GUM.
         Gay Lussac
         and Thenard.
Carbon     42-23
Hydrogen   6-93
Oxygen    50-84
Goebel.
 42-2
  6-6
 51-2
Berzelius.
 42-682
  6-374
 50-944
Calculated.
C12H11OU
 42-58
  6-37
 51-05
            NOTE (15), p. 74.
  ANALYSIS OF OATS   (Boussingault). a
100 parts of oats contain of dry matter  84-9
Ditto
water
17-1
100-0
  100 parts of oats dried at 212° = 117-7 parts dried at the
ordinary temperature, contain
             Carbon
             Hydrogen
Oxygen
Nitrogen
Ashes
Water
 50-7
  6-4
 36-7
  2-2
  4-0

100-0
 17-7
 Oats dried in the air 117-7 contain, in 100 parts,
                             1-867 of nitrogen.
a Ann. de Chimie et de Phys., LXXL, 130. 
               analytical  evidence.            299

                   Analysis  of Hay.
 100 parts of hay dried in the air contain 86 of dry matter,
                                      14 of water.

                                      100
                           212° = 116-2 parts dried in air,

                                 45-8
                                  5-0
                                 38-7
                                  1-5
                                  9-0

                                100-0
                                 16-2 water,

                                116-2 hay dried in the air.
  100-0 of hay dried at the ordinary temperature contain 1-29 of
nitrogen.
240 oz. of such hay = 15 lbs. contain . . . 3-095 oz. of nitrogen.
 72 oz. of oats     = 44 lbs. contain . . . 1-34       ditto

                            Total . . . 4-435      ditto
                   NOTE (16), a, p. 77.
  AMOUNT OF CARBON IN FLESH AND IN STARCH.
  100 parts of starch contain 44 of  carbon; therefore, 64
oz.  (4 lbs.) contain 28-16 oz. of carbon.
  100 parts of fresh meat contain 136 of carbon (see Note
III.);  hence  240  oz.  (15 lbs.) contain  32*64  oz.  of car-
bon4
  t  By an error in calculation in the original, the amount of carbon in
15 lbs. of meat is stated to be 2764 oz.  It follows, that the carbon of
4 lbs. of starch is not equal, as stated in the text, to that of 15 lbs. of
flesh, but to that of 13 lbs.  This difference, however, is not sufficient
to affect the argument at p. 84.—Editor.
  100 parts of hay dried at
contain
             Carbon
             Hydrogen  .
             Oxygen
             Nitrogen
             Ashes . 
300
appendix.
NOTE (16), b, p. 84.
	COMPOSITION OF		
	Hog's Lard.	Mutton fat. Chevreul. a	Human fat,
Carbon	. 79-098	78-996	79-000
Hydrogen	. 11-146	11-700	11-416
Oxygen .	. 9-756	9-304	9-584
a Recherches Chim., sur les		corps gras. Paris.	1823.
                   NOTE (17), p. 84.

           COMPOSITION OF CANE SUGAR.
                          According to
           Berzelius.  Prout. W. Crum
Carbon  .   42-225  42-86  42-14
Hydrogen   6-600   6-35   6-42
Oxygen .  51-175  50-79  51-44
  For the composition of gum and of starch, see Notes (14)
and (11).
Liebig.*	Gay Lussac Calculated & Thenard. C12H11O11.
42-301	42-47 42-58
6-384	6-90 6-37
51-315	50-63 51-05
          NOTE (18), p. 85.

COMPOSITION OF CHOLESTERINE.
	According to	
	Chevreul. a Couerbe. 6 Marchand.	Calculated C36H32O.
Carbon	. . 85-095 84-895 84-90	84-641
Hydrogen. .	. . 11-880 12-099 12-00	12-282
Oxygen . .	. . 3-025 3-006 3-10	3-077
a Recherches sur les corps gras, p. 185.
b Ann. de Ch. et de Phys. LVI., p. 164. 
ANALYTICAL  EVIDENCE.           301
                   NOTE (19), p. 87.

   THE  PRODUCTION OF WAX FROM SUGAR, a

   As soon as the bees have filled their stomach, or what
is  called the  honey bladder, with  honey, and cannot de-
posit  it for want  of cells, the honey passes  gradually in
large quantity into the  intestinal canal, where  it is di-
gested.   The greater part is expelled  as excrement ;  the
rest enters the fluids of the  bee.   In consequence of this
great flow of juices a fatty  substance is produced, which
oozes out on the  eight spots  formerly mentioned, which
occur  on the four lower scales of the  abdominal rings,
and  soon  hardens into  laminae of  wax.   On the  other
hand, when  the bees  can  deposit their honey, only so
much enters  the intestinal canal as is necessary  for  their
support.    The  honey  bladder  need  not  be filled  with
honey longer than forty hours in order to bring to maturi-
ty, on the eight spots,  eight laminae of wax, so  that  the
latter fall off.   I made  the  experiment of giving to bees,
which I had enclosed in a  box with their queen about the
end of September, dissolved sugar-candy instead of honey.
Out  of  this food laminae of wax were formed; but these
would not separate and fall  off readily, so that the  mass,
which continued to  ooze out, remained, in most of the
bees, hanging to  the upper laminae :  and the laminae of
wax  became as thick  as  four under ordinary circum-
stances.   The  abdominal  scales  of  the  bees  were, by
means  of  the wax,  distinctly  raised, so that the  waxen
laminae  projected  between  them.   On examination,  I

  a From F. W. Gundlach's Natural History of Bees. p. 115.  Cassel,
1842.  We are acquainted with no more beautiful or convincing proof
of the formation of fatty matter from sugar than the following process
of the manufacture of wax by the bee as taken from observation,
                           26 
302
APPENDIX.
found that these thick laminae, which under  the  micro-
scope exhibited  several  lamellae,  had a  sloping  surface
downwards near the head, and upwards in the vicinity of
the tail.   The  first  waxen laminae, therefore,  must have
been pushed  downwards  by  the  second, because, where
the abdominal scales are attached to the skin,  there is  no
space for two laminae, the second by the  third, and thus
the inclined surfaces on  the sides  of the thick lamina; had
been produced.   I saw distinctly  from this,  that the first
formed laminae are detached by those which  follow.  The
sugar had been converted into wax  by the bees, but it would
seem that there was some imperfection in the  process, as
the laminae did not fall off, but adhered to the  succeeding
ones.
   In order to produce wax in the manner described, the
bees require  no  pollen, but only  honey.   I  have  placed,
even in October, bees in an empty  hive, and fed them with
honey ;  they soon formed comb, although the weather was
such that they  could not leave the hive.  I cannot, there-
fore, believe  that  pollen furnishes food for the  bees, but I
think they only swallow it in  order, by mixing  it with ho-
ney and  water, to prepare the liquid food for  the grubs.
Besides, bees often starve in April, when their stock of ho-
ney is consumed, and when  they  can obtain in the fields
abundance of  pollen, but no honey.   When  pressed  by
hunger  they  tear the nymphae out of the cells, and gnaw
them in order to support life by the sweet juice which they
contain.   But, if in this condition they are not artificially
fed, or if the fields do not soon yield their proper food, they
die in the course of a few days.   Now, if the pollen were
really nourishment for bees, they ought to be able to  support
life on it, mixed with water.
   Bees  never build  honeycomb unless they have a queen,
or are provided with young out of  which they can educate 
ANALYTICAL EVIDENCE.           303
a queen. But if bees be shut up in a hive without a queen,
and fed with honey, we can perceive  in forty-eight hours
that they have laminae of wax on their scales, and that some
have  even separated.   The building of cells is  therefore
voluntary,  and  dependant on  certain conditions, but the
oozing out  of wax is involuntary.
  One might suppose that a large proportion of these lami-
nae must be lost, since the bees may allow them  to fall off,
out of the  hive as well as in it;  but the Creator has wisely
provided against such a loss.  If we give to bees engaged
in building cells honey in  a flat dish, and  cover the dish
with perforated paper, that the bees may not be entangled in
the honey,  we shall find, after a day, that the honey has dis-
appeared, and that a large number of laminae  are lying on
the paper.   It would appear as if the bees, which have car-
ried off the honey, had let fall the scales;  but it is not so.
For, if above the paper  we  lay two  small rods, and on
these  a board, overhanging the dish on every  side, so that
the bees can creep under the board and  obtain the honey,
we shall find next day  the  honey gone,  but no laminae on
the paper ;  while laminae will be found in abundance on the
board above.  The bees, therefore, which go for  and bring
the honey, do not let  fall  the laminae  of wax, but only
those  bees  which remain  hanging to  the top  of the hive.
Repeated  experiments  of this kind  have convinced  me
that the bees, as soon as  their laminae  of wax are ma-
ture,  return to the hive  and  remain  at rest,  just  as
caterpillars do, when about  to  change.  In a  swarm that
is  actively employed in building we  may see  thousands
of bees hanging idly at the top of  the  hive.  These are
all bees whose laminae of  wax are  about   to separate.
When  they  have fallen off, the activity  of  the  bee re-
vives, and  its place is  occupied for  the  same purpose by
another. 
304
APPENDIX.
  (From page 28 of the same work.)  In order to ascertain
how much honey bees require to form wax, and how often,
in a swarm engaged in building, the laminae attain maturity
and fall off, I made the following experiment, which appears
to me not uninteresting.
  On the 29th  of August, 1841, at a time when the bees
could obtain in this district no farther supply of honey from
the fields, I emptied a small hive, placed the bees in a small
wooden hive, having  first selected the queen  bee, and shut
her up in a box, furnished with wires, which I placed in the
only door of the hive, so that  no embryos could  enter the
cells.  I then placed  the hive in a window, that I might be
able to watch it.
  At 6  p. m. I gave the bees 6 oz. of honey run from the
closed  cells, which  had   thus the exact consistence  of
freshly made honey.   This had disappeared next morning.
In  the  evening of the 30th  I gave the bees 6 oz. more,
which, in like manner, was removed by the next morning •
but already some laminae  of wax  were seen lying on the
paper with which  the  honey was covered.   On  the 31st
August  and the 1st  September the bees had in  the even-
ing 10 oz., and on the 3rd of September  in the evening
7 oz.; in all, therefore, 1  lb, 13 oz. of honey, which had
run cold out of cells which the bees had already closed.
On the  5th  of September  I  stupified the bees,  by means
of puff-ball, and counted them.   Their number was 2,765,
and they weighed  10 oz.  I next weighed  the  hive, the
combs of which were  well filled with honey, b^ut the cells not
yet closed;  noted the weight, and  then allowed  the honey
to be carried off by a strong swarm  of bees.   This was
completely effected in  a few hours.   I now  weighed it a
second  time, and found it  12 oz.  lighter ; consequently the
bees still had in the  hive  12  oz. of the 29 oz. of  honey
given to them.  I next extracted the  combs, and found 
ANALYTICAL EVIDENCE.           305
that  their weight was £ of an  ounce.   I  then placed  the
bees  in another box,  provided with empty combs, and fed
them with the same honey as before.  In the first few days
they lost daily rather  more than 1 oz. in weight, and after-
wards half an ounce daily, which was owing to the circum-
stance, that from the digestion of so  much  honey, their
intestinal  canal was  loaded with  excrements; for  1,170
bees, in autumn, when they have been but a short time con-
fined to the hive, weigh 4  oz. j consequently  2,765 bees
should  weigh 9 oz.  But they actually weighed 10 oz., and
therefore had  within  them  1 oz. of excrement,  for their
honey bladders were empty.  During the  night the weight
of the box did not diminish at all, because the small quanti-
ty of honey the bees had deposited in the cells, having
already the proper  consistence, could  not lose weight by
evaporation, and because the bees could not then get rid of
their excrements.  For this reason, the loss of weight oc-
curred always during the day.
   If, then, the  bees, in seven days,  required 3| oz.  of
honey  to support and  nourish their bodies, they must have
consumed 13^  oz. of honey in forming f of an  ounce of
wax; and  consequently,  to form 1 lb.  of wax, 20 lbs. of
honey  are required.   This is the reason why the strongest
swarms in the best honey seasons, when  other hives, that
have no occasion to build, often gain in one day 3 or 4  lbs.
in weight, hardly become heavier, although their activity is
boundless.  All that they gain  is expended in making wax.
This is a hint for those who keep bees, to limit the  build-
ing  of comb.  Cnauf has already recommended this, al-
though he was not acquainted with the true relations of the
subject.   From 1 oz. of wax, bees can build  cells enough
to contain 1 lb. of  honey.
   100 laminae of wax weigh 0-024 gramme (rather more
than ^ of a grain), consequently, 1 kilogramme (= 15,360
               26* 
306
APPENDIX.
grains)  will contain  4,166,666 laminae.   Hence, f  of an
ounce  will  contain  81,367 laminae.   Now  this quantity
was  produced by 2,765 bees in six days ; so that the bee
requires  for  the  formation  of its 8  laminae (one crop)
about thirty-eight hours, which agrees very well with my
observations.
  The  laminae, when formed, are as  white as bleached
wax.  The cells also, at first, are quite white, but they are
coloured yellow by the honey, and still more by the pollen.
When the  cold weather  comes on, the bees retire to the
hive under the honey, and live on the stock they have ac-
cumulated.
  P. 54.  Many  believe that bees are hybernating ani-
mals ;  but  the opinion is quite  erroneous.   They are lively
throughout  the  winter;  and the hive  is  always  warm
in consequence of the heat which  they  generate.  The
more numerous the bees in  a hive, the more heat is de-
veloped ; and hence strong hives can  resist the most in-
tense cold.   It once happened  that I forgot to remove from
the door, which was unusually large, of a hive  in winter,
a perforated plate of tinned  iron, which I had fastened
over the opening  to diminish  the heat in  July ;  and yet
this  hive came well through  the winter, although the cold
was very  severe, having  been  for several  days so low
 as 0°.  But I had added to this hive the bees of two other
hives!   When the cold  is very intense, the bees begin to
hum.   By this means  respiration is accelerated and the
developement of heat increased.  If, in summer, bees  with-
out a queen are shut up in a glass box, they become uneasy
and  begin  to hum.   So much heat is by this  means de-
veloped, that the plates of glass become quite hot.   If the
door be not opened in this case, or if  air be not  admitted,
and if the  glass be not cooled by the aid of water, the bees
are soon suffocated< 
ANALYTICAL  EVIDENCE.
307
            COMPOSITION OF  BEES'  WAX.

          &aTheUnaSrd.'a De saussure.& Oppermann.c Ettling.d Hess.e °aJ0CHlI2*o3d
Carbon    81-784     81-607     81-291    81-15  81-52  81-38
Hydrogen  12-672     13-859     14-073    13-75  13-23  13-28
Oxygen     5-544     4-534     4-636     5-09   5-25   5-34
       a Traite de Chimie, par Thenard, 6me Ed.. IV., 477.
       * Ann. de Ch. et de Phys., XIII., 310.
       c Ibid. XLIX., 224.
       d Annal. der Pharm., II., 267.
       e Ibid. XXVII., 6.
                   NOTE (21) a, p. 104.

COMPOSITION OF  HYDRATED  CYANURIC  ACID,  OR
  HYDRATED CYANIC ACID, AND  OF  CYAMELIDE, IN
  100  PARTS, ACCORDING  TO  THE   ANALYSIS  OF
  WOHLER AND LIEBIG.* a
                                  Cyanuric acid, cyanic
                                    acid, cyamelide.
               Carbon     .     .     .28-19
               Hydrogen   .     .     .    2-30
               Nitrogen    .     .     .   32-63
               Oxygen     .     .     .   36-87
           a Poggendorff's Annalen, XX., 375 et seq.
                    NOTE  (21) b, p. 104.
COMPOSITION OF  ALDEHYDE, METALDEHYDE, AND
                      ELALDEHYDE. a
          Aldehyde.  Metaldehyde.       Elaldehyde.        Calculated
            Liebig.*              Fehling."             C4H4Oa.
Carbon    55-024     54-511    54-620 ~~54-467'   55-024
Hydrogen   8-983      9-054      9-248      9-075    8.983
Oxygen    35-993     36-435    36-132     36-458   35-993
         a Ann. der Pharm., XIV., 142, und XXVII., 319. 
308
APPENDIX.
      NOTE (22), p. 105.
COMPOSITION OF PROTEINE.
	cry	stXelens. From albumen. Scherer.* a	From fibrine.
Carbon		55-300 55-100	54-848
Hydrogi	in	6-940 7-055	6.959
Nitrogen		16-216 15-966	15-847
Oxygen	'	21-544 21-819	22,346
		Scherer.* a	CcLlCUlclt6(l
	From hair. From horn.		C48H36N,6Oh
Carbon	54-746	55-150 55-408 54-291	55-742
Hydrogen	7-129	7-197 7-238 7-082	6-827
Nitrogen	15-727	15-727 15-593 15-593	16-143
Oxygen	22-398	21-926 21-761 23-034	21-228
	a, Ann. <	der Chrm. und Pharm., XL., 43.	
^2* From fibrine. From albumen.			From cheese.
		Mulder, a	
Carbon	54-99	55-U 55-30	55-159
Hydrogen .	6-87	6-95 6-94	7-176
Nitrogen	15-66	16-05 16-02	15-857
Oxygen	22-48	21-56 21-74	21-808
	a Ann. der Pharm., XXVIII., 75.		
                 NOTE (23), p. 107.
COMPOSITION OF THE ALBUMEN OF THE YOLK AND
          OF THE WHITE OF THE EGG. a
	From the yolk. Jones.*			From the white. Scherer.*
	I.		II	
Carbon	. 53-72		53-45	55-000
Hydrogen	. 7-55		7-66	7-073
Nitrogen .	. 13-60		13-34	15-920
Oxygen				
Sulphur	[ 25-13		25-55	22-007
Phosphorus				
.a Ann, der Chem. und Pharm. XL., 36,. ibid. 67.				
 
ANALYTICAL EVIDENCE.
309
                   NOTE (24), p. 111.
           COMPOSITION OF LACTIC  ACID.
                                    C6H505.
               Carbon............ 44 90
               Hydrogen..........  611
               Oxygen...........  4899

                   NOTE  (25), p. 115.
GAS FROM THE ABDOMEN OF COWS AFTER EATING
  CLOVER TO EXCESS, OBTAINED BY  PUNCTURE.
  a Examined by Lameyran and Fremy.  b By Vogel.
c By Pfluger.
  Air.         Carbonic acid. Inflammable gas.  Sulphuretted hydrogen.
a  5           5   —        15            80 Vol. in 100 Vol.
b 25           —   27        48            —
c —           —   60        40            —
c —           —   20        80            —

                   NOTE (26), p. 118.
MAGENDIE FOUND  IN THE  STOMACH AND  INTES-
          TINES  OF EXECUTED CRIMINALS:
   a In the case  of an individual who had taken  food in
moderation one  hour  previous to death  ;  b, in the case of
one who had  done so  two hours previously; and c, in  the
case of a third, who  had done so four hours previous to ex-
ecution.
                              100 Volumes of the gas contained.
                            Oxygen.  Nitrogen. Carbonic Inflammable
                                             acid.     gas.
  ( From the stomach...........1100 Vol.  7145  1400    355
a\   —   small intestines.... 0000      2003  2439   5553
  (   —   large intestines.... 0000      51-03  4350    547
  r From the stomach..........0000      00-00  0000   0000
b\   —   small intestines.... 0000       8-85  4000   5115
  (   —   large intestines.... 0000      1840  7000   1160
  , From the stomach...........0000      0000  0000   0000
 c)   —    small intestines.... 0000      6660  2500    840
  )   _-    large intestines.... 0000      4596  4286   U18 
310
APPENDIX.
         NOTE (27), referred to in NOTE (7), p. 43.
COMPOSITION OF ANIMAL ALBUMEN AND FIBRINE,
  AND OF THE DIFFERENT TISSUES OF  THE BODY.
		1. Albumen.			
	From the serum of blood.			From eggs.	From yolk of egg.
		Scherer.	'a		Jones.* b
	i.	n.	III.	IV.	V. VI.
Carbon. . .	. 53 850	55461	55-097	55 000	53-72 53-45
Hydrogen .	. 6983	7-201	6-880	7073	7-55 7-6G
Nitrogen . .	. 15673	15673	15-681	15-920	13-60 1334
Oxygen. . .^
Sulphur. . .  \ 23494
21-655    22-342    22007   2513  2555
Phosphorus  I
a Ann. der Chem. und Pharm., XL.
b Ibid. 67.
36.
Carbon .  .
Hydrogen.
Nitrogen..
Oxygen. .
Sulphur. .
Phosphorus
Jones. *
  From
 albumen
 of brain.

  VII.
 . 55-50
 .  719
 . 1631

 • 21 00
Scherer.*
  From
hydrocele.

 VIII.
54-921
  7077
15465
  From
congestive
 abscess.
        r
  IX.
54-757
 7-171
15-848
From pus.
 X.
54-663
 7022
15-839
54101
 6-947
15-660
                    Mulder, a
Carbon. ........  54 84
Hydrogen.......    709
Nitrogen........  15-83
Oxygen........  2123
Sulphur........    0-68
Phosphorus......    033
 From
fluid of
dropsy,

 XII.
54-302
 7176
15-717
22-537    22-224    22476   23292   22 805
Ann. der Pharm.
XXVIII., 74. 
ANALYTICAL EVIDENCE.
311
		2.	Fibrine. Scherer. *a	
	i.	n.	III. IV.	V. VI. VII.
Carbon . .	, 53-671	54-454	55002 54-967	53-571 54686 54844
Hydrogen .	. 6-878	7069	7216 6-867	6-895 6-835 7219
Nitrogen . .	. 15-763	15-762	15-817 15913	15-720 15-720 16065
Oxygen	)			
Sulphur	} 23-688	22-715	21-965 22-244	23-814 22-759 21-872
Phosphorus	)			
a Ann. der Chem. und Pharm., XL., 33.

     Carbon..........5456
     Hydrogen........  690
     Nitrogen.........15-72
     Oxygen.........2213
     Sulphur.........  0-33
     Phosphorus.......  036

   a Ann. der Pharm., XXVIII., 74.
3.  Gelatinous  Tissues.
			Tendons of the	Tunica Calculated.	
	Isinglass. 50-557		calf's foot.	sclerotica. C4sH4iN7iOi8.	
Carbon. . .		49-563	50-960	50-774 50-995	50.207
Hydrogen	, 6-903	7-148	7-188	7-152 7-075	7001
Nitrogen. ,	18-790	18-470	18-320	18-320 18-723	18170
Oxygen .	, 23-750	21-819	23-532	23-754 23-207	24-622
a Ann. der Chem. und Pharm., XL., 46.
Mulder.
Carbon........50048    50048
Hydrogen......  6477     6643
Nitrogen.......18350    18-388
Oxygen........25125    24-921 
312
APPENDIX.
4. Tissues containing Chondrine.
Scherer. 'a
Cartilages of the
ribs of the calf.
Carbon
Hydrogen
Nitrogen
Oxygen
49-496
 7133
41-908
28-463
50-895
 6-962
14-908
27235
Cornea.

49 522
 7097
14-399
28-982
 Calculated.
C'4SlIloN6 O20.

  50-745
   6904
  14-69*2
  27659
Mulder.

50.607
 6-578
11437
28-378
a Ann. der Chem. und Pharm., XL., 49.
5. Composition of the Middle Membrane of Arteries.
	Scherer.		'a	
				Calculated. C48H38N6 0I6.
	f I.		II.	
Carbon	53-750		53-393	53-91
Hydrogen	7079		6-973	696
Nitrogen	15-360		15-360	15.60
Oxygen	23-811		21-274	23 53
a Ann. der Chem. und Pharm., XL., 51.
6.  Composition of Horny Tissues.
                    Scherer. *a
    External skin   Hair of
of the sole of the foot, the beard.
 Hair of the head.
Fair.   Brown.  Black.
Carbon
Hydrogen
Nitrogen
Oxygen )
Sulphur \
51036   50-752  51529  50652  49345  50622  49935
 6 801    6-761   6-687   6769   6576   6-613   6631
17-225   17-225  17936  17936  17936  17936  17936
24-938   25-262  23848  24643  26143  24829  25498
Scherer. 'a
Buffalo horn.
—, Calculated.
Nails.   Wool. C48H39N-?Ol7
Carbon
Hydrogen
Nitrogen
Oxygen )
Sulphur J
51-990  51162  51-620  51-540
 6-717   6-597   6754   6779
17-284  17-284  17-284  17284
51089   50-653
 6-824    7029
16-901   17-710
51-718
 6-860
17469
24009  24957  24342  24397  25186  24608    23953

      a Ann. der Chem. und Pharm., XL., 63. 
ANALYTICAL EVIDENCE.            313
  The composition of the membrane lining the interior of
the shell of the egg approaches closely to tha^ of horn.  Ac-
cording to Scherer, it contains
                                         Scherer. *«
            Carbon........50674
            Hydrogen  .......    6608
            Nitrogen.......16-761
            ?V?en}.......25-957
            Sulphur )
               a Ann der Chem. und Pharm., XL., 60.

  The composition of feathers is  also nearly the same as
that of horn.
                            Scherer.* a
                      _,______________A________________,
                      Beard ofthe  Quill ofthe     Calculated.
                        feather.      feather.    C48H39N7C-16.
     Carbon  ....   50434      52-427      52-457
     Hydrogen  .  .  .    7110       7 213        6 958
     Nitrogen   .  .  .   17682      17 893      17-719
     Oxygen ....   24-774      22467      22-866

   The  analysis here  given of the beard  of  feathers  agrees
closely with that of horn, while that of the quill  is more ac-
curately represented by the attached formula, which differs
from that of horn  by 1 eq. of oxygen only.

               a Ann. der Chem. und Pharm., XL., 61.
7. Composition of the Pigmentum nigrum Oculi.

                                 Scherer.* a
Carbon  ....  58273      58-672      57-908
Hydrogen   .   .  .   5-973       5-962       5-817
Nitrogen   .   .  .  13768      13-768      1.3-768
Oxygen ....  21-986      21-598      22-507
        a Ann. der Chem. und Pharm., XL., 63.
27 
314
APPENDIX.
                     NOTE (28),  p. 133.

   According to the analyses of Play fair and Bceckmann,

0-452 parts of dry muscular flesh gave 0-83G of carbonic acid.
0-407..........0-279 of water.
0-242..........0-450 of carb. acid & 0164 water.
0-191..........0-360   ....   0130
0-305 of dried blood gave 0575 carbonic acid and 0 202 of water.
0-214......0-402......0.138
1-471 of dried blood, when calcined, left 0-065 of ashes = 442 pr. cent.
    The dried flesh wa» found to contain     of ashes   4-23 pr. cent.
    The nitrogen was found to be to the carbon as 1 to 8 in equivalents.

                            Hence
                Flesh  (beef).        Ox-blood.         Blood.
             Playfair.  Bceckmann.  Play fair. Bceckmann.  Mean of 2 analyses.
Carbon . .  .  51-83    51-89    51-95    5196          51-96
Hydrogen  .   7-57     759      7-17     7-33           7  25
Nitrogen .  .  15-01    15 05    1507    15 08          15-07
Oxygen  .  .  21-37    21-24    21 39    21-21          21-30
Ashes  . .  .   4-23     4-23      4-42     4-42           4-42
   Deducting  the ashes, or inorganic matter, the composi-
tion of the organic part is,
     Carbon  ....  5412    54-18     5419     54-20
     Hydrogen  .   .   .   7-89     7-93      7-48     7-65
     Nitrogen   .   .   .  15-67    15-71     15-72     15-73
     Oxygen ....  22-32    2218     22-31     22-12

   This corresponds to the formula
             C48......-.   54*62
             Hs9.......7-24
             N6.......15*81
             015.......2233 
ANALYTICAL EVIDENCE.            315
          NOTE (29), p. 134.

COMPOSITION OF CHOLEIC ACID, a
Carbon .	Demargay. . 63707	Dumas. 635	Calculated Cl6H66N2022. 63-24
Hydrogen	. 8-821	93	8-97
Nitrogen .	. 3255	33	3-86
Oxygen .	. 24-217	239	2395
a Ann. der Pharm., XXVII., 284 and 293.
                    NOTE (30), p. 135.

COMPOSITION OF TAURINE AND OF CHOLOIDIC ACID.
	1. Taurine.	a	
Carbon	Demargay.* . 1924	Dumas. 1926	Calculated C4H7NO10. 19-48
Hydrogen	. 5-78	5 66	5-57
Nitrogen •	• 11-29	1119	1127
Oxygen .	. 6369	6389	6368
a Ann. der Pharm., XXVII., 287 and292.
2. Choloidic Acid, a
                        Dumas.

                         73-3
                          9-7
                         170
a Ann. der Pharm., XXVII., 289 and 293.
	Demargay.	*
	1.	H.
Carbon .	. 73301	73-522
Hydrogen	. 9511	9-577
Oxygen .	. 17-188	16 901
Calculated.
C36H5fiOl2.
  74-4
   9-4
  162
  In reference to the researches of Demargay oh the bile I
would make the following observations, 
316
APPENDIX.
   The matter to which I have  given  the name of choleic
acid is the bile itself separated from the inorganic constitu-
ents (salts,  soda, &c.) which it contains.   By the action
of subacetate of lead  aided  by ammonia, all the organic
constituents of  the  bile are  -made to unite  with  oxide of
lead, with which they  form  an insoluble, resinous precipi-
tate.   The substance here combined with oxide of lead con-
tains  all the carbon and nitrogen of the  bile.   The sub-
stance which I have named choloidic  acid  is that which is
obtained, when the  bile, purified by alcohol from the sub-
stances insoluble in that fluid, is boiled  for some time with
an excess of muriatic acid.  It  contains all the carbon  and
hydrogen  of the bile, except those  portions which have  se-
parated in the form of taurine and ammonia.   The cholic
acid contains the elements of bile,  minus those of carbonate
of ammonia.
  These three compounds, therefore, contain the products
of the  metamorphosis of the entire bile ; their formulae  ex-
press the amount of the elements of the constituents of  the
bile.  No one of them exists ready formed  in the bile in
the shape  in which  we  obtain it;  their elements are com-
bined in a  different way from that in which  they were
united  in the bile ; but the way  in  which these elements  are
arranged has not the slightest inference on the determina-
tion by analysis  of the  relative proportions of the elements.
In  the  formulae themselves, therefore,  is involved  no hy.
pothesis ;  they  are simply expressions of the results of
analysis.  It signifies nothing  that the choleic  or  choloi-
dic acids  may be composed of several compounds united
together.  No matter  how many such they may contain,
the relative proportions  of all the  elements taken together
is  expressed  by the formula which  is derived from   the
analysis.
  The study of  the products  which are produced from  the 
ANALYTICAL  EVIDENCE.          317
bile  by the action of the  atmosphere, or of chemical re-
agents, may be of importance in  reference  to certain pa-
thological conditions; but except as concerns  the  general
character of  the bile, the knowledge of these products is of
no value to the physiologist; it is only a burthen which im-
pedes his progress.  It cannot be maintained of any one of
the 38 or 40 substances, into which the bile has been  divid-
ed or  split up, that  it exists  ready formed in  the  healthy
secretion ; on  the contrary, we know with certainty that
most of them  are mere products  of the  action of the re-
agents which are made to act on the bile.
  The  bile contains soda;  but it is a most remarkable and
singular compound of soda.   When we cause that part of
the bile which dissolves in alcohol (which contains nearly
all the  organic part) to combine  with oxide of lead, thus
separating the soda, and then  remove the oxide of lead, we
obtain  a  substance, choleic  acid,  which, when placed in
contact with soda, forms a compound similar to bile in its
taste;  but it is  no  longer  bile;  for  bile  may be mixed
with organic acids, nay, even with dilute  mineral  acids,
without becoming turbid  or  yielding  a  precipitate;  while
the new compound, choleate of soda, is decomposed by the
feeblest acids, the whole of the choleic acid being separated.
Hence, bile cannot be considered, in any sense, as  choleate
of soda.   Further, it may be  asked, in what form  are  the
cholesterine, and  stearic, and margaric  acids, which  are
found in bile, contained in that fluid ?   Cholesterine is in-
soluble  in water, and  not  saponifiable by alkalies ; and if
the two fatty acids just named were  really present in  the
bile as soaps of soda, they would be instantly separated by
other acids.  Yet  diluted acids cause no such separation of
stearic and margaric acids in bile.
  It is possible  that, in the  course of new and repeated
investigations, the composition of  the  substances obtained
              27* 
318
APPENDIX.
from bile may be found different from that which has been
given  in  our analytical developement of  this  subject.
But this, if it should happen, can  have but little effect on
our formulae ; if the relative  proportions of  carbon and
nitrogen be  not  changed, the differences will  be confined
to. the proportions of oxygen and  hydrogen.   In that case
it will  be necessary for the  developement  of our views  in
formulae,  only to assume that more water and  oxygen, or
less water and oxygen, have taken a share in the meta-
morphosis of the tissues; but  the truth  of the develope-
ment  of the  process itself will  not be by this  means af-
fected.
               NOTE (31), p. 135.
      COMPOSITION OF CHOLIC ACID, a
                     Dumas.        Calculated C74H6"oOi»,
Carbon    .    .    .  68-5              68-9
Hydrogen .    .    .   9-7              9-2
Oxygen    .    .    .  21-8              21-a
           a Ann. der Pharm. XXVII., 295.
                   NOTE (32), p. 137.
COMPOSITION OF  THE  CHIEF  CONSTITUENTS  OF
         THE URINE OF MEN AND ANIMALS.

                     1. Umc Acid.
             Liebig. 'a    Mitscherlich. 6    Calculated C10H4N4O6.
Carbon    . 36*083      35-82            36-00
Hydrogen  .  2*441        2-38             23*6
Nitrogen   . 33-361      34*60           33-37
Oxygen.   •  28*126      27-20            28*27
            a Ann. der Pharm., X., 47.
            b Poggendorff's Ann., XXXIII., 335. 
ANALYTICAL  EVIDENCE.            319
                       2.  Alloxan, a

  A PRODUCT OF THE OXIDATION OF URIC ACID.
                     Wohler and Liebig.*       Calculated C8H4N2O10,

Carbon  ....   30-38           30-18           30-34
Hydrogen  .  .  .    2-57            2-48            2-47
Nitrogen.  .  .  .   17-96           17-96           17-55
Oxygen ....   49-09           49-38           49-64
              a Ann. der Pharm., XXVI., 260.

                         3. Urea.
                 Prout. a    Wohler and Liebig. b Calculated C2H4N2O3.
Carbon   .   .   .   19-99          20-02           20-192
Hydrogen.   .   .    6-65           6-71            6-595
Nitrogen .   .   .   46-65          46-73           46-782
Oxygen  .   .   .   26 63          26-54           26-425
               a Thomson's Annals, XL, 352.
               b Poggend. Ann., XX., 375.

            4. Crystallized Hippuric Acid.
                        ,,     .     »»■.  1.  i- u .   Calculated
           Liebig.'a      Dumas, b     Mitscherlicn.c   C18H8NC-5.
Carbon     60-742         60-5        60-63         60-76
Hydrogen   4-959          4-9          4-98          4-92
Nitrogen    7-816          7-7          7-90          7-82
Oxygen    26-483         26-9        26-49     "    26-50
            a Ann. der Pharm., XII., 20.
            b Ann. de Ch. et de Phys., LVIL, 327.
            c Poggend. Ann., XXX1IL, 335.

                     5. Allantoine. a
                          Wtihler and Liebig. *   Calculated CsH6N4 O&.
     Carbon......30-60              30-66
     Hydrogen   .   .   .   ,  .    3-83               3-75
     Nitrogen.....•   35-45              35-50
     Oxygen......30-12             30-09
                 a Ann. der Pharm., XXVL, 215. 
320
APPENDIX.
	6.	Uric or Xanthic Oxide	. a	
		Wohler and Liebig.*	Calculated C5H2N2 02	
Carbon .		39-28		39-86
Hydrogen		2-95		2-60
Nitrogen		36-35		37-72
Oxygen .		21-24		20-82
a Ann. der Pharm., XXVI.. 341.
7. Cystic  Oxide, a
	Thaulow.*	Calculated C6 H6 NO4 S^	
Carbon .	30-01		30-31
Hydrogen	5-10		4-94
Nitrogen	11-00		11-70
Oxygen .	28-38		26-47
Sulphur .	25-51		26-58
	a Ann. der Pharm., XXVII.	200.	
  The  cystic  oxide  is distinguished from all  the  other
concretions occurring in  the  urinary bladder by the sul-
phur it contains.  It can be shewn with certainty, that
the sulphur is  present neither in the oxidised state, nor in
combination with  cyanogen ; and in regard to its origin
the remark is not without interest, that four atoms  of
cystic oxide contain the  elements of uric acid ; benzoic acid,
sulphuretted hydrogen,  and water;  all of which are sub-
stances, the occurrence  of which in  the body is beyond  all
doubt.
1 atom uric acid . . .
1 atom benzoic acid
8 atoms sulphuret- 5
  ted hydrogen. ,. $
7 atoms water ....
CI0N4H4O6
C14   H503
      H8   S£
      H707
4 atoms cystic oxide = C24N4H24Ol6S8 =4 (CeNH604S2). 
ANALYTICAL EVIDENCE.           321
  An excellent method of detecting the presence of cystic
oxyde in calculi or gravel is the following :
  The calculus is dissolved in a strong solution of caustic
potash, and to the solution is added so much of a solution of
acetate of lead, that all the oxide of lead is retained in solu-
tion.  When this mixture is boiled there is formed a black
precipitate of sulphuret of lead, which gives to the liquid the
aspect of ink.   Abundance of ammonia is also disengaged ■
and the alkaline fluid is found to contain, among other pro-
ducts, oxalic acid.
                   NOTE (33), p. 137.
COMPOSITION OF OXALIC, OXALURIC, AND PARABA-
                       NIC ACIDS.
Carbon
Hydrogen
Oxygen
Carbon
Hydrogen
Nitrogen
Oxygen
Carbon
Hydrogen
Nitrogen
Oxygen
 1. Oxalic Acid (hydrated.)
Gay Lussac & Thenard.  Berthollet.
   .  26-566        25-13
   .   2-745         3-09
   .  70-689        71-78
      Oxaluric Acid, a
        Wohler and Liebig."
2.
27-600
 3-122
21-218
48-060
27-318
 3-072
21-218
48-392
a Ann. der Pharm., XXVL, 289.
    3. Parabanic Acid, a
         Wohler and Liebig."
31-95
 2-09
24-66
41-30
31-940
 1-876
24-650
41-534
 Calculated
Ca 03 +HO
  26-66
   2-22
  71-12
 Calculated
C6 H4 N2 oa
  27-59
   3-00
  21-29
  48-12
31-91
 1-73
24-62
41-74
a Ann. der Pharm., XXVL, 286. 
322
APPENDIX.
                    NOTE  (34), p. 138.
         COMPOSITION OF ROASTED FLESH.
(1.) 0-307 of flesh gave 0-584 of carbonic acid and 0.206 of water.
(2.) 0-255     do.     0-485        do.        0-181   do.
(3.) 0-179     do.     0-340        do.        0-125   do.

Hence—
Flesh of roedeer(l). Flesh of beef (2).  Flesh of veal (3).
   Bceckmann."              Play fair."
Carbon
Hydrogen .
Nitrogen  .
Oxygen  ?
Ashes    s
52-60
 7.45
15-23
24-72
52-590
 7-886
15-214
24-310
52-52
 7-87
14-70
24-91
                   NOTE  (35), p. 142.
  The  formula C)08H84N18O40, or  C54H42N9O20, gives, when
reduced to 100 parts,
               C-                     50 07
H42
N9
Oan
 6-35
19-3-2
24-26
Compare this with the  composition of gelatine, as given in
Note (27.)
            NOTE (37), p. 154.
COMPOSITION  OF LITHOFELLIC ACID, a
Ettling and Will*.
Wohler *
Calculated.
C40H36C-8
Carbon    .  71-19    70-80    70-23    70-83     70-83
Hydrogen    10-85    10-78    10-95    10-60     10-48
Oxygen   •  17-96    18-42    18-92    18-57     18-69
   a Ann. der Chem. und Pharm. XXXIX., 242, XLL, 154. 
ANALYTICAL EVIDENCE.             323
                    NOTE (38),  p. 177.

COMPOSITION  OF SOLANINE FROM  THE  BUDS OF
              GERMINATING POTATOES, a
			Blanchet.
Carbon .	.		62-11
Hydrogen		.	8-92
Nitrogen	.	.	1-64
Oxygen.	.	.	27-33
a Ann.	der Pharm., VII.	150.	
                    NOTE (39), p. 177.
          COMPOSITION OF PICROTOXINE. a
                                            Francis.*
           Carbon.....60-26
           Hydrogen    .     .     .    .      5-70
           Nitrogen     ....      1-30
           Oxygen.....32-74
  a In another analysis, M. Francis obtained 0-75 per cent, of nitrogen.
The picrotoxine employed for these analyses was partly obtained from
the manufactory of M. Merck, in Darmstadt, and was partly prepared
by M. Francis himself; it was perfectly white, and beautifully crystal-
lized.  Regnault, as is well known, found no nitrogen in this compound.
	NOTE (40),	p. 177.	
COMPOSITION OF Q.UININE.			
		Liebig.*	Calculated C20H12NO2.
Carbon .		. 75-76	74-39
Hydrogen	.	. 7-52	7-25
Nitrogen	.	. 8-11	8-62
Oxygen.	.	. 8-62	9-64
 
324
APPENDIX.
       NOTE (41), p. 177.
COMPOSITION OF MORPHIA, a
                      Regnault.
Carbon  .
Hydrogen
Nitrogen.
Oxygen »
Liebig."
72-340
 6 366
 4-995
16-299
72-87
 6-86
 5-01
15-26
72-41
 6-84
 5-01
15-74
Calculated
C35H20NOJ

  72-28
   6-74
   4-80
  16-18
a Ann. der Pharm., XXVL, 23.
NOTE (42), p. 177.
COMPOSITION  OF CAFFEINE, THEINE,  GUARANINE,
          THEOBROMINE,  AND ASPARAGINE.
Carbon
Hydrogen
Nitrogen ,
Oxygen  .
    Caffeine, a
Pfaff and Liebig.*
 .  49-77
 .   5-33
 .  28-78
 .  16-12
Theine. 6
 Jobst.
50-101
 5-214
29009
15-676
Guaranine. c
  Martius.
  49-679
   5-139
  29-180
  16-002
 Calculated
C8 H5 N2 Oa
 49-798
  5-082
 28-832
 16-288
a Ann. der Pharm., I., 17.
b       Do.      XXV., 63.
c       Do.      XXVL, 95.
   Guaranine is the name given to the crystallized principle
of the guarana officinalis, till it  was shewn to be identi-
cal with caffeine and theine, as the above analyses demon-
strate.
          COMPOSITION OF THEOBROMINE, a
		Woskreseusky.		Calculated C9 H5 N8 Og
Carbon. . .	. 47-21	46-97	46-71	46-43
Hydrogen. .	. 4-53	4-61	4-52	4-20
Nitrogen . .	. 35-38	35-38	35-38	35-85
Oxygen . .	. 12-88	13-04	13-39	13-51
a Ann. der Chem. und Pharm., XLL, 125. 
ANALYTICAL  EVIDENCE.            325
       COMPOSITION OF ASPARAGINE. a

                    Liebig. *    Calculated C8 Hs N2 C-6 + 2HO
Carbon .  .  *  .     32-351              32-35
Hydrogen.  .  .      6-844               6-60
Nitrogen  .  .  .     18-734              18-73
Oxygen   .  .  .     42021              42-32

             a Ann. der Pharm., VIL, 146.
  ON  THE CONVERSION OF  BENZOIC ACID INTO
                     HIPPURIC ACID*

                 By Wilhelm  Keller.

         (From the Annalen der Chemie und Pharmacie.)

   So early as  in the edition of Berzelius's " Lehrbuch der
Chemie," published in  1831, Professor Wohler had expressed
the opinion, that benzoic acid,  during digestion, was proba-
bly converted into hippuric acid.   This opinion was founded
on  an experiment  which he had made on the  passage of
benzoic acid into the urine.   He found in the urine of a dog
which  had  eaten  half a  drachm of benzoic  acid  with

  * To the evidence produced by A. Ure, ofthe conversion of benzoic
acid into hippuric acid in the human body, M. Keller has added some
very decisive proofs, which I append to this work on account of their
physiological importance.  The  experiments of M. Keller were made
in  the laboratory of Professor Wohler, at Gottingen; and they place
beyond all doubt the fact that a non-azotised  substance taken in the food
can take a share, by means of its elements, in the act of transformation
of the animal tissues,  and in the formation of a secretion.  This fact
throws a clear light on the mode of action of the greater number of reme-
dies • and if the influence of caffeine on the formation of urea or uric acid
6hould admit of being demonstrated in a similar way, we shall then pos-
sess the key to the action of quinine and of the other vegetable alkalies.—
J. L.
               28 
326
APPENDIX.
his  food,  an  acid  crystallizing in  needle-shaped  prisms,
which  had the  general  properties  of  benzoic acid, and
which  he  then  took  for  benzoic  aeiJ.    (Ticdemann'a
Zeitschrift fur Physiologic, i. 142.)  These crystals were
obviously  hippuric   acid,  as  plainly  appears from  the
statements, that they  had  the aspect of nitre, and, when
sublimed,  left  a residue of carbon.   But at that time hip-
puric acid was not yet discovered ;  and it is well known,
that till 1829, when  these  acids  were first  distinguished
from  each other by Liebig, it  was  uniformly confounded
with benzoic acid.
  The  recently  published statement of A.  Ure,  that  he
actually found hippuric acid  in the urine of a patient who
had taken benzoic  acid, recalled  this relation, so  remark-
able in a physiological  point of  view, and induced me to
undertake the following experiments,  which, at  the sug-
gestion of Professor Wohler, I made on myself.  The sup-
posed  conversion of benzoic acid into  hippuric acid has,
by  these experiments, been unequivocally established.
   I took, in the  evening before bed-time,  about thirty-
two grains of pure  benzoic acid in syrup.  During the
night  I perspired strongly* which was  probably an effect
of the acid, as in general I am with great difficulty made
to transpire profusely.  [  could perceive no other  effect,
even when, next  day, I took  the same dose three times;
indeed, even the perspiration did not again  occur.
   The urine  passed in  the  morning had an uncommonly
strong acid reaction,  even after it  had been evaporated,
and had  stood for twelve hours.  It  deposited  only the
usual  sediment of earthy salts.   But when  it was  mixed
with  muriatic acid, and  allowed  to stand, there  were
formed in it  long prismatic, brownish  crystals,  in great
quantity,  which,  even in this state, could not  be taken  for
benzoic  acid.  Another portion, evaporated  to the con- 
ANALYTICAL  EVIDENCE.           327
sistence of syrup, formed, when mixed with muriatic  acid,
a magma of crystalline scales.  The crystalline mass was
pressed, dissolved  in hot water, treated with  animal char-
coal, and  recrystallized.   By this means the acid was ob-
tained in colourless prisms, an inch in length.
  Their crystals were pure hippuric  acid.  When heated,
they melted easily; and  when  exposed to  a  still stronger
heat, the mass was carbonized, with a smell of oil of bitter
almonds,  while benzoic  acid  sublimed.    To  remove  all
doubts,  I  determined  the proportion  of  carbon  in  the
crystals,  which I found to be 6)4 par cent.  Crystallized
hippuric  acid, according  to  the formula Cl8H8N05 + HO,
contains  60-67  per cent,  of carbon ; crystallized  benzoic
acid,  on  the other  hand, contains 69*10 per cent, of car-
bon.
  As long as I continued  to take benzoic acid, I was able
easily to  obtain hippuric  acid in large quantity from the
urine; and since the benzoic acid seems so devoid  of any
injurious effect  on  the  health, it  would be easy  in this
way to supply one's self with large quantities  of hippuric
acid.   It would only be necessary to engage a person  to
continue for some  weeks this new species of  manufacture^
  It was of importance to examiie the  urine  which con-
tained hippuric acid, in reference to the  two normal  chief
constituents, urea and uric acid.  Both were contained in
it, and apparently in the same proportion as in  the  normal
urine.
  The inspissated  urine, after the  hippuric acid had been
separated by muriatic acid,  yielded, on the addition of  ni-
trie acid, a large  quantity of nitrate of urea.  It had pre-
viously deposited a powder, the  solution of which in nitric
acid gave, when  evaporated to  dryness,  the  well-known
purple colour characteristic of uric acid.  Tnis  observation
is opposed to the statement of Ure ; and he is certainly  too 
328
APPENDIX.
hasty in recommending benzoic acid as a  remedy for the
gouty and calculous concretions of uric  acid.   He  seems
to suppose that the uric acid has been employed in the con-
version  of benzoic acid into hippuric acid ;  but as his obser-
vations  were made on a gouty patient, it may be supposed
that the urine,  even without the internal  use  of benzoic
acid, would have been found to contain no uric acid.  Final-
ly, it is  clear that the hippuric  acid  existed in the urine in
combination with a base, because it only separated after the
addition of an acid. 
INDEX.
 
 
INDEX.
                             A.
Acid.
—Acetic.   Composition ; and relation to that of aldehyde, 279,
    280.
—Benzoic.  Composition, and  relation to that of oil of bitter al-
    monds, 279. 280.   Converted  into hippuric acid in the hu-
    man body* 150, 325.
—Carbonic.  Is the form in which the inspired oxygen and  the
    carbon of the food are  given out, 13.   Its formation in  the
    body the chief source of animal heat, 17—22.   Occurs com-
    bined with  potash  and soda, in the serum of the blood, 41.
    Formed by the action of oxygen on  the  products of the
    metamorphosis of the  tissues, 60.  Its formation may also
    be connected with the production of fat from starch, 85—91.
    Generated b}' putrefaction of food in the stomach of animals,
    115.  Also by the fermentation of bad wine in man, when
    it causes death  by penetrating  into the lungs, 116.  Escapes
    through  both skin  and lungs,  ib.   Produced, along with
    urea, by the oxidation of uric acid, 140.  Produced, with
    several other compounds, by the oxidation of blood, ib.  May
    be  formed,  along  with choleic acid,  from hippuric acid,
    starch,  and oxygen, 152.  Also, along  with  choleic acid,
    urea, and ammonia, by the action of water and oxygen on
    6tarch and proteine, ib.  Produced, along with  fat and urea,
    from proteine,  by the action  of water and oxygen, in the
    absence of soda, 154.  Combines with  the  compound of 
332
INDEX.
Acid.
     iron present in venous blood, and is given off when oxygen
     is absorbed, 269.   Is absorbed by the serum of blood in all
     states, 270.
—Cerebric.  Its composition, 184.  Its properties, 186.
—Choleic.   Represents the organic portion of the bile, 133.   Its
     formula, 134.   Its  transformations, 125.   Half its formula,
     added to that of  urate of ammonia, is equal to  the formula
     of blood -f a  htlle  oxygen and] water,  136.  Produced in
     the oxidation of blood, 140.   Views which may be taken of
     ils composition,  148.   May b*e  formed  by  the  action of
     oxygen  and water on proteine and starch, 152.  Products of
     its oxidation, 154.  Various ways in which it may be sup-
     posed to be formed  in the body, 160.  Tts composition, 315.
     Cannot  be said to exist ready formed in the bile, 317.
—Cholic.  Its composition, 318.   Derived from choleic acid, 134,
     135.  Possible relation to choleic acid, 148.
—Choloidic.  Its composition, 315.   Derived from choleic acid,
     135.  Possible relation  to choleic acid,  148.  Possible re-
     lation to starch, 157.  Possible relation to proteine, 141.
—Cyanic.  Its formula, 281.
—Cyanuric.   Its formula, 281.
—Hippuric.   Its composition,  319*   Appears in the urine of
     stall-fed  animals, 82.  Is destroyed by exercise, 82. 139.  Is
     probably formed  in  the oxidation of blood, 140.  Is found
     in the human urine after benzoic acid has been administered,
     150, 325.   May be derived from  proteine when acted on by
     oxygen  and uric  acid,  151.   With  starch and oxygen, it
     may produce choleic and carbonic acids, 152.  May  be de-
     rived from the oxidation of choleic acid, 154.
—Hydrocyanic or Prussic.   Its poisonous action explained,  274.
—Lithofellic.  Its composition, 322.  Probably derived from the
     oxidation of choleic acid:  is the chief constituent  of bezoar
     stones, 154.
—Lactic.  Its composition. 309.  Its origin, 111.   Does not exist
     in the healthy  gastric juice, 112.
—Margaric.  Exists in  bile, 317.
—Muriatic.  Exists in  the free state  in the  gastric juice,  109,
     112.   Is derived from common salt, 112; 161. 
INDEX.
333
Acid.
—Oxaluric.   Analysis of, 321.
—Parabanic.  Analysis of, 321.
—Phosphoric.  Exists in the urine of the carnivora in consider-
    able  quantity, 78, 163.  Its proportion  very small in that
    ofthe graminivora, 79.  Derived from the phosphorus of the
    tissues, 78.  It is retained in the body  to form bones and
    nervous matter, 80.
—Sulphuric.   Exists in the urine ofthe carnivora, 78, 163.  De-
    rived from the sulphur ofthe tissues, .78.
— Uric.   Its  composition, 31$.   Products of its oxidation,  al-
    loxan, oxalic  acid, carbonic  acid, urea, &c, 137, 140.   Is
    probably  derived, along with choleic  acid, by the action of
    oxygen and water on blood  or  muscle,  136.  Disappears
    almost entirely in the system of man and ofthe higher ani-
    mals, 55, 137.  Appears as  calculus, when there is a defi-
    ciency of oxygen, 137.   Never occurs in  pthisical cases, ib.
    Yields mulberry calculus when the quantity of oxygen is
    somewhat increased,  but only urea and carbonic acid with a
    full supply of oxygen, ib.  Uric  acid calculus promoted by
    the use of fat  and of  certain  wines, 139.   Unknown on the
    Rhine, ib.  Uric acid and urea,  how related to allantoine,
    141;  to gelatine.  142.  Forms the  greater part of the urine
    of serpents, 54.  Yields, with the elements of proteine and
    oxygen,  hippuric acid  and urea,  151.   How  related  to
    taurine, 155, 156.  Calculi of it  never occur in  wild  car-
    nivora, but often  in men who use little animal food,  146.
Affinity, Chemical. Is the ultimate cause of the vital pheno-
  mena, 9, 10.  Is active only in the case  of contact,  and de-
  pends much on the order in which  the particles are arranged,
  205.  Its equilibrium renders a compound  liable to transfor-
  mations, 207.   In producing the vital phenomena,  it is  mo-
  dified by other forces, 209.  It  is not alone the vital force  or
  vitality, but is exerted in subordination to that force, 232.
Air.   Introduced  into the stomach  during  digestion with  the
  saliva, 113.  Effects of its temperature  and density, dryness,
  &c, in  respiration, 15, 16. 
334
INDEX.
Albumen.  Animal  and vegetable albumen identical.  47, 48.
  Their  composition, 293, 294,  308, 309.  Vegetable albumen,
  how obtained, 45.   Is a compound of proteine, and in organic
  composition identical with fibrine and caseine,  47, 104, 106.
  Exists in the yolk as well as the while of eggs, 107.   Also in
  the serum of the blood, 41.  Is the true starting point of all
  the animal tissues, 107, 108.
Alcohol.  Is hurtful to carnivorous savages, 179.   Its mode of
  action: checks the change of matter, 239.  In  cold climates
  serves as an element of respiration, 22.
Aldehyde.  Its composition ; how related to that of acetic acid,
  279, 280.
Alkalies.  Mineral alkalies essential both to vegetable and ani-
  mal life, 164.   Vegetable alkalies all contain nitrogen, all act
  on  the nervous system, and are all  poisonous in  a moderate
  dose, 177, 182.  Theory of their action : they take a share in
  the transformation or production of  nervous matter, for which
  they are adapted by their composition, 182—189.  Action of
  caustic alkalies on bile, or choleic acid, 134.
Allantoine.  Is found in the urine ofthe  foetal calf.  How de-
  rived from  proteine.   How related to uric acid and urea, 141.
  How related to choleic acid, 148.  Its composition, 319.
Allen and Pepys.  Their calculation ofthe amount of inspired
  oxygen, 283.
Alloxan.  Formed by the oxidation  of uric acid,  137.   Con-
  verted by oxidation into  oxalic acid and urea,  oxaluric and
  parabanic acids, or carbonic acid and urea, ib.  How  related
  to taurine, 156.   Seems to act as a  diuretic.  Recommended
  for  experiment in hepatic diseases, ib. (note).
Almonds,  Bittku.  Oil of.  Its composition;  how related to
  benzoic acid, 280.
Ammonia.  Combined with uric acid  it forms the urine  of ser-
  pents,  birds, &c, 54.   Its relation  to choleic, choloidic, and
  cholic  acids,  135.   Is  one of the   products which may  be
  formed by the oxidation  of blood, 140 ; or of proteine, 152.
  Its  relation  to uric  acid, urea, and  taurine,  155.  To allan-
  toine and taurine, 155,  156.   To alloxan and  taurine, 156.
  To choleic  and  choloidic acid  and taurine, 158.  To  urea, 
INDEX.
335
  water, and carbonic acid, 159.  Is found in combination with
  acids in the urine ofthe carnivora, 163.
Analysis.  Of dry blood, 283, 314.  Of dried flesh, 314.   Of
  feces, 285.   Of black bread, ib.  Of potatoes, ib.  Of peas,
  ib.   Of beans, ib.   Of lentils, ib.   Of fresh meat, ib.   Of
  moist  bread, ib.  Of moist  potatoes, ib.  Of the  fibrine  and
  albumen of blood.  293,  310,  311.   Of vegetable  fibrine  and
  albumen,  vegetable caseine and gluten, 294, 295.   Of animal
  caseine, 295.  Of starch, 296, 297.   Of grape or starch sugar,
  297.   Of sugar of milk, 298.   Of gum, ib.  Of oats, ib.   Of
  hay, 299.   Of fat, 300.  Of cane-sugar, ib.   Of cholesterine,
  ib.   Of wax, 307.  Of cyanic acid, cyanuric acid, and cyame-
  lide, 308.   Ofaldehyde, metaldi hyde, and elaldehyde, 307. Of
  proteine, 308.   Of albumen from the yolk and  white of egg, ib.
  Of  lactic acid, 309.   Of gas from the stomach of cows after
  eating to excess,  ib.  Of gas from stomach and  intesiines of
  executed criminals, ib.  Of gelatinous tissues, 311.  Of tissues
  containing  chondrine, 312.    Of arterial  membrane,  ib.   Of
  horny  iissues, ib.  Of the lin'ng membrane of the egg, 313.
  Of  lent hers, ib.   Of the pigmeritum nigrum,  ib.   Of choleic
  acid, 315.   Of taurine, ib.   Of choloidic  acid, ib-   Of cholic
  acid, 318.   Of uric  acid, ib.  Of alloxan, 319. Of  urea, ib.
  Of  hippuric  acid, ib.  Of allantoine,  ib.  Of xanthic oxide,
  320.   Of cystic oxide, ib.  Of oxalic  acid, 320.   Ofoxaluric
  acid, ib.   Of  pnrabanic  acid, ib.  Of roasted flesh, 322.   Of
  lithofellic  acid, ib.   Of solanine, 323.   Of  picrotoxine,  ib.
  Of  (|uinine, ib.  Of morphia,  324.   Of caffeine, theine, or
  guaranine, ib.  Of theobromine, ib.   Of asparagine, 325.
Animal Heat.   Derived from the combination  of oxygen with
  the  carbon  and I^'drogen of the metamorphosed tissues, which
  proceed ultimately from the food, 17, 18.  Is highest in those
  animals whose respiration is most  active, 19. Is ihe same
  in man in  all climates, 19,  20.   Is  kept up  by  ihe  food
  in proportion to amount  of external cooling, 22.   Is not  pro-
  duced  either  by any direct influence  ofthe nerves,  or  by mus-
  cular  contractions, 29—34.   Its amount in man, 34. Che-
  mical  action  the  sole source of it, 38.  The  formation of fat
  from  starch or sugar must produce heat,  91, 94.  The  ele- 
336
INDEX.
   ments of the bile, by combining with oxygen,  serve chiefly to
   produce it, 61.
Animal Life.  Distinguished from vegetable life by the absorp-
   tion of oxygen, and the production of carbonic acid, 2.   Must
   not be conlotinded  with consciousness, 6, 7.   Conditions  ne-
   cessary to animal life, 9, 12.  Depends on an  equilibrium be-
   tween waste and supply, 245, 254, 265.
Antiseptics.  They act by putting a stop to fermentation, putre-
   faction, or  other forms of metamorphosis, 170.  Their action
   on wounds and ulcers, 121.
Arteriks.  Composition of their tunica media, 312.  How  de-
   rived from  proteine, 126.
Arterial Blood.   Conveys oxygen to every part of the body,
   60, 269.  Contains  a compound of iron, most probably per-
   oxide, 269.   Yields oxygen in passing through the capillaries,
   60, 271.  Contains  carbonic acid dissolved or combined with
   soda, 272.
Asparagine.   Its composition, 325.  Its relation to  taurine and
   bile, 180.   Theory of its action on the bile, 181.
Assimilation.  In  animals it is independent of external influ-
   ences, 3.  Depends on the presence in the blood of compounds
   of proteine, such as fibrine, albumen, or caseine, 40,  106.  Is
   more energetic i.-i the young than  in the adult animal, 67.  Is
   also more energetic in the herbivora than in the carnivora,  81.
Atmospiikrk.  See Air.
Azotised Products.   Of vegetable life, 45, 176—182.  Ofthe
   metamorphosis of tissues.   Necessary for the formation of bile
   in the herbivora, 158.  In  man, 166, 168.  May  be  replaced
   by azotised  vegetable compounds, 169—170.   Theorv of this,
   177—182.   Of the  transformation of the  bile, or of choleic
   acid ; how related to the constituents of urine, 155.

                            B.

Beans.  Composition of, 285.
Beer.  Forms part of the diet of soldiers in Germany, 286, 288.
Bees.   Their power of forming wax from honey, 301—306.
Benzoic Acid.  See Acid,  Benzoic. 
INDEX.                      337
Berthollet.   His analysis of oxalic acids 321.
Berzelius.  His analysis of potato starch, 297 ; of sugar of milk,
  298 ; of gum, ib.;  of cane sugar, 300.
Bezoar stones.  See Acid, Lithofellic.
Blanchet.  His analysis of solanine, 323.
Bile.  In the carnivora is a product ofthe metamorphosis ofthe
  tissues,  along  with  urate of ammonia, 136.  May be  repre-
  sented by choleate of soda, with which, however, it is not iden-
  tical, 317.  Products  of  its  transformation,  135,  317.   Re-
  marks on these, 315—318.   Origin of bile, 61, 144.  Starch,
  &c, contribute  to  its formation  in the herbivora,  146—
  150, 159,  160, 166.   Soda essential to  it,  154,  162—164.
  Relation of bile to urine,  156.  To starch, 157.  To fibrine,
  136.  To caffeine, &c,  asparagine, and theobromine,  180.
  For the  acid  substances  derived from bile, choleic, choloidic,
  and cholic acids, see Acid, choleic, &c.  Yields  taurine,  135.
  Contains  cholesterine,  85, 317.   Also  stearic and margaric
  acids, 317.  Its function: to support respiration and produce
  animal  heat  by presenting carbon  and hydrogen  in a very
  soluble  form  to ihe  oxygen of  the arterial  blood,  61—64.
  Amount  secreted by the  dog, the horse, and man, 64.  It re-
  turns entirely into  the circulation, and disappears completely,
  60—66,
Blood.  The fluid from which every part of the body is formed,
  8.  Its chief constituents, 40.   How formed  from vegetable
  food, 45.  Can only be formed from compounds of proteine, 48.
  Is therefore entirely derived from vegetable  products in the
  herbivora, and indirectly also by the carnivora, which feed on
  the flesh ofthe former, 48.  Its composition identical with that
  of flesh, 133.   Analysis of both, 314.  The secretions contain
  all the  elements of the blood, 132.  Its  relation to  bile and
  urine, 136.  Products of  the oxidation of blood, 140.   Excess
  of azotised food produces fulness of blood and  disease,  145.
  Soda is present in the blood,  161—164.   Important properties
  ofthe blood, 171—175.  Venous blood contains iron,  probably
  as protoxide;  arterial  blood, probably as  peroxide, 271,  273.
  Theory of the poisonous action of sulphuretted hydrogen and
  Prussic  acid:  they decompose the compound of iron  in the
                    29 
338
INDEX.
  blood, 274.  The blood, in analogous morbid states, ought to be
  chemically examined,  275.
Blood-letting.   Theory of its mode of action, 258.  It may
  produce opposite effects in different cases, 264.
Bceckmann.  His analysis of black bread, 285;  of potatoes, ib.;
  of dry beef, 314; of dry blood, ib.; of roasted  flesh, 322.
Bones. Phosphoric acid ofthe food retained to  assist in forming
  them, 80.  Gelatine of bones digested by dogs, 97.  See, fur-
  ther, Gelatine.  Cause of brittleness in bones, 99.
Boussingault.  His analysis of potatoes, 285.  His comparison
  of the food and excretions in the horse and cow, Table, 290.
  His analysis of gluten, 294; of vegetable albumen,  ib.;  of ve-
  getable caseine, 295; of oats, 298; of hay, 299.
Braconnot. On the presence of lactic acid in gastric juice, 112;
  of iron in the gastric juice ofthe dog, 113.
Brain.  See Acid,  Cerebric, and Nervous  Matter.
Bread.  Analysis of, 285.
Brunn.   His analysis of sugar of milk, 298.
Buckwheat.   Analysis of starch from, 296.
Burdach.  His statement of the amount of bile secreted by ani-
  mals, 64.
Butter.  Forms a part ofthe food of soldiers in Germany, 286,
  288.
Buzzard.  Its excrements consist of urate of ammonia, 54.

                            c.

Caffeine.  Identical with theine, 179.   Its relation to taurine
  and bile, 180.  Theory of its mode of action, 181.   Its compo-
  sition, 324.
Cane Sugar.  Its composition, 300.
Carbon.   Is accumulated in the bile, 61.   Is  given off as car-
  bonic acid, 13.  Excess of carbon causes  hepatic diseases,  24.
  By combining with oxygen,  it yields  the  greater  part  of  the
  animal heat.   See Animal Heat, Bile, and Acid, Carbonic.
  Amount of carbon oxidised daily in the body of a man,  14.
  Calculations  on which this statement  is  founded, 284__289.
  Amount consumed by the horse and cow, 14.  Different pro- 
INDEX.                      339
  portions of carbon in different  kinds of food, 17.  Carbon of
  flesh compared with that of starch, showing the advantage of a
  mixed diet, 76.  Calculation on which this statement is founded,
  299. Amount of carbon in dry blood calculated, 283.  Amount
  in the food of prisoners calculated, 293.
Carbonic Acid.   See Acid, Carbonic.
Carbonates.  They occur in the blood, 41.
Calculus, Mulberry.   Derived from the imperfect oxidation of
  uric acid, 137.  Uric acid calculus is formed in consequence of
  deficiency of inspired oxygen, or excess of carbon in the food,
  137.  See Acid,  Uric.  Bezoar stones composed of  lithofellic
  acid, 154.
Carnivora.  Their nutrition the most simple, 44.  It is ultimate-
  ly derived from vegetables, 48, 49.  Their young, like gramini-
  vora, require non-azotised compounds in their food, 50.   Their
  bile is formed from the metamorphosis of their tissues, 59, 61.
  The process  of  assimilation in adult and  young  carnivora
  compared, 67.  Their urine, 78.  The assimilative process in
  adult carnivora less energetic than in graminivora, 80.   They
  are destitute of fat, 82.  They swallow less air with  their food
  than graminivora, 118.  Concretions  of  uric acid are never
  found in them, 146.  Both soda and ammonia  found  in their
  urine, 163.
Caseine.  One of the azotised nutritious products of  vegetable
  life, 47.  Abundant in leguminous plants, 47.   Identical in
  organic composition with fibrine and albumen, 47, 48.  Animal
  caseine found in milk  and cheese; identical with  vegetable
  caseine,  51.  Furnishes blood  to the young animal,  52.  Is
  one of the plastic elements of nutrition, 96.   Yields proteine,
  105, 106.  Its relation to  proteine, 126.   It contains sulphur,
  ib.   Potash  essential to its production, 164.   Contains more
  ofthe earth of bones than blood  does, 52.   Its analysis, 295.
Cerebric  Acid.   See Acid, Cerebric.
Change of  Matter.   See Metamorphosis  of Tissues.
Chemical Attraction.  See Affinity.
Chevreul.   His researches on fat, 84. His analysis of fat,  300;
  of cholesterine, ib.
Chloride of Sodium.  See Common Salt. 
340
INDEX.
Choleic Acid.  See Acid, Choleic.
Cholesterine-  See Bile.
Cholic Acid.  See Acid, Cholie.
Choloidic-Acid.  See Acid, Choloidic.
Chondrine.   Its relation to proteine, 126.  Analysis of tissues
  containing it, 312.
Chronic Diseases.  The action of inspired oxygen is the cause
  of death in them, 27, 28.
Chyle.  When  it has reached the thoracic duet, it is alkaline,
  and contains albumen coagulable by heat, 145.
Chyme.  It is formed independently of the vital force, by a che-
  mical transformation,  108.   The  substance which causes this
  transformation  is derived from the living membrane of the
  stomach, 109.  Chyme is acid, 145.
Clothing.  Warm clothing is a substitute for food  to a certain
  extent, 22.   Want of clothing accelerates the rate of cooling,
  and the respirations, and thus increases the appetite, ib.
Cold.  Increases the appetite by accelerating the respiration, 22.
  Is most judiciously employed as a remedy in cerebral inflam-
  mation, 261.
Concretions.   See  Calculus, and Acid, Uric;  also Acid,
  Lithofellic.
Constituents, Azotised.  Of blood : see Fibrine, and Albu-
  men.   Of vegetables : see Fibrine, Vegetable ; Albumen,
  Vegetable; Caseine, Vegetable; Alkalies, Vegetable; and
  Caffeine.   Of bile: see Acid, Choleic,  Cholic, and Choloidic.
  Of urine: see Acid, Uric; Urea, and Allantoine.
Cooling.  See Cold and Clothing.
Couerbe.  His analysis of cholesterine, 300.
Cow.  Amount of carbon expired by the, 14.   Comparison of
  the food with the excretions ofthe cow, 291.
Crum.  His analysis of cane sugar, 300.
Cultivation.  Is the economy offeree, 78.
Cyamelide.  Its formula, 280.
Cyanic Acid.  See Acid, Cyanic.
Cyanide of Iron.   Its remarkable properties,  269,
Cyanuric Acid.  See Acid, Cyanuric. 
INDEX.
341
                            D.

Davy.   Oxygen consumed by an adult man, 283.
Death.   Cause of, in chronic  diseases, 27, 28.  Caused in old
  people by a slight depression of temperature, 255.  Definition
  of it, 254.
Demarcay.  His analysis of choleic acid, choloidic acid, and
  taurine, 315.  Remarks on his Researches on Bile, 316.
Denis.   His experiments on the conversion of fibrine into albu-
  men, 42.
Despretz.   His calculation of the heat developed in the com-
  bustion of carbon, 34.
Diabetes Mellitus.  The  sugar found in the urine in this
  disease is  grape sugar, and is derived from the  starch ofthe
  food, 95.
Diastase.  Analogy between its  solvent action on starch, and
  that ofthe gastric juice on coagulated albumen, 111.
Diffusion of Gases.  Explains  the fact that nitrogen is given
  out through the skin of animals, 118; and the poisonous action
  of feather-white wine, 116.
Digestion.  Is effected  without the aid of the vital force, by a
  metamorphosis derived from the transformation of a substance
  proceeding from the lining membrane  of the  stomach, 109.
  The oxygen introduced with the saliva assists in the process,
  113.   Lactic acid has no share in it,  111, 112.
Disease.  Theory of, 254 et seq.  Cause of death in chronic dis-
  ease, 27.   Disease of liver caused by excess of carbon or de-
  ficiency of oxygen, 23.  Prevails in hot weather, 24.
Dog.  Amount of bile secreted by, 64.  Digests the gelatine of
  bones,  97.   His excrements contain  only bone earth, 98.
  Concretion of urate  of ammonia said to have been  found by
  Lassaigne in a dog, doubtful, 146 (note).
Dumas.   His analysis of choleic  acid, 315; of choloidic acid,
  ib.; of taurine, ib.; of cholic acid, 318; of hippuric acid, 319.

                             E.

Eggs.   Albumen  of the white  and of the yolk identical, 107.
/ 
342
INDEX.
  Analysis of both, 308;  of lining membrane, 313.  The fat of
  the yolk may contribute to the formation of nervous matter,
  108.  This fat contains iron, 107.
Elaldehyde.  See Aldehyde.
Elements.  Of nutrition, 96.  Of respiration, ib.
Empyreumatics.  They check transformations, 170. Their ac-
  tion on ulcers, 121.
Equilibrium.  Between waste and supply of matter is the ab-
  stract state of  health, 245, 258.   Transformations occur in
  compounds in which the chemical forces are in unstable  equi-
  librium, 109.
Ettling.  His analysis of wax,  307.   Ettling and  Will*
  Their analysis of lithofellic acid,  322.
Excrements.  Contain  little or no bile in man and  in the
  herbivora, none at  all in  the dog and other carnivora, 64.
  Those of the dog are phosphate of lime, 98. Those of serpents
  are urate of ammonia, 54.  Those of birds  also contain that
  salt, 54.  Those of the horse and cow  compared with their
  food, 290, 291.
Excretions.  Contain, with the secretions, the elements of the
  blood or of the tissues, 132—136.  Those of the  horse and
  cow compared  with their  food,  290, 291.  Bile is not an ex-
  cretion, 63.

                            F.

Fjeces.   Analysis of, 285.
Fat.  Theory of its production from starch, when oxygen is de-
  ficient,  83 et seq. ;  from other substances, 86.  The formation
  of fat supplies a new source of oxygen, 89;  and produces heat(
  90 et seq.  Maximum of fat, how obtained,  94.  Carnivora
  have no fat, 82. Fat in stall-fed animals, 89.  Occurs in some
  diseases in the  blood, 95.   Fat in  the women of the East, 99*
   Composition compared with that of sugar, 84, 85.   Analysis
  of fat, 300.  Disappears in starvation, 25.   Is an element of
  respiration, 96.
Fattening of Animals.   See Fat.
Featherwhite  Wine.  Its poisonous action, 116. 
INDEX.
343
Febrile Paroxyism.   Definition of, 256.
Fehling.  His analysis of metaldehyde and elaldehyde, 307.
Fermentation.   Maybe produced by any azotised matter in a
  state  of decomposition, 120.   Is arrested by empyreumatics,
  ib.   Is analogous to digestion, 119.
Fever. Theory and definition of, 256.
Fibre.  Muscular.  See Flesh.
Fibrine.  Is an element of nutrition, 96.  Animal and vegetable
  fibrine are  identical, 45.  Is a compound of proteine, 105.   Its
  relation to proteine, 126.   Convertible  into albumen, 42.  Is
  derived from albumen  during incubation, 107.   Its analysis,
  293, 294, 311.   Vegetable fibrine, how obtained,  45, 46.
Fishes.  Yield phosphuretted hydrogen, 191 (note).
Flesh.  Consists chiefly of fibrine, but, from the mixture of fat
  and membrane, has the sa:re formula as blood, 133. Analysis
  of flesh,  314, 322.  Amount of carbon in flesh  compared with
  that of starch, 77, 299.
Food.   Must contain both elements of nutrition and elements of
  respiration, 96.    Nutritious  food,  strictly  speaking,  is  that
   alone which is capable of forming blood, 40.  Whether derived
  from animals or from vegetables, nutritious food  contains  pro-
  teine, 44, 106 et seq. Changes which the food undergoes in
  the organism of the carnivora,  53 et seq.  The food of the
  herbivora  always contains starch, sugar, &c, 70.  Food, how
   dissolved, 108 et seq.  Azotised food has no direct influence on
   the formation  of uric acid  calculus, 138. Effects of super-
   abundant azotised food,  145, 146.  Non-azotised food  contri-
   butes to the formation of bile, and thus to respiration, 147 et
   seq.   Salt must  be added to the food of herbivora, in order to
   yield soda for the bile, 162.  Caffeine,  &c, serve as food for
   the liver,  188.   The vegetable alkalies  may be viewed as food
   for the organs which form the nervous matter, 189.  Amount
   of food consumed by soldiers in Germany, 286.  Its analysis,
   284.  Food of  the horse and cow compared with their excre-
   tions, 290, 291.
  Formula.  Explanation of their use, 280.  How  reduced to 100
   parts, 281.  Formulae of albumen, fibrine, caseine, and animal
    tissues, 126.   Formula  of  proteine, 121; of  blood and  flesh, 
344
INDEX.
  133 ;  of fat, 85 ;  of cholesterine, 85 ; of aldehyde, acetic acid,
  oil of bitter almonds, and benzoic acid,  280 ; of cyamelide,
  cyanic acid, and cyanuric acid, 280 ;  of choleic acid, 134 ; of
  choloidic acid and cholic acid, 135 ; of gelatine, 142 ; of hippu-
  ric acid,  150 ;  of lithofellic acid, 154 ;  of taurine, 155 ; of
  alloxan, 156.  See Analysis.
Francis.  His analysis of picrotoxine,  323.
Fremy.  Lameyran and Fremy.   Their analysis of gas from
  the abdomen of cows  after excess in  fresh food, 309.  His re-
  searches on the brain, 43, 184.
Frequency ofthe pulse and respiration in different animals, 19,
  292.
Fruits.  Contain very little  carbon, and hence are adapted for
  food in hot climates, 17.

                             G.

Cas.  Analysis  of gas from abdomen  of cows  after  excess in
  fresh food, 115, 309.  Analysis of gas from the stomach  and
  intestines of executed criminals, 115, 309.
Gastric Juice.  Contains no solvent but a substance in a state
  of metamorphosis, by the  presence of which  the food is dis-
  solved, 109.  Contains free acid,  ib.   Contains no lactic acid,
  112.  In the dog has been found to contain iron, 113. SeeDi-
  gestion, Chyme,  Food.
Gay-Lussac and Thenard.   Their analysis of starch, 297 ; of
  sugar of  milk, and of gum, 298 ;  of cane sugar, 300; of wax,
  307;  of oxalic acid, 321.
Gelatine.   Is  derived from proteine, but  is no longer a com-
  pound of proteine, and cannot form blood, 127 et seq.  May serve
  as food for the gelatinous tissues,  and thus spare the stomach
  of convalescents, 98, 130.   In starvation the gelatinous tissues
  remain intact, 97.   Its relation to proteine, 126.  Its formula,
  142.  Its analysis, 311, 322.
Goebel.   His analysis of gum, 298.
Globules  of the blood are the carriers of oxygen to all parts of
  the body, 171—175.  They contain iron, 265 et seq.
Gluten.  Contains vegetable fibrine, 45.  Analysis of it, 295. 
INDEX.                      345
Gmelin.  On the sugar of bile, 147.
Goose.  How fattened to the utmost, 94.
Graminivora.   See Herbivora.
Grape-sugar.  An element of respiration, 96.  Is identical with
  starch sugar and diabetic sugar, 72.   Its composition, 73.  Its
  analysis, 297.
Growth, or  increase of mass, greater in graminivora  than in
  carnivora, 80.   Depends on the blood, 40 ;  and on compounds
  of proteine, 106.   See Nutrition.
Gum.  An element of respiration, 96.  Its composition, 73.  Is
  related to sugar of milk,  ib.  Its analysis, 298.
Gundlach.  His researches on  the formation of wax from honey
  ofthe bee, 301.

                            H.

Hair.   Analysis of, 312.  Its relation to proteine,  126. Analysis
  of proteine from hair, 308.
Hay.  Analysis of, 299.
Hepatic Diseases.  Cause of, 23.
Herbivora.   Their blood derived from compounds of proteine
  in their food, 48.  But they require also for their support non-
  azotised substances, 70.   These last assist in the formation of
  their bile, 147 et seq.  They retain the phosphoric acid of their
  food to form bone and nervous matter, 80.   Their urine con-
  tains very little phosphoric acid, 79. The energy of vegeta-
  tive  life in them is very  great, 81.  They become fat when
  stall-fed, 82.
Hess.   His analysis of wax, 307.
Htbernating Animals.   Their fat disappears during the win-
  ter sleep, 25.  They secrete  bile and urine  during the same
  period,  61.
Hippuric Acid.  See Acid, Hippuric.
Horn.  Analysis of, 312.   Contains proteine;  its  relation to
  proteine, 126.  Analysis of proteine from horn, 308.
Horse.   Amount of carbon expired by, 14.  Comparison of his
  food with  his excretions, 290.   Force  exerted by a  horse in
  mechanical motion compared to that exerted by a whale, 337.
                     30 
346
INDEX.
Hydrocyanic Acid.  See Acid, Hydrocyanic.
Hydrogen.  By combining with oxygen contributes to produce
  the animal heat, 25.

                             I.

Ice.  Is judiciously employed as a  remedy in cerebral  inflam-
  mation, 261.
Inorganic  constituents of albumen,  fibrine, and caseine,  41,
  121, 126.
Jobst.   His analysis of theine, 324.
Jones, Dr. Bence.  His analysis of vegetable fibrine, 291; of
  vegetable albumen, ib.; of vegetable caseine, 295; of gluten,
  ib.; of the albumen of yolk of egg, 308, 310; ofthe albumen
  of brain, 310.
Iron.  Is an essential constituent of the globules of the  blood,
  265 et seq.   Is found in the fat of yolk of egg, 107.  Also in
  the gastric juice  of the  dog, 113.  Singular properties  of its
  compounds, 268.
 Isomeric Bodies.  103, 280.

                             K.

 Keller.  His researches on the conversion of benzoic acid into
   hippuric acid in the human body, 325.
 Kidneys.  They separate from the arterial  blood the nitroge-
   nised compounds destined for excretion.

                             L.

 Lactic Acid.  See Acid, Lactic.
 Lavoisier.   His calculation of the amount of inspired oxygen,
   12, 283.
 Lehmann.  On the presence of lactic acid in gastric juice, 112.
 Liebig.   His analysis of sugar of milk,  298; of cane  sugar,
   300; of aldehyde, 307;  of uric  acid,  318;  of hippuric acid,
   319; of quinine, 323; of morphia, 324; of asparagine,  325.
   His calculation of the carbon daily expired as carbonic acid, 
INDEX.
347
  14, 284.  Table, 289. His remarks on Demargay's researches
  on bile, 315—318.
Liebig and Pfaff.  Their analysis of caffeine, 324.
Liebig and Wohler.   Their analysis of alloxan, 319 ; of urea,
  ib. ; of allantoina, ib. ; of xanthic  oxide, 320;  of  oxaluric
  acid, 321; of parabanic acid, ib.
Lentils.  Contain vegetable caseine, 47.  Analysis  of, 284,
  285.   Form part of the diet  of soldiers in Germany, 287.
  Table, 289.
Light.   Its influence on vegetable life analogous to that of heat
  on animal life, 233.
Lime.   Phosphate of.   See Bones.
Liver.   It separates from the venous  blood the carbonised con-
  stituents destined for respiration, 58.  Diseases of the  liver,
  how  produced, 23.   Accumulation of fat in the  liver of  the
  goose, 95.

                           M.

Maize.   Analysis of starch from, 297.
Marchand.  On the  amount of urea in the urine of the dog
  when fed on sugar, 61.  His analysis of cholesterine, 300.
Marcet.  His analysis of gluten, 294.
Martius.  His  analysis of guaranine, 324.
Mechanical Effects.  See Motion.
Medicine.  Definition'of the objects  of, 257 et seq.  Action of
  medicinal agents, 170 etseq.
Menzies. His calculation of the amount of inspired oxygen,
  12, 283.
METALDEHYDE.  See ALDEHYDE.
Metamorphosis of Tissues.   103  et seq.  In other parts o*
  the volume, passim.
Milk.   Is the  only natural product  perfectly fitted to sustain
  life, 51. Contains  caseine, ib.  Fat (butter), ib.  Sugar of
  milk, ib.  Earth  of bones, 52.   And potash, 164.
Morphia.  Contains less  nitrogen than quinine, 177.  Its ana-
  lysis,  324.
Mitscherlich.  His  analysis of uric acid, 318;  of hippuric
  acid, 319. 
348
INDEX.
Momentum.   Of force, 202.  Of motion, ib.
Motion.  Phenomena of motion in the animal body, 196 ct seq.
  Different sources of motion, 199.  Momentum of motion, 202.
  Motion propagated by  nerves, 219.   Voluntary and involun-
  tary motions accompanied by a change of form and structure
  in living parts, 220.  Motion derived from  change of matter,
  221 et seq.   The cause of motion in the animal body is  a pe-
  culiar force, 232.  The sum  of the effects of motion  in the
  body proportional to the amount of nitrogen in  the urine, 245.
Mulberry Calculus.   See Calculus.
Mulder.   Discovered proteine, 105.   His analysis of fibrine of
  blood, 293.  Of animal caseine, 296.  Of proteine,  308.  Of
  fibrine, 311.   Of gelatine, ib.  Of chondrine,  312.
Muscle.  See Flesh.
Muscular Fibre.   Its transformation depends on the annoaal
  of force expended in producing motion, 220.

                             N.

Nerves.  Are the conductors ofthe vital force,  and of mechani-
  cal  effeets, 219.   Effects of the disturbance of their conducting
  power, 229.   They are not the source of animal heat, 29.
Nervous Life.   Distinguished from vegetative, 38.
Nervous Matter.  Contains albumen,  and fatty matter of a
  peculiar kind, 43.  Vegetables cannot produce  it, 50.   The
  fat  of yolk of egg probably contributes to its formation, 108.
  The phosphoric acid and phosphates, formed in the metamor-
  phosis of the tissues of  the herbivora, are retained to assist in
  the  formation  of  nervous matter, 80.  The vegetable alkalies
  affect the nervous system, 182—184. Composition of cerebric
  acid, 184.  Theory of the action ofthe vegetable alkalies, 185.
Nitrogen.  Essential to all organized structures, 42, 43.   Sub-
  stances in the body which are destitute of it  not organized, 43.
  Abounds  in nutritious vegetables,  45.  Nutritious  forms in
  which it occurs, ib. et seq.  Occurs  in alL vegetable  poisons,
  177; also in a few substances which are  neither  nutritious nor
  poisonous, but  have  a  peculiar effect on the system* such aa
  caffeine,. 177 et seq. 
INDEX.
349
Nitrogenised.   See Azotised.
Non-Azotised.  Constituents of food.   See Starch.
Nutrition.   Depends on the blood, 40.  On Albumen, fibrine,
  or caseine, 40 et seq.  Elements of nutrition, 96.  Compounds
  of proteine alone are nutritious,  106.   Occurs when the vital
  force is more powerful than the opposing chemical forces, 198.
  Theory of it, 210.   Is almost unlimited in plants from the ab-
  sence  of nerves, 212.  Depends  on  the  momentum of force
  in each part, 227.   Depends also on heat, 243.

                            o.

Oats.  Amount required to keep a horse in good condition, 74.
  Analysis of, 298.
Oil of Bitter Almonds.  Its composition.  How related to
  benzoic acid, 279,  280.
Old Age.  Characteristics of, 248  et seq.
Oppermann.  His analysis of wax, 307.
Organs.  The food of animals always consist of parts of organs,
   2. All organs in  the body  contain nitrogen, 42, 43.  There
   must  exist organs for the production of nervous matter, 189 ;
   and the vegetable alkalies may be  viewed  as food for these
   organs, ib.
Organized  Tissues. All contain nitrogen, 42,  43.  All such as
   are destined for effecting the change of matter are full of small
   vessels, 223.   Their composition, 126.  The gelatinous and
   cellular tissues, and the uterus, not being destined for that
   purpose, are differently constructed, 224.  Waste of organized
   tissues rapid in carnivora, 76.
 Origin.  Of animal heat, 17,  31.   Of fat, 81 et seq.  Of the
   nitrogen exhaled from the lungs, 114  el seq.  Of gelatine, 127
   et seq., 143.  Of uric acid and urea, 135 et seq.  Of bile, 135,
   143,  146 et seq., 159.  Of  hippuric  acid, 150, 325.  Of the
   chief secretions and excretions, 152.  Of  the soda ofthe bile,
   161  et seq.  Of the nitrogen in  bile, 168.  Of nervous matter,
   183 et seq.
 Ortigosa.   His analysis of starch, 297.
 Oxalic Acid.   A product, along with urea, ofthe partial oxida-
                  30* 
350
INDEX.
  tion of  uric acid, occurring in the  form of mulberry calculus,
  137.  Its analysis, 321.
Oxygen.   Amount consumed by man daily, 12, 283.  Amount
  consumed daily in oxidising carbon by the horse and cow, 14.
  The absorption of oxygen  characterizes  animal life, 2.  The
  action of oxygen is the cause  of  death  in  starvation  and in
  chronic diseases, 25—28.  The  amount of oxygen inspired
  varies with  the  temperature, dryness, and density of the air,
  16.  Is carried by arterial blood to all parts of the body, 171.
  Fat differs from sugar and starch only in the amount of oxy-
  gen, 84.  It also contains less oxygen than  albumen, fibrine,
  &c, 86.  The formation of fat depends on a deficiency of oxy-
  gen, 88 et seq.;  and helps to supply this deficiency, 89.  Oxy-
  gen essential  to digestion,  113.  Relation of oxygen to some
  of the tissues formed from proteine, 126.   Oxygen and water,
  added  to blood or to flesh,  yield the elements of bile  and of
  urine, 135.  Action of oxygen on uric acid,  136, 139: on hip-
  puric acid, 82,139; on blood, 140; on proteine, with uric acid,
  151 ; on proteine and  starch, with water, 152 ; on choleic acid,
  154 ; on proteine, with water, 154.  By depriving starch of
  oxygen  and  water, choloidic acid may be formed, 157.   Oxy-
  gen is essential to the  change of matter, 173.   Its action on the
  azotised constituents of plants when separated, 213.  Its action
  on the muscular fibre essential to the production of force, 220
  —226.   Oxygen is absorbed  by  hybernating animals,  241.
  Is the cause of the waste of matter, 243 ; and of animal heat,
  244, 252. Blood-letting acts by diminishing the amount of oxy-
  gen which acts on the body, 258.   Its absorption is the cause
  of the change of colour from venous to arterial blood,  265.  The
  globules probably contain oxide of iron,  protoxide  in venous
  blood, peroxide in arterial, 267 et seq.  All parts ofthe arterial
  blood contain oxygen,  173, 174, 266, 271.

                            P.
Pears.  Analysis of starch from unripe, 297.
Peas. Form  part of the diet of soldiers in Germany, 287,  289.
  Abound in vegetable  caseine, 47.   Analysis of peas, 285 ;  of
  starch from peas, 296. 
INDEX.
351
Pepys and Allen.   Their calculation ofthe amount of inspired
  oxygen, 283.
Peroxide of Iron.  Probably exists in arterial blood, 267 et seq.
Pfluger.  His analysis of the gas obtained  by puncture from
  the abdomen of cattle after excess in green food, 309.
Phenomena of motion in the animal body,  195 el seq.
Phosphates.  See Bones.
Phosphoric Acid.   See Acid, Phosphoric.
Phosphorus.  Exists in albumen and fibrine, 41, 48, 126.  It is
  not known in what  form, 121 et seq.  Is an essential constituent
  of nervous matter, 184, 190.
Phosphuretted Hydrogen. Occurs among the   products of
  the putrefaction of fishes, 190, 191.
Picrotoxine.  Contains nitrogen, 177 (note). Its analysis, 323.
Plants.  Distinguished from animals by fixing carbon and giv-
  ing out oxygen, 2,213; by the want of nerves and of locomotive
  powers, 3.  Their  capacity of growth almost unlimited, 212.
  Cause of death in plants, 214.
Playfair, Dr. L.   His formula  for blood, 113.  His analysis
  of faeces, of peas, of lentils, of beans, 285;  of flesh and of blood,
  314 ;  of roasted flesh, 322.
Poisons,  Vegetable.   Always contain  nitrogen, 176 et seq.
  Different kinds of poisons, 170.  Theory of the action of Prussic
  acid and sulphuretted hydrogen, 274.
Polymeric Bodies,  103.
Potash.  Essential to the production of caseine or milk, 164.
Potatoes.  Amount of carbon in, 287.   They form part of the
  diet  of  soldiers in  Germany, ib.  Analysis of, 285; of starch
  from, 297 ; of solanine from the buds of germinating potatoes,
  323.
Prevost and Dumas. On the frequency ofthe pulse and respi-
  rations, 292.
Products. Of the  metamorphosis of tissues found in the bile
  and urine, 132.  Ofthe action  of muriatic  acid on bile, 133.
  Of the action of potash on bile, 134.  Of the action of water
  and oxygen on blood or fibre, 136.   Of  the oxidation  of uric
  acid, 137.  Of the oxidation of blood, 140.  Of the action of
  water on proteine,  141.  Of the action of urea on lactic  and 
352
INDEX.
  benzoic acids, 150.  Of oxygen and uric acid on proteine, 151-
  Of oxygen on starch and hippuric acid, 152.  Of oxygen and
  water on proteine and starch, 153.   Of oxygen and water on
  proteine when soda is abs?nt, 154.   Of the separation of oxy-
  gen from starch, 157.   Of the action of water on urea, 159.
  Ofthe action of water and oxygen on caffeine or theine, aspara-
  gine, and theobromine, 180.
Proteine.  Discovered by  Mulder, 105.   Its composition, ib.
  Produced alone by vegetables, 106.   Is  the source of all  the
  organic azotised constituents of the  body, 107.  Its formula,
  121.   Its relation to fibrine, albumen,  caseine, and all the
  animal tissues, 126.   Gelatine  no longer yields it,  although
  formed from it, 129.   Its relation to  bile  and urine,  136.  Its
  relation to allantoine and choloidic acid, 141; to gelatine, 142;
  to hippuric acid, 151; to the chief secretions and excretions,
  152, 153;  to fat,  154.  Analysis of  proteine from the crystal-
  line lens, from albumen, from fibrine, from hair, from  horn,
  from  vegetable albumen and fibrine,  from cheese, 308.
Prout. His analysis of starch, 297 ; of grape sugar from honey,
  ib. ; of sugar of milk, 298; of cane  sugar, 300; of urea, 319.
  His discovery of free muriatic acid  in  the gastric juice, 112,,
  On the effect of fat food on  the urine,  139.
Prussic Acid.  See Acid, Hydrocyanic.
Pulmonary  Diseases.   Arise from excess  of oxygen,  23.
  Prevail in winter, 24.
Pulse.  Its frequency in different animals, 292.
Putrefaction.    Is a process of transformation, 109.  Mem-
  branes very liable to it, 110.  Effects of the putrefaction of
  green food in the  stomach of animals, 115.  Is analogous to di-
  gestion, 119.  Putrefying  animal matters cause the fermenta-
  tion-of sugar, 120.  Is checked by empyreumatics, 121, 170.



Quinine.  Contains nitrogen, 177.  Its analysis, 323.

                             R.

R.egnault.   His analysis of morphia, 32.4- 
INDEX.
353
Reproduction of Tissues.   See Nutrition.
Reproduction of the Species, 39.
Rhenish  Wines.  Contain so much  tartar, that their  use pre-
  vents the formation of uric acid calculus, 139.
Respiration.  Theory of, 265 et seq.  Its connection with the
  food  and with animal heat, 12 et seq.

                             s.

Salt,  Common.  Essential to the formation of bile in the herbi-
  vora, and to that of gastric juice,  161 et seq.
Saussure, De.   His analysis  of grape sugar and of starch sugar,
  297 ; of wax, 307.
Scherer, Dr. Jos.   His analysis  of albumen from  serum of
  blood, 293;  of  fibrine of blood, ib.; of vegetable fibrine, 294  ;
  of vegetable caseine, 295 ; of animal caseine, ib. ; of proteine
  from different  sources,  308; of albumen from white of egg,
  ib. ; of albumen from different sources, 310; of fibrine, 311  ;
  of gelatine  from  different sources, ib. ;  of  tissues containing
  chondrine, 312; ofthe tunica media of arteries, ib.; of horny
  tissues, ib.; ofthe lining membrane of the egg, 313 ; of feath-
  ers,  ib.; ofthe  pigmentum nigrum  oculi, ib.  Results of his
  researches, 125, 126.
Secretions.   See Bile and Urine.
Seguin.  His calculation ofthe amount of inspired oxygen, 283.
Serpents.  Their excrements consist of urate of ammonia, 54.
  The process of digestion in them,  53.
Sleep, Theory  of,  228.  Amount of sleep  necessary for  the
  adult, the infant, and the old man, 247 et seq.  Induced by al-
  cohol or wine,  240.
Soda.  Essential to  blood and bile, and derived from common
  salt, 161 et seq.
Sodium, Chloride of.   See Salt.
Solanink.   Contains nitrogen, 177.   Its analysis, 323.
Starch.  Exists in the food ofthe  herbivora, 70.  Is convertible
  into sugar,  70, 71.  Its  relation  to gum and sugar,  73.  Its
  function in food, 74 et seq.   Amount of carbon in starch com-
  pared with  that in flesh, 7G, 77.  Its composition  compared 
354
INDEX.
  with that of fat, 84, 90.   Is the source of diabetic sugar, 95.
  Is an element of respiration, 96.  Dissolved by diastase,  111.
  Its relation  to choleic acid, 152.  Its  relation to the  principal
  secretions and excretions, 153 ;  to choloidic acid, 157 ; to bile,
  158, 162, 164, 166.  Its  analysis from fifteen different plants,
  297.
Starvation.  Process of, 25.   Cause of death in, 27.
Strecker.  His analysis of starch from 12 different plants, 297.
Sugar.   Analysis  of grape-sugar, 297; of sugar of milk,  298 ;
  of cane-sugar, 300.  Is an element of respiration, 96.
Sulphur.  Exists in albumen, and caseine, 41,  126.
Sulphuretted Hydrogen.  Theory of its  poisonous action,
  274.
Sulphuric Acid.   See Acid,  Sulphuric.
Supply of matter.   See Nutrition.
Supply  and  Waste.  Equilibrium between them constitutes
  the abstract state  of health, 254, 255.  Effects of its disturb-
  ance, ib. et seq.  Means for restoring the equilibrium, 248, 257
  et seq.

                            T.

Tables ofthe food consumed by soldiers in Germany, 289.  Of
  the food and excretions ofthe horse and cow, 290, 291.
Taurine.  How produced from bile, 133.  Its relation to cho-
  leic acid, 135.   Tts relation to uric acid and urea, and to allan-
  toine, 155 ; to uric acid, 156; to alloxan, ib. ;  to choloidic and
  choleic acids, and ammonia, 158; to caffeine or theine, 1§0;
  to asparagine, ib.; to theobromine, ib., 181.
Temperature.   Its effects on the amount of inspired oxygen, 16,
  and on the appetite, 17  et seq.   A slight depression of tem-
  perature causes death in aged people, 255.   Temperature of
  the blood in different animals, 292.  Temperature ofthe body
  constantly  kept up by internal  causes, 19—22.
Tendons.  Analysis of, 311.
Thaulow.   His analysis of cystic oxide, 320.
Theine.   Identical with  caffeine, 179.   And  with guaranine, 
INDEX.
355
  324.  Theory of its action, 181 et seq.  Its relation to bile,
  180.  Its analysis, 324.
Theobromine.  Analogousto theine, 179.   Theory of its action,
  181 et seq.   Its relation to bile, 180, 181.  Its analysis, 324
Theory.  Of animal heat, 17 et seq.  Of digestion, 108 et seq.
  Of respiration, 265 et seq.   Of the  motions  in the animal or-
  ganism, 195 et seq.  Of disease, 254 et seq.  Of the  action of
  caffeine, &c, 181 et seq.  Ofthe action of the vegetable alka-
  lies, 182 et seq.  Of health, 254, 255.
Tiedemann and Gmelin.   Their attempt to support a  goose
  upon albumen alone, unsuccessful, 106.
Tissues, Metamorphosis of :  see Metamorphosis.   Ana-
  lysis ofthe animal tissues, 310, 313.  Formula: of, 126.
Tobacco.  Arrests or retards the change of matter, 179.
Transformation.  See Metamorphosis.
Turnips.  Juice of, contains vegetable fibrine and albumen, 45,
  46.

                            u.

Urea.  Derived from uric  acid, 137, 140.  Also from the oxi-
  dation of blood, 140;  from allantoine, 141.  Its relation to
  choleic acid, 148; to hippuric acid, 150 ;  to proteine, 151 •
  to proteine  and  starch, 153;  to proteine  and fat, 154;  to
  taurine, 155, 156 ;  to carbonate of ammonia, 159; to theobro-
  mine, 180.  Its  analysis, 319.   Occurs in  the urine of those
  who have taken  benzoic acid along with hippuric acid, 327.
Urinary Calculi.   See Calculus.
Uric Acid.  See Acid,  Uric.

                            V.

Varrentrapp and Will.  Their  analysis of vegetable albu-
  men, 294.  Of sulphate of potash and caseine, 295.
 Vegetables.  Alone produce compounds  of proteine  106.
  Azotised constituents of, nutritious, 45 : medical or poison-
  ous, 176.  Analysis of those  vegetables which  are used  for
  food, 285 et seq. 
V-  .'✓"/,
356                     INDEX.

Vegetable Life.  Distinguished from nervous life, 38.  Pre-
  dominates in the early stages of life, ib.  Also in the female,
  39.
Venous Blood.   See  Blood.
Vital Force, or vitality.   Definition of, 1 et seq.   Theory of,
  195 et seq.
Vogel.  His analysis of gas from the  abdomen of cattle after
  excess in green food, 309.

                            w.

Water.   Is one of the two constituents of the body which con-
  tain no nitrogen, 43.   Its use  as a solvent, ib.  Contributes
  to the greater part ofthe transformations in the body,  136, 140,
  141, 142, 148, 153, 154,  155, 156, 157, 159, 180, 181.
Wax.  On its production from honey by the bee, 301—306.  Its
  analysis, 307.
Wheat.   Contains vegetable  fibrine, 46.  Analysis of fibrine,
  albumen, and gluten, from wheat, 294.
Will and Ettling.   Their  analysis of lithofellic acid, 322.
Wine.  The wines ofthe  south promote the formation  of calcu-
  lus, 139.  But not  Rhenish  wines, ib.  Theory of its  action,
  239, 240.
Woskresensky.  His analysis of theobromine, 324.

                            Y.
Yams.  Analysis of starch from, 297. 
 
 
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