ARMY MEDICAL  LIBRARY

         WASHINGTON

             Founded 1836
Se.
 NEX
ection.
Number . J/JA..:.?__7- ~
        Form 113c, W. D.. S. G. O.
3—10543    (Revised June 13, 1936) 
 DUE TWO WEEKS FROM LAST DATE






MAT 24 t96E
GPO 887422 
I 

ANIMAL CHEMISTRY, 
 
   ANIMAL  CHEMISTRY,^^

                 OR

       ORGANIC CHEMISTRY

           IN ITS APPLICATION TO


PHYSIOLOGY  AND  PATHOLOGY.

                 BY

   JUSTUS LIEBIG, M. D., Ph. D., F. R. S., M. R. I. A.,
      PROFESBOR OF CHEMISTRY IN THE UNIVERSITY OP GIESSEN,
               ETC., ETC., ETC.

        EDITED PROM THE AUTHOR'S MANUSCRIPT,

  By WILLIAM GREGORY, M. D., F. R. S. E., M. R. I. A.,
     PROFESSOR OF MEDICINE AND CHEMISTRY IN THE UNIVERSITY
           AND KINO'S COLLEGE, ABERDEEN.
WITH ADDITIONS, NOTES, AND CORRECTIONS,

        Br Dr. GREGORY,

           AND OTHERS BY

     JOHN W. WEBSTER, M. D.,
 ERVINO PROFESSOR OF CHEMISTRY IN HARVARD UNIVERSITY.

          ______C
blJUtAKY
      D*itirftf oft $4HtiiK*$orrici
            JM-12 4902
CAMBRIDGE:   I   0 ^ | L
PUBLISHED 0Y ffliftftTm
J.
BOSTON, JAMES MUNB,OE AND COMPANY, AND C. C. LITTL* ^.ND JAMES BROWN;

  NEW YORK, D. APPtETONylND C .llll —»»JIIILADELPHIA, CAREY AND HART,

       AND TH^M'^JfciKfERTHWAia^SW COMPANY ;

          BALllhidffi!Ol^A*N»SRO'rHER'
 
"»"»« l»» %
1  «•#,
Qu
Ll/lo
/m
   Entered according to Act of Congress, in the year 1842, by

               John Owen,

in the Clerk's Office of the District Court of the District of Massachusetts.
;' Jki 7* H U t*
,■».*!> VV  V
"*■'
i. .... .: -CAM»B RIDGE:


 METCALF, KEITH, AND NICHOLS,

   PRINTERS TO THE UNIVERSITY. 
     ADVERTISEMENT

TO  THE CAMBRIDGE  EDITION.
  This edition  of the admirable  work  of Dr.
Liebig  is  published  in  compliance  with the
wishes both of the author and of the translator,
and is the only American edition authorized by
them.  It contains valuable matter which is not
in the English edition.
   Great care  has been bestowed upon the cal-
culations and  estimates,  which form  so  impor-
tant a feature  in the body of the work,  and  in
the analytical  results, which constitute the Ap-
pendix, — upon  the vast  accumulation of which
the whole  force  of the  reasoning  depends.
Without presuming that the present  edition is
perfect, or  that  some errors will not  be  found
in it,  it is believed  that  it contains fewer than
any other,  and  the editor has the satisfaction
              a* 
vi
ADVERTISEMENT.
of feeling  that no  pains  have been spared  to
effectuate this object.   For the ready  and able
cooperation of Professor  Peirce, Dr.  Samuel
L. Dana, and especially  Mr. Thomas Hill of
this  University,  in the laborious examination
and  revision of  the tables and analytical re-
sults, the editor is bound  to record his grateful
acknowledgments.
  The  reception of  Dr.   Liebig's  volume  in
Europe has been  enthusiastic, and it  has fully
sustained the high encomiums and anticipations
expressed by the translator in one of his letters
to the editor; in  whose opinion  it would mark
the commencement of a new era in physiology.
In translating it, he expresses himself as hav-
ing experienced the highest admiration of the
profound sagacity, which  enabled the author to
erect so beautiful  a  structure on  the founda-
tion  of facts which others had allowed  to re-
main for so long  a time utterly useless, and of
the  logical structure  and  extreme  cogency of
his arguments, — the  brightest light being shed
upon almost every  point in physiology accessi-
ble to chemistry, — the true path having been 
ADVERTISEMENT.
vii
opened, leading to the anticipation  of the most
astonishing results.
   Dr. Gregory undertook the translation at the
express request of the author;  and, from  long
and  very intimate knowledge of the mind and
thoughts, as well  as  the  style  of his friend, in
addition to his well  known acquirements  as  a
chemist  and physiologist, was  peculiarly fitted
for this act of friendship;  with  the  faithful per-
formance  of which  Dr.  Liebig has expressed
his high  satisfaction.
   The editor would  express his obligations to a
fellow countryman of the author for the mate-
rials  from which the sketch of  his life has  been
prepared,  regretting  only that he is not permit-
ted  to prefix to it his name.
                                   J. W. W.
   Cambridge, Jiipril, 1843. 
 
      MEMOIR
           OF

THE   AUTHOR.
  Justus Liebig, Professor Ordinarius in the
University of Giessen, Grand-duchy of Hesse-
Darmstadt, was born at Darmstadt, on the 8th
of May,  1803.  His  father,  who  was  a  mer-
chant,  indulged the predilection of his  son for
natural  philosophy, and, after having acquired
a scientific education in the Gymnasium (Latin
school) of Darmstadt, he became an apprentice
in a Dispensary in 1818, where he passed two
years in  practical  preparation  for  his future
pursuits.  From 1819 to  1822 he studied in
Bonn and Erlangen, where Goldfuss, Bischoff,
Kastner, and others, were  his teachers.   Hon-
ored now by  the Grand-duke of  Darmstadt
with a salary which enabled him to travel, he
went to Paris, where he  remained till 1824. 
X
MEMOIR OF THE AUTHOR.
By an essay on  the  nature of Fulminic  Acid
(Knallsaeure), which  he offered to the Acad-
emy,  he  gained the attention and  friendship of
Alexander von  Humboldt, who recommended
him  to  Gay-Lussac.   That  eminent  chemist
opened to him his laboratory, which had never
before been accessible to pupils, and here Lie-
big finished  his  labors on the  fulminic  acid.
Immediately  after his return  from Paris, the
young chemist, probably  through  the  recom-
mendation of Humboldt, was appointed  to  an
extraordinary  professorship  at  Giessen.   As
early  as  1826, he received the appointment of
Ordinary Professor of Chemistry in the  same
University, and  the Medical Faculty  honored
him with its Doctorate.
  Among his independent scientific works may
be mentioned his " Anleitung  zur  Analyse or-
ganischer Koerper," (Introduction to the Analy-
sis of Organic Bodies,) Brunswick, 1837, and
his " Practical Pharmacy," as a part of the new
edition of the "Manual of Pharmacy of Geiger,"
Heidelberg, 1839, which was printed  again  as
a separate work in 1840.  In conjunction with
Dr. Poggendorf,  in  Berlin, he commenced  a 
           MEMOIR OP THE AUTHOR.          xi
" Dictionary  of Chemistry," which  is not  yet
completed.  The chief organ of his  communi-
cations  to the public has been  the "Annals of
Pharmacy," and which  is now,  chiefly through
his labors,  the principal journal for Organic
Chemistry.
   Dr. Liebig is without doubt one of the most
eminent chemists of  Europe, and, in organic
chemistry, he may be called, without  hesitation,
the first living  authority.   His  labors are the
more important, inasmuch  as they are not con-
fined to researches in one department, but,  like
those of Berzelius,  embrace the whole science
of Chemistry.   His investigations of organic
bodies should, however, be particularly noticed,
as they have roused a spirit of greater activity
in all who are engaged in chemical pursuits.
   Almost from the  beginning, Liebig has ex-
ercised  in his labors a very  severe  criticism.
This criticism  was  the  more useful, as it  was
an experimental one, refuting  experiments by
experiments, for which  he  was particularly dis-
tinguished by Berzelius in  his " Jahresberich-
ten " (Annual Reports).  We must not omit to
observe, however, that the severity of his criti- 
xii
MEMOIR OF THE AUTHOR.
cisms,  especially of his  later ones, has  been
thought by some to be occasionally tinged by
personal and even ambitious motives.
  The beneficial effects of the labors of Liebig
were  soon visible  in Germany and   in  the
neighbouring  countries.   The  French chem-
ists were led to show more  respect  to  Ger-
man Chemistry  than  ever before, and this re-
spect  is  now established  in the  place  of for-
mer disregard;  for  " the  French now acknowl-
edge," as Liebig himself  once remarked, " that
Germany is the real seat of public opinion in
chemical affairs." — In Germany his criticism
was efficacious, because it attacked with merci-
less severity all  that was  false, and showed at
the same time  the  right  method of coming at
correct results, and  which not only commanded
the attention of neighbouring countries, but in-
creased and secured it.
  This  may be  said, however, only in respect
to the department  of Organic Chemistry ; for,
when Liebig commenced his  researches, Inor-
ganic Chemistry had reached such a degree of
perfection, that  it  was partly through contrast
with  it,  that the imperfections of the former 
           MEMOIR OF THE AUTHOR.         Xlii
were  perceptible,  partly, also, because  a  true
basis  on  which   it  should  be  founded  was
wanting.
  To this design of recreating, as it were, Or-
ganic Chemistry, in his  native country,  Liebig
was  always faithful; and, though he no longer
stands alone  as  a distinguished promoter  of
that  department, yet no  one  can overlook the
influence  he has  had upon his  colleagues and
pupils.   This  influence operates in  Germany
and England to urge on the science,  in France
more to moderate its progress ; that is, to keep
theory within  its  proper  limits.   The  conse-
quence  has been, that, whereas, before, many
chemical  students  repaired to the laboratories
of Paris, the young chemists of all nations are
now assembled in the little town of Giessen,
to profit by the instructions of this great  mas-
ter.   In  the  present  year  there  are  around
him  one  hundred and  thirty-five  foreigners.
The British  chemists are looking  with eager-
ness to Germany ; and  to undervalue German
Chemistry, at  the present day, would be  ridi-
culed even in France.   We  know  very  well
that Dr. Liebig  has not  produced this effect
                b 
xiv         MEMOIR OF THE AUTHOR.
alone ; but who can tell how soon it would have
happened without him ?
  By his unwearied efforts to simplify Organic
analysis, and  to make it more accesible, he has
been rendering invaluable services to the young
chemist. He  has also simplified the apparatus,
and his improvements in it are now extensively
known  and employed,  having  already super-
seded  much that was formerly in  use ; and  in
this, too, he has conduced to  the great advances
in his favorite department of science.
   From the commencement  of his brilliant ca-
reer, Dr. Liebig has been  an unflinching  op-
ponent of traditional authorities, and  has  never
hesitated to attack the weaker parts  of the old
school.  It may  be asked, Does he not, in the
place of old authorities, set up his own ?  Has
he not been too ambitious  of founding a new
school ? We  think not, unless we should  honor
with his name the school  of all who are in-
spired with the love of truth and the ambition
of attaining the best methods of research.
   It cannot  be wondered at, that a man like
 Liebig should concentrate  about him  a  circle
 of young men, many of whom  are blind  to all 
MEMOIR OF  THE AUTHOR.
XV
other merit than that of  their master, and who
extend  it even to external preparations, for ex-
ample,  to  single  parts of his apparatus,  &c.
But they may be excused, after the proofs he
has  given  how fully equal he is  to his  task,
by  a series  of experiments always  so chosen
that  they  have aided  in  the  promotion of  his
general object, while he has aroused in so many
others  the  true  spirit of research, already re-
warded by the most valuable  results.
   From among the many examples of the skill
and sagacity of Liebig,  we  may mention  his
examination  of  the  Platinum-black   (Platin-
schwarz),  of Chloral,  of Aldehyde*;  his the-
ory of Alcohol and of Ether, and that of the
formation  of  Acetic Acid  (Essigbildung),  of
Alkaloids, of the analysis of  Organic Elements
 (Organische  Elementar-Analyse);  on all  of
 which  he  has left the impress of his analytical
 tact.  Nor should we overlook his investigation
 of the products  of the  decomposition of  the
 Sulphocyanates  (Schwefel-Cyan), of  the con-
 stitution of  the Organic  Acids, and  his  experi-

   * Though not the discoverer of Aldehyde, Liebig was the
 first to insulate it, and describe its properties. 
xvi
MEMOIR OF THE AUTHOR.
ments, performed in connexion with Mr. Wohler,
on the Oil of Bitter Almonds, on Cyanic Acid,
and on the products  of Decomposition of Uric
Acid.   These  are  but  a few of his many im-
portant researches.
  Dr. Liebig,  young as he  is,  has attained  a
reputation which secures to him one of the first
places in  the  history  of Chemistry, notwith-
standing  the great opposition which  his  criti-
cisms have excited, and will continue to excite
as he advances.  A  few years  since, Professor
Liebig was selected by Dr.  Turner to aid him
in the completion of  the sixth edition  of his
Elements  of Chemistry.  To Liebig was com-
mitted the department of Organic Chemistry.
On the decease of  the lamented  author, the
work  was continued by Liebig and Dr. Gregory
of Aberdeen.  The manner  in which they have
completed  their undertaking  has  shown  that
it could not  have been placed  in abler hands.
And the choice of Professor Liebig,  says his
accomplished coadjutor, " has been ratified by
the unanimous voice of European chemists, by
whom he is admitted  to be the first living au-
thority in Organic Chemistry."   The  transla- 
MEMOIR OF THE AUTHOR.
xvii
tion of  the First  Part of  Dr.  Liebig's Report
on  Organic  Chemistry,*  which  has passed  to
a fourth edition in  this country, and of which

the present work  is a  continuation, has  made
the name of the author familiar to us ; and the

appearance of a new work from the laboratory

of Giessen has  not been less welcome on this

side the Atlantic  than it was on the continent
of Europe.

  Cambridge, 1842.

  * "Chemistry in its application to Agriculture and Physiology.
By Justus Liebig, M. D., Ph. D., F. R. S., M. R. I. A., Professor
of Chemistry in the University of Giessen, etc., etc., etc.  Edited
from  the Manuscript of the Author,  by Lyon  Playfair,  Ph. D.
Fourth  American edition, with very numerous additions, a new
chapter on Soils, Notes, and Appendix, by John W. Webster,
M. D.,  Erving Professor of Chemistry in Harvard University.
Cambridge: Published by John Owen. 1843."
b* 
 
                    TO

THE  BRITISH  ASSOCIATION
                  FOR THE

    ADVANCEMENT  OF  SCIENCE.
  At the meeting  of the British Association in
Glasgow,  in 1840, I had  the  honor  to present
the first part of a report on  the then present
state  of  Organic  Chemistry,  in which  I  en-
deavoured  to  develope 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 As-
sociation for the  present  year the second  part
of my labors;  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
phenomena have been treated  in their chemical
relations; and, although it would be presump-
tuous to consider  the questions here raised as
being  definitely  resolved, yet those who are 
XX
DEDICATION.
familiar with chemistry will  perceive  that the
only method which can lead  to their final reso-
lution,  namely, the quantitative  method, has
been employed.
   The  formula? 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 logi-
cal 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 in-
 dependent  of all  hypothesis.   It  remains for
 the physiologist to determine, by  experiment,
 whether  the  conclusions drawn by the chemist
 from  such  a fact be accurate or erroneous.
 And, whether this question  be answered in the
 affirmative or in the negative, the fact remains,
 and will some day find its true explanation.
    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 he has received in the various 
DEDICATION.
xxi
branches  of medicine,  and  his intimate  ac-
quaintance  with the  German 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 investi-
gation of the food  of man and animals, the  an-
alysis  of all articles  of diet, and the  study of
the changes which the raw food undergoes in
its preparation ;  as,  for example, in fermenta-
tion  (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 spe-
cies of fodder, &c, as food, the  ultimate analy-
sis alone is not sufficient;  there are required
comparative investigations, which present very
great difficulties.
                          Dr. JUSTUS  LIEBIG.
  Giessen, 3d June, 1842. 
 
PREFACE.
  By the application to Chemistry of the meth-
ods which had for centuries been followed by
philosophers in ascertaining the causes of natu-
ral phenomena 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 ob-
servation 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 light on
those natural phenomena which were previous-
ly the most obscure and incomprehensible.
  The  most useful applications to the arts, to
industry, and  to all branches of knowledge re-
lated to chemistry, sprung from the  laws thus 
xxjv               PREFACE.

established ; and this influence was not delayed
till chemistry  had  attained its  highest  perfec-
tion, but came into  action with each new ob-
servation.
  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 from 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 attain-
ed 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 physiology 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 acquaintance with  chemical  observa-
tions.  Indeed, the  great physicians who lived
towards  the end of  the seventeenth 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 
PREFACE.
XXV
day ;  it was  the victory of philosophy over the
rudest empiricism.
   With  all its  discoveries,  modern  chemistry
has performed but  slender  services  to physi-
ology  and pathology ;  and we cannot  be de-
ceived  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
livino- body, with the characters of its constitu-
 ents, on the other.
   Physiology took no share in the advancement
 of chemistry, because, for a long period, she re-
 ceived from  the latter science  no assistance  in
 her own development.   This  state of  matters
 has  been   entirely   changed  within  five and
 twenty years.  But  during  this  period physi-
 ology 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 for-
 ward to a change in the direction of  the  labors
 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, 
xxvi
PREFACE.
 of fresh points of departure for researches, ren-
 der physiology more extensive, but neither more
 profound nor more solid.
   No one will  venture to maintain  that  the
 knowledge of the forms and of the phenomena
 of motion in organized beings is either unne-
 cessary or unprofitable.   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
 different organs,  and  of  their mutual  connex-
 ion in  the  animal body, was formerly the  chief
 object  of physiological researches ;  but  lately
 this  study  has fallen into   the   background.
 The greater part of all the modern discoveries
 has served  to  enrich  comparative anatomy far
more than  physiology.
  These researches have yielded  the most val-
uable results  in relation  to  the recognition of
the dissimilar 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  processes.
  The most exact anatomical knowledge of the 
PREFACE.
XXV11
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 more as to their functions than
we have learned concerning vision from count-
ing  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
not  act at sensible distances;  which are mani-
fested in the same way as those ultimate causes
by which the vital phenomena are determined ;
and which are  invariably found active, when-
ever dissimilar substances come into contact.
   Physiology,  even  in the  present day,  still
endeavours,  but always after the fashion of the
phlogistic chemists  (that is,  by the qualitative
method), to  apply chemical experience to the
removal of diseased conditions ;   but  with  all
these  countless experiments we  are  not one
step nearer to the  causes  and the essence of
disease.
   Without  proposing  well-defined  questions,
experimenters  have  placed blood, urine,  and
all the constituents of  the  healthy or diseased
frame, in contact with  acids, alkalies, and  all
6orts  of chemical  reagents;  and  have drawn, 
XXVIII
PREFACE.
 from observation of the changes thus produced,
 conclusions as to their  behaviour in the  body.
   By pursuing this method, useful remedies or
 modes of treatment might by accident  be dis-
 covered ;  but a  rational  physiology cannot be
 founded on mere reactions, 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
 cannot 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  ten-
 dency to remove the cause of disease.  Again,
 when we observe, in typhus, insoluble 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 Aris-
 totelian philosophy,  has formed certain concep-
 tions  in regard to nutrition and sanguification;
articles of  diet  have been divided into  nutri-
tious  and   non-nutritious;  but these theories
being  founded  on observations destitute of the
conditions most essential to the drawing  of just 
                      PREFACE.                 Xxix

conclusions,  could  not  be  received  as expres-
sions of the  truth.
   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, be-
cause maize  does  not  contain  the  thousandth
part of its weight of fat,   or of any substance
resembling fat.*   And when a  certain  number
  * Dumas and Payen have recently stated, that they obtained
from maize 9 per  cent,  of yellow  oil, and maintain that the
source of the fat in the above and in analogous cases is the fatty
matter in the food.* Mr. A. A. Hayes, whose chemical science
and practical skill are so well known and acknowledged in this
country, has devoted much  attention to the examination of the
varieties of maize,  and has  kindly  favored  the editor with the
following results and observations. — W.
  u The fact is, both Liebig  and Dumas are right, if the expres-
sion in Liebig's work has a general meaning. The proportion of
oil in maize varies  with the varieties and seasons.  In no in-
stance has so much as j§0 been obtained from our grain.  1 think
Dumas has overestimated  the proportion, from the fact that
alcohol  extracts  from  the  maize other  principles  which  are
united with the oil.  The weight of a bushel of sound maize ia
nearly 54 avoirdupois pounds.  In the manufactories of spirits

  • See Comptes Rendus des Seances de  l'Academie des Sciences, Octo-
ber and November, 1842.
                  C* 
XXX                    PREFACE.

of bees,  the  weight of  which is exactly known,
being  fed  with  pure  honey,  devoid  of wax,


and oil, I found  a mean  produce of oil to be 9 gallons from 45
bushels; 45 X & = 2430 lbs.;  and the gallon of oil, reckoned at
8 lbs. X 9 = 72 lbs. = to  nearly 3 per cent.  This will be the full
quantity for the Indian  corn  of our northern sections of country.
The color is accidental; white corn gives a colorless oil, and the
darker colored varieties a more highly colored oil. There is a vari-
ety of maize, which is known as the ' Tuscarora corn,' and highly
valued as an article of human food, which contains no oil.  An-
other variety, much cultivated in our Southern States, contains a
very small proportion only. The native maize of the Rocky Moun-
tains, from  which our varieties have been obtained by cultivation,
closely resembles, in proportion of oil and other constituents, the
' flat southern ' and western corn, the great staple  article of food
for a portion of the population and for animals.   Rice and  rye
both contain oil,  and the proportions vary with the seasons, as in
the case of Indian corn.   The Indian corn offers an interesting
instance of the union, in one grain, of matters  which are quite dis-
tinct in properties and unequal in value  as  articles of food. I
have elsewhere  shown, that, by applying chemical reagents to
the sections of kernels, we can point out the precise place where
eacli substance reposes, and the relative proportions, by bulk, of
each.  In the central soft part, and surrounding the germ, is the al-
buminous matter, the phosphate and peroxide of iron. The .starch
in a state of purity occupies another place apart from the ferrugin-
ous salt, and  its position  and quantity mark  the variety of corn.
The oil saturates a compound substance and woody fibre, giving
a translucent appearance to the grain. The chemical examination
of a large number of specimens of varieties, including nearly all
found  on this continent,  has established  the fact of the perfect
individuality of the several constituents which the grain contains.
If, however, the grain is  not  of mature  growth,  a blending of
parts becomes  evident;  the ferruginous  constituent  is  mixed
throughout with  the starch, and the phosphates are not found in
the same  parts  as when  the grain is mature.   During the  ma-
turation of the grain, we can easily trace  the conversion of one
organic matter  into another;  as the changes advance, the inor-
ganic  elements,  which were before mixed throughout the others
•^ssume their proper places.  No Indian corn has  yet been found 
                        PREFACE.                    XXxi

yield  one part  of  wax  for every  twenty  parts
of honey  consumed, without  any change  being
perceptible  in  their  health  or  in  their  weight,
it is impossible  any longer to entertain  a  doubt


destitute of phosphoric acid  and peroxide of iron.   When  the
kernel  germinates, the inorganic matters move with the  radicle
and plumula; the plant at one stage of growth absorbs from the
soil  additional  proportions  of these substances,  to supply  the
increased demand in the grain.  Experiments have been made
to ascertain  if the  phosphates  and oxide of iron are really
as essential  to the growth of the plant, as they are to the  ex-
istence  of the grain.   Specimens of Indian corn (maize) and  rye
were steeped in  solutions  of copper, which removed the iron,
and  substituted copper  as phosphate  of  copper;  these were
planted on different soils, under the care of different persons,  and
carefully attended.   The plants were  vigorous for some time,
but, before fructification took place, disease was apparent  and
the  vegetating power was  lost.   The nutritive and fattening
powers  of this grain have long been acknowledged,  but its value
as an article  of food  for man is a subject on which  minds differ.
The digestive organs of man and of some animals cannot render
the whole of this grain  capable  of assimilation.   Even when
quite finely  ground, horses  do  not digest the  parts saturated
with oil, while swine and fowls subsist and fatten on it.   After
the fine flour has been fermented so as to form a spongy bread,
or before the grain has ripened, its constituents are digested by
man. In the fattening of swine and fowls, the largest increase
of fat is produced by those grains  and nuts which contain the
most oil.  Swine eagerly  select, from the produce of forest-trees,
those nuts which  contain most oil; and if they are deprived of
food which does  not  contain oil ready formed, the diminished
production of fat  and its altered quality are plainly perceptible.
in the statements of Dr.  Liebig I think there is a well grounded
reliance on facts ; but the remarks above, and the case supposed
at page 83, would be a better illustration of the formation of tis-
sues and  fat, with a slight alteration in  the elements of the food.
The fact, however, that there is a variety of maize containing no
oil is indisputable, and this forms a favorite and nutritious food
for man and animals." 
xxxii
PREFACE.
as to the formation 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 investigation 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 earn-
estly and conscientiously for the true answers
to our questions;  that  we take the trouble,
by means of weight and  measure,  to fix  our
observations, and express them  in  the form of
equations, these answers are obtained without
difficulty.
  However numerous our observations may be,
yet,  if they only bear on one side of a ques-
tion, they will never enable  us to penetrate  the
essence of a natural  phenomenon in  its  full
significance.  If we  are  to  derive  any advan-
tage  from them, they must be  directed to a
well-defined object; and there must  be an or-
ganized connexion between  them.
  Mechanical philosophers  and chemists justly
ascribe 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 perfec-
tion, may always be given  in few words ;  but
these few words are eternal truths, to the dis- 
PREFACE.
XXX111
covery of which numberless experiments and
questions were essential.  The researches them-
selves, the  laborious experiments and compli-
cated apparatus, are forgotten as soon  as  the
truth is  ascertained.  They were  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,
however  insignificant,  which lays  claim to  at-
tention,  must  in the present day possess  this
character.  From  a certain number  of obser-
vations it must enable us to draw some conclu-
sion, 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  established  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  acquaint-
ance of  physiologists with the methods of re-
search employed in chemistry will  continue 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 
Xxxiv               PREFACE.
Priestley, chemistry was not more closely  re-
lated  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 diffi-
cult matter  to  draw the line between  them
distinctly.   The  connexion 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 to truth.  It is the  points  of  inter-
section that indicate 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 time, in
following the direct line ; but  all  are  prepared
for  circuitous paths.  Never doubting of the ul-
timate success of their efforts, provided they ex-
hibit  constancy and perseverance,  their eager-
ness and courage are only exalted  by difficulties.
  Detached observations,  without  connexion,
are points  scattered over  the  plain, which  do
not allow us to  choose  a decided  path.   For
centuries chemistry presented nothing but these
points, although sufficient means were available
to  fill  up the intervals between them.   But per- 
PREFACE.
XXXV
manent 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 col-
lection of problems,  such as  chemistry at pres-
ent  requires to be resolved ; and a number of
conclusions, drawn  according  to the rules  of
that science,  from  such observations as  have
been made.
   These  questions  and  problems  will  be  re-
solved ;  and  we  cannot doubt  that  we shall
have in that  case a new physiology and a  ra-
tional 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 sufficiently
 obvious.  In  the hands of the  physiologist,  or-
 ganic chemistry must become  an intellectual
 instrument, by means of which he will  be  en-
 abled to  trace the causes of phenomena invisi-
 ble  to the bodily sight ; and if, among the re-
 sults  which I have developed  or indicated in
 this work, one  alone  shall admit  of a  use-
 ful  application,  I shall  consider the  object for 
XXXvi                 PREFACE.

which it was  written  as  fully attained.   The
path which  has  led  to it will  open  upon  other
paths;  and  this  I  consider as  the most impor-
tant object to  be gained.
                                    JUSTUS LIEBIG.
  Giessen, JlptH,  1842.
                      NOTE.

  At page 316 of the Appendix will be found an interesting
paper by Keller, confirming the very important observation of
A. Ure, Junior,  as to  the conversion of benzoic acid into  hip-
puric acid in the human body, and the more recent confirmation
of the  same by M. Garrod, from the London  and Edinburgh
Philosophical Magazine, for June, 1842.  The reader will  per-
ceive that this fact strengthens materially the argument  of the
Author on the  action of remedies.
  Q^^ For  an explanation of the formulae and equations  em-
ployed  in  this work,  see the Introduction  to the Appendix,
page 2G7.
  For Tables  of corresponding Hessian and English  weights,
&c, see Organic Chemistry in its Application  to  Agriculture,
4th edition, page 416. 
CONTENTS.
                        PART I.
                                                       PAGE
Vital force, vis vita?, or vitality.....1
Distinction between animal and vegetable life  ...   2
Assimilation the result of chemical forces    ...     4
Vitality independent of consciousness      ....   6
Laws of the vital force  ....*..     8
Conditions of animal  life.......9
Nutrition depends on chemical changes ....    10
Amount of oxygen inspired by an adult man    .     .     .12
It combines with carbon and hydrogen in the body     .    13
The consumption of oxygen varies.....15
Effect of heat  on these variations.....16
The mutual action of oxygen and carbon in the body is the
     true source of animal heat.....17
The amount of oxygen regulates that of food   .     .     .20
Effects of climate  on the appetite.....22
The process of starvation.......24
Cause of death in starvation and chronic diseases   .    .    26
Nerves and muscles not the source of animal heat    .     .  28
Amount of animal heat......    .    32
Nervous and vegetative life......36
Nutrition depends on the constituents of blood     .    .    38
Identity of organic composition in fibrine and albumen     .  39
                   d 
XXXviii                CONTENTS.
Nutrition in the carnivora the most simple    ...    43
In the herbivora, depends on the azotized products of veg-
     etables   .........44
These products identical with  the constituents of blood     47
The blood of animals is therefore formed by vegetables  .    48
Uses of the non-azotized ingredients of food    .     .     .49
Changes of the food in the organism of carnivora  .     .    52
Carbon accumulates in the bile......56
Nitrogen in the urine.......58
The carbon is consumed or burned.....59
True function of the bile......61
Amount of bile secreted.......62
Assimilation more energetic in the young animal  .     .    65
The butter, sugar, &c, of its food support respiration    .  66
The same is true of the  class of herbivora   ...    68
Waste of matter very rapid in carnivora  .    .    .    .  73
Importance of agriculture to population  ....    75
Assimilation less energetic in the carnivora     .    .    .78
Origin of fat in domesticated animals    ....    79
Its formation is a source of oxygen   .    .    .    •    .83
It is formed when  oxygen is deficient, and  is a source of
     animal heat........86
Elements of nutrition and of respiration      ...    92
Gelatine incapable  of serving for nutrition, strictly so called 93
But it may serve to nourish the gelatinous tissues  .    .    94

                        PART  II.
           THE METAMORPHOSIS  OF TISSUES.
 Discovery of  proteine.......101
 It is formed by vegetables alone.....102
 Theory  of chymification.......J04
 Uses of the saliva.......108 
CONTENTS.
xxxix
109
116
120
122
126
127
130
131
Source of the nitrogen exhaled from the lungs and skin
Composition of proteine.....
Composition of the animal tissues   ....
Gelatjne contains no proteine,  although formed from it
The secretions contain all the elements of the blood
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.......153
Certain remedies take a share in the vital transformations  161
Chief qualities of the blood.....
Modus operandi of organic remedies
All organic poisons contain nitrogen
Theine identical with caffeine.....
Relation of th£ine  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
133
135
137
140
142
144
146
148
150
163
165
168
170
170
171
173
174
176
178
180 
xl
CONTENTS.
                      PART III.
1. The phenomena of motion in the animal organism    .   185
2. The same subject, with particular reference to the waste
    and supply or change of matter     ....   221
3. Theory of disease.......242
4. Theory of respiration.......253

                    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.........265
On the conversion of benzoic acid into hippuric acid in the
     human body,  by W. Keller.....316
Excretion  of carbon      .     .    .    .   .     .    .   320
Action of the heart.......320
Exosmose  and endosmose......321
Index
323 
       ORGANIC  CHEMISTRY

                    APPLIED TO

PHYSIOLOGY AND  PATHOLOGY.
  I. In the animal ovum, as well  as  in the seed of a
plant, we recognise a  certain remarkable force,  the
source of growth,  or increase in  the  mass, and of re-
production,  or  of supply  of the  matter  consumed ; a
force in a state of rest.   By the action of  external  in-
fluences, by impregnation, by the  presence 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 crystallized  minerals.
This force is called the vital force, vis vitaz  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 influence  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 distinguished min-
                1 
2                   VEGETABLE AND
eralogists, we consider atmospherical  air  and  certain
other gases as minerals, it may be said that the vital pro-
cess in vegetables  accomplishes 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  become
component parts of the plant; and  a comparison of the
chemical composition of the  plant with that of its nour-
ishment 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 contributed to es-
tablish the  fact, that the growth and  development  of
vegetables depend  on the elimination of oxygen, which
is  separated from the  other component  parts  of their
nourishment.
   In contradistinction  to  vegetable life,  the life of ani-
mals exhibits itself in the continual  absorption  of the
oxygen of the air, and its combination with certain  com-
ponent parts of the animal body.
   While  no part of an organized  being can  serve  as
food to vegetables, until,  by  the processes of putrefac-
tion and  decay, it has assumed the form  of inorganic
matter, the animal organism requires, for its support and
development, highly organized atoms.  The food of all
animals, in  all circumstances, consists  of parts of or-
ganisms. 
                     ANIMAL LIFE.                   3
  Animals are distinguished from vegetables by the fac-
ulty of locomotion, and, in general,  by the  possession
of senses.
  The  existence and  activity of these distinguishing
faculties  depend on certain  instruments which are never
found in  vegetables.   Comparative  anatomy shows, that
the  phenomena  of  motion  and sensation 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, essentially 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 ner-
vous apparatus.  The  phenomena  of motion  in vegeta-
bles, the  circulation of the sap, for  example, observed
in many  of the characese, 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  recognise in  the   nervous  apparatus  a source of
power, capable of renewing itself at every moment of
their existence.
   While the assimilation of food in vegetables,  and the
whole process of their  formation, are dependent on cer-
tain external  influences  which produce motion,  the
development  of  the  animal organism  is, to  a  certain
extent, independent of these external  influences, just 
4               ASSIMILATION THE RESULT
because the animal body can produce 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 con-
sciousness.
  The  activity  of vegetative  life manifests itself,  in
vegetables, with the  aid of external  influences ;  in ani-
mals, 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 rad-
ical fibres  of the vegetable the same wonderful  proper-
ties, is the same as  that residing in the secreting mem-
branes 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  organized beings.
   While  the organs of the  vital motions   are  never
wanting  in  the  lowest orders  of animals, as in  the im-
pregnated  germ of the ovum, in which they are devel-
oped first  of all, we  find, in  the  higher  orders  of ani-
mals, peculiar organs of  feeling and sensation, of  con-
sciousness and of a higher intellectual existence.
   Pathology informs  us, that the  true vegetative life is
in no way  dependent on the presence of this apparatus • 
                  OF CHEMICAL FORCES.                 5
that the process of nutrition proceeds in those parts of
the body where  the  nerves of sensation  and voluntary
motion  are paralyzed, exactly in the same way as in
other parts where these nerves are in the normal condi-
tion ; and, on  the  other hand, that  the  most energetic
volition is incapable of exerting any influence  on the
contractions of the  heart, on  the motion of the intes-
tines, or on the processes  of secretion.
   The  higher phenomena of mental existence  cannot,
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 manifes-
tations  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 exercises
a  certain  influence on the activity  of vegetative 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 pro-
cess of vegetative life.  In a manner exactly analogous,
the vegetative  life  reacts  on  the conscious mental ex-
istence.
   There  are thus two forces, which are found in activity
together ; but  consciousness  and  intellect may  be ab-
sent in animals as they are in  living  vegetables, without
their vitality being  otherwise affected than by the want
of a peculiar source of increased energy or of  disturb-
                 1* 
Q                VITALITY INDEPENDENT
ance.  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  physiology.   In  this
attempt men left  the province of philosophical research
for that of fancy; physiologists, carried away by ima-
gination, were far from being  acquainted with the laws
of purely animal  life.   None of them had a clear con-
ception 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  atmosphere  takes in  the  processes of vitality; all
these  foundations  for future   conclusions  were  still
wanting.
  What  has  the soul, what  have  consciousness  and
intellect,  to  do  with  the  development of  the  human
foetus, or the foetus  in a fowl's egg ?  not more  surelv
than  with  the  development of the  seeds  of a  plant.
Let us first endeavor to refer to their ultimate  causes 
            OF CONSCIOUSNESS AND INTELLECT.           7
those phenomena of life  which are not psychological;
and  let  us beware  of drawing conclusions before we
have a groundwork.   We know exactly the  mechanism
of the eye ; but  neither anatomy nor chemistry  will
ever explain how the rays of light act  on conscious-
ness, 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  intellect  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 gravitation  and
of the planetary motions led to an entirely new concep-
tion of the cause  of these phenomena.   This  concep-
tion could  not  have  been formed  in all its  clearness
without a knowledge of the phenomena  out of which  it
was  evolved ;  for,  considered  by itself,  gravity,  like
light to  one  born  blind, is  a  mere  word, devoid of
meaning.
  The modern science of  physiology has left 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, 
8                    LAWS OF THE
whose true connexion 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  manifestations from all
other causes which produce motion or change  of condi-
tion ; if, therefore, we regard  the vital  force  as an  in-
dependent  force,  then,  in the  phenomena of organic
life, as in all other phenomena  ascribed to  the  action of
forces, we  have  the  statics, that is, the state of equilib-
rium  determined 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 organism, a  continued
change of matter, more  or less accelerated, is  going on ;
that a part of the structure is transformed  into unorgan-
ized  matter, loses its  condition of  life, and  must  be
again renewed.   Physiology  has  sufficiently decisive
grounds  for the opinion, that every motion,  every mani-
festation of force, is  the result of a transformation of
the  structure or of its  substance ;  that every concep-
tion, every  mental affection, is followed  by changes in
the chemical  nature of the secreted  fluids ; that every 
VITAL FORCE.
9
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 organisms, which
we call  nourishment.   In consequence of  a  series of
alterations,  they serve  either for the increase of the
mass  (nutrition), or for the  supply of the matter con-
sumed (reproduction), or, finally, for the  production of
force.

   II.  If the first condition of animal life be the assimi-
lation  of what is commonly called  nourishment, the
second  is a continual absorption of oxygen from the
atmosphere.
   Viewed  as   an  object of scientific research,  animal
life  exhibits itself in  a series of phenomena,  the con-
nexion  and  recurrence of which are  determined by the
changes which  the  food  and the oxygen absorbed from
the atmosphere undergo in the organism under the influ-
ence of  the vital force.
   All vital  activity  arises  from the mutual  action of
the  oxygen of the atmosphere and the  elements of
the  food.
   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, deter- 
 10           NUTRITION AND REPRODUCTION
mined 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  or-
ganism, and  these are  the results of processes of  de-
composition,  to  which either  the  food  itself,  or  the
structures  formed from  it, or  parts of organs, are sub-
jected.
   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 diminishes  in size.   If decompo-
sition 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-
ized,  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  chemical
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  phenomena of vitality, may 
DEPEND ON CHEMICAL CHANGES.
11
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 sub-
stances possessing a well-defined chemical action.
   As, in the closed galvanic circuit, in consequence of
certain  changes  which an inorganic body, a metal, un-
dergoes 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 constituting 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 phe-
nomena of attraction and repulsion, which it  excites  in
other bodies naturally motionless, and  by the  phenom-
ena  of  the  formation  and  decomposition of chemical
compounds, which occur  everywhere, when  the  resist-
ance 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  incompre-
hensible than the production of a leaf or of a muscular
fibre ; and the production of vermilion, from mercury
and sulphur, is as  much  an enigma as  the formation of
an eye from the  substance of the blood.
   The  first  conditions  of animal life are nutritious mat-
ters and oxygen, introduced into the system. 
12                OXYGEN REQUIRED
  At every moment of his  life  man is  taking  oxygen
into his system, by means of the organs of respiration ;
no pause  is observable while life continues.
  The observations of physiologists have shown, that
the body of an adult man, supplied with  sufficient 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 consid-
erable.
  According to the experiments of Lavoisier, an adult
man takes into his system, from the  atmosphere, in one
year, 746 lbs., according to Menzies, 837 lbs. of oxy-
gen ;  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. (i)*
  What, it may be asked, has become of the enormous
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 oxygen
introduced through  the lungs and through the skin, and
have been given  out in the forms  of carbonic acid gas
and the vapor of water.
   At  every moment,  with every  expiration, certain
quantities of  its  elements  separate from  the  animal or-
* The Numbers refer to the Appendix. 
AS WELL AS FOOD.                13
ganism, after  having  entered into  combination,  within
the body, with the oxygen of the atmosphere.
   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 cu-
bic 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
required.   This quantity will be taken  into  the system
of an adult in four days two 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  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 car-
bon 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
                 2 
14              OXYGEN COMBINES WITH
an adult, taking moderate exercise, consumes 13.9 oz.
of carbon daily. (3) (A)
  These 13j?0 oz.  of carbon escape  through the skin
and lungs, as carbonic acid gas.
  For conversion  into carbonic acid gas, 13j9s 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 69i95 oz.
The quantities of carbon here mentioned are those given
off from the bodies of these animals 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 lime. (4)
  Since no part of the oxygen taken into the  system is
again given  off in any other form but  that of a com-
pound of carbon  or hydrogen ;  since, further, the car-
bon  and hydrogen  given off are, in a normal  condition
of health, replaced by carbon and  hydrogen supplied in
the food, it is clear, that  the amount of nourishment re-
quired for its support 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 
               THE CARBON OF THE FOOD.             15
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 natural-
ly in a state of great activity, requires food oftener, and in
greater proportion to its  bulk, than an adult, and bears
hunger less easily.   A bird, deprived of  food, dies  on
the third day, while  a serpent, which, if kept under a
bell-jar, hardly consumes  in an hour so much oxygen  as
that we can detect the carbonic  acid produced, 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 quantity of food
necessary in both conditions must vary in the same ratio.
   An  excess of food is incompatible  with deficiency
in respired oxygen, that is, with deficient exercise ; 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 which an animal takes  up
by the lungs, depends not only on the number of respi-
rations ; it is also affected by the temperature and densi-
ty of  the atmosphere.
   The  capacity of the  chest  in  an animal is a constant
quantity.   At every respiration a quantity of air  enters,
the volume of which may be considered as  uniform ;  but
its weight,  and that  of the oxygen it contains, is  not
constant.    Air  is expanded  by heat, and contracted
by cold, and equal volumes of hot and cold air contain
unequal  weights  of  oxygen.   In summer  air contains
aqueous vapor, in winter it is dry ;  the space occupied 
16     EFFECT OF HEAT ON THE OXYGEN CONSUMED.
by vapor in warm air is filled by air  itself in winter ;  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 warmed during respiration in the air passages
and  pulmonary cells,  acquires  the temperature of the
body.   To introduce into the lungs a given volume of
oxygen, less  expenditure of force is necessary in winter ;
and for the same  force, more oxygen is inspired.
   In an equal number of respirations we consume more
oxygen at the level of the sea than on a mountain.  The
quantity both of oxygen inspired and of carbonic acid ex-
pired, must therefore vary with the height of the barometer.
   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 ar-
ranged, that  the articles of food in different climates
are most unequal in the proportion of carbon they con-
tain.  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 
SOURCE OF ANIMAL HEAT.
17
moderation  in eating, and  men  can bear hunger 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 an-
imal HEAT.

   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, be-
sides, to the germination of seeds, to the flowering 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 feath-
ers do not possess an elevated temperature.
   This high temperature of the animal body, or, as it
may be called, disengagement of heat,  is uniformly 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 temperature ; the amount of heat
liberated is  a constant quantity.
   The carbon of the food, which is converted into car-
                   2* 
18                   RESPIRATION.
bonic acid within the body, must give out  exactly 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, 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 intro-
duced in equal times by  respiration.  Those  animals
which respire  frequently, and consequently 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 am-
phibia, 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
elimates, in the temperate zones as well as at the equa-
tor  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 cir-
cumstances under which they live !
   The animal body is a heated mass, which bears  the
 same relation to surrounding objects as any other heated 
       UNIFORM TEMPERATURE OF THE ANIMAL BODY.      19
mass.   It  receives  heat when  the  surrounding objects
are hotter,  it loses heat  when  they are colder, than
itself.
   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 re-
quired for the cooling of the heated 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 re-
gions, 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 in-
habitant  of the arctic circle has  a temperature as high as
that of a 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  medi-
um is restored  within  the  body  with great rapidity.
This  compensation  takes  place  more  rapidly in winter
than in summer, at the pole than at the equator.
   Now,  in  different climates  the  quantity  of oxygen
introduced into  the system by respiration, as  has  been
already  shown,  varies  according  to the  temperature
of the external air ;  the  quantity of inspired oxygen in-
creases with the loss of heat by external cooling, and
the quantity of  carbon  or  hydrogen necessary to com- 
20     UNIFORM TEMPERATURE OF THE ANIMAL BODY.
bine with this oxygen must  be increased in the same
ratio.
  It is evident, that the supply of the heat lost by cool-
ing is effected by the mutual action of the elements  of
the food  and the inspired oxygen, which combine  to-
gether.   To make  use  of a  familiar, but  not on that
account a less just  illustration, the animal body acts, in
this respect, as a  furnace, which we  supply with fuel.
It  signifies  nothing what intermediate forms food may
assume,  what changes it may undergo in the body,  the
last change  is uniformly the conversion of its carbon into
carbonic acid, and  of its hydrogen into water ; the  un-
assimilated  nitrogen of the food, along with the unburned
or  unoxidized 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. 
QUANTITY OF FOOD REGULATED.           21
  In cold and temperate climates, the air, which inces-
santly strives to  consume the body, urges man to labori-
ous efforts in order to furnish the means of resistance to
its action, while, in hot climates, the necessity of labor
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, because 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 bargain, daily, as warm-
 ly 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, be-
 cause  the  carbon  and hydrogen of  these  substances
 would  only  suffice to keep up the equilibrium between
 the external temperature and that of our bodies.
   According to the preceding  expositions, the  quantity
 of food  is regulated  by the  number of  respirations, by
 the temperature of the air, and by the amount of heat
 given off to the surrounding medium.
   No isolated fact, apparently opposed to this statement
 can affect the truth of this natural  law.   Without tem-
 porary or permanent injury  to health,  the  Neapolitan
 cannot take more carbon  and  hydrogen in the shape of
 food than  he  expires as  carbonic acid and water ; and 
22           QUANTITY OF FOOD REGULATED.
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 dis-
appearance of his  appetite,  previously a source  of fre-
quently recurring enjoyment ;  and he  succeeds, by the
use of cayenne pepper and the most powerful stimulants,
in enabling himself  to take as much food as he was  ac-
customed 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 res-
pirations 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  de-
gree 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 oxidizing  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  dis-
eased organs of digestion have sufficient power to place
the diminished amount of food in  equilibrium with the
inspired oxygen ; in the colder climate, the organs of
respiration  themselves  would  have been  consumed  in 
               IMPORTANCE OF HYDROGEN.             23
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  winter,  pul-
monic  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 vaporiza-
tion, 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 increases the appetite, and persons  of weak constitu-
tion 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 appreciable 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  com-
bining with oxygen, serve to produce animal 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 clear-
 ly developed,  when we  consider  the  state of a man, or
 other  animal, totally deprived of food. 
24
EFFECTS OF STARVATION.
   The first effect of starvation is the disappearance of
fat, and this fat cannot be  traced  either in the urine or
in the scanty  fasces.   Its  carbon  and  hydrogen  have
been given off through  the  skin  and lungs in the  form
of  oxidized 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  com-
bination with a part of his body.  Currie  mentions the
case of an individual who was unable to 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 dimin-
ished  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 vari-
ous animals, of fat,  which, at other periods, entirely
disappears, prove  that  the  oxygen,  in  the  respiratory
process,  consumes, without  exception, all such substan-
ces as are capable of entering  into combination with it.
It combines with whatever is  presented  to it ; and the
deficiency of hydrogen  is the  only reason why carbonic
acid is the chief product ; for, at the temperature of the
body, the affinity of hydrogen  for oxygen far surpasses
that of carbon for the same  element.
   We know in fact, that the graminivora  expire a vol-
ume of carbonic acid equal to that  of  the oxygen in-
spired, while the carnivora, the  only class  of animals
whose food contains  fat, inspire  more  oxygen than is 
                EFFECTS OF STARVATION.              25
equal in volume to the carbonic acid expired.  Exact
experiments  have  shown, that in  many cases  only half
the volume of oxygen 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  experiments ;
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 ; especial-
ly when, as in the present case,  nature affords the op-
portunity for observation, and when we  make a rational
use of that opportunity.
   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  dissolved.  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 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
oxidizing power of the atmospheric oxygen ceases, and
the chemical  process  of eremacausis, or  decay,  com-
mences, in which every part of  the body, the  bones
excepted, enters into combination  with oxygen.
   The time which is required to cause death by starva-
tion depends on the amount of  fat in the body, on the
                3 
26            DEATH CAUSED BY RESPIRATION.
degree of exercise, as in labor or exertion of any kind,
on the temperature of the air, and finally, on the pres-
ence 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 accessi-
ble 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 atmosphere.
When  those substances are wanting, whose function in
the  organism  is  to  support the process of respiration;
when  the  diseased organs  are incapable of performing
their  proper function  of producing  these  substances;
when  they have lost the power of transforming the food
into that shape in  which it may, by entering into combi-
nation 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 con-
 sumed. *
    The true cause of death  in  these  cases is the respira-
 tory process, that is, the action of the atmosphere.
    A  deficiency  of food, and a want of power to con-
 vert  the  food into a part  of the organism,  are  both,

   * 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 ia
 effected in the body of the carnivora, which  will be found further on. 
RESPIRATION TENDS TO CONSUME THE BODY.      27
equally, a want of resistance ; and  this is  the  negative
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 deprivation of
food, these substances are removed from the body with-
out 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 color.   Over the whole surface of the body oxy-
 gen is absorbed, and  combines with all the substances
 which offer  no  resistance to it.  In  those parts of the
 body where  the access of oxygen is  impeded  ; for ex-
 ample,  in the  arm-pits,  or in the  soles  of  the  feet,
 peculiar compounds are given  out, recognisable by their
 appearance, or by their  odor.   These compounds  con-
 tain  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  regu-
 late  it.  In  our ordinary  time-pieces, we know  with
 mathematical accuracy the effect  produced on their rate
 of going, by  changes in the length of the  pendulum,  or
 in the  external  temperature.  Few, however,  have a
 clear conception of the influence of air and temperature
 on  the health of the human body ; and yet the research 
28               NERVES AND MUSCLES
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 connexion of natural  phenomena, has
led  chemists to attribute  a part of the heat generated in
the  animal  body to  the  action of the nervous  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 ner-
vous  apparatus  has  in  the  respiratory process ; for no
change of condition  can occur in the  body without the
nerves ;  they are essential to all vital motions.  Under
their  influence, the viscera  produce 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 func-
tions, 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 continues  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  observa-
tions have been  made on the cutting of  the spinal  cord, 
NOT THE SOURCE OF ANIMAL HEAT.          29
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  car-
bon, 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.
   As, by the division of the  pneumogastric  nerves, the
 motion of the  stomach  and the  secretion of the gastric
juice are arrested, and an immediate check is thus given
 to the  process of digestion,  so the paralysis of the or-
 gans of vital motion  in the abdominal viscera affects the
 process of respiration.   These processes  are most in-
 timately connected ; and every disturbance  of the  ner-
 vous system or of the  nerves of digestion reacts 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 expenditure of
 force  consumed  in producing them ; how then, we may
 ask, is this  force produced ?
    By the  combustion of  carbon,  by the  solution  of
                3* 
30
SOURCES OF HEAT.
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 dis-
tinct, we can thus produce  one and the same  effect.
In  combustion  and in the  production of galvanic  elec-
tricity we  have  a change of condition in material par-
ticles ;  when  heat  is  produced  by  the  absorption  of
light  or by friction,  we have  the conversion of one
kind  of motion  into  another, which affects our  senses
differently.   In  all  such cases  we  have  a  something
given, which merely takes  another form ;  in all we have
a  force and its effect.   By  means of the fire  which
hea'ts  the  boiler  of a  steam-engine  we can produce
every kind of motion, and by a certain amount of mo-
tion 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  author-
ities 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 me-
chanical causes,  such as friction or motion.
  But,  admitting  all  the  influence which  electric  or 
SOURCE OF  ANIMAL HEAT.
31
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 material
particles, which may be expressed  by the conversion,
within a certain time, of the elements of the food into
oxidized products.   Such of these  elements as do  not
undergo this  process of slow combustion, are given off
unburned or incombustible in the excrements.
   Now, it is absolutely impossible that a given amount
of carbon or hydrogen, whatever different  forms they
may  assume in  the  progress  of  the  combustion,  can
produce more  heat  than if directly burned in  atmos-
pheric air or in oxygen 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  current  to produce
heat, the  amount of heat obtained is  never, in any cir-
cumstances,  greater than  we might have  by the combus-
tion of the zinc which has been dissolved in the acid.
   The contraction  of muscles produces heat; but the
force necessary for the contraction has manifested itself
through the  organs  of  motion, in  which it has been ex-
cited  by  chemical  changes.   The ultimate 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 
32                  GREAT AMOUNT
which many different effects may be produced.   The
cause of these 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 motion
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 different causes of motion
may be made to produce  the same effect.   But  in the
animal body we  recognise 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  mu-
tually exercise  on  each  other.   The  only known  ulti-
mate cause  of vital force, either in animals or in  plants,
is a chemical process.  If this  be prevented, the phe-
nomena  of life  do  not  manifest themselves, or they
cease to be recognisable by our  senses.   If the  chem-
ical 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  78*15  oz.  of water at
32° to  212°, that  is, by 180 degrees ; in all, therefore,
78-15  times 180°= 14067  degrees of heat.   Conse-
 quently, the  13-9 oz.  of carbon, which  are  daily con-
 verted  into  carbonic acid in  the body of  an  adult,
 evolve 13-9 X 14067°= 195531-3  degrees  of heat.
 This amount of heat is sufficient to raise the  tempera-
 ture of  1 oz. of water by that  number of degrees, or 
OF ANIMAL HEAT.
33
from  32° to 195563-3°; or to cause 67-9 lbs. of wa-
ter  at 32°  to boil; or to heat 184-3  lbs. of water  to
98-3° (the temperature  of  the  human body) ;  or  to
convert into vapor 11-4 lbs.  of water at 98-3°.
  If  we now assume, that the  quantity  of  water vapor-
ized through the skin and lungs in 24 hours amounts  to
48 oz. (3 lbs.),  then there will remain, after  deducting
the  necessary amount of heat, 144137-7 * degrees of
heat,  which are  dissipated by  radiation, by heating the
expired air, and  in the excrementitious matters.
  In  this calculation, no account has been taken of the
heat  evolved by the hydrogen of the  food,  during 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 combus-
tion,  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 quantity
of oxygen which an animal consumes in  a given  time,
and also the conclusions  deduced from them as to  the
  *  In the above, the latent heat of vapor at  212° is taken, according
to Despretz, at 955.8. 
34                 AMOUNT OF OXYGEN
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.   Prisoners  in the Bridewell at  Ma-
rienschloss (a prison where labor  is  enforced),  do  not
consume more than  10-5 oz. of carbon daily  ; those in
the  House of Arrest 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  consumed
in these different  cases are in the ratio  of these num-
bers ; 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 oxidized,  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
   * In this family, the monthly consumption was 151  lbs. of brown
 bread, 70 lbs. white bread, 132 lbs. meat, 19 lbs. sugar,  159 lbs. but-
 ter, 57 maass (about 24 gallons) of milk ; the carbon of the potatoes
 and other vegetables, of the poultry, game, and wine consumed, hav-
 ing been reckoned as equal to that contained in the excrementitious
 matters, the carbon  of the  above articles  was considered as  being
 converted into carbonic acid. — L. 
                CONSUMED BY ANIMALS.              35
been  equally  unsatisfactory.   Animals  have  been al-
lowed  to respire  in  close  chambers surrounded  with
cold water ;  the  increase of temperature in the  water
has been measured by the thermometer, and the  quan-
tity of oxygen consumed has  been calculated from the
analysis of the air before 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 obtained
of a rise in  the  temperature  of the  water without any
 consumption  of oxygen.  The animal  was at the tem-
 perature of  98° or 99°, and  the water, in the experi-
 ments  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 surrounding medium, and when  no motion is al-
 lowed, more heat is given off than corresponds  to  the
 oxygen consumed.  In equal times, with free and  un-
 impeded motion,  a  much larger quantity  of oxygen
 would be consumed without  a perceptible  increase in
 the amount  of heat lost.  The cause of these phenom-
 ena 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 sen-
 sation 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 
36                  NERVOUS AND
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 ex-
periments 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 appreciable  by the thermometer, we
can hardly be at a loss what value we ought to attach to
the  conclusions 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 equilibrium,
as vegetative life; it is obvious that  in all classes  of ani-
mals,  the latter,  namely, vegetative life, prevails  over
the  former, nervous life,  in the earlier stages  of ex-
istence.
  The passage or change of matter  from a state  of mo-
tion to  a state of  rest, appears in  an increase of the 
                     VEGETATIVE LEFE.                 37
 mass,  and in the supply  of waste ; while  the  motion
 itself, or the  production of force, appears  in the  shape
 of waste of matter.
   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 vegetative  life.  This con-
 dition does not cease in the  female as in the male, with
 the complete development of all the organs of the body.
   The female in  the  lower  animals, is, at certain sea-
 sons,  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 inde-
 pendent of  those external causes, which increase the in-
 tensity of vegetative  life.   When the  organism  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 certain age, of producing all
 parts of its  organization in greater quantity than is re-
 quired to supply the daily waste.
   This  excess of production  can be shown to contain
 all the elements of  a  new organism ;  it is constantly ac-
cumulating,  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.
                4 
38            NUTRITION DEPENDS ON THE
   Exercise and labor cause  a diminution in the quantity
of the menstrual discharge ;  and when  it is suppressed
in consequence of disease, the  vegetative life is mani-
fested in a morbid  production of fat.   When  the equi-
librium between  the vegetative  and nervous life is dis-
turbed 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  ani-
mal body, the development of its organs, and the  supply
of waste, — that all this is dependent on the blood,  that
is, on the ingredients of  the blood, then only those sub-
stances 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 nourishment, it  is only necessary to  ascer-
tain the composition 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  withdrawn  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 gelatinous  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, when the latter is purified from all  foreign matters. 
                 CONSTITUENTS OF BLOOD.              39
   The second principal ingredient of the blood is con-
tained  in  the  serum, and  gives to this  liquid all the
properties of the white of eggs, with wfiich it is identi-
cal.  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,  phosphorus, 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.   Besides these,  the  blood
contains certain  fatty bodies in  small quantity,  which
differ from ordinary fats in several of their properties.
   Chemical analysis has led to the  remarkable result,
that fibrine and albumen contain the same organic  ele-
ments united in the same  proportion, so that  two analy-
ses, 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  dif-
ference  of their  external properties ;  but in chemical
composition, in  the ultimate proportion of the organic
elements,  they  are  identical.
   This conclusion  has lately been beautifully confirmed
by a distinguished  physiologist  (Denis),  who has sue- 
40              NUTRITION DEPENDS ON THE

ceeded in  converting  fibrine into  albumen, that  is, in

giving it the solubility, and coagulability by heat, which

characterize the  white of egg.*


  * This remarkable experiment was first  performed by M. Prosper
Denis; but as it  confirms, in an unexpected  and very interesting
manner, the conclusion drawn by Professor Liebig from the researches
of Mulder, and from those made at Giessen :  namely, the identity of
the organic part of  vegetable fibrine, albumen,  and caseine with that
of animal fibrine, albumen,  and caseine; and as  M. Dumas has
made a claim to this discovery, as  being  previously well  known to
the French chemists, it appears advisable to  mention a few circum-
stances connected with the history of these researches.
  The opinions of Liebig on this subject were not  only detailed in
his lectures in the winter session of 1840 -41,  but communicated to
Mailer, Wagner, and Tiedemann, and  also among others  to M. Ma-
rignac of Geneva, a friend of M. Dumas, who shortly after returned
from  Giessen to Paris, viz., in February, 1841.
  In the mean time, M. Denis, having  made his curious researches,
found, that they were not received as they ought to have been by
the Parisian  chemists.  On the  contrary, he  was laughed at for his
facts!  He then applied  to Liebig, who, at once, caused his experi-
ments to be repeated, and confirmed his conclusions.  To those who
know the care with which  every  new observation  is protected in
Paris, there can be no stronger proof that no other French chemist
had any idea of the truth as  it now appears, otherwise it would have
been  announced and the date taken.
   In  a work published by Dumas and  Boussingault, on the composi-
tion of the air, in the spring of 1841, the ideas in regard to  the cause
of the uniform amount of oxygen in the atmosphere, are those  pre-
viously published in Liebig's Organic  Chemistry applied to Aoricul-
ture,  published in 1840.
   Further, M. Dumas, in a lecture published by him in the end of
August, 1841,  consequently long  after  the  views  of  Liebig  were
known in Paris, put forth views, coinciding with  those of Liebig in
regard to the nutrition of animals, and  the composition of the azotized
vegetable nutritious compounds, without the slightest  acknowledg-
ment.
   The  researches which led to these views were not  Parisian; for
M. Dumas had never made researches  on vegetable fibrine, albumen,
and caseine ; while the researches of Boussingault led to the conclu-
sion, that these substances differed in  composition from the constitu-
ents of blood.  Now, during the two preceding  years, Mulder  had 
CONSTITUENTS  OF BLOOD.
41
   Fibrine and  albumen, besides having the  same com-
position,  agree  also  in this, that both  dissolve  in  con-

published his admirable papers, while Liebig and his pupils at Giessen
had  confirmed and extended the conclusions of Mulder, and Liebig
himself had made the important deductions  on which the present
work is founded, and had, as we  have seen, publicly taught them in
the winter  of 1840-41.
  It is impossible to speak too highly of the labors of Boussingault,
and accordingly, Liebig, in the present volume, has availed himself
of them, with the fullest acknowledgment.  It is only to be regretted
that that eminent chemist, in the work already mentioned, published
along  with Dumas,  should not have  done  the same justice to his
distinguished German contemporary.
  Finally, on a careful review of the above facts, it cannot be doubt-
ed, that, as in the case of the Agricultural Chemistry, our author
was the first to advance those views, founded as well  on the experi-
ments of others as on his own, which have for the first time given a
consistent  shape to  Physiological  Chemistry.  These views being
once published, nothing is  easier  than to attach  a meaning to older
observations and remarks, which even their authors had allowed to
fall into oblivion from not perceiving their true bearing ; and every
great advance in science is sure to draw on its author similar charges
of plagiarism.  The voice of posterity, however,  never fails to de-
clare itself in favor of the true  discoverer, and Liebig will not lose
the honor to which he is so justly entitled.
  The conduct of the French chemists in regard to the observations
of Denis, is a  clear proof, that, previous to  the time when Liebig's
views reached Paris, they had  not  formed any distinct opinions on
these important points.   In fact, it is universally known, that during
that period, M. Dumas, who now steps forward to claim a share in
discoveries, the value of which he, along with all chemists, now fully
appreciates, was  occupied with researches,  interesting  indeed, but
of far less  value and importance,  on  his favorite theory of substi-
tutions.  Indeed, up to  the  publication of the paper on air, with
M. Boussingault, in 1841, M. Dumas had not appeared at all in the
interesting field now in question; whereas, previous  to that period,
the views of Liebig were matured.
   We could easily prove, by the internal  evidences of M. Dumas's
writings, that his views are borrowed from Liebig ; as, for example,
his formula for  fibrine  and  albumen, the origin of which was un-
known to him.  But we  have done  enough to show how groundless
is the charge of plagiarism against Liebig.
                    4# 
42
IDENTITY OF ANIMAL
centrated muriatic acid, yielding a solution of an intense
purple color.   This solution, whether made with fibrine
or albumen, has  the very same reactions with all  sub-
stances yet tried.
   Both albumen and fibrine, in the process of nutrition,
are capable  of  being converted into muscular fibre, and
muscular fibre is capable of being reconverted into blood.
These facts have long been established by physiologists,
and chemistry has merely proved, that these metamor-
phoses  can  be accomplished  under the influence of a
certain force,  without 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 organized
parts with that of fibrine and  albumen,  the  following
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  and life
is destitute of nitrogen ;  all of them contain likewise
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 con-
tains  less than  17 per cent,  of nitrogen.(7)*
   The most convincing  experiments and observations
have proved, that the  animal  body is absolutely incapa-
* See Note XXVII. 
                  FIBRINE AND ALBUMEN.              43
 ble 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, muscular fibre,  &c, must  con-
 tain 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 nitrogen 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 ingredients
 of the body which are  destitute of nitrogen.   Both are
 amorphous or unorganized, and  only so far take part in
 the vital process  as that their  presence  is required for
 the due performance of the  vital functions.  The  inor-
 ganic 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  differences  can be
discovered. 
44             NUTRITION OF GRAMINIVORA.
  The  nutriment  of  carnivorous  animals  is derived
originally from blood ; in their stomach  it becomes dis-
solved,  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  organization  which  have  undergone  change or
metamorphosis.
  With  the exception of hoofs, hair, feathers, and the
earth of bones, every  part of the food  of  carnivorous
animals is capable of assimilation.
  In a chemical  sense, therefore, it may be said that a
carnivorous animal, in supporting  the vital process,  con-
sumes itself.   That  which serves for  its  nutrition is
identical with those parts of its  organization which are
to be renewed.
   The  process of nutrition  in  graminivorous  animals
appears at  first sight  altogether different.   Their diges-
tive  organs are less simple, and  their food consists of
vegetables, the great  mass of which contains but  little
nitrogen.
  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 animals  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  nitrogenized 
VEGETABLE FIBRINE.
45
constituents.   Animals cannot be fed on  matters desti-
tute of these nitrogenized constituents.
   These important products of vegetation are especially
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  nitrogenized forms of nutriment in the vegeta-
ble kingdom may be reduced to three substances, 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 min-
utes.   A  gelatinous precipitate, commonly of a  green
tinge,  is deposited, and this, when acted on  by liquids
which  remove  the  coloring  matter,  leaves  a grayish
white substance, well known to  druggists as  the deposit
from vegetable juices.   This is  one of the  nitrogenized
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 be
 longs,  not  to vegetable fibrine, but to  a  foreign sub
 stance, present in  small quantity, which is  not found in
 the other cerealia.
   The method by which it is obtained sufficiently proves 
46              ALBUMEN, AND CASEINE.
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 nitrogenized compound remains dissolved
in the juice after the separation of the fibrine.  It does
not separate from the juice at the ordinary temperature,
but  is instantly coagulated when the liquid containing it
is heated  to the boiling point.
   When  the   clarified juice of  nutritious  vegetables,
such as cauliflower, asparagus,  mangel-wurtzel, or  tur-
nips, is made  to boil, a coagulum is  formed, which  it is
absolutely impossible to distinguish from the  substance
which separates as a coagulum, when the serum of blood
or  the white of an  egg, diluted  with water, are heated
to the  boiling point.  This is vegetable  albumen.   It is
found in the greatest abundance in certain seeds, in nuts,
almonds,  and  others, in  which  the  starch of the  gra-
mineae is replaced by oil.
   The  third  nitrogenized constituent of the  vegetable
food of animals is vegetable caseine.  It is chiefly  found
in the  seeds of pease,  beans, lentils, and similar  legu-
minous  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 nitrogenized  compounds, vegetable fi-
brine,  albumen, and caseine, are the true nitrogenized
constituents of the food of graminivorous animals ;  all 
                       NUTRITION.                    47
other nitrogenized compounds,  occurring  in  plants, are
either rejected by animals, as in the case of the charac-
teristic principles of poisonous and  medicinal  plants, or
else they occur in the  food  in  such very  small  propor-
tion,  that they cannot possibly contribute to the increase
of mass  in the animal body.
   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 composition with the chief constituents
of blood, animal fibrine, and albumen.   They all three
dissolve  in concentrated muriatic acid with  the  same
deep purple color, and even in their physical characters,
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,
phosphorus, and  phosphate  of  lime, no difference can
be observed, (s)
   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 vegetable principles, which  in
animals are used to form blood, contain the  chief  con-
stituents  of blood, fibrine, and  albumen, ready formed,
as far as  regards their composition.  All plants, besides,
contain  a  certain  quantity of iron,  which reappears  in
the coloring matter of the blood.  Vegetable fibrine and 
48                    NUTRITION.
animal fibrine, vegetable albumen and animal albumen,
hardly differ, even in form ; if these principles be want-
ing in the food, the nutrition of the animal is arrested ;
and when they are present, the  graminivorous  animal
obtains in its food the very same principles on the pres-
ence  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 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 devel-
opment of the  animal organism  and its growth are de-
pendent  on  the reception of certain principles identical
with the  chief constituents  of blood.
   In  this sense  we may say, that the animal  organism
gives  to  blood only  its  form ;  that it  is  incapable  of
creating  blood out of other substances which do  not  al-
ready 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 extensive  series of com-
pounds,  differing  in composition from the chief constitu-
ents  of blood ; but these last, which form the starting
point of  the series, it cannot produce.
   The animal organism is a higher kind  of vegetable, 
USES OF THE SUGAR.                49
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 begins
with carbonic  acid, ammonia, and water,  the sources of
the nutrition of vegetables, and  includes the most com-
plex constituents of the animal brain, there is no blank,
no interruption.   The first substance capable of afford-
ing nutriment to animals is the last  product of the crea-
tive energy of vegetables.
   The  substance of cellular tissue and of membranes,
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 constituents 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 tfeeqtrineipal ingredient of  butter
in palm oil, and of-horse fat, and train oil in certain  oily
seeds.              .   :     '<   "-

   X. While the feeding confutations leave little or
no doubt  as to the 1^*jJj^W^i^«h'e increase 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  sub-
stances  containing  no nitrogen, such  as  sugar, starch,
gum, pectine, &c.
                    5 
50           USES OF THE STARCH.  CASEINE.
  The most extensive class of animals, the graminivora,
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 consti-
tuents of the food of carnivorous animals in the earliest
periods  of life ; for this food also contains substances,
which are not  necessary for their support in the  adult
state.
  The  nutrition of the young  of carnivora is obviously
accomplished by means  similar to  those  by which  the
graminivora are  nourished ; their  development is  de-
pendent on the supply of a fluid, which the  body of the
mother secretes in the shape of milk.
  Milk contains only one nitrogenized constituent, known
under the name of  caseine ; besides this, its chief ingre-
dients 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 nitrogenized  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 identi-
cal in composition with the chief constituents of blood,
fibrine and  albumen.  Nay, more, a  comparison  of its
properties with those of vegetable caseine  has shown
that these two substances  are identical in all their  prop- 
USES OF THE BUTTER, &c.
51
erties ;  insomuch,  that  certain  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  ani-
mal. (9)
   The young animal, therefore,  receives, in the form
of caseine,  which is distinguished from fibrine  and al-
bumen  by  its great solubility, and by not coagulating
when  heated, the  chief  constituent  of  the mother's
blood.   To convert caseine  into blood no foreign  sub-
stance is required, and in the conversion of the mother's
blood into  caseine, no elements  of the constituents of
the blood have  been separated.   When chemically ex-
amined, caseine is  found to contain a much  larger  pro-
portion 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, dependent on the
supply of a substance, identical  in 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  composition
 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 precisely in  the  proportion
 to form water. 
52
ANIMAL AND VEGETABLE
  There  is added, therefore, .by means of these com-
pounds, to the  nitrogenized  constituents of food, a cer-
tain amount of carbon, or, as in the case of butter, of
carbon and hydrogen ; that is,  an  excess of elements,
which  cannot possibly be employed  in the  production
of blood,  because the nitrogenized substances contained
in the  food already contain exactly the amount  of car-
bon which is required for the  production of  fibrine  and
albumen.
  The following  considerations  will show that hardly a
doubt  can be  entertained,  that this  excess  of  carbon
alone, or  of carbon  and hydrogen, is expended  in  the
production of animal heat,  and serves to protect  the
organism from the action of the  atmospheric  oxygen.

  XL  In order to obtain a clearer insight into  the na-
ture 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  constrictor, 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 re-
tained their natural form and  aspect, but have become
brittle, because of all their  component parts they have
lost only that one which was capable  of solution, name-
ly,  the gelatine.   Fseces,  properly  so  called,   do  not
occur in serpents any more than in carnivorous birds.
  We  find, moreover,  that, when  the serpent  has re-
gained  its  original weight, every other  part of its prey, 
CASEINE IDENTICAL.
53
the flesh, the blood, the brain,  and nerves, in  short,
every thing, has disappeared.
   The only excrement, strictly speaking, is a substance
expelled by the  urinary passage.   When dry, it is pure
white, like  chalk ; it  contains  much nitrogen,  and a
small quantity of  carbonate and phosphate  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 it contains  two  equiv-
 alents of carbon.
   But muscular fibre, blood, membranes, and skin, con-
 tain 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  consumed, for every equiv-
 alent of nitrogen, much  more than eight  equivalents of
 carbon.
   If now we  assume, that the urate of ammonia contains
 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 differ-
 ent form from  the  two equivalents which are found in
 the urate of ammonia.
   Now we know, with  perfect certainty,  that this  car-
 bon  has been  given  out  through the skin  and  lungs,
 which  could only take place in the form of  an oxidized
 product.
    The excrements of a  buzzard which  had been fed
                    5* 
54             NUTRITION OF CARNIVORA.
with beef,  when  taken out of the rectum,  consisted,
according to L. Gmelin and Tiedemann,  of urate of
ammonia.  In like manner, the fseces 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 car-
bon 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 car-
bonic acid and water.   The incombustible parts would
have taken the form of ashes, and any part of the car-
bon unconsumed from a  deficiency of oxygen, would
have appeared as soot, or lampblack.   Now the solid 
FOOD OF CARNIVORA.
55
excrements are 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 oxygen ab-
sorbed in the lungs into oxidized products ; the carbon
into  carbonic acid, the hydrogen  into water, and the
nitrogen  into  a  compound containing the same elements
as carbonate of ammonia.
  This is only true in appearance ; the body, no doubt,
after a certain  time, acquires  its original  weight.   The
amount  of carbon, and of the other  elements,  is not
found  to be  increased, — exactly as much carbon, hy-
drogen, and nitrogen  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 appetite,
had no other  object   than the  production of urea, uric
acid, carbonic  acid, and other excrementitious matters,
— of  substances which the system expels, and conse-
quently applies to no  useful purpose 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 sub-
stance of  the  organs, and have been metamorphosed
into new combinations, which are amorphous and unor-
ganized.
   The food of the carnivora  is  at once  converted into 
56
CARBON IS ACCUMULATED
blood ;  out of the newly-formed blood those parts of
organs which have undergone metamorphoses are repro-
duced.   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 cellular
tissue, of the nerves, and brain ?
  These new compounds  cannot, owing  to  their solu-
bility,  remain in the situation where they are  formed,
for  a  well-known force, namely, the circulation of the
blood, opposes itself to this.
  By the expansion of  the  heart, an organ  in  which
two systems  of tubes  meet, which are ramified  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  atmo-
sphere.   This motion is powerfully assisted by the con-
traction of the heart, alternating with its expansion, and
caused  by  a force independent  of  the  atmospheric
pressure.
  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 
IN THE BILE.
57
kind, as soon as they enter the absorbent 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  compounds formed by the
transformations  of organized parts, must be  compelled
to move towards the heart.
   These compounds  cannot be  employed for the re-
production of those tissues from which they are derived.
 They pass through  the absorbent and lymphatic vessels
into the veins, where their  accumulation would speedily
put  a stop to the nutritive process, were it not that this
accumulation is prevented by two contrivances adapted
 expressly to this purpose, and which  may be  compared
 to filtering 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 sep-
 arate from both all substances incapable of contributing
 to nutrition. (A)
   Those new compounds which contain the nitrogen  of
 the transformed organs are  collected  in  the urinary blad-
 der, and being utterly incapable  of  any further applica-
 tion in the system, are expelled from the body.
    Those, again,  which contain the carbon of the trans-
 formed tissues, are collected in  the gall-bladder in the
 form of a compound  of soda, the  bile, which  is miscible 
58
THE CARBON OF THE BILE
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 solubility, return during that process into  the
circulation in  a state  of extreme division.   The soda
of the bile, and those highly carbonized  portions which
are  not  precipitated  by a weak acid (together  making
!9090ths of the  solid contents of the bile), retain the  ca-
pacity of resorption by the absorbents of the small and
large intestines ; nay,  this capacity has been directly
proved by the administration of enemata containing bile,
the whole of  the bile  disappearing  with the  injected
fluid in the rectum.
   Thus  we know with  certainty, that  the  nitrogenized
compounds produced  by the  metamorphosis of organ-
ized  tissues,  after being  separated from the  arterial
blood by means of the kidneys, are  expelled  from  the
body as utterly incapable of further alteration ;  while
the compounds rich  in carbon, derived from the  same
source, return into the system of carnivorous animals.
   The food of the carnivora is identical with the  chief
constituents of their  bodies,  and hence the metamor-
phoses which their organs undergo must be the same as
those which, under the influence of the vital force, take
place in  the matters which constitute 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, 
UNDERGOES COMBUSTION.
59
strictly speaking, the carbon of the compounds formed
in the metamorphoses of living 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 organized tis-
sues ; 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 pas-
sage 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 the
metamorphosed tissues ; this  carbon  disappears  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  water ; 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 substances, such as phos-
 phate of lime ; and the small quantity of organic matter
 which is found mixed with these is derived from excre- 
60
USES OF THE URINE
tions,  the  use of which is  to promote their passage
through the intestines,  such  as mucus.   These excre-
ments  contain 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  find the gall-bladder dis-
tended 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 most
highly  nitrogenized  constituent, urea, as  in  the normal
condition.   (Marchaud.  Erdmann's Journal  fur prak-
tische 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 organized  tissue  which  undergoes  metamorphosis.
Thus,  after a  walk, the secretion of urine in  man is in-
variably increased.
   The urine  of  the mammalia,  of birds,  and  of am-
phibia, contains uric acid or  urea  ; and the excrements
of the  mollusca,  and of insects,  as  of cantharides and 
AND OF THE BILE.
61
of the butterfly of the  silkworm,  contain  urate  of am-
monia.   This constant  occurrence of one or two nitro-
genized  compounds in  the  excretions 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  fiir
Physiologie, 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 de-
gree as  we know them to be, and  which, as  already
stated, cannot be employed in the production of blood,
must,  when returned through the intestines into the cir-
culation, 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 excreted ;
and  nothing is more  certain, than that a substance con-
taining so very small a proportion  of  nitrogen can have
no share in the process of nutrition or reproduction of
organized  tissue.   But quantitative physiology  must  at
once and decidedly reject the opinion, that  the bile serves
                 6 
62             AMOUNT OF BILE SECRETED
no purpose in the economy, and is incapable of further
change.
  No part of any organized  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 converted into mus-
cular fibre, membrane, or cellular tissue, the soda  they
contain  must enter into new  combinations.  The blood
which is transformed  into organized tissue  gives up its
soda to  the  compounds formed by the metamorphoses
of the previously 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, with the excep-
tion  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 faeces.   The soda of the  bile,
therefore, at  all events, must have returned from the
intestinal canal into the organism, 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  Physiologie, V.
p. 260.)  But the faeces 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 water, and  7| lbs. dry  faeces.
(Boussingault.)   The latter yield to alcohol  only ^th
part of  their  weight of soluble matter. 
IN MAN AND ANIMALS.
63
  If we assume  the bile  to contain 90  per cent, of
water,  a horse secretes daily 592 oz. of bile, containing
59-2 oz. of solid matter ; while  7±  lbs. or 120  oz. of
dried excrement yield  only 6  oz. of matter soluble in
alcohol, which might  possibly be bile.  But this matter
is not bile ;  when the alcohol is  dissipated by evapora-
tion, there remains a soft, unctuous  mass, altogether in-
soluble  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 phosphate, 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,  therefore,  would contain only 21.6
grains  of dried bile, equivalent to  216  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  accuracy
of  the physiological experiments, in regard to the quan-
tity of bile secreted by  the different classes of animals ;
thus much  is  certain, that  even the  maximum 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 
64
THE CARBON OF THE FOOD
69  per  cent,  of  carbon.   Consequently, if a  horse
secretes  37 lbs. of bile, this quantity will contain only
40.848 ounces  of carbon.   But the horse  expires daily
nearly twice as much in the form of carbonic acid.   A
precisely similar proportion 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  whatever combina-
tion  the oxygen may  enter in the blood, it must be held
as certain,  that such of the constituents of blood  as are
employed for reproduction,  are not materially altered by
it.   In muscular fibre we find fibrine, with all the prop-
erties it had in  venous blood ; the albumen in the blood
does not combine with oxygen.   The oxygen may pos-
sibly serve  to  convert  into  the gaseous state some un-
known constituent of the  blood ; but those well-known
constituents which are employed in reproduction, cannot
be destined to support the respiratory 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  op-
erations, it follows,  as  has been  observed, from  the
simple comparison of those parts  of  the food of  the
carnivora which  are  capable of  assimilation, with the
ultimate  products into which it is converted, 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 sub-
stance of  the  metamorphosed tissues ; and  this  being
admitted, the question of  the  necessity of  substances 
                 SUPPORTS RESPIRATION.              65
containing  much carbon  and no nitrogen in the food of
the young of the carnivora, and  in that of the gramini-
vora, is resolved in a strikingly simple manner.

   XII. It cannot be disputed, that in an adult carnivor-
ous animal, which neither gains nor loses weight, per-
ceptibly, from day to day, its nourishment, the waste of
organized tissue, and its  consumption of oxygen, stand
to each other in a well-defined and fixed relation.
   The carbon of the carbonic acid given off, with  that
of the urine ;  the nitrogen of the urine, and the hydro-
gen  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 exactly 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,  the weight does
not remain  unchanged  ; on  the contrary,  it  increases
from day to day by an appreciable quantity.
   This fact presupposes, that the assimilative process
in the  young animal  is more  energetic,  more intense,
than the process of transformation in the existing tissues.
If both processes were equally active, 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 respira-
                 6* 
66
BUTTER, SUGAR, STARCH, <fcc.
tions are more frequent ;  and, for equal bulks, the con-
sumption of oxygen must be greater rather than  smaller
in the young than in the  adult  animal.   But, since  the
metamorphosis of organized parts goes on more  slowly,
there would ensue a deficiency of those substances,  the
carbon and hydrogen of which are adapted for combina-
tion with oxygen ;  because, in  the  carnivora, it is  the
new  compounds, produced by the  metamorphosis of
organized parts, which nature  has  destined to furnish
the necessary resistance to  the action of the  oxygen,
and to produce animal heat.   What is wanting for these
purposes, an infinite wisdom has supplied  to the young
animal in its natural food.
   The carbon and  hydrogen of butter, and  the carbon
of the  sugar of milk, no  part of either of which  can
yield blood, fibrine, or albumen,  are destined  for  the
support  of the respiratory process,  at an  age  when  a
greater resistance is  opposed  to the  metamorphosis of
existing organisms ; or, in  other words, to  the  produc-
tion  of compounds, which in the adult state are produced
in quantity amply sufficient for the  purpose of  respira-
tion.
   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  can-
not be detected in the faeces.
   The butter  and  sugar of milk are given out in the 
CONSUMED IN RESPIRATION.
67
form of carbonic acid and water, and their conversion
into oxidized products furnishes the clearest proof,  that
far more oxygen is absorbed than  is required to convert
the carbon and hydrogen of the  metamorphosed tissues
into carbonic acid and water.
   The change and  metamorphosis of organized tissues
going on in the vital process in the young animal,  con-
sequently yield, in  a  given time,  much  less carbon and
hydrogen in the form  adapted for the respiratory process
than corresponds to the  oxygen  taken  up in the lungs.
The  substance of its organized  parts would undergo  a
more rapid consumption, 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 process,  have  no
other function than to protect the  newly-formed organs
from the action of  the  oxygen.   It is  the elements of
 these substances which  unite  with the  oxygen ; the
 organs themselves  could  not do so without being con-
 sumed ;  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 substances devoid
 of nitrogen,  which their  organism cannot  employ  for
 nutrition, strictly so  called, that is, for  the  production 
68               PROPERTIES OF STARCH
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  organized
parts ; hence, milk is not provided for them.
  The nutritive process in  the  carnivora thus presents
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 existence
depends on the supply of substances having a compo-
sition 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 sub-
stances 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 chemi-
cal composition, (u)  In the same plant,  in the pea, for
example,  we find  starch, the globules of  which differ in
size.   Those  in the expressed juice  of the stalks have a
diameter of from 5so to  i|5 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 remark-
ably small.
   It is  well known that starch  may be  converted into 
EASUVY CONVERTIBLE INTO SUGAR.
69
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  metamor-
phosis of starch into sugar depends 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 elements  have been separated, and,  except  the
elements of water,  no foreign element  has been added
to it in this transformation.
   In many, especially  in pulpy fruits, which  when  un-
ripe 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 unripe  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,  deposits a very fine
flour of starch, of which not  even a trace  can be  de-
tected 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 gather-
ing.   The after-ripening, as  this change  is called, is  a
purely  chemical  process, entirely  independent of the
vitality of  the plant.   When vegetation ceases, the fruit
is capable  of reproducing  the  species, that is, the ker-
nel, stone, or true  seed is fully ripe, but the  fleshy cov-
ering from this  period  is  subjected to the  action of the
atmosphere.  Like all  substances in a state  of erema- 
70
SUGAR OF MILK, GUM, &c.
causis,  or  decay,  it absorbs  oxygen, and  gives off a
certain quantity of  carbonic acid gas.
   In the same way as the starch in putrefying 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 eremacausis, is transformed into grape
sugar.  The more starch the  unripe  fruit contains, the
sweeter does it become when ripe.
   A close  connexion thus  exists  between  sugar and
starch.   By means of a  variety  of  chemical actions,
which exert no other  influence  on the  elements  of starch
than  that  of changing the direction of their  mutual at-
traction, 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  fermenta-
tion, but it acquires the property of resolving itself into
alcphol 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 transformation, when  it is kept  in  contact with
acids, —with sulphuric acid, for example,—at the  or-
dinary temperature.
   Gum has  the  same composition in 100 parts as cane-
sugar, (u)  It is  distinguished from the different varieties
of sugar by  its not  possessing the property of being re-
solved into alcohol and carbonic acid by the  process of
putrefaction.  When  placed in contact with  fermenting
substances, it undergoes no appreciable change, whence 
                 COMPARED WITH STARCH.              71
we may conclude, with 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 oxidized product, name-
ly,  mucic acid, which cannot under the same circum-
stances, 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  composition of
these substances the following expressions : —
          Starch .  . . .  = 12 C + 10 aqua.
          Cane Sugar . = 12 C -J- 10 aqua -L.,1 aqua.
          Gum.....= 12 C -|- 10 aqua -f- 1 aqua.
          Sugar of milk = 12 C -\- 10 aqua -j- 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 equiva-
lents, sugar of milk 12 equivalents, and  grape-sugar 14
equivalents, of water,  or the elements of water.

  XIV. In these different substances, some  one of
which is  never  wanting in the food of the  graminivora,
there is added to the  nitrogenized  constituents  of this
food, to the  vegetable albumen, fibrine, and caseine, 
72
GRAMINIVORA REQUIRE
from which their blood is formed,  strictly speaking, only
a certain  excess of carbon, which the  animal organism
cannot possibly employ to produce fibrine  or albumen,
because  the  nitrogenized constituents of the food  al-
ready contain the  carbon necessary 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 nitrogenized constituents of their food,  which bears
no proportion whatever 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 ascertained  by
analysis (1-5  per cent, in the hay, 2*2 per cent, in the
oats), (is) 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, 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 support  respiration,
for with  the  nitrogen  expelled  in the urine there  are 
                     MUCH CARBON.                  73
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 consumed,
and,  as  a  necessary consequence,  the  amount of car-
bonic 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 carbon, and  the  deter-
mination of Boussingault, according to which a  horse
expires  79 oz. daily, cannot be very far from the truth.
   In the nitrogenized constituents of his food, therefore,
 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 graminivora,
 whose  food contains  so  small a proportion, relatively,
 of the  constituents  of blood, the  process^ of metamor-
 phosis in existing  tissues, and consequently their resto-
 ration  or reproduction, must go on far  less rapidly than
 in the  carnivora.  Were  this not the case, a vegetation
    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 organized  tissues,
                   7
a 
74
WASTE OF ORGANIZED TISSUES
would contain enough  of carbon to support the  respira-
tory 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, be-
cause  when he  has  the opportunity, he kills  without
eating.
   A nation  of hunters, on a  limited space, is  utterly
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 sup-
posed.  These  animals  collect from  plants the  con-
stituents  of their  organs 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, dur-
ing the life of the animals, served to support the res-
piratory process.  In such men, confined 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
4 lbs. of starch, (i6) and while the savage with one ani-
mal  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 respiration, during the same  time,
to consume five such animals.
  It is easy  to  see,  from these considerations,  how
close the connexion is between agriculture and the mul- 
VERY RAPID IN CARNIVORA.
75
tiplication  of the  human species.   The cultivation of
our crops has ultimately no other object than  the pro-
duction of a maximum of those substances which are
adapted for assimilation and respiration, in  the  smallest
possible  space.   Grain  and  other  nutritious 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,  albu-
men, 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 produced
by the metamorphosis of organized tissues ; and, just
as the lion,  tiger, hyaena, in  the cages of a menagerie,
are compelled to  accelerate the  waste  of the organized
tissues by  incessant motion, in order to furnish  the mat-
ter 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  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
with the  smallest expenditure of power, and with  given
means to produce a maximum of force.   The  unprofit-
able exertion of  power, the  waste  of  force in  agricul-
ture, in  other branches of industry,  in science,  or in
social economy, is characteristic of the savage state, or
of the want of cultivation. 
76
PHOSPHATES ABOUND IN
   XV. A  comparison  of  the urine of the  carnivora
with that  of the graminivora  shows very  clearly, that
the process of  metamorphosis in  the  tissues is  differ-
ent,  both in form and in  rapidity, in  the two  classes
of animals.
   The urine of carnivorous animals  is acid, and con-
tains alkaline  bases, united with uric,  phosphoric, 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 sul-
phuric acid by the oxygen of the arterial blood.   In the
various fluids of the body there are only traces of  phos-
phates or sulphates, except  in the urine, where both are
found  in abundance.   It is plain  that they are derived
from the  metamorphosed  tissues ; they enter into the
arterial blood in  the form of soluble salts,  and are sep-
arated  from  it in its passage through the kidneys.
   The urine of the graminivora is alkaline ;  it contains
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 urine  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 nitrogen  in  his  daily
food (about 4| oz.), and that the quantity of tissue met-
amorphosed is  equal  to that  newly formed,  then the 
                THE URINE OF CARNIVORA.              77
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. according 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 pro-
duced  in the form  of soluble alkaline  phosphates, must
reenter 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 earth
of bones  is obtained by the direct assimilation of phos-
phate of lime, while the  soluble phosphates  are better
adapted for the  production of nervous  matter.
   In the graminivora, therefore, whose food contains so
small a proportion  of phosphorus or of phosphates,  the
organism collects all the soluble phosphates produced by
the metamorphosis of tissues and employs them for  the
development of the bones and of the  phosphorized con-
stituents 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 excre-
ments in the form of insoluble earthy  phosphates."
               7# 
78
ASSIMILATION IN CARNIVORA
   XVI.  If we now compare  the  capacity for increase
 of mass, the assimilative power in the graminivora and
 carnivora, the commonest observations  indicate a verv
 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 perhaps
 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, require less food
 for their mere support, because their  skin is destitute of
 perspiratory pores, and because they  consequently lose,
 for equal  bulks, much less  heat than graminivorous ani-
 mals, which are  compelled  to  restore the lost heat  by
 means of food adapted for respiration.
   How different  is the  energy and intensity of vegeta-
 tive life in  the graminivora.   A cow,  or a  sheep, in
 the meadow, eats, almost without interruption, as long
 as the sun is above the horizon.  Their system  possesses
 the power of converting  into  organized  tissues  all the
 food they devour beyond the quantity required  for mere-
 ly 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 carniv-
 orous 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 
           LESS ENERGETIC THAN IN HERBIVORA.        79
and  sheep, it is  evident, that, when well supplied with
food, their growth in size, their  fattening, must depend
on the quantity of vegetable albumen, fibrine, or caseine,
which they consume.   With free and unimpeded mo-
tion  and exercise, enough of oxygen is absorbed to con-
sume the carbon  of the  gum, sugar, starch, and  of all
similar soluble constituents of their food.
  But all this is very differently arranged in our domes-
tic animals, when, with  an abundant supply of food, we
check the processes  of cooling and exhalation, as we do
when we feed them in stables, where  free motion  is im-
possible.
  The stall-fed animal  eats, and reposes merely for di-
gestion.   It devours in the shape of nitrogenized com-
pounds far more food than is required for reproduction,
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 respiration  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 carbonic 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 constituent of
the nerves and brain.  This substance is fat.
  In the normal condition, as to exercise and labor, the 
80
ORIGIN OF FAT IN
urine of the horse  and ox contains benzoic  acid  (with
14 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  substance.
When  the fattened animal  is  allowed to 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  propor-
tion  between the food taken  into the  stomach  and the
oxygen absorbed by the lungs and the skin.
  A  pig, when fed with  highly nitrogenized food, be-
comes 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 ni-
trogen 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 formation of
fat in other  domestic  animals at  pleasure, but only by
means o£ food  containing no nitrogen  ; we  can hardly 
DOMESTICATED ANIMALS.
81
entertain a doubt that such food, in its various forms of
starch,  sugar, &c, is closely connected with  the  pro-
duction 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 nitrogenized  con-
stituents of plants we draw certain inferences  as to the
nitrogenized constituents of the blood ; and it  is  quite
in  accordance  with  this,  the  natural  method,  that we
should  seek to  establish the  relations of those  parts of
our food which are  devoid of nitrogen  and  those  parts
 of the  body which contain none of that element.  It is
 impossible to overlook  the very intimate  connexion be-
 tween  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 hog's lard contain 79 per  cent, of carbon
 to 111,  11-4, and 11-7 per cent, of hydrogen respec-
 tively. (l6)
         Starch contains 4491 carbon to 611 hydrogen.
         Gum and sugar 42 58  ----  to 6-37   ditto.(it)
    It  is  obvious that these  numbers, representing the
 relative  proportions of carbon and  hydrogen  m starch,
 gum, and sugar, are in  the same ratio as the carbon and
 hydrogen in the different kinds of fat; for
                 44-91 :  tMI = 70 : 10-75
                 42W :  (i-H7 = 79 :  11-82 
82
ORIGIN OF FAT IN
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 of  starch,
C13H10O10,  we  take 9 equivalents of oxygen, there will
remain in 100 parts —
             C12...............80-4
             H10...............10 8
             O   ...............10-8
   The  empirical formula of fat, which comes nearest
to this, is  CnH10O, which gives in 100 parts —
             C1X ...............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  equivalent 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 for-
mulae.
   If from  3 equivalents  of sugar of milk, 3C12H12012
= 036H36O36, we take  away four equivalents of water
and 31 of oxygen, there will remain C36H320, a formula
which accurately represents the composition of choles-
terine, the fat of bile, (is)
   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 given to swine ;  and that the 
DOMESTICATED ANIMALS.
83
food of geese  or fowls  contains no  goose fat or capon
fat.   The masses  of  fat found  in  the bodies of these
animals  are  formed  in  their organism ; and  when the
full value of  this fact is recognised, it entitles us to con-
clude  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 substances.
   The chemical analysis of the constituents of the food
of the  graminivora shows,  in the  clearest manner, 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 contained,
    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 ani-
mal 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  equivalents of carbon
 deposited as fat, 26 equivalents of oxygen must  be sep-
 arated from  the elements of  these  substances ;  and fur-
 ther,  if we conceive fat to  be formed from starch, sugar,
 or sugar  of milk, that  for the  same  amount of carbon 
84
THE FORMATION OF FAT.
 there must be  separated  90,  100,  and 110  equivalents
 of oxygen from these compounds respectively.
   There is, therefore, but one way in which  the forma-
 tion 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 ele-
 ments of the food.
   The carbon  which we find deposited in the seeds and
 fruits of vegetables, in the form of  oil and fat, was  pre-
 viously  a  constituent  of  the  atmosphere,  and was  ab-
 sorbed by the  plant as carbonic acid.  Its  conversion
 into  fat was accomplished under the  influence 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 system absorbs  oxygen
from the atmosphere, and  that this oxygen is again given
out in combination 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 animal heat.
  Whether fat be formed  by the decomposition  of
fibrine and albumen, the chief constituents of blood, or
by that of starch,  sugar, or  gum, this decomposition
must be accompanied by the  separation of  oxygen from
the elements of these  compounds.  But this  oxygen is

  * See Appendix, Note 19, on the formation of wax and  honey by
the bee. 
FAT HOW FORMED.
85
not given out in the free  state, because it meets in the
organism with substances possessing the property of en-
tering 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 connexion exists between  the forma-
tion of fat  and  the respiratory process.

   XVII.  The abnormal condition, which  causes the
deposit of  fat in the  animal  body,  depends, as was for-
merly 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 quan-
tity of carbon given out is exactly equal  to   that which
is taken in  the food, and the body acquires no  increase
of  weight from the accumulation of substances  contain-
ing much carbon and  no nitrogen.
   If we increase the  supply of highly  carbonized food,
then the normal state  can only be preserved on the con-
dition  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
a  deficient supply of oxygen, for oxygen is  absolutely
indispensable for the dissipation of  the excess of carbon
in  the food.    This  excess  of carbon, deposited 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
                   8 
86
HEAT DISENGAGED.
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 appears  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 oxy-
gen ;  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 hydrogen ;  and
whether this carbon  and   hydrogen  proceed  from the
substance that yields the  oxygen, or from  other  com-
pounds, still there must  have  been generated  by  this
formation  of carbonic acid or water as much heat  as  if
an equal weight of carbon 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 devel-
oped, as  if  these  9 equivalents  of carbon  had  been
directly burned.   In this  form, therefore,  the disen-
gagement of heat as  a consequence of the formation  of
fat would  be undeniable ; and  it could  only be consider-
ed hypothetical,  on  the supposition  that   carbon  and
oxygen were  disengaged from one and  the same  sub-
stance, in the proportions to yield carbonic acid.
   If, for  example, we suppose that from  2 atoms  of 
FORMATION OF FAT.
87
starch, C24H20O20, the elements of 9 equivalents of car-
bonic acid are separated, there will remain a compound
containing, for 15 equivalents of carbon, 20 of hydro-
gen and  2 of  oxygen ;  for
              C24H20O20 = C9O18 -f- C15H20O2.
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 equivalents of water and
6 of carbonic acid,  there would  remain the compound
C18H1402 ; for
          C24H20O20 = C6013 + H606 4- 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 separa-
tion  might occur without the disengagement  of heat;
but  if the carbon  and hydrogen were  present  in any
other form in the starch  (or in the  compound  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 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 va-
rieties  of sugar, will justify no  other conclusion than
 this, that these substances contain  no ready formed car-
 bonic acid.
   We  are acquainted with a large number of  processes 
88
THE FORMATION OF FAT IS
of metamorphosis of a similar kind, in which the ele-
ments  of carbonic  acid  and water are  separated  from
certain  preexisting  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 example,
occurs in all processes of fermentation or putrefaction,
which  are,  without exception,  accompanied with the
generation of heat.
   In the fermentation of a saccharine solution, in con-
sequence 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 an-
other result  of this  decomposition, we obtain 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, there remain  6
equivalents of alcohol.
    (C24H24024 + H12012) — 024 = C24H36012 = 6 eq. alcohol.
   These  24  equivalents of oxygen suffice  to oxidize
completely  a  third equivalent of sugar, — that  is, to
convert its carbon into  carbonic  acid and its hydrogen
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.
            C12H12Q12 + 024 = 12C02 + 12HO. 
               A SOURCE OF ANIMAL HEAT.            89
  According  to the ordinary  view,  12 equivalents of
carbonic acid separate from 3 of sugar,  yielding 6 of
alcohol, — that is, exactly the same amount of these pro-
ducts as if two thirds of the sugar had yielded oxygen
to the remaining third, so  as completely to oxidize  its
elements.
             C36H36036 = C24H36012 + 12C02.*
   By a comparison of these two  methods of represent-
ing  the  same  change, it  will easily  be seen, that the
division or splitting of a compound like sugar into car-
bonic acid, on the one hand, and a compound containing
little oxygen, on the other, is, in its results, perfectly
 equivalent to a  separation of oxygen  from a certain por-
 tion of the compound  and the oxidation or combustion
 of another portion of it at the expense of this oxygen.
   It is well  known that the temperature of a fermenting
 liquid rises ; and if we assume that a hogshead of wort,
 holding 1,200 litres =2,400  lbs., French weight, con-
 tains 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 heat, by which every
 pound of  the liquid might be heated  by 298-9° ;  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
   * For an explanation of the formula, and  equations employed, see
 the Introduction to the Appendix.
i* 
90
FORMATION OF FAT.
degrees of heat during a period of 120 hours.  In each
hour there is, therefore, set free  an  amount of heat ca-
pable of  raising the  temperature  of  each pound of
liquid 2-4  degree ; a rise  of temperature which is very
powerfully counteracted by external  cooling and by the
vaporization of alcohol and water.
   The  formation of fat, like other  analogous phenom-
ena, in which oxygen is separated  in the form of car-
bonic acid,  is consequently accompanied by a disen-
gagement  of  heat.  This  change supplies to the animal
body a certain proportion of the oxygen indispensable to
the vital processes ; 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 combination.
   This  excess of carbon,  as it cannot be employed to
form a  part  of any organ, is deposited  in the  cellular
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 pro-
ducts contributes  to  keep up the  temperature of  the
body.  Every pound of carbon which obtains the oxygen
necessary  to  convert  it into carbonic  acid  from sub-
stances  which thereby pass into fat, must disengage as
much heat as would raise  the  temperature of 200 lbs.
of water by 70°, — that is, from 32° to  102°. 
FORMATION OF FAT.
91
   Thus, in the formation of fat,  the vital force pos-
sesses a means of counteracting a deficiency in the sup-
ply of oxygen, and  consequently in that  of the heat
indispensable for the vital process.
   Experience teaches us that in  poultry, the maximum
of fat is  obtained  by tying  the feet, and by a medium
temperature.   These  animals,  in  such circumstances,
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  organized  tissues, while  that of
starch, sugar, &c, is converted into fat.   When  ani-
mals 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 organized 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  difference 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 consequently to  be
converted  into  fat.   Thus,  in  diabetes  mellitus, the
starch is only converted into grape sugar,  which is ex-
pelled from the body without further change. 
92
CONSTITUENTS OF FOOD.
   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 con-
stituents may be transformed into fat.

   XVIII. 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
nitrogenized and non-nitrogenized.    The  former  are
capable of conversion into blood ; the latter incapable
of this transformation.
   Out  of  those  substances which are adapted  to  the
formation of blood are formed all  the  organized tissues.
The other  class of substances, in the  normal state of
health,  serve  to  support  the process of  respiration.
The former may be called the plastic  elements of nutri-
tion ; 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 *5n our food, are —
              Fat.                    Pectine.
              Starch.                  Bassorine.
              Gum.                   Wine.
              Cane sugar.              Beer.
              Grape sugar.             Spirits.
              Sugar of milk. 
                CONSTITUENTS OF FOOD.              93
  XIX. The most  recent  and exact  researches  have
established  as  a universal fact,  to  which  nothing  yet
known is opposed, that the  nitrogenized constituents of
vegetable food  have a  composition identical with  that
of the constituents of the blood.
  No nitrogenized 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
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 cartilages
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 chon-
drine, 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 altera- 
94
GELATINE
tion ; 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.*

   While, 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 tendons  and

membranes  retain their natural  condition ; the limbs of

  * It is probably known to the reader, that a controversy has for
some time  been carried on on this subject.  D'Arcet first  proposed
the use of gelatine as an article of hospital diet, and introduced it  in
Paris with  the greatest success.
  But experiments made with pure gelatine used exclusively as food,
showed that animals, thus fed, soon died with the symptoms of starva-
tion ; and it was found that men fed for a day or two on  gelatine ex-
clusively, acquired an absolute disgust at it. It was hence concluded,
that the use of gelatine in any shape was  hurtful, and  ought not to
be permitted.
  Now that we know, as the author  has  proved, that  gelatine, al-
though formed from  proteine, is no  longer a compound of  proteine,
and cannot yield blood, we can easily see how it is incapable, alone,
of supporting life and health.  But on the other hand, when  we con-
sider,  how great a  part of the bodj'  (membranes and bones, for
example) is formed of gelatine, when we see the  dog digesting per-
fectly the gelatine of bones, and  man that of soup or jelly ;  we must
admit the great probability of the author's most ingenious supposition,
namely, that gelatine is  dissolved in  the  stomach, and enters the
blood, where it serves as  a means of restoring  the waste of  the gela-
tinous tissues; while the weak digestive powers of a convalescent or
patient are  not taxed to convert albumen, fibrine, or caseine into gela-
tine ; and thus its use, as a part only of the  diet of hospitals, becomes
at once obvious.
  We can no longer reject the facts proved by D'Arcet, (although
peremptorily denied by some,) namely, that  the period of the stay of
patients in  the hospital, is, on the average, much shortened where
gelatine has been employed, while, when mixed with other food, the
patients relish  it highly.   At least, we  cannot reject them without
examination.   On the other hand, we can  now clearly perceive the
error of those,  who, because the composition of gelatine approaches
to that of fibrine, &c, maintained it to be equally nutritious.   For
our knowledge on this subject we are indebted, first, to the discovery
of proteine  by Mulder; secondly, to the discovery, that gelatine  is 
                 MAY SERVE TO NOURISH.              95
the dead  body  retain  their connexions, 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 undergone a change, and must have served
some purpose 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 composed of fibrine,
the identity in  composition of the two  substances  ren-
ders  the change easily  conceivable.   Indeed, we find
the change of a  dissolved substance into an  insoluble
organ  of  vitality, chemically speaking, natural and easily
explained, on account  of this very  identity  of compo-
sition.  Hence,  the opinion is not unworthy of a closer
investigation, that gelatine, when  taken  in  the  dissolved
state,  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

not a compound of proteine; and, thirdly, to the sagacity of Liebig,
in first drawing the conclusions now so obvious  to all who attend to
the subject. 
96
GELATINE.
are affected by a change of the health, then, even should
the power of forming blood remain the same, the organic
force by which  the  constituents of the blood are trans-
formed into cellular tissue and  membranes must neces-
sarily be enfeebled  by sickness.   In  the  sick  man, the
intensity  of the vital force, its  power to produce  meta-
morphoses, 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
gelatinous  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 stom-
ach, by due preparation of the food in general.   Brittle-
ness in the bones  of  graminivorous  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 Turkish women, in their diet of rice, and in
the frequent use of  enemata of strong soup, have united
the conditions  necessary for  the formation both of cel-
lular tissue and of fat. 
PART II.
           THE




METAMORPHOSIS OF TISSUES.
9 
 
THE
METAMORPHOSIS OF  TISSUES.
  1. The absolute identity of composition in the chief
constituents of blood and  the nitrogenized compounds
in vegetable food would, some years ago, have furnished
a plausible reason  for  denying  the accuracy of the
chemical analyses leading  to such  a result.   At  that
period,  experiment  had not as yet demonstrated the
existence of numerous  compounds, both containing ni-
trogen  and devoid  of that  element, which, with the
greatest diversity in external characters,  yet possess the
very same  composition in 100 parts ; nay,  many of
which even contain the  same absolute amount of equiv-
alents of each element.   Such examples  are now  very
frequent, and  are known by the names of isomeric and
polymeric compounds.
  2.  Cyanuric acid,  for  example, is a  nitrogenized
compound, which  crystallizes  in  beautiful transparent
octahedrons, easily soluble in water and  in acids, and
very permanent.  Cyamelide is  a second body, abso-
lutely insoluble in  water and acids, white and opaque
like porcelain or magnesia.  Hydrated  cyanic acid is a
third  compound, which is  a liquid, more volatile  than
pure acetic acid, which  blisters the skin, and  cannot be 
100
ISOMERIC BODIES.
brought in contact with water without being instantane-
ously resolved into  new  products.   These three sub-
stances 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 avidity,  and  is  there-
by  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 de-
posits long, hard, needle-shaped crystals,  which at 212°
are not volatilized, and the supernatant liquid is no long-
er aldehyde.  It now boils at 140°, cannot be  mixed
with water, and when cooled to a moderate degree crys-
tallizes in a  form like  ice.  Nevertheless, analysis has
proved, that these three   bodies, so  different  in their
characters, are identical in composition, (it)
  3.  A similar  group of three occurs in the  case  of
albumen, fibrine, and caseine.   They differ  in  external
character, but contain exactly the same proportions of
organic elements.
  When animal albumen, fibrine, and caseine are dis-
solved in  a  moderately strong solution of caustic pot-
ash, and the  solution  is  exposed for some time  to-a
high  temperature, these  substances  are  decomposed. 
DISCOVERY OF PROTEINE.
101
The addition of acetic acid to the solution causes, in all
three, the separation of a gelatinous  translucent precipi-
tate, which has exactly the same  characters and  com-
position, from whichever of the three substances above
mentioned it has been obtained.
   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
phosphorus they  contain, and  then calculate  the  re-
mainder for  100 parts,  we obtain the same result as in
the  analysis  of the precipitate  above described, pre-
pared by potash, which is free from inorganic matter. (22)
   Viewed in this  light,  the  chief  constituents  of  the
blood and the caseine of milk may be regarded as com-
pounds  of phosphates  and other salts,  and of sulphur
and phosphorus, with a compound of carbon,  nitrogen,
hydrogen, and oxygen, in which  the relative proportion
of these elements is invariable ; and this compound may
be considered as the commencement and  starting-point
of all  other  animal tissues, because these  are  all pro-
duced from the blood.
   These considerations induced Mulder to  give to this
product of the  decomposition of albumen, &c. by pot-
ash, the  name of proteine (from  tt^wtsv'w, "I  take the
first rank").   The blood, or the  constituents of the
                 9* 
J 02            PROTEINE EXISTS IN FIBRINE,
blood,  are consequently  compounds  of this proteine
with variable proportions of inorganic substances.
   Mulder  further  ascertained, that  the insoluble  nitro-
genized  constituent of wheat flour (vegetable fibrine),
when treated with potash, yields the very same product,
proteine ;  and it has recently been proved  that vegeta-
ble albumen  and  caseine  are acted  on by  potash pre-
cisely as animal albumen and caseine are.
   4.  As far,  therefore, as our researches  have  gone, it
may be laid down as a law,  founded on experience, that
vegetables produce, in their  organism, compounds  of
proteine ;  and that out of these compounds of proteine
the various tissues  and parts of the animal body are de-
veloped by the vital force,  with  the  aid of the oxygen
of  the atmosphere and of the elements of water. *
   Now, although it cannot be demonstrated that proteine
exists ready formed  in  these vegetable  and animal pro-
ducts,  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  preexistence
of  proteine, as a point of  departure  in developing and
comparing their properties,  is exceedingly convenient.
At all events, it is certain, that the elements of these
  * The experiment of Tiedemann and Gmelin, who found it impos-
sible to sustain the life of geese by means of boiled white of egg, may
be easily explained, when we  reflect that  a graminivorous animal,
especially  when  deprived 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 3£ oz. of carbon,
of which, among the last products of transformation, a fourth part is
given off in the form of uric acid. — L. 
                ALBUMEN, AND CASEINE.             103
compounds assume the same arrangement when acted on
by potash at a high temperature.
  All the organic  nitrogenized constituents of the body,
how different soever they may be in composition, are
derived from proteine.   They are formed  from it, by
the  addition  or subtraction of the  elements of water  or
of oxygen, and by  resolution  into two  or more com-
pounds.
  5. This proposition  must  be received  as an undenia-
ble  truth, when we  reflect on the development of the
young animal in the egg of  a fowl.   The egg can  be
shown to contain no nitrogenized compound except  albu-
 men.   The  albumen of  the yolk is identical with that
 of  the  white ; (23)  the yolk  contains, besides, only a
 yellow fat, in which cholesterine and  iron  may be de-
 tected.   Yet  we  see, in  the  process  of   incubation,
 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  the blood,  fibrine,  mem-
 brane  and  cellular tissue, arteries, and  veins,  are pro-
 duced.   The fat of the yolk may have contributed, to a
 certain extent, to the formation of the nerves and brain ;
 but the carbon of this  fat cannot  have been employed to
 produce the organized tissues in which vitality resides,
 because  the albumen  of the  white  and of  the yolk  al-
 ready contains, for the quantity of nitrogen present, ex-
 actly the proportion of carbon  required  for the forma-
 tion of these tissues.
     6. The  true  starting-point for all the tissues is, con- 
104
DIGESTION COMPARED
 sequently, albumen ; all  nitrogenized 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 nutrition.
   All the food consumed by an animal becomes in the
 stomach soluble,  and capable of entering into the circu-
 lation.  In the process by which this solution 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 chymification is independent
 of the  vital force ; that it  takes place in virtue of a pure-
 ly chemical action, exactly similar to those processes of
 decomposition  or transformation  which are  known  as
 putrefaction, fermentation, or decay  (eremacausis).
  7.  When  expressed  in the simplest form, fermenta-
 tion, or putrefaction, may be  described as  a process of
 transformation, — that is,  a new arrangement of  the ele-
 mentary particles, or atoms, of  a compound,  yielding
 two or more new groups or compounds, and caused by
 contact with other substances, the elementary particles
 of which are themselves 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  substance
in a state  of transformation, by the  contact of which 
TO FERMENTATION.
105
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 vi-
tality of the digestive organs has been proved by a num-
ber  of the most beautiful experiments.  Food,  enclosed
in perforated  metallic tubes, so that it  could not  come
into contact with the stomach, was found to disappear as
 rapidly, and to be as perfectly digested, as if the cover-
 ing had been absent; and fresh gastric juice, out of the
 body, when boiled  white of egg, or muscular fibre, were
 kept in 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 doubted, that the substance which
 is  present in the gastric juice in a state of change is a
 product of  the  transformation of the  stomach  itself.
 No  substances  possess, in  so high a  degree as those
 arising from the progressive decomposition of the  tis-
 sues  containing  gelatine or  chondrine, the property of
 exciting a change in the arrangement of the elements of
 other compounds.   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 pro-
  duces  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 
106
POWER OF ANIMAL MEMBRANE.
the air, or dried, and  then placed in contact with such
substances, the sugar is changed, according  to  the state
of decomposition of the animal matter, either into lactic
acid, into  mannite and mucilage, or into alcohol  and
carbonic acid ; while  milk is instantly coagulated.  An
ordinary animal bladder retains, when dry,  all its prop-
erties  unchanged ; but when exposed to air and moist-
ure, it undergoes a change not indicated by  any obvious
external signs.   If, in  this state, it be placed in a solu-
tion of sugar of milk,  that substance is quickly changed
into lactic acid.
   10.  The fresh  lining membrane of the  stomach of
a calf, digested with weak muriatic acid,  gives to this
fluid no power of dissolving boiled flesh  or coagulated
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  solution.  If coagulated  albumen be
placed  in  this  solution, the state of decomposition  is
communicated  to  it,  first  at the edges, which become
translucent, 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 solution turbid.   Oxygen  is
conveyed to every part of the body by  the  arterial
blood ; moisture is everywhere  present ;  and  thus we
have  united  the chief conditions of all  transformations
in the  animal body.
  Thus, as  in the germination of seeds,  the presence 
LACTIC ACID.
107
of a body in a state of decomposition or transformation,
which has  been  called diastase, effects  the  solution 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 metamorphosis 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 produce  out of sugar by means of mem-
brane 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 Braconnot could detect lactic acid in
the gastric juice ; and even Lehmann  (see  his " Lehr-
buch der Physiologischen Chemie,"  Tom.  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
observed  by  Prout,  has been  confirmed by  all  those 
108
GASTRIC JUICE.
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 con-
version 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  re-
spect,  is equal  to  lactic acid.    There  is consequently
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.  Berzelius,  indeed, has found
lactic acid in the  blood and flesh of animals ; but when
his experiments were made,  chemists were  ignorant of
the extraordinary  facility and  rapidity with which  this
acid is formed from  a  number  of substances containing
its elements,  when in contact with animal matter.
   In the gastric juice of a dog, Braconnot found, along
with free muriatic  acid, distinct traces  of a salt of  iron,
which  he at first  held to  be  an accidental  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 regard 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 
                   NITROGEN GIVEN OUT.             109
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 stomach with the food, and there its oxygen
enters into combination,  while its  nitrogen  is given out
through the skin and lungs.    The longer digestion con-
tinues, that is, the  greater the resistance offered  to the
solvent action by the food,  the  more saliva, and conse-
quently the more air enters the stomach.   Rumination,
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 solution.
   The unequal quantities of air which reach  the  stom-
ach with the  saliva in different  classes of animals, ex-
plain 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 animal
membranes possess of allowing  all gases  to permeate
them, a property which  can  be  shown to  exist by the
most simple experiments.   A bladder, filled with car-
bonic acid, nitrogen, or  hydrogen gas, if  tightly closed
and suspended in the air, loses in twenty-four hours the
whole of the  enclosed gas ; by a kind  of exchange,  it
passes outwards into the atmosphere, while its  place is
                10 
    HO               USE 0F THE SALIVA.
    occupied by atmospherical air.   A  portion of intestine,
    a  stomach, or a piece of skin or membrane, acts pre-
    cisely as the bladder, if filled with any gas.   This per-
    meability to gases is a mechanical 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 a
    peculiar condition is produced, in which, by the act of
    inspiration, not  only oxygen but atmospherical air, with
    its whole  amount  (|ths)  of  nitrogen,  penetrates  into
    the cells of the  lungs.   This air is carried  by the cellu-
    lar tissue to every part of the  body, so that  every  part
>    is  inflated  or puffed  up with  the air, as with water in
    dropsy.   This  state  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
    accumulated in  the cellular tissue, enters into combina-
    tion, while its nitrogen  is expired through  the  skin  and
    lungs.
       Moreover, it is well  known that in many graminivo-
    rous animals, when the  digestive organs have been over-
    loaded  with fresh juicy vegetables,  these   substances
    undergo in the stomach the same decomposition as they
    would at the same temperature out of the  body.   They
    pass  into  fermentation  and  putrefaction, whereby so
    great a quantity  of  carbonic acid gas and of inflamma-
    ble gas is generated, that these  organs are  enormously
    distended, sometimes even to bursting.  From the struc-
    ture of their stomach or stomachs, these gases cannot
    escape through the  oesophagus ; but in the  course  of a 
               GASES PERMEATE MEMBRANES.           Ill
few hours, the  distended  body of the animal becomes
less swollen,  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  drinking
of  what  is  called feather-white wine  (der federweisse
 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 pene-
trates unsized paper.   This poisonous 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,  penetrates  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 ammonia (which combines  with it)
is recognised as the best antidote against this  kind  of
poisoning.
   The  carbonic acid of effervescing wines and of soda-
water, when taken  into the  stomach, or of water satur-
ated with thi?  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 venous
circulation through  the absorbent  and lymphatic vessels, 
112
SOURCES OF THE NITROGEN
and thus reach  the  lungs, where  they are  exhaled ; but
the presence of membranes offers not the slightest ob-
stacle  to their passing directly  into the  cavity of the
chest.   It is, in fact, difficult to suppose that the absor-
bents  and lymphatics  have any peculiar  tendency to
absorb  air,  nitrogen,  or  hydrogen,  and  convey these
gases into the circulation, since the intestines, the stom-
ach, and  all  spaces in the body  not filled  with solid  or
liquid matters, contain gases, which only quit their po-
sition when their  volume exceeds a certain  point, and
which, consequently, are not absorbed.   More especial-
ly in reference  to  nitrogen, we  must suppose that it is
removed from the  stomach by some more direct  means,
and not by the  blood, which fluid must already, in pass-
ing through the lungs, have become saturated with that
gas, that is, must have absorbed a quantity of it, propor-
tioned to its  solvent power, like  any other liquid.   By
the respiratory  motions all the gases which fill the other-
wise empty spaces of the body  are  urged towards the
chest ;  for by the  motion of the  diaphragm and the ex-
pansion  of  the  chest  a partial vacuum is produced, in
consequence of which air is forced into the  chest from
all sides by the atmospheric pressure.  The equilibrium
is, no  doubt,  restored, for the  most part, through the
windpipe, but all the gases in the body must, neverthe-
less, 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 |th of a cubic inch of air with  the saliva,
this makes in eighteen  hours  135 cubic inches; and if 
EXHALED FROM THE LUNGS.
113
^th be deducted as oxygen, there will still  remain 108
cubic inches of nitrogen,  which  occupy 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 quanti-
ty of nitrogen found in the intestines  of executed  crim-
inals 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 re-
sorption  through the  skin, and is  afterwards  exhaled by
the  lungs.
  When animals are made to respire in gases contain-
ing  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 explained ;
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  sep-
arated from the body,  communicates the state  of de-
composition existing in its  elements to the  peroxide of
nydrogen, so a  certain product, arising by means of the
vital process, and  in  consequence of the transposition
of the  elements of  parts  of the  stomach  and of the
other digestive  organs, while its  own metamorphosis  is
                10* 
114               DIGESTIVE PROCESS.
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 (cohe-
sion)  without  the  slightest  change.   Their elementary
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 undergoes a change
in its  state of cohesion,  becoming  fluid without any
other change of properties.
   The greatest obstacle to forming a clear conception
of the nature  of the digestive process, which  is  here
reckoned among those  chemical metamorphoses which
have been called fermentation and putrefaction,  consists
in our involuntary recollection of the phenomena which
accompany  the fermentation of sugar and of animal sub-
stances (putrefaction),  which phenomena we  naturally
associate  with any similar change ; but  there  are num-
berless cases  in which  a  complete chemical  metamor-
phosis of the  elements  of a compound occurs without
the smallest disengagement 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 con-
ception of the digestive process.
   All  substances which can  arrest  the phenomena of
fermentation and putrefaction in liquids, also arrest di- 
                  NATURE OF FERMENT.              115
gestion when  taken into  the  stomach.  The  action of
the empyreumatic matters in coffee and  tobacco-smoke,
of creosote, of mercurials,  &c, &c,  is, on  this ac-
count,  worthy of peculiar  attention with reference to
dietetics.
   The identity in composition of the chief constituents
of blood, and of the nitrogenized constituents of vege-
table  food,  has certainly furnished,  in  an unexpected
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 decomposition  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  substances
having  the  same composition  with  the  constituents of
flesh,  blood, or  cheese.   The putrefaction  of  these
animal matters is a process  identical with the  metamor-
phosis of the vegetable matters  identical 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 influence of the vital force, then the  putrefaction of
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 
116            COMPOSITION OF PROTEINE.
differ.   The practice of medicine has furnished the most
beautiful and  interesting observations on the action of
empyreumatic substances,  such  as wood, vinegar, creo-
sote, &c, on malignant wounds and ulcers. In such mor-
bid 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
entirely suppressed or arrested  by empyreumatic sub-
stances ; and this  effect is precisely  opposed  to the
poisonous influence exercised on the organism  by pu-
trefying blood when introduced into a fresh wound.
   14.  The formula C48H36N6014*  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.   Albumen, fibrine,
and caseine contain proteine ; caseine contains, besides,
sulphur, but no  phosphorus ; albumen and fibrine con-
tain both these substances  chemically combined, — the
former more sulphur 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
oxidized  state.   All  these substances, when  heated
with a moderately strong  solution of potash, yield the
sulphur which we find in  the solution  as sulphuret of
potassium ; and,  on the  addition of an acid,  it is given
off as  sulphuretted hydrogen.   When  pure  fibrine, or
ordinary albumen is  dissolved  in  a weak solution of

  * For the  method of converting this and other formulae into pro-
portions per cent, see Appendix. 
FIBRINE.
117
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 sul-
phuret 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  phosphorous acid.
Since,  in this case, sulphur and phosphorus are elimina-
ted  on the one hand,  and oxygen and hydrogen on the
other, it might be  concluded, that fibrine and  albumen,
when analyzed with their sulphur and phosphorus, would
yield a larger proportion 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 manner,  by the
 elimination of the  phosphorus in  combination with oxy-
 gen, 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 analy-
 ses are,  on an average, beyond ^th  per cent, in  hydro-
 gen, and beyond  T45ths per cent,  in  the oxygen ; while
 in  the supposed  case  the difference in the hydrogen
  would not be  greater than ,lBth per cent.
    Finally, if we  reflect, that  the elimination of oxygen 
118
COMPOSITION OF FD3RINE.
and hydrogen with the  sulphur and  phosphorus  does
not exclude the addition of the elements of water, and
if we assume that fibrine and  albumen, in  passing  into
proteine, do combine  with  a  certain quantity of water,
an occurrence which  is highly probable, we  shall  see,
that  there is no probability,  that the ultimate  analysis
of these  compounds will ever enable us to decide such
questions, or to fix the chemical view of the relation
of proteine  to albumen, fibrine, or caseine, farther than
has been done above.
   Some  have endeavoured to prove the existence of
unoxidized phosphorus in albumen and fibrine from the
formation of sulphuret of  potassium  when  they are
acted on  by potash,  supposing  the oxygen of the pot-
ash to have formed phosphoric  acid with the phospho-
rus ; but  caseine, which contains no phosphorus, yields
sulphuret of potassium, just  like the other substances ;
and  here its formation cannot  be accounted  for, unless
we admit the previous production  of sulphuretted hy-
drogen.   In the  mere 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 phosphorus.   Sulphuret of
potassium is formed  from caseine,  which is not  sup-
posed  to contain  any uncombined  phosphorus ; and it 
COMPOSITION OF TISSUES.
119
is  formed,  also, from  albumen,  which  contains only
half as much phosphorus 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 phosphorus are taken, not in
fractions, but in entire  equivalents,  must be  fruitless,
because  we  are absolutely unable to  determine with
perfect  accuracy the exceedingly  minute quantities of
sulphur and  phosphorus  in  such  compounds ;  and  be-
cause a variation in the sulphur or phosphorus, smaller
in extent than the usual  limit of  errors of observation,
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  representing
the relative proportions of  the organic elements are the
same in albumen and  fibrine, and hence we conclude
that they have the same composition.   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 estab-
 lished 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 
120
DIFFERENCES IN COMPOSITION
certain elements have been added to, or removed from,
their constituent parts.
   If we now, for example, look for  an analytical ex-
pression  of the composition of cellular tissue, of the
tissues yielding gelatine,  of 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  in-
cludes all  that physiology requires 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 ob-
tain the following empirical formulae : —
            Composition of organic tissues.
    Albumen...........C48N6H36014-f P + S*
    Fibrine............C48N6H36014+P-j-2S
    Caseine............C48N6H360,4 + S
    Gelatinous tissues, tendons . .  . C48N7.5H41018
    Chondrine...........C48N6H40O20
    Hair, horn...........C48N7H39017
    Arterial membrane.......C48N6H38016
   The composition of  these formulse  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, C48N6H36014

  * The quantities of sulphur and phosphorus  here  expressed by
S and P are not equivalents, but only give the relative proportions
of these two elements to each other, as found by analysis. 
OF ORGANIC TISSUES.
121
by Pr, then nitrogen, hydrogen, and oxygen have been
added to  it in the form of known compounds,  and  in
the following proportions, in  forming the gelatinous tis-
sues, hair, horn, arterial membrane, &c.
                     Proteine. Ammonia.  Water. Oxygen.
     Fibrine, Albumen ....  Pr
     Arterial membrane  ...  Pr .  . .  .  -\- 2HO
     Chondrine.......  Pr .  . .  .  -f 4HO + 20.
     Hair, horn.......Pr -f- NH3  . .  .  +• ?,0.
     Gelatinous tissues   . . . 2Pr -f 3NH3 -f- HO + TO.*
   16. From this  general statement it  appears, that  all
the tissues of the body  contain, for the same amount
of carbon, more oxygen than the constituents of blood.
During their formation, oxygen, either from the atmo-
sphere  or from the elements of water, has been added
to the elements of proteine.  In.hair and gelatinous mem-
brane we observe, further, an excess of nitrogen and hy-
drogen, and that in the proportions  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 pro-
nounce arterial membrane a  hydrate of proteine, chon-
drine a hydrated oxide of proteine, and hair and mem-
branes compounds of ammonia with oxides of  proteine.
   The above formulae express with precision the differ-
ences of  composition in the chief  constituents of the
animal body ; they show, that for the same  amount  of
carbon  the proportion of the other elements varies, and
how much more oxygen or nitrogen one compound con-
tains than another.
 • See Note XXVII.
11 
122         GELATINE CONTAINS NO PROTEINE.
  17.  By  means of these formulae  we  can  trace  the
production of the different compounds from the constit-
uents 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 nitrogen,  oxy-
gen, and hydrogen, than proteine.  It is conceivable, that
they are formed from albumen by the addition of oxygen,
of the  elements of water, and of those of  ammonia,
accompanied  by the separation of sulphur and  phos-
phorus ; at all  events,  their composition is entirely dif-
ferent from that of the  chief constituents of  blood.
   The action of caustic alkalies on the  tissues yielding
gelatine  shows, distinctly, that  they  no  longer contain
proteine ;  that substance cannot in any way be  obtained
from them ; and all  the products  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, albu-
men, and caseine, or not, it is certain that their elements,
under the  influence of the alkali, arrange themselves so
 as  to form  proteine ; but  this  property  is wanting in the
 elements  of the tissues which yield gelatine.
    The other,  and  perhaps the more  probable explana-
 tion of the production of these  tissues from  proteine,
 is  that which   makes  it dependent on  a separation of
 carbon.
    If  we  assume  the nitrogen of  proteine to remain en-
 tire in the gelatinous tissue, then the  composition of the 
ORIGIN OF GELATINE.
123
latter, calculated on 6 equivalents of nitrogen, might be
represented by the formula, C38N6H32014.  This formula
approaches most closely to the analysis of Scherer, al-
though it is not an exact expression of his results.   A
formula corresponding more perfectly to the analyses, is
C32NsH27012;  or,  calculated  according  to Mulder's
analysis, C64N9H42O20. *
   According to the first formula, carbon  and hydrogen
have been  separated ; according  to  the two  last, a cer-
tain proportion of all the elements has been removed.
   18.  We must admit, as the most  important result  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  destined com-
pounds 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  contains  no  sulphur, no
phosphorus, and  it  contains  more  nitrogen  or less car-
bon 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 composition ; while  these organs, as far as our expe-

   ».The formula C62N8H40O20, adopted by Mulder, gives, when re-
 duced to 100 parts, too  little nitrogen to be considered an exact ex-
 pression of  his analyses. 
124
ORIGIN OF GELATINE.
rience reaches, do  not  possess  the  power of producing
compounds of proteine, by virtue of any  influence, out
of  substances  which  contain  no proteine.    Animals
which were fed exclusively with gelatine, the most high-
ly nitrogenized element of the  food of carnivora, died
with the symptoms of starvation ; in short, the gelatin-
ous tissues are incapable of conversion into blood.
   But there is  no doubt  that these tissues are formed
from  the constituents of  the blood ; and we can  hardly
avoid  entertaining the  supposition,  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  themselves out  of
matters brought by the blood ; for how  could any  matter
become  a  portion  of cellular tissue, for example,  by
virtue  of a force which  has as  yet  no organ ?   An  al-
ready existing cell  may possess the power of reproduc-
ing or  of multiplying  itself, but  in both cases the pres-
ence of a substance  identical in composition with  cellu-
lar tissue is essential.    Such matters are formed in the
organism, and nothing can be better fitted  for their pro-
duction 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.
  19.  In the  following pages I offer to the  reader  an
attempt to  develope analytically the  principal  metamor-
phoses which  occur in  the animal body ; and, to pre-
clude all misapprehension, I do this with a distinct pro- 
METAMORPHOSIS OF TISSUES.           125
test  against all  conclusions and  deductions which  may
now or at any subsequent period be derived from  it in
opposition to the views developed in the preceding part
of this work, with which it has no manner of connexion.
The results  here to be described have surprised me no
less than they will others, and have excited in my  mind
the same doubts as others will conceive ; but  they are
not the  creations of fancy, and I give them  because I
entertain 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 animal
 matters which are made are equally worthless for  phys-
 iology and for  chemistry, so  long as  they are not  insti-
 tuted with a well-defined  object, or to answer a  ques-
 tion clearly  put.
    If we take  the letters of a sentence which we wish
 to decipher, and place them in a line, we advance not
 a  step  towards  the  discovery  of their meaning.  To
 resolve an enigma, we must have a perfectly clear con-
 ception  of the problem.   There are many  ways  to  the
 highest  pinnacle  of a mountain ; but those  only can
 hope  to reach it who  keep the  summit constantly in
  view.   All our labor and all our efforts, if we strive to
  attain it through a morass, only serve to cover us more
  completely with mud ; our  progress is impeded  by dif-
  ficulties of  our own  creation, and  at last even the great-
  est strength must give way when so absurdly wasted.
     20.  If it be true, that all parts of the body are form-
  ed and developed from  the  blood  or the constituents of
                   11 * 
12G
THE .SECRETIONS CONTAIN
the blood, that  the existing organs at every moment  of
life are transformed  into new compounds under the  in-
fluence of the oxygen introduced in the  blood, then the
animal secretions must of necessity contain the products
of the metamorphosis of the tissues.
  21.  If it be further true, that the urine contains those
products of metamorphosis which  contain the most  ni-
trogen, and the bile  those which are richest  in  carbon,
from all the  tissues which in the vital process have been
transformed into unorganized compounds, it is clear that
the elements of the  bile and of the urine, added togeth-
er,  must be  equal, in the  relative proportion of these
elements to the composition of the blood.
  22.  The organs are formed from the  blood, and con-
tain the elements  of the  blood ;  they  become  trans-
formed 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.                        t
  If then we subtract from the  composition of blood
the elements of the  urine, then -the  remainder, deduct-
ing 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 car-
bonic acid.
   It will surely appear remarkable, that this manner  of
viewing the subject  has led to the  true formula of bile,
or, to speak  more accurately, to the most correct em- 
            ALL THE ELEMENTS OF THE BLOOE.         127
pirical expression of its composition ; and has furnished
the key to its  metamorphosis, under  the  influence of
acids and alkalies, which had previously been sought for
in vain.
   23. 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.   Muscu-
lar 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  (2s)
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  formula,
namely, C48N6H39015.  This may be called the empir-
ical formula of blood.
   24. The chief constituent of bile,  according to the
researches of Demarcay, is a compound,  analogous
to soaps,  of soda with a peculiar  substance, 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 men-
struum, is mixed with acetate of lead.
   Choleic acid is  resolved,  by the action of  muriatic
acid, into  ammonia, taurine, and  a  new acid, choloidic
acid, which contains no nitrogen.
   When  boiled with caustic potash, choleic acid is re-
solved 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 
128             METAMORPHOSES OF BILE.
must include the analytical expression of these modes
of decomposition ;  in  other words,  that it must enable
us to show that the composition of the products derived
from it is  related, in a clear and  simple manner, to the
composition of the acid  itself.   This  is  the only satis-
factory test of a formula ;  and  the analytical  expression
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 compounds ; for the relative proportions of
the elements cannot in any way be  altered by this  cir-
cumstance.
   25.  In order to develope the  metamorphoses which
choleic acid suffers  under the influence  of acids  and
alkalies, the following  formula  alone can be  adopted as
the empirical  expression of the results of its  analysis.
           Formula of choleic acid : C76N2H66022 (29)
   I repeat, that this formula may express  the composi-
tion of one, or of  two or  more compounds ; no matter
of how many compounds the  so-called choleic  acid
may be made up, the  above  formula represents the rela-
tive proportions of all their elements taken together.
   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......   C76N2H66022
           subtract —
         1  atom taurine  . . .  C4NH7O10  )   n  ss n  rt
                            iv h     ( = U* iN2tl10U10
         1  eq. ammonia  ...    1NH3    }
         There remains the formula of cho-
           loidic acid............   = C72  H66012 (30) 
METAMORPHOSES OF BILE.
129
  26.  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......= C76N2H66022
          subtract —
        2 eq.  carbonic acid = G,    04 )   r> i*r u  n
        2 eq.  ammonia     =   N2H6   ^
          Remains the formula of cholic
           acid  ...............= C74  H60O18 (31)
  When we  consider  the  very close coincidence be-
tween  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 proportion of
its  elements, no  matter in  how many  different forms
they may be  united to produce that acid.
  27.  Let us  now add the half of the  numbers which
represent the formula of choleic acid, to the elements
of the urine of serpents, — that is, to neutral  urate of
ammonia, as  follows :
      £ the formula of  choleic acid  . .  . . = C38N H33On
         Add  to this —
      1 eq. uric acid .  . . = C10N4H4O6 > = q^^ 0g
      1 eq. ammonia .  . . =   N H3   )    _________
         The  sum is.............= C48N6H40O17
  28.  But this  last formula expresses the  composition
of blood, with the  addition of 1 eq.  oxygen  and 1 eq.
water. 
130
RELATION OF BILE TO FIBRINE.
      Formula of blood...........C48N6H39014
      1 eq. water.......= HO )__     HO
      1 eq. oxygen......=  O \        _____
        The sum  is...........= C48N6H40O17
  29. If, moreover,  we  add  to  the  elements  of pro-
teine those of 3 eq.  water, we obtain, with  the excep-
tion of 1 eq. hydrogen, exactly the same formula.
      Formula of proteine.........= C48N6H36014
      Add 3 eq. of water  .........=      H3 Oa
        The sum is..............C48N6H39017
differing  only by 1  eq. of hydrogen from the  formula
above  obtained  by  adding  together choleic  acid and
urate of ammonia.
  30.  If,  then,  we consider choleic  acid  and  urate
of ammonia the products of the  transformation of mus-
cular  fibre, since no other tissue in  the  body   con-
tains proteine (for albumen  passes  into  tissues, without
our being able to say, that in the vital  process  it  is di-
rectly resolved into choleic acid,  and urate of ammonia),
there exist in fibrine, with  the  addition  of the  elements
of water, all the elements  essential  to this  metamor-
phosis ; and, except the  sulphur and  phosphorus, both
of which are probably oxidized, no  element is separated.
   This form of metamorphosis is applicable to the vital
transformations  in the lower classes of amphibia, 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 production
of urea  plainly stand in  a  very close  relation to the
amount of oxygen  absorbed in  respiration, and to the 
                 OXIDATION OF URIC ACID.            131
 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.
   31.  In  the  so-called mulberry  calculi we  find oxa-
 late of lime, in  other  calculi  urate  of  ammonia, and
 always  in   persons,  in whom, from want  of exercise
 and labor,  or from other causes,  the  supply of oxy-
 gen has  been  diminished.    Calculi  containing  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 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 oxygen they would have
 yielded,  in  healthy subjects, only  the last 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 or-
 ganism, are separated by the  kidneys and expelled from
 the  body in  the urine, altered or  unaltered,  has led
practical medical men  to  the idea, that the food, and 
132
URIC ACID AND UREA DERIVED
especially nitrogenized food, may have a direct influence
on  the formation of  urinary  calculi.   There are  no
reasons which support this opinion, while those opposed
to it are innumerable.   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 composition 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 transformation
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 severe  and con-
tinued 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.)
  32.  In  the same way, therefore,  as the hippuric acid,
present in the urine  of the horse when at rest, is con-
verted 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 suffi-
cient to oxidize the products of the transformation  of
the tissues.   The  use of wine  and fat, which  are only 
RELATION OF BLOOD TO URINE.
133
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 dissolved,
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  1  atom of uric  acid we add 6 atoms of  oxygen
and 4 atoms of water, it  resolves itself into urea  and
carbonic acid :
   1 at. uric acid C,0N4H4O6 1
   4 at. water >          )■= $ 2 at" urea.....°< N<H8°4
   6 at. oxygen \____51i^!° j    ( 6 at carb°niC uid ^_____2"
              C10N4H8O16                    C10N4H8O16
   33. 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 for-
 mula of their blood  multiplied by 5,  we obtain  the  ele-
 ments 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 metamorphosis, then we  obtain 6 at. of
 benzoic acid, 13| at. of urea, 3 at. of choleic  acid, 15
 at. of carbonic acid, and 12 at. of water.
                  12 
134       RELATION OF PROTEINE TO ALLANTOINE.
         5 (C48N6H3901&) + 09 = C240N30H195O84
    '6 at. hippuric acid, 6 (C18N H8 Os ) = C103N6 H48 O30
     9 at. urea......9 (C2 N2H4 02 ) = C18 Ni8H36 Oia
 = ^3 at. choleic acid,  3 (C38N H33On) = Cn4N3 H99 03a
     3 at. ammonia, . . 3 (   N H3    ) =    N3 H9
    ,3 at. water, .... 3 (     H  O ) =       H3 03
     The sum is...............  C240N30H195Og4
         or, —
         5 (C48NsH39015) + 045 = CmoNsoH^Ojjo
   f  6 at. benzoic acid,  6 (C14  Hs 03 ) = C84   H30 018
   J 27 at. urea,.....27 (C NH2 O  ) = C27 N27H64 027
= «(  3 at. choleic acid,  3 (C38NHMOXI) = Cn4N3 H99 033
    15 at. carbonic acid, 15 (C      02 ) = Clb       O30
   ,12 at. water,  ...  12 (     H  O  )=      H,, 012
         The som is..............C240N30H19SOi20
   34. Lastly,  let us  follow the metamorphosis  of the
tissues in the foetal calf,  considering the  proteine furnish-
ed 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 (C48N6H36014)-f-2at. water= 2  HO = C^N^H^O^
        ( 6 at. allantoine,   6 (C4N2H303) = C24N12H18Oia
        f 1 at. choloidic acid (          = C72   H56012
                                       C96N12H74O30
   35. But the elements of the six  atoms  of allantoine
in the last  equation correspond exactly to the elements
of 2 at. of uric acid, 2 at.  of urea, and 2 at. of  water.
                                  !2 at. uric acid C20N8 H8 0,2
                                  2 at. urea     C4 N4 H8 04
                                  2 at. water         H2 02
                                               ^^N^HjgOjg
   The  relations  of allantoine,  which  is  found  in the 
          RELATION OF PROTEINE TO GELATINE.         135
urine of the foetal  calf, to the  nitrogenized constituents
of the urine in  animals which respire, are, as may be
seen  by  comparing the above formulae, such as cannot
be  overlooked or  doubted.   Allantoine  contains the
elements of uric acid and  urea, —that is, of the nitro-
genized  products  of the  transformation  of the  com-
pounds of proteine.
   36. Further, if  to the formula of proteine, multiplied
by 3, we add the elements of 4 at.  of water, and if we
deduct from the sum of all the elements half of the ele-
ments of choloidic  acid, there remains a formula which
expresses  very nearly the  composition  of gelatine.
From
         3 (C43N6H36014) -f- 4 HO... = C144N18HU2046
         Subtract £ at. choloidic acid = C3S    H28 Os
             There remain.......CI08N18H 84O40(3s)
   37. 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) C108N18H84O40
          Subtract 2 at. proteine  .... C 96N12rl72Q2g
             There remain.......C 12N 6H12012 ==
   ( 1 at. uric acid C10N4H4 Os J   (     a]lantoine c N H Q
= < 1 at. urea .  . C2 N2H4 02  > = <                  ho
   )                 „'        3at. water . .      H3 Oa
   <• 4 at. water       H4 04  >   ^-
                C12N6H12012                  C12N6H12012
   38. The  numerical proportions  calculated from  the
above formula differ from those  actually obtained in the
analyses  of Mulder  and  Scherer in  this,  that  the
latter indicate somewhat  less of nitrogen in gelatine ; 
136
ORIGIN OF GELATINE.
but if  we assume the formula to be  correct, it then  ap-
pears, from the statement just given, that the elements
of two atoms of proteine, plus the nitrogenized products
of the transformation of a third  atom of proteine (uric
acid and urea) and water ;  or three atoms  of proteine,
minus the elements of a compound  containing no nitro-
gen, which actually occurs  as  one  of the products of
the transformation of choleic acid, yield  in both cases  a
formula closely approaching to the composition of gela-
tinous  tissues.   We  must, however, attach to such for-
mulae,  and  to the  considerations  arising  from  them, no
more importance than justly belongs to them.  I would
constantly remind  the reader, that their  use is to serve
as points of connexion,  which may enable us to acquire
more accurate views as  to the  production and decompo-
sition of those compounds which form the animal tissues.
They are the first attempts  to discover the  path which
we  must follow in order to attain  the object of our  re-
searches ; and this  object, the goal  we strive to reach,
is, and must be, attainable.
  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 previ-
ously 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 com-
pounds of proteine.   It may be produced by the addi-
tion, to  the  elements  of  proteine, of  allantoine  and 
ORIGIN OF THE BILE.
137
water, or of water, urea, and uric acid ;  or by the sep-
aration  from the  elements  of proteine of a compound
containing no nitrogen.   The solution of  such problems
becomes less difficult, when the problem to be solved,
the question to be answered, is matured and clearly put.
Every experimental decision of any such  question in the
negative forms the starting-point of a new question, the
solution of which, when  obtained, is the  necessary con-
sequence of our having put  the first question.
   39.  In the foregoing sections, no other constituent 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 nitro-
gen 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 carni-
vora, the constituents of the urine and the bile are de-
rived from the  transformation of compounds of proteine ;
for, except  fat, they  consume no food but such  as con-
tains proteine, or has been  formed from  that substance.
Their food is identical with  their blood ;  and it is a mat-
ter 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 regard
to the nutritive  process, than to suppose that the nitro-
gen 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
                12* 
138
ORIGIN OF THE BILE.
its amount, ought to be taken into consideration, suffers
not the  slightest change  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 or-
gans cannot be adapted for  the alteration  or decomposi-
tion of the substance from which all the other organs of
the body are to be formed.
   40.  From the characters of chyle and lymph, it ap-
pears 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 air or heat, recover
these properties by degrees.   In the chyle, the acid re-
action of the chyme  has already passed  into the weak
alkaline reaction of  the  blood ; and the chyle, when,
after  passing  through the  mesenteric   glands, it   has
reached the thoracic  duct, contains albumen coagulable
by heat; and, when  left to  itself, deposits fibrine.   All
the compounds of proteine,  absorbed  during the passage
of the chyme through the intestinal canal, take the  form
of albumen, which, as the  results of incubation in the
fowl's  egg testify, contains  the fundamental elements of
all  organized tissues, with the exception  of iron, which
is obtained from other sources.
   Practical medicine has long ago answered the ques-
tion, what becomes in man  of the compounds of prote-
ine taken  in excess,  what change is  undergone  by the
superabundant  nitrogenized  food ?  The blood-vessels
are  distended  with excess  of blood,  the other vessels 
                   ORIGIN OF THE BILE.               139
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 natu-
ral purposes, if the  soluble matters be not taken up by
the  proper organs, various gases are  disengaged, as in
processes of putrefaction, the  excrements assume an al-
tered quality in color, 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.
   41.  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 observations
which  have  been made in reference to the influence of
nitrogenized 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  suscepti-
ble of another and a far more simple interpretation, if,
along with the food, we consider the  mode  of life  and
habits of the individuals 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 mam-
malia,  living  in  the wild  state,* and among  nations
which  live entirely on flesh, deposits of uric acid con-

  * The occurrence of urate of ammonia in a concretion  found in a
dog, which was examined by Lassaigne, is to be doubted, unless
Lassaigne extracted it himself from the bladder of the animal. — L. 
140                 ORIGIN OF BILE
cretions in the limbs or  in the bladder  are  utterly un-
known.
  42.  That  which  must be  viewed  as  an  undeniable
truth  in regard to  the  origin of the bile, or, more ac-
curately  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  sup-
pose, that  all its  carbon is derived from the metamor-
phosed tissues.
  Assuming  the   59 oz.  of dry bile  (from  37 lbs. of
fresh  bile secreted by an ox) to contain the same  per-
centage of nitrogen as choleic  acid (3-85 per cent.),
this  would amount  to  nearly  2| oz.  of  nitrogen ; and
if  this nitrogen proceed  from  metamorphosed  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,  how-
ever, far below the quantity which, according to obser-
vation, is secreted in this class of animals.
  43.  Other  substances,  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-nitrogenized  constituents of  their
food.
  44.  The sugar of bile of Gmelin  (picromel or biline
of Berzelius),  which Berzelius considers as  the chief
constituent of bile, while Demarc,ay ass'gns  that  place
essentially  to choleic acid, burns, when heated in the 
                   IN THE HERBIVORA.                141
air, like resin, yields ammoniacal 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 separ-
ation  of  the nitrogen,  we obtain a crystallized  acid,
very similar  to  the oily acids (ch'olic acid), and  capa-
ble of forming with bases salts, which have the general
characters of soaps.   Nay,  we may even consider the
chief constituents of the bile, sugar of bile and choleic
acid,  as compounds  of oily acids with organic oxides,
like  the fat  oils, and only differing  from  these in  con-
taining  no oxide of  glycerule.   Choleic  acid,  for  ex-
ample,  may be viewed as a compound of choloidic acid
with allantoine and water :
     Choloidic acid.  Allantoine.   Water.  Choleic acid.
      ^72H56013  +  C4N2H303  + H707 = C76N„H66022
Or, as  a compound  of cholic  acid, urea,  and water  :
      Cholic acid.      Urea.      Water.   Choleic acid.
      C74H60O18  +  C2N2H402  + H202 = C7SN„HMOa3
   45.  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 constituents of bile,
as far as our knowledge at present extends.
   If starch  be  the chief  agent in  this process, it  can 
142         FORMATION OF BILE IN HERBIVORA.
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), contains  five  times
as much oxygen as choloidic acid.
   Without  the separation of oxygen from the elements
of starch,  it  is impossible to conceive  its  conversion
into  bile ;  and this separation being admitted, its con-
version  into a compound,  intermediate  in composition
between starch and fat, offers no difficulty.
   46. 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 consideration of
the  quantitative  proportion of the bile secreted in  the
herbivora leads to  the following conclusions : —
   The chief constituents of the  bile of the herbivora
contain nitrogen, and  this nitrogen is derived from com-
pounds of proteine.
   The bile of this class of animals  contains  more car-
bon  than  corresponds  to  the  quantity  of  nitrogenized
food taken, or to  the portion  of tissue,  that has under-
 gone metamorphosis in the vital process.
   A part  of this carbon  must,   therefore,  be derived
 from the  non-nitrogenized  parts  of the food  (starch,
 sugar,  &c.) ; and  in  order to be converted into a ni-
 trogenized  constituent of bile, a  part  of the elements
 of these bodies  must necessarily have combined with
 a nitrogenized  compound derived  from  a compound of
 proteine.
   In reference  to this conclusion, it is  quite indifferent 
               PRODUCTION OF HIPPURIC ACID.           143
whether  that  compound of  proteine  be  derived from
the food  or from the tissues of the body.
   47. 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 tis-
sues  in  the animal body, under the  influence of certain
matters taken  in  the food,  assumes a new form with re-
spect  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 . . .  . C2 N,H4 02 \    (n        „.   , ,.
,  A ,   .    .,   „    TT  „ f    1 2 at crystallized hippuric acid
1 a . lactic acid   C6   H4 04   = {
2 at. benzoic acid C28   Hj0O6 J    \    \  i»   »  /
               C36N2H180,2
   48. If we consider  the  act of  transformation  of the
tissues in  the  herbivora, as we have  done in the car-
nivora, 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 am-
monia (see p.  129) ;  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 transfor-
mation,  owing to the  presence of  this acid, assumes
another form, the elements  of the uric  acid  being  incor
  * The analysis  of the crystals  deposited  from the urine on the ad
dition of muriatic acid has not been  performed.  Besides, the state-
ment of A. Ure, that hippuric acid, dissolved in  nitric acid, is red
dened by ammonia, is erroneous,  and shows, that the crystals he ob-
tained  must have contained uric  acid — L. 
144
HIPPURIC ACID.
porated in the final products, — it will appear, for exam-
ple,  that 2 at. of proteine, with the addition  of the  ele-
ments of  3  at. of uric  acid and 2 at. of oxygen, might
give rise to  the production of  hippuric acid and urea.
        2 at. proteine, 2 (C48N6H36014) = C96 N12H72028
        3 at. uric acid, 3 (C10N4H4 Os ) = C30 N12H12018
        2 at. oxygen                =          Oa
            The sum is.......= C,26N24 H84048 =
     _ ( 6 at. hippuric acid, 6 (C,8N H8Os) = C108N6 H48O30
     - } 9 at. urea.....9 (Cs N2H402) =. C18 NI8H36018
            The sum is...........C126N24H84048
  49.  Finally, if we bear  in  mind, that,  in  the herbi-
vora,  the  non-nitrogenized 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 nitrogenized
compound,  in order to  produce the nitrogenized  constit-
uents of the bile, the most striking  result of  the combi-
nations thus suggested is this, that the elements of starch
added  to  those of hippuric acid are  equal  to the  ele-
ments of  choleic  acid,  plus a certain quantity of  car-
bonic acid:
        2 at. hippuric acid, 2 (C18NH8 Ob ) = C36N2H16O10
        5 at. starch,  ... 5 (C1S   H10O10) = C60   H50O50
        2 at. oxygen, ...               =        02
              The  sum is........= C96N2H66062
    _( 2 at. choleic acid,  2 (C38NH33On) = C76N2H66022
      f 20 at. carbonic acid, 20 (C     02 ) = C20      O40
             The sum is........= C96N2H66063
  50.  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 above) ;  since, further,  uric  acid,  choleic acid, 
CHOLEIC ACID, AMMONIA, &c.            145
and ammonia contain the elements of proteine in a pro-
portion almost identical with that of proteine itself, (see
p. 129) ; 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 remainder will  represent  the  elements of
hippuric acid and of urea ;  and that if, when this separa-
tion  occurs,  and during the  further transformation, the
elements of  starch  be present  and enter into the new
products, we shall obtain an additional quantity of choleic
acid, as well as a certain amount of  carbonic 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,
 we obtain, as the products of this metamorphosis, urea,
 choleic acid, ammonia,  and  carbonic  acid, and besides
 these, no other product ivhatever.
    The elements of
              5 at. proteine "|    f 9 at. choleic acid
             15 at. starch   I   ;  9 at. urea
             12 at. water   j   j  3 at. ammonia
              5 at. oxygen  j   160 at. carbonic acid
            In detail,—
          5 at. proteine, 5 (C48NsH36014) = C240N30H180 >70
         15 at. starch,   15 (C,2   H,0Oi0) = C180    Hi50Ols0
         12 at. water,   12 (      HO   ) =        H12 Oia
          5 at. oxygen,                =_________*_
            The sum is.........= C420N30H342O237
              and,—
       9 at. choleic acid,  9 (C38N H33On) = C342N9 H297099
       9 at. urea,  . .  .  . 9 (C2 N2H4 02 ) = C,8 N18H36 018
       3 at ammonia,  . . 3 (   N  H3    ) =    N3 H9
      60 at carbonic acid, 60 (C      02 ) = C60        <->i20
                                         420^30^3420237 
146
SODA ESSENTIAL TO THE
    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 share in
 these metamorphoses, is opposed to the supposition, that
 a  part of the carbon of the non-azotized food enters into
 the composition of the bile.
   51. Fat, in  the  animal body,  disappears  when  the
 supply of oxygen  is  abundant.   When  that  supply is
 deficient, choleic  acid may be  converted into hippuric
 acid, lithofellic acid, (37)  and water.   Lithofellic acid is
 known to be the chief constituent of the  bezoar stones,
 which occur in certain herbivorous animals :
 2 at. choleic acid  C76N2H66022 >   (  2 at hiP- acid  C3SN2H16O10
 10 at. oxygen  ...       O10  $ ~~ )  1 at- lith- acid C4o   H3608
              ----------     (. 14 at. water   . .    H14014
              C76N2H66032                   C76N2H66032
   52. For the  production of bile in the animal body a
certain quantity of soda is, in all  circumstances, neces-
sary ; without  the presence of a compound  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  com- 
FORMATION OF THE BILE.
147
posed  according  to the  empirical  formula  CxlH.0O,
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 = CMNiaHM0M =
              !6 at. urea  .  . . . = C12N12H24012
              Fat.......= C66   H60O6
              18 at. carbonic acid = Ci8      036
                                C9SNi,H84054
   The composition of all  fats lies between the empirical
formulae C„H10O and  C12H10O.   If we  adopt  the lat-
ter,  then the elements of 2  at. proteine, with the ad-
dition  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 pro-
duction  of  fat, that the  absence of  common  salt  (a
compound of sodium, which  furnishes soda  to the ani-
mal  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 produce  a purgative
effect.
   53.  As a kind  of general view of the  metamorphoses
of the nitrogenized animal  secretions,   attention  may
here  be  very properly directed  to  the fact, that the
nitrogenized  products of  the  transformation  of the bile
are  identical  in ultimate  composition with the constitu-
ents of the  urine,  if to  the  latter be added a  certain
proportion of the elements of  water. 
148
RELATION OF URINE TO BrLE.
*£}-«:
 1 at. uric acid . C,nN4H4 Os .
              ^  „ „  ~  /    {3 at. taurine C.-NaH-Oan
 1 at. urea  . . . C2 N„H4 O, > = <0 .       .   \T TI   M
~.                 ".  „" (    (3 at. ammonia  N3H0
22 at. water .  . .
             Cj2N6H3()O30                 C12N6H30O30
1 at. allantoine  C4 N2H3 03 ) _ ( 1 at. taurine  C4N H7 O10
7 at. water  . .      H7 Ot S   ) 1 at. ammonia  N H,
                C4N2HwO10                 C4N2H10Oi0
  54.  In reference to the metamorphoses of uric 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 elements of  water to the
elements of uric acid may yield either taurine and  urea,
or taurine, carbonic acid, and ammonia.
 1 at. uric acid  Cl0N4H4 Oe j         ^.^
14 at. water  .  .      H140,* > = ■?- .            ~   "  "
2 at. oxygen
4H4U6 N
 HI4014} = ]
   O, )   <
1 at. urea . .  . C2 N2H4 02
C10N4Hj8O22'
Add 2 at. water      H, O,  J
              CloN4"lg022
2 at. taurine .  .  C8 N2H14O20
2 at. carbon, acid C2     04
2 at. ammonia .    N2He
              Ci0N4H20O24                    C10N4H20O24
   55.  Alloxan, plus a certain amount of water, is iden-
tical in  the  proportion of elements with taurine ; and,
finally,  taurine  contains the elements of  superoxalate
of ammonia.
 1 at. alloxan*    C8N2H4 O10 1       Taurine.
10 at. water .  . .     H10O10 ]  =  2 (C<NH7°io)
                         !2 at. oxalic acid C4    Os
                         1 at. ammonia    NH3
                         4 at. water .  .    H404
C4NH,0,
* It would be most interesting to investigate the action of alloxan 
RELATION OF STARCH TO BILE.
149
  56.  The comparison of the amount of carbon in the
bile  secreted  by an herbivorous  animal, with the quan-
tity of carbon of  its tissues, or of the nitrogenized con-
stituents of its food, which, in consequence of  the con-
stant 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  metamorphosed tissues  or
from the nitrogenized  constituents of the food ; and we
may regard as well  founded the  supposition,  that the
non-azotized  constituents  of  the food  take a  decided
share  in the production  of  bile in the herbivora ; for
neither  experience   nor   observation  contradicts  this
opinion.
   57. We have  given,  in  the  foregoing paragraphs,
the  analytical proof,  that the nitrogenized products  of
the  transformation of  bile, namely,  taurine and  ammo-
nia, may  be  formed  from all  the  constituents  of the
urine, with the exception of urea, — that  is, from hip-
puric  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 ; —
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 very  probably be found a most  powerful
remedy. — J. L.
                   13* 
 150         RELATION OF STARCH, &c. TO BDLE.
         From 6 at. starch  = 6 (C12H10O10) = C72H60O60
    Subtract 44 at. oxygen )
            4 at. water  \ =                    4°4a
         Remains choloidic acid.....= C72H66012 ; —
 that, finally, choloidic  acid,  ammonia,  and taurine,  if
 added together,  contain the elements of choleic acid ; —
             1 at. choloidic acid = C72   H66012
             1 at. taurine  . .  . = C4 N H7 O10
             1 at. ammonia  .  . =   N H3
             1 at. choleic  acid  . = C70N2 H66022; —
 if all  this be considered, every doubt as to the possi-
 bility of these  changes is removed.
   58. 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-azotized  constituents  of food  (of
 starch, &c, the elements of respiration) is secreted by
 the liver  in the  form  of  bile ; and  further,  that  the
 nitrogenized 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-azotized
 constituents  of the food ; they are returned  to the cir-
 culation 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 substances employed in
respiration.
   59.  When the urine  is left to  itself,  the urea which 
ORIGIN OF THE BILE.
151
it  contains  is  converted into  carbonate  of ammonia ;
the elements of urea are in such proportion, that by the
addition of the elements of water, all its carbon  is con-
verted into carbonic acid, and all  its nitrogen  into am-
monia.
    1 at. urea  C2N2H402 >__C 2 at. carbonic acid C2    04
    2 at. water     H202 $   ( 2 at. ammonia .  . .  N2H6
             C2N2H604                    C2N2H604
   60.  Were  we able  directly to produce taurine  and
ammonia out of uric acid or allantoine, this might per-
haps be considered as an additional proof of the share
which  has been  ascribed  to these compounds in the
production of bile ; it  cannot, however, 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 influence of the
same  reagent; and when, instead of  the acid, we use
potash, we obtain the same  elements, although arranged
in another, and quite a  different manner.  If taurine were
present,  ready formed, in  bile,  we should obtain the 
152
ORIGIN OF THE BILE.
same products by the action of acids and of alkalies.
This, however, 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  insight into  the
true theory of the  formation of  bile, just because  the
preexistence of ammonia  and taurine in  the bile must
be doubted, and because we  have no reason  to believe
that urea  or allantoine, 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 combina-
tions, or what is the chemical character of  the nitro-
genized compound  which  unites with  the elements of
starch to form bile,  or rather choleic acid.
  61. Choleic acid may  be  formed from the elements
of starch  with those of uric  acid and urea, or of allan-
toine, 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 nitrogen-
ized compounds  is sufficient to show, that all the nitro-
genized products 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 employed.
  By  the action of  caustic  alkalies  allantoine  may
be  resolved into oxalic  acid and  ammonia ; the same
products are obtained when  oxamide  is  acted  on  by the
same reagents.   Yet we cannot, from  the similarity of
the products, conclude that  these two compounds have
a similar  constitution.   In like  manner the  nature of 
                VITAL METAMORPHOSES.              153
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.
   62. If the problem to be solved by organic  chemistry
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  elements  must be
added, what elements  must  be separated, in  order to
effect, or, in general, to render 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
 organism 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 dis-
 covery  of the  share which  the atmosphere  or  the ele-
 ments 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  organized part.
    63.  The presence of free muriatic acid in the  stom-
  ach, and that of soda in the blood, prove  beyond  all
  doubt the necessity of common salt for the organic pro-
  cesses  ; but the quantities of soda  required by animals
  of different classes, to support  the vital processes, are
  singularly  unequal.
     If we  suppose, that a given amount of blood, con-
   sidered as a compound of soda, passes, in  the body of
   a carnivorous  animal, in consequence of the change of 
154
USES OF COMMON SALT.
  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 transforma-
  tion.  The soda which  has been used in the  vital pro-
  cesses, 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 produced
  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-azotized
  constituents  of the food,  then  the soda  of the blood
  which has been formed into organized tissue (assimilated
 or metamorphosed) cannot possibly suffice for the  sup-
 ply of the daily secretion 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 com-
 pounds 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
 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 expelled in  the urine.
  When  the carnivora  obtain in their  food as much
soda as suffices  for the production of their  blood, an 
USES OF SALT.
155
equal amount  is excreted in the urine ; when the food
contains  less, a part of that which would otherwise be
excreted, is retained by the organism.
   All these statements are most unequivocally confirmed
by the composition of the urine in these different classes
of animals.
   64. 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 nitrogen 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 favor 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 am-
monia in their  urine.   This urine, moreover, has an
acid  reaction.
   In contradistinction  to  this,  we find, in  the urine 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 consump-
tion  of blood.   In their food are united all  the  condi-
tions for the production of a second compound of soda, 
156
LARGE AMOUNT OF ALKALIES
destined fcr the support of the respiratory process ; and
it  can only be a very limited knowledge  of the  vast
wisdom  displayed   in  the  arrangements 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 develop-
ment  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  pro-
duction of the  first food of the young animal ; for with-
out an  abundant supply  of potash,  the  production of
milk becomes  impossible.
   66.  All observation leads,  as appears from the  pre-
ceding  exposition,   to  the  opinion,  that certain  non-
azotized   constituents  of the food  of  the  herbivora
(starch,  sugar,  gum, &c.) acquire the  form of a com-
pound of soda, which, in their  bodies,  serves for the
same  purpose  as that which  we  know certainly to be
served by the  bile (the most highly carbonized product
of the transformation of their  tissues) in  the bodies of
the carnivora.    These substances are employed to sup-
port  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 
REQUIRED BY HERBIVORA.
157
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-azotized constituents
of the food of  the herbivora impede the change of mat-
ter, or  retard  it, and render unnecessary, at all events,
so rapid a  process as occurs in the carnivora.
   67.  The quantity of azotized matter, proportionally
so small, which the herbivora  require  to  support  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 respiratory  process ; and
this consideration  seems  to render  it  not improbable,
that the necessity  for more complex organs of digestion
in the herbivora is rather owing to the difficulty of ren-
dering soluble  and  available for the vital processes cer-
tain non-azotized compounds (gum ? amylaceous fibre ?)
than to any thing in the  change  or transformation of
vegetable  fibrine,  albumen,  and  caseine into  blood ;
since,  for this latter purpose, the less complex digestive
apparatus of the carnivora is amply sufficient.
   68.  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 formation of the bile
in man  as in these animals ;  then  it follows, that a  part
of  the  azotized products  of the  transformation of  the
tissues  in  the human body, before they are expelled
through the  bladder, returns into the  circulation  from
                 14 
158
STARCH, &c, ASSIST IN FORMING
the liver in the  shape of bile, and is  separated  by the
kidneys from the blood, as the  ultimate product of the
respiratory process.
   69.  When there is a deficiency of non-azotized  mat-
ter in  the food of man, this  form of the  production of
bile  is rendered  impossible.  In that  case, the secre-
tions  must possess  a different  composition ; and the
appearance of uric acid in the urine, the deposition 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 deficiency  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 azo-
tized  compounds, formed during the change of matter,
will either remain in the situation where  they  have been
formed,  in which  case  they will not be sent  from the
liver into the  circulation,  and therefore will  not undergo
the final changes  dependent  on  the action of oxygen ;
or they will be separated by the kidneys in some form
different from  the normal  one.
   70.  In the  preceding paragraphs I  have endeavored
to prove, that the  non-azotized  constituents of food ex-
ercise a most decided influence on the  nature and quality
of the animal secretions.  Whether this occurs directly ;
whether, that  is to say, their elements  take an immedi-
ate share in the act of  transformation of tissues ;  or
whether their share in that process be an indirect one, is
a question probably  capable of being resolved by care-
ful and  cautious  experiment  and  observation.   It  is 
BILE IN THE HUMAN BODY.
159
possible,   that the  non-azotized constituents  of food,
after undergoing  some  change,  are  carried from  the in-
testinal canal directly  to  the  liver,  and that  they are
converted into bile  in  this organ, where they meet with
the products of the  metamorphosed tissues, and subse-
quently complete their  course through the circulation.
   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 as-
cribe to  these  substances,  since   they  are  wanting in
arterial blood, any share in  the nutritive process ;  and
the occurrence of sugar in  the urine of those  affected
with  diabetes mellitus,  (which  sugar, according to the
best  observations,  is derived  from the  food,)  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 circulation.
   71.   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 healrh, although
their quantity can hardly be determined.   Indeed, if we
suppose  8| lbs.   (57,750 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 ^th  part of  the  weight of the blood,
a  proportion  far too  small to  be  quantitatively ascer-
tained by analysis.
   72.  The greater  part of the  bile in the  body of the
herbivora, and in that  of  man  fed  on mixed food,  ap- 
160
ORIGIN OF THE NITROGEN.
pears from the preceding  considerations  to be  derived
from  the  elements of the  non-azotized  food.   But its
formation  is impossible without the addition of  an  azo-
tized body, for the bile is  a compound of nitrogen.   All
varieties of bile  yet examined yield, when subjected to
dry distillation, ammonia   and other nitrogenized  pro-
ducts.   Taurine 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 animals, a
sufficient quantity of bile for the experiment.
   Now,  whether the  nitrogenized  compound which
unites with the elements of starch to form bile be  de-
rived from the food,  or  from the  substance of the meta-
morphosed tissues, the  conclusion, that  its presence is
an essential  condition for  the secretion of bile, cannot
be considered doubtful.
   Since  the herbivora obtain  in their  food  only  such
nitrogenized compounds as are  identical in composition
with the  constituents of their blood, it is  at  all events
clear, that the nitrogenized compound which enters into
the composition of the bile, is derived from a compound
of proteine.   It  is  either formed in consequence  of  a
change  which the compounds of proteine 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.
   73.  If  the conclusion be  accurate, that nitrogenized
compounds,  whether derived from  the blood or  from 
           MEDICINAL AND POISONOUS SUBSTANCES.       161
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 nitrogenized substances
capable  of being  rendered  soluble,  without exception,
when introduced into the organs of circulation  or of di-
gestion, must, if their composition be  adapted for such
purposes,  be employed by the organism  in the  same
manner as the nitrogenized  products which are formed
in the act of metamorphosis of tissues.
   We  are acquainted with a multitude  of substances,
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 uniformly substances, the particles
of which are in a  certain state of motion or of decompo-
sition, which state is  communicated to all such parts of
the  organism as  are  capable of  undergoing  a similar
transformation.
   74. Medicinal and  poisonous  substances form a sec-
ond and  most extensive class of compounds, the   ele-
ments 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 chemi-
cal  combination  with  certain parts  or  constituents of
the body,  while the vital force is insufficient to destroy
                14* 
162       MEDICINAL AND POISONOUS SUBSTANCES.
the compounds  thus  formed.   The  second  division,
consisting of the essential oils, camphor, empyreumatic
substances, and antiseptics, &c, possesses the  property
of impeding or retarding  those  kinds of transformation
to which  certain 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 body.   When intro-
duced into the system, they augment the energy  of the
vital activity of one or more  organs ; they excite mor-
bid phenomena in the  healthy body.  All of them pro-
duce a marked effect in a  comparatively small dose, and
many are  poisonous  when administered in larger quan-
tity.   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 different from that
of blood,  and, partly,  because  the proportion  in which
they must be given, to exert  their influence, is as noth-
ing, compared with  the mass  of the blood.
   These  substances, when   taken into the circulation,
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  efficacy,  we  must assume
that  their composition is not  affected by the organic in-
fluence of the stomach.   If  insoluble when given,  they
are rendered soluble in that organ, but  they are not de- 
               ACTION OF ARTERIAL BLOOD.           163
composed ; otherwise,  they would be  incapable of ex-
erting  any influence on the  blood.
   75.  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 the genera-
lion  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 prop-
erty which it  possesses of  becoming part of  an organ-
ized tissue, and its consequent adaptation to promote the
formation and  the  growth of organs, as well  as to the
reproduction  or supply of waste in the tissues, is owing,
chiefly, to the presence of  dissolved fibrine  and albu-
men.  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 atmosphere as entirely to lose
the power of extracting oxygen from the other substan-
ces present in the blood.
   76.  We  know  for certain  that  the globules of the
venous blood, when they come in contact with air in the
lungs,  change  their  color, and  that  this change  of color
is  accompanied by an  absorption  of oxygen  ; and that 
164            ACTION OF ARTERIAL BLOOD.
all those constituents of the blood, which possess in any
degree  the power of combining with oxygen,  absorb  it
in the lungs,  and become  saturated with it.   Although
in contact  with these other compounds,  the  globules,
when arterialized, retain their florid,  red color in the
most  minute  ramifications  of  the  arteries ; and we ob-
serve them  to  change their  color, and to assume the
dark  red color which characterizes venous blood, only
during 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 arterialized globules of the oxygen which they have
absorbed from the air ;  and we can  draw no other con-
clusion  from the change  of color which occurs in the
capillaries, than  that the  arterialized  globules, during
their passage  through the  capillaries, return to the con-
dition which  characterizes  them in venous blood ;  that,
consequently, they give up the oxygen  absorbed in the
lungs, and  thus acquire  the power of  combining with
that  element  afresh.
  77. We find, therefore, in arterial  blood,  albumen,
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 ex-
tend (in the  development  of the  chick during incuba-
tion), 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 consumed in 
ACTION OF MEDICINAL AGENTS.          165
the growth or reproduction of organs, combines 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.
   78.  It is  obvious, that  all compounds, of whatever
kind, which are present in the capillaries,  whether sepa-
rated there, or introduced by endosmosis (B)  or imbibi-
tion, if not altogether incapable  of uniting with oxygen,
must, when in contact with the arterialized globules, the
carriers of oxygen, be  affected exactly in the  same way
as the solids forming part of living organs.   These com-
pounds, 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 different kind.
   79. 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 ; assuming, further, that it is
not in a  condition of transformation  capable of being
communicated to the constituents of the blood or of the
organs,  and  of continuing in   them ;  assuming, lastly,
 that it is incapable, by its contact with  the living  parts,
 of putting a stop to the change  of matter,  the  trans-
 formation of their elements ; then, in  order  to  discover
 the modus  operandi of this class of medicinal agents, 
166
ORGANIC REMEDIAL AGENTS.
nothing is left but to conclude that  their elements  lake
a  share in the formation  of certain  constituents  of the
living body, or in the production of  certain secretions.
   80.  The vital process of secretion, in so far as it is
related  to  the chemical  forces, has been  subjected  to
examination in the  preceding pages.  In  the  carnivora
we have reason to  believe, that, without the addition of
any foreign  matter  in the  food, the bile and the constit-
uents of the urine  are formed in those parts where  the
change  of matter takes  place.  In other  classes of ani-
mals, 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 nitrogenized  product of the
metamorphosis of the tissues.   But  this supposition by
no  means excludes  the opinion,  that in the  carnivora the
products of the metamorphosed tissues are  resolved into
bile, uric acid, or urea, only after reaching  the secreting
organ ;  nor the opinion, that the  elements  of the non-
azotized 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 metamor-
phosed  tissues, to form  the constituents of  the  bile and
of the urine.
  81. 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  composition  of the 
NITROGENIZED ORGANIC REMEDIES.         167
new products ; or they are conveyed to  the  organs of
secretion, where they exert an  influence on the forma-
tion 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  sufficient  cer-
tainty, that  this class  of  medicinal  bodies disappears in
the  body without leaving a trace.   In fact,  if we  as-
cribe to them any effect,  they cannot lose their peculiar
character by the  action  of the stomach ;  their disap-
pearance, therefore, presupposes that they  have been
applied to certain purposes, which  cannot be imagined
to occur without a change in their composition.
   82.  Now, however limited  may be  our knowledge
of the composition  of the different secretions, with the
exception of the bile, this  much is certain, that  all  the
secretions contain nitrogen chemically combined.  They
pass into fetid putrefaction, and  yield   either  in  this
change, or in the  dry distillation, ammoniacal products.
Even the saliva, when acted on by caustic  potash, dis-
engages ammonia freely.
   83.  Medicinal or remedial agents may be divided into
two classes, the nitrogenized and the non-nitrogenized.
The nitrogenized vegetable principles, whose composi-
tion differs  from  that  of the  proper nitrogenized  ele-
ments  of nutrition,  also  produced  by a vegetable  or-
ganism, are   distinguished, beyond  all  others, for their
powerful action on the animal economy.
  * See note XLIII. on the conversion of benzoic acid into hippuric
acid. 
168              VEGETABLE ALKALIES, &o.
   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  organism,
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.*
   84.  The  medicinal or  poisonous action of the nitro-
genized vegetable principles  has a fixed relation to their
composition ; it  cannot be supposed to be  independent
of the  nitrogen  they  contain, but is certainly not  in di-
rect proportion to the quantity of nitrogen.
   Solanine  (3a), and picrotoxine  (39), which contain
least nitrogen, are powerful poisons.  Quinine (40)  con-
tains  more nitrogen  than morphia (41).  Caffeine  (42),
and  theobromine, the most  highly  nitrogenized  of all
vegetable principles, are not poisonous.
   85.  A nitrogenized 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 chemical
character, be  capable of taking the  same share  as the
nitrogenized products of  the  animal  body do  in the for-
mation  of the bile ;  that  is, it must  play  the  same  part
  * This consideration or comparative view has led lately to a more
accurate investigation of the composition of picrotoxine, the poison-
ous principle of cocculus indicus; and M. Francis has discovered the
existence of nitrogen in it, hitherto overlooked, and  has also  deter-
mined its amount. — L. 
NITROGENIZED COMPOUNDS.
169
as a product of the vital process.   On  the other hand,
a non-azotized medicinal agent, in so far  as  its action
affects the  secretions, 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-azotized
elements of food.
   Thus, if we suppose that the  elements of hippuric or
uric acids are  derived from the  substance of the organs
in which vitality resides ;  that, as products of the trans-
formation of these organs, they lose the vital  character,
without losing the capacity of undergoing changes under
the influence of the inspired oxygen, or of the  appara-
tus of secretion ;  we can  hardly doubt that  similar ni-
trogenized  compounds, products of the vital process in
plants, when introduced into the  animal  body, may be
employed  by the organism exactly in the  same  way as
the nitrogenized products  of the metamorphosis of the
animal tissues themselves.  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 nitrogenized compounds.
   WTe  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  decoction  of certain
roasted  seeds  (coffee).   Some cause there must be,
which would  explain  how the  practice has  become a
necessary  of  life  to whole nations.  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 vegeta-
                   15 
170
VEGETABLE PRODUCTS: CAFFEINE.
bles,  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 shown, in such a  manner as to
exclude  all doubt, that caffeine,  the  peculiar  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 himself,
in tobacco smoke, a means of retarding the change of
matter in  the tissues of his body, and thereby of mak-
ing hunger  more  endurable ;  and  that he  cannot with-
stand 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  cof-
fee were originally met with  among nations whose  diet
is chiefly vegetable.
   86.  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 influence on
the process  of  secretion,  that this substance,  with  the
addition of oxygen and the elements of water,  can yield
taurine, the nitrogenized compound peculiar to  bile :
            1 at. caffeine or theine = C8N2H5 O,
            9 at. water.....=     H9 Og
            9 at. oxygen.....=;        09
                                 C8N2H14O20 =
          = 2 at. taurine.....=2 (C4NH7Oi0)
   A  similar relation exists in the case of the peculiar
principle of asparagus  and of  althaea, asparagine; which 
RELATION OF CAFFEINE AND ASPARAGINE.      171
also,  by the  addition  of oxygen  and  the  elements of
water, yields the elements of taurine :
               1 at. asparagine = C8N2H8 Os
               6 at. water  .  . =     H6 Os
               8 at. oxygen  . =       Og
                               C8N2H14O20
             = 2 at. taurine   . == 2 (C4NH7O10)
   The  addition of the elements of water and  of a cer-
tain quantity of oxygen to the elements of theobromine,
the characteristic principle of the  cacao  bean (theo-
broma cacao), yields  the  elements of taurine and urea,
of taurine,  carbonic  acid,  and ammonia, or of  taurine
and uric acid :
°«)   <4at.
o::H-
 1 at. theobromine C18N6H10O4  .
                     1U    /   ( 4 at. taurine . .  Ci^H^O^
22 at. water  . .  .      H2,U22 > = \ .  .           „ _T tT  „
                     z-    I   ( 1 at. urea .  . .  C, N,H4 O,
16 at. oxygen .  .        Oi6
               CjgNgHjjaO^                   C^^H^O.^
                         or,—
 1 at. theobromine C18N6H10O4  \   / 4 at. taurine .  . C16N4H28O40
24 at. water .  . .      H24024 > = < 2 at. carbon, acid C3      04
16 at. oxygen  . .         Oj6)   (2 at. ammonia  .    N2H6
               C18N6H34044                   C18N6H34044
                         or,—
 I at. theobromine CI8N6H10O4  \
 Q t                tt  ^  l   S 2 at taurme •  • cs N2H14O20
 8 at. water .  .  .      H8Og  }=<       .   .,   _  v „  _
, A t                   ^  (   (I at. uric acid  . C10N4H4 Ofi
14 at. oxygen .  .         (J14 )
               C18N6Hi8026                   Ci8N6Hi8026
  87.  To see how the  action of caffeine,  asparagine,
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 
172   RELATION OF THEOBROMINE TO BILE AND URINE.
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  0-171  parts  of nitrogen in  the shape of
taurine.  Now this  quantity is  contained  in 0-6 parts
of caffeine ; or  2i80ths 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 ith  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-azotized food and a deficiency of motion, which
is  required  to  cause  the  change of  matter  in the  tis-
sues,  and thus  to yield the nitrogenized product which
enters into  the composition of the bile ;  that in  such
a  condition,  the health  may be  benefited by the  use
of compounds  which are capable of supplying the place
of the  nitrogenized  product produced in the  healthy
state of the body, and essential  to the production 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 virtue of their composition, better
adapted  to  this purpose,  than all  other nitrogenized
vegetable principles.  The  action of these substances,
in "ordinary  circumstances,  is  not  obvious,  but it un-
questionably exists.
   88. With respect  to the  action  of the other nitro- 
       ACTION OF ALKALIES ON THE NERVOUS SYSTEM.   173
genized vegetable  principles,  such as quinine, or the
alkaloids of opium, &c, which  manifests itself, not in
the processes  of secretion, but in phenomena of an-
other kind, physiologists and  pathologists  entertain  no
doubt, that it is exerted chiefly on the brain and nerves.
This  action  is  commonly said to be  dynamic, — that
is, it  accelerates, or retards, or alters  in some way the
phenomena of  motion in animal life.  If  we reflect,
that  this  action is exerted  by substances  which are
material, tangible, and ponderable ; that they disappear
in the organism ; that a  double dose acts more power-
fully 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 considerations, viewed chemi-
cally,  permit only one form  of explanation ;  the sup-
position, namely, that  these  compounds,  by means of
their  elements, take a share in  the formation of new,
or the  transformation of existing  brain  and nervous
matter.
   However strange the idea may,  at first sight, appear,
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 energy, from which the organic mo-
tions  of the  body  derive  their origin ; that  these sub-
stances form a  constituent  of that matter, by the  re-
moval of which the seat of  intellectual life, of sensation,
and of consciousness,  is annihilated : it is, nevertheless,
certain, that all these forms of power and  activity  are
most  closely dependent, not  only on the existence,  but
                 15* 
174
COMPOSITION AND ORIGIN
also on a certain quality of the substance of the brain,
spinal marrow, and nerves ; insomuch, that all the mani-
festations of the  life  or vital  energy of these modifica-
tions of nervous matter,  which are  recognised  as the
phenomena of motion, sensation, or feeling, assume an-
other form as soon as their composition is altered.  The
animal  organism has produced the brain and nerves out
of compounds  furnished  to it by vegetables ; it is the
constituents of  the food of the animal, which, in  conse-
quence  of a series of changes, have assumed the prop-
erties and the  structure which we find in  the brain and
nerves.
  89. If it must be admitted as an  undeniable truth,
that  the substance of the  brain and  nerves is 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 con-
stituents of vegetables, intermediate  in  composition be-
tween the  fats and  the compounds of proteine, may be
applied  in the organism to the same purpose.
  90. 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 
OF THE NERVOUS MATTER.
175
differs entirely, both  from that of ordinary fats and of
the compounds of proteine.   Common fats contain no
nitrogen, while the compounds of proteine contain nearly
17 per cent.   Leaving  the phosphorus out of view, the
composition of this acid approaches most nearly  to that
of choleic acid, although these two compounds are quite
distinct.
   91.  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 highly nitrogenized com-
pound from  the  elements of blood, or by the combina-
tion of a nitrogenized product of the vital process with a
non-azotized 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 supposed to be
formed, all  the conclusions which we attained in regard
to the cooperation of  azotized  and non-azotized ele-
ments 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 presupposes a change in the  compo-
sition 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 
176        RELATION OF VEGETABLE ALKALIES.
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  com-
pound of proteine.   Indeed, it  cannot be  considered
merely accidental, that  the  composition of  the most ac-
tive  remedies,  namely, the vegetable  alkaloids, cannot
be shown to  be related  to that of any constituent of  the
body, except only the substance of the nerves and brain.
All of these contain a certain quantity of nitrogen, and,
in regard to their composition, they are intermediate be-
tween the compounds of proteine and the fats.
  92.  In contradistinction  to  the chemical  character,
we  find that the substance of the brain exhibits the char-
acters of an  acid.   It  contains far more oxygen than
the organic bases or alkaloids.  We  observe, that quin-
ine  and cinchonine, morphia and codeine, strychnia and
brucia,  which are, respectively, so nearly alike in com-
position, 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 narcotine), 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 ac-
tion than this last fact;  it must stand in the closest rela-
tion to their composition.   If these compounds, in point
of fact, are capable of  taking a share in the formation or
in the alteration of the qualities  of brain  and nervous 
RELATION OF VEGETABLE ALKALIES.        177
matter, their  action  on the healthy as well as the  dis-
eased organism admits of a surprisingly simple explana-
tion.  If we are not  tempted to deny, that  the chief
constituent of soup may be applied to a  purpose  corre-
sponding 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 (gelatine in
both cases) is absolutely incapable of yielding blood ;  if,
therefore, nitrogenized compounds, totally different from
the compounds of proteine, may be employed for pur-
poses  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, originally  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  incomprehensible obscurity.    Now
that we know that these  effects  are  caused by crystalli-
zable 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  inexplicable ;
 and to  do  so, as many have done, because  they act in 
178         ACTION OF NITROGENIZED PRODUCTS.
very minute doses, is as unreasonable as it would be to
judge of the sharpness of a razor by its weight.
   93.  It  would serve no purpose to give  these  con-
siderations a greater extension at present.   However
hypothetical they may appear, they only deserve  atten-
tion in so far as they point out  the way which chemistry
pursues, and which she ought 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, forwards  and backwards, to the  conversion of
food into the various tissues and secretions, and to their
metamorphosis into lifeless compounds ; his investigations
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 dependent on  certain  matters, which differ
in composition ; and  if,  by the introduction  of a sub-
stance, certain abnormal conditions are rendered normal,
it will  be impossible to reject the opinion, that this phe-
nomenon 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 simi-
lar to  that which the vegetable elements of  food  have
taken  in the formation of fat,  of  membranes,  of the
saliva, of the  seminal fluid, &c.   Their carbon, hydro-
gen, or nitrogen,  or whatever else belongs to  their com-
position, are derived from the vegetable organism ; and,
after   all,  the action and effects of quinine, morphia,
and the vegetable poisons in general, are no hypotheses.
   94.  Thus,  as  we  may say, in a  certain  sense,  of
caffeine, or theine  and asparagine,  &c, as well as  of 
NITROGENIZED VEGETABLE PRODUCTS.        179
the non-azotized 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 nitrogenized com-
pounds, so remarkable for their  action on the brain  and
on the substance of the organs of motion,  as  elements
of food for the  organs as yet unknown, which are des-
tined 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 transforma-
tion 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 chemi-
cal sense, there is  no objection  to the opinion,  that
substances of a composition analogous  to  that of ner-
vous  and cerebral matter,  and, consequently, adapted
to form that  matter, may be  employed,  instead of the
substances produced from  the  blood,  either  to furnish
the necessary resistance, or to  restore  the  normal con-
dition.
   95.  Some physiologists and chemists have expressed
doubts of the peculiar and distinct character of cerebric
acid, a substance which, from its  amount of carbon and
hydrogen, and from  its external characters, resembles a
nitrogenized fatty acid.  But a nitrogenized fat, having
an  acid  character, is,  in fact,  no anomaly.   Hippuric 
180
PHOSPHORUS SEEMS ESSENTIAL
acid is  in many of its  characters  very similar  to  the
fatty acids, but is essentially distinguished from them by
containing nitrogen.  The  organic  constituents of bile
resemble the 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 nitrogenized fatty acid
is as little improbable as the existence of a nitrogenized
resin with the characters of a base.
   96.  An accurate  investigation would  probably dis-
cover differences in the composition of the brain, spinal
marrow, and nerves.  According  to the  observations
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  re-
quired  for the  separation of  foreign matters, not prop-
erly belonging to the substance of the spinal  marrow or
brain.   But, however difficult it may appear, the inves-
tigation  seems yet to  be practicable.  We know, in the
mean time, that  all  experience 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  cerebral and  nervous  matter,  appears,  at all
events,  improbable.  This substance, moreover,  can-
not be  classed with  ordinary fats, because we find the
cerebric 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 spontane- 
TO THE NERVOUS MATTER.
181
ously inflammable  phosphuretted hydrogen were  disen-

gaged from  the trough of  a spring  in  Carlsruhe,  on

the  bottom  of  which  fish  had putrefied ;  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.)
16 
 
PART III.
         THE





PHENOMENA OF MOTION



        IN THE




  ANIMAL ORGANISM. 
 
THE
PHENOMENA  OF MOTION
                IN THE
     ANIMAL  ORGANISM.
                         I.

   It might appear an unprofitable  task to add one more
 to the innumerable forms  under which the human intel-
 lect  has viewed the nature and essence of that peculiar
 cause, which must be considered as the ultimate  source
 of the  phenomena which characterize vegetable  and
 animal life, were it not that certain conceptions  present
 themselves as necessary deductions from the views on
 this  subject  developed  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  manifestations,
nothing  in common  with  other known  causes  which
produce motion  or change  of form and  structure in
matter.
  But a comparison of its peculiarities with the modus
operandi  of  these other  causes, cannot, at all events,
fail to be  advantageous, inasmuch  as  the nature  and
                lfi * 
1S6            THE PHENOMENA OF MOTION
essence of natural phenomena are  recognisable, not  by
abstraction, but only by comparative observations.
  If the vital  phenomena be considered as  manifesta-
tions 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 pre-
serve in their courses the worlds of our own  and other
systems, and which also determine  changes of form and
structure in  material bodies ;  altogether independent
of the  matter 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, struc-
ture, and composition of  the substance of the tissue in
which  the vital energy resides.
  This force further  manifests itself as a cause  of  mo-
tion 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  conveyed to the living
tissues, in the form of food, are held together.
  The vital  force causes  a decomposition of the con-
stituents of food,  and  destroys  the  force of attraction
which  is continually exerted  between their molecules ;
it  alters the  direction  of the chemical  forces in such
wise, that  the  elements of the  constituents of food  ar-
range  themselves  in another form,  and combine to pro-
duce new  compounds, either identical  in  composition 
IN THE ANIMAL ORGANISM.
187
with the living tissues, or differing from them ; it further
changes the direction and force of the  attraction of co-
hesion,  destroys  the  cohesion  of the  nutritious com-
pounds, and forces the new compounds to assume forms
altogether  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  at-
traction, 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 composition
differs from that  of the living  tissue, are removed 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 anal-
ogous changes.
   The  vital force is manifested in  the form  of resis-
tance, inasmuch as by its presence in the living  tissues,
their elements  acquire the power of withstanding the
disturbance and change in tht.r  form  and composition,
which  external agencies  tend to produce ;  a  power
which,  simply as  chemical compounds,  they  do not
possess.
   As in the case  of other  forces, the  conception of an
unequal intensity  of the  vital  force  comprehends not
only an unequal capacity for growth in the mass, and an
unequal power of overcoming  chemical resistance, but
also an inequality  in the amount of that resistance which 
188           THE PHENOMENA OF MOTION
the parts or constituents 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 external
cause,  mechanical or  chemical, tending  to separate  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 deter-
mined  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  dependent
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.
   The phenomena  of vitality in a  living  organism  di-
minish 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 manifes-
 tations of  vitality. 
                 IN THE ANIMAL ORGANISM.            189
    The contact of the living tissues with the elements of
 nutrition is determined  in  the  animal body by  a  me-
 chanical force produced  within the body,  which gives to
 certain organs the power of causing change  of  place,
 of  producing motion, and of overcoming  mechanical
 resistance.
   W e 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 pro-
 duced 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  gives  them
 the power of resistance  to external agencies ;  it is  the
 vital force.
   In order to attain a clear conception of these mani-
 festations of the vital force,  so different in  form,  we
 must bear in mind, that every known force is recognised
 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 
190
THE PHENOMENA OF MOTION
the senses when the stone, for  example, rests  upon a
table, the particles of which oppose a resistance 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  motion.   The  manifestation of its
gravity  in the state of rest, we call its weight.
   That which  prevents  the  stone from falling is a  re-
sistance  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 acquires motion, or
falls.   Resistance is invariably the  result of a force in
action.
   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  powerful obstacles,
or that of communicating  motion to  bodies  in  a state
of rest.
   If it  fall  from a certain  height it  makes a permanent
impression on the spot on which it falls ; if it fall from a 
                 IN THE ANIMAL ORGANISM.             191
 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,  propor-
 tional 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 fall-
 ing on the  moon, would acquire in one second only a
 velocity of 335°sths of a foot = 1  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 di-
 rectly proportional  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  to the
 pressure multiplied into  the  time, which  is  called  the
 momentum of force.
   In two  equal masses  the velocity expresses the  mo-
 mentum 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 
1 92           THE PHENOMENA OF MOTION
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 sup-
pose that a less pressure acting, for  example, during 10
seconds, is equal  to a pressure ten times greater, acting
only during one second.
   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 lat-
ter has  expended twice  as  much force as the  former.
 A third who  raises  60 lbs. to a height of 50 feet, ex-
pends no  more force than the first did in raising 30 lbs.
to the height of  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,  arc  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
 they 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 displayed to the  senses. 
              IN THE ANIMAL ORGANISM.           193

  Every force, therefore, exhibits itself in matter either
in the form of resistance  to external  causes of motion,
or of change in form  and structure ; or as a moving
force when no  resistance is opposed to. it ;  or, finally,
in overcoming resistance.
   One and the  same force communicates motion  and
destroys motion ;  the  former,  when its manifestations
are opposed  by no resistance ;  the latter, when it puts
a stop to the manifestation of some  other cause of mo-
tion, 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  observe  both these manifestations of activity in
that force which gives  to the living tissues their pecu-
liar  properties.
   The vital  force appears as  a moving force  or cause
of motion when it overcomes  the chemical forces (co-
hesion and affinity) which act between the constituents
of food, and when it changes the position  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 possessed
of vitality, which has,  therefore, the power  of over-
coming  resistance, and  of giving motion to the elemen-
tary particles of the food, by means  of the vital force
                   17 
194
THE PHENOMENA OF MOTION
manifested in itself,  must have a momentum 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 employed  in
giving motion to bodies at rest (that is, in causing  de-
composition, or overcoming resistance), and, if the vital
force is analogous  in its manifestations to other forces,
this  momentum  of motion must be capable of being
conveyed or communicated by matters, which in them-
selves do not destroy its effect  by an opposite manifes-
tation  of force.
   Motion, by whatever  cause  produced, cannot  in it-
self be annihilated ;  it  may, indeed, become inappre-
ciable to the senses,  but, even when arrested  by resist-
ance  (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, pro-
duces an  effect when  it reaches the table.   The im-
pression 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,  equilib-
rium,  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 re- 
IN THE ANIMAL ORGANISM.
195
sistance to external, disturbing influences, to those  of
heat,  or of electricity,  which tend  to  separate their
particles,  as  well as their power  of overcoming resist-
ance  in other compounds (of causing decomposition) ;
that,  in a word,  the  active  force in a compound  de-
pends on  a certain order or arrangement, in which  its
elementary particles 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 resistance.   In  one
form  the force manifested is available (the body is ac-
tive,  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).
   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 op-
 posed  an invincible  resistance  to  the  action of the
 decomposing agent.
   In  the same way as  two equal inelastic masses, im-
 pelled with equal  velocity  from opposite  points,  on
 coming into  contact are brought to rest; in  the same
 way,  therefore,  as two  equal  and  opposite  momenta
 of motion  mutually  destroy each other ; so  may  the
 momentum  of  force  in a chemical  compound be  de-
 stroyed in whole  or  in  part  by an equal, or  unequal,
 and  opposite momentum of  force  in a  second com- 
196
THE PHENOMENA OF MOTION
 pound.   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 disappear,
 to  the senses,  from the action  of a chemical force (in
 solution),  or  of heat (in fusion), without  being  in  re-
 ality annihilated or even weakened.  If we remove  the
 opposing  force or resistance, the force of cohesion  ap-
 pears unchanged in crystallization.
   By means  of the electrical  force,  or  that of heat,
 we can give the most varied directions to the manifes-
 tations  of chemical  force.   By  these means we can
 fix, as  it  were,  the order  in which the elementary
 particles shall  unite.  Let  us  remove the cause (heat
 or  electricity)   which has  turned the  balance in  favor
 of  the  weaker attraction  in  one  direction, and  the
 stronger attraction will  show itself continually active  in
another direction ; and  if this  stronger attraction  can
overcome the  vis  inertias of the elementary 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 
                 IN THE ANIMAL ORGANISM.          197

impeded by other forces,  a blow, or mechanical fric-
tion,  or  the contact  of a  substance, the particles  of
which are in  a state of motion (decomposition, trans-
formation),  or any external  cause,  whose  activity  is
added to the  stronger attraction of the elementary par-
ticles in another direction,  may suffice to give the pre-
ponderance  to this stronger attraction, to overcome the
vis inertias, to alter the form and structure of the com-
pound,  which  are the result  of foreign  causes, and  to
produce the  resolution of the  compound into  one  or
more new compounds 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 chemi-
cal force of another chemical  compound, and  that with-
out  its  manifestation being enfeebled or arrested by
resistance.  Thus the equilibrium in the attraction be-
tween the elements of cane-sugar  is  destroyed by con-
tact 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 influ-
ence, arrange themselves with those  of water in  a new
form, while  the sulphuric acid, which  has  served  to
produce  these transformations, 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-
                   17* 
198           THE PHENOMENA OF  MOTION
called  mechanical forces,  we  have recognised in the
chemical forces causes of motion and of change in form
and structure, without any observable exhaustion 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 mo-
mentum  of force in  a chemical  compound) seem  to
depend on a certain order in which the elementary par-
ticles are united  together, so experience tells us, that
the vital phenomena are inseparable 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 manifestations of vitality disappear.
   There is nothing to prevent  us from considering the
vital force as a  peculiar property, which  is possessed
by certain  material bodies,  and becomes sensible  when
their elementary particles are combined in  a certain ar-
rangement or form.
   This  supposition takes  from  the  vital  phenomena
nothing of their wonderful peculiarity ; it  may  there-
fore 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 depend- 
               IN THE  ANIMAL ORGANISM.             199
ent on  a certain luminiferous matter, or ether, which
has no  further connexion  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 the electrical phenomena.
   The vital  force  does not act,  like the force of gravi-
tation or the magnetic  force, at infinite distances, but,
like chemical forces,  it is active only in the case of im-
 mediate contact.   It  becomes sensible by means of an
 aggregation of material particles.
   A living part acquires, on the above supposition, the
 capacity of  offering  and  of overcoming  resistance, by
 the combination of its  elementary  particles 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 pos-
 sesses, 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 compounds of two
  or more elements, which are  kept together by certain
  chemical forces ; if we  reflect that in the  act of mani- 
200
THE PHENOMENA OF MOTION
festation of force  in a living 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  chemical force which kept the elements together
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 undergone
a change.
   If we  now suppose that a certain amount  of  vital
force must have been  expended  in bringing to an equi-
librium  the chemical  force, there must  still remain an
excess  of force,  by which the  decomposition  was ef-
fected.    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 ac-
quires a permanent power of causing further  decompo-
sitions,  and of retaining its condition,  form, and struc-
ture, in opposition to external agencies.
   We  may  imagine  this  excess  to be removed, and
employed  in some other  form.   This  would not of it-

  * The  hands of a man, who raises, with a rope and simple pulley,
30 lbs. to the height of 100 feet, pass over a space of 100 feet, while
his muscular energy furnishes the equilibrium to a pressure of 30 lbs.
Were the force which the man  could exert not greater than would
suffice to  keep in equilibrium a pressure of 30 lbs., he would be unable
to raise the weight to the height mentioned. 
IN THE ANIMAL ORGANISM.
201
self endanger the existence of the living  part, because
the opposing forces would be left in equilibrio ; but, by
the removal of the excess of force, the part would  lose
its capacity of growth, its  power  to  cause further de-
compositions, and its  ability to resist  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 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.   According 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 chemical
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 entertain  a doubt, that,
with the  combination of the elements 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  pre-
viously existing momentum in the plant; insomuch, that,
with the  increase of  mass, the sum  of  vital force is
augmented.
   According to the  amount of  available vital force, the 
202           THE PHENOMENA OF MOTION
products formed  by its activity from the food are va-
ried.    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-azotized  constituents  of plants we may
assert, that no part of  the  momentum of force is ex-
pended in  maintaining  their form and structure, when
their  elements  have  once  combined in  that order  in
which they become parts of organs endued with vitality.
  Very different is the  character of  the  azotized vege-
table  principles ; for,  when separated from the plant,
they pass, as is commonly said, spontaneously,  into
fermentation  and  putrefaction.   The cause of this de-
composition  or transformation of their elements  is the
chemical action which  the  oxygen  of the  atmosphere
exercises on  one of their constituents.  Now we know,
that,  as  long as  the  plant  exhibits  the  phenomena  of
life, oxygen  gas is given off from its surface ; 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  azotized
principles in the form, order, and structure which be-
long  to  them ;  and   partly as  a  means of resistance
against  the  incessant tendency  of the  oxygen of  the
atmosphere to act on their  elements, as well as against 
               IN THE ANIMAL ORGANISM.           203
that  of the oxygen separated in the  organism of the
plant by the vital process.
  With the increase of these easily  altered compounds,
in the flower and  in the  fruit, for example, the sum of
chemical  force (the free  manifestation of which, coun-
teracted by an equal measure of vital force, is employed
to furnish resistance)  also increases.
  The  plant increases in mass  until the vital  force  in-
herent 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  previ-
ously existing, (a change  of temperature, for example,)
deprives  it of the power of offering resistance,  and it
dies down.
  In perennial plants, (in trees, for example,) the mass
of the easily decomposable  (azotized) compounds, com-
pared  with that  of the non-azotized. is  so  small, that,
of the whole sum of force, only a minimum is  expend-
ed  as  resistance.   In animals,  this proportion  is  re-
versed.
  During every  period of  the life of a plant, the avail-
able vital force (that which is not neutralized  by  resist-
ance) is expended only in  one  form of vital manifesta-
tion, that of growth or increase of  mass, or the over-
coming of resistance.   No part of  this force is applied
to other purposes.
  In the  animal organism,  the vital  force exhibits itself,
as in the  plant, in the form of the  capacity of growth,
and  as the means of resistance  to  external agencies ; 
204           THE PHENOMENA OF MOTION
but both of these manifestations are confined within cer-
tain 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 organs,  and is ef-
fected by a  distinct system of organs,  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, dependent  on  a  second  similar
system of organs or apparatus.  Both of these systems
of apparatus, as well as the phenomena of motion  pro-
ceeding 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 modus oper-
andi of other forces,  which  in their manifestations are
most  closely allied to the vital force.
   When  a  number  of plates of zinc and  copper, ar-
ranged in  a certain order, are brought into contact  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 singu-
lar 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. 
IN THE ANIMAL ORGANISM.
205
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.
  When the wire is divided in the middle, and its con-
tinuity 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 original energy.
  By means of the force  present in  the wire, we  can
produce  the most varied  effects ;  we can overcome 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 hinderance.
  Those properties which,  when firmly  attached  to
certain bodies, we call the strongest and most energetic
affinities, we find, to all appearance, free and uncombin-
ed 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 combination) which in them-
selves they do not  possess.  According to  the amount
of force circulating  in the wire, we are able by means
of it to  decompose compounds, the elements of which
have the  strongest  attraction for each  other,  let  the
substance of the wire takes not  the smallest share in
                   18 
206           THE PHENOMENA OF MOTION
all these manifestations of force ; it is merely the con-
ductor of force.
  We observe, further,  in this wire, phenomena of at-
traction and  repulsion, which we must ascribe to  the
disturbance  of the equilibrium in the  electric or mag-
netic  force ;  and when  this equilibrium is restored,  the
restoration is accompanied by the development of light
and heat, its never-failing companions.
  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  en-
ters into combination  with it.   The  manifestations of
force  produced in  the wire  are  the immediate conse-
quence of the change in the  properties of the acid and
the metal.
  One particle of acid after another loses its peculiar
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 duration
of the latter is most  closely connected with the carrying
away, by conduction, of the force. 
               IN THE ANIMAL ORGANISM.           207
   If we check the propagation of the current of force,
the acid retains its chemical character.   If 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 par-
ticle of acid after another changes its properties.
   In  the preceding  paragraphs  we have considered
these  remarkable phenomena  in  a form which  is inde-
pendent 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 conduc-
tor 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 supposi-
tions  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 ; name-
ly,  that  all  the effects which may be produced  by  the
wire are determined  by the change of properties in  the
zinc and in  the acid ; for the term " chemical action "
signifies  neither more nor less than the act of change in
them ; that  these effects depend on the  presence of a
conductor, of a substance which propagates in all direc-
tions, where it  is  not  neutralized by resistance,  the
force or momentum produced ; that this force becomes
a momentum of motion,  by  means  of which  we can 
208
THE PHENOMENA OF MOTION
produce mechanical  effects,  and which,  when  trans-
ferred to other bodies, communicates to them all those
properties, the ultimate cause of which  is the chemical
force itself; for these bodies acquire the power of caus-
ing 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 gener-
ate the moving power in themselves, but receive it from
other quarters.
   We know with  certainty that the nerves are the con-
ductors  and  propagators  of  mechanical  effects ;  we
know, that by means of them  motion  is propagated  in
all  directions.  For each motion we recognise a sep-
arate  nerve, a peculiar conductor, with the conducting
power of which, or with its interruption, the propagation
of motion is affected or destroyed.
   By means of the nerves all  the parts of  the body, all
the limbs, receive the moving force which is indispen-
sable  to their functions, to change of place, to  the pro-
duction 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  organ cannot pro- 
               IN THE ANIMAL ORGANISM.            209
 duce 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 consume in itself.
   We  observe further, that  the voluntary and involun-
 tary motions, in  other words, all  mechanical effects in
 the animal organism, are accompanied by, nay,  are de-
 pendent 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 measures  of  motion,  or  the amount of
 force consumed in the motions performed.
   As  an immediate effect of the  manifestation  of me-
 chanical force, we see, that  a part of  the muscular sub-
 stance loses its vital  properties,  its  character 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
 experience  proves, that this conversion of living  mus-
 cular fibre into compounds destitute of vitality is accel-
 erated or retarded, according to the amount of force
 employed to produce motion.  Nay, it may safely be
affirmed, that they  are  mutually  proportional ;  that a
rapid transformation of muscular fibre, or, as it may be
called, a rapid  change of matter, determines a  greater
                18* 
210
THE PHENOMENA OF MOTION
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 consumed in
mechanical motion, no other conclusion can be drawn
than 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  ex-
ternal causes of  change.   It is obvious that the  ultimate
cause, the vital  force, from which they acquired those
properties, has served for  the production of mechani-
cal  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 conveyed
to it by the arterial blood, and  should  be  deprived
of the power to overcome  chemical resistance, unless
the  momentum of the vital force, which  had  given to
it all these  properties,  had been  expended for other
purposes ?
  By  the  power  of  the  conductors,  the  nerves,  to 
IN THE ANIMAL ORGANISM,
211
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 direc-
tions where the force, or rather its momentum of mo-
tion, is consumed without resistance (for without motion
no  change  of matter  occurs,  and when  motion has
begun, there is no  longer resistance), 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 exerting
an  influence on the form, structure, and  composition  of
the organ meets with no  further resistance.   If oxygen
were  not  conveyed to it, the organ would  maintain  its
condition, but without  any manifestation of vitality.  It
is only with the commencement 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 mechani-
cal 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 quan-
 tity 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 of vital force consumed as me-
 chanical force, an  equivalent of chemical force is  mani-
 fested ; that is, an  equivalent of oxygen  enters  into 
212
THE PHENOMENA OF MOTION
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 oxidized compound.
   All  those  parts of the  body which nature has des-
tined  to effect the change of matter, that is, to the pro-
duction of mechanical force, are penetrated in all direc-
tions by a multitude of the most minute tubes or vessels,
in which a current of oxygen continually 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 disturbance of their equilibrium, this
oxygen is absolutely essential.
   As  long as the vital  force of these parts is not con-
ducted 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 con-
ducting power,  and, consequently, to the mechanical
effects produced.
   The  oxygen of the atmosphere is the proper,  active,
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 chemical  agent, the dis-
turbance proceeding from it, is held in  equilibrium by
the vital force, which is free and available in the living
tissue, or  is annihilated  by a  chemical agency opposed 
               IN THE ANIMAL ORGANISM.            213
to that of oxygen, the manifestation of which  must be
considered as dependent on the vital force.
   In  chemical  language, to annihilate the chemical ac-
tion 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 neutralized
by means  of the  elements  of organized  parts, which
combine with it (after the free vital force has been con-
ducted  away), or else the organ presents to it the pro-
ducts 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 chemical action
of oxygen, and neutralizes  it completely.
   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  pro-
 cess, affect, in all  cases, only their surface.
   The gelatinous tissues, mucous membranes,  tendons,
 &c, are  not designed to  produce mechanical force;
 they contain  in their substance no conductors of me-
 chanical   effects.   But the  muscular  system  is  inter-
 woven 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 con- 
214
THE PHENOMENA OF MOTION
tains no organs for conducting away the moving power.
Cellular  tissue,  gelatinous  membranes,  and   mucous
membranes, are far  from being destitute of the power
of combining  with  oxygen, when  moisture is present;
we know that, when moist,  they cannot be  brought  in
contact with oxygen without undergoing  a progressive
alteration.  But one surface of the intestines  and the
cells of  the lungs  is  constantly in contact with oxy-
gen ;  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  resistance, 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 influ-
ence  of  the vital force, and which surpass  the  tissues
above-mentioned  in  their  power  of  neutralizing  its
chemical  action.
   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
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. 
               IN THE ANIMAL ORGANISM.            215
  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  oxygen
which are  indispensable  to  their  preservation.  Ac-
cording to  the rapidity of this  process, the quantity of
bile secreted increases ; while that of the fat present in
the body diminishes in the same proportion.
  For carrying  on the involuntary motions in the  ani-
mal  body, a certain amount of vital  force is expended
at every moment of  its existence ; and, consequently,
an incessant change of matter goes on ;  but the  amount
of living tissue, which,  in  consequence of this  form of
consumption of vital  force,  loses its condition  of life
and its capacity  of growth,  is  confined within  narrow
limits.  It is directly proportional  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 apply
to those parts of  the  body whose  available vital force 
21Q           THE PHENOMENA OF MOTION
has been  expended  in producing  mechanical effects.
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 ex-
pended,  a corresponding portion of muscle diminishes
in volume ; it  is obvious, that an equilibrium between
supply and toaste of matter (in living tissues)  can only
occur when the portion separated or expelled  in a life-
less  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 depends
on the momentum  of force belonging to each  part ;
and  must be  capable of continued  manifestation (if
there  be  a sufficient supply  of  nourishment), as long
as it does not lose this momentum, by expending  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.
   A living part cannot increase in volume at the same
 moment  in which  a portion of it  loses  the vital con-
 dition, 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 determines, there-
 fore,  a continued  separation of matter ;  and  only from 
IN THE ANIMAL ORGANISM.           217
the period at which the cause of waste ceases to oper-
ate, can the capacity of growth  be  manifested.
   Now, since, in different individuals, according to the
amount of force consumed  in producing voluntary me-
chanical  effects,  unequal quantities of living  tissue are
wasted, there  must occur,  in  every individual, unless
the phenomena of motion are to cease entirely, a con-
dition  in  which  all voluntary  motions  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 vol-
ume,  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,
if  the original equilibrium is  to be restored, we must
suppose,  that, during  sleep, an amount of force is accu-
mulated  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 mat-
 ter be in the least degree disturbed,  this is instantly
 seen  in  the different  amount of force available  for me-
 chanical  purposes.
                     19 
218
THE PHENOMENA OF MOTION
  It is further obvious, that, if there should occur a dis-
proportion between the conducting power of the nerves of
voluntary  and involuntary motion, a  difference 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 circulat-
ing  system  and of the intestines increase, the power of
producing mechanical  effects in  the limbs must diminish
in the same proportion (as in wasting fevers) ;  and if, in
a given  time, more  vital force  has been  consumed  for
mechanical  purposes  (labor,  running, dancing,  &c.)
than is properly available for the voluntary and  involun-
tary motions  ; if force be  expended  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  in-
voluntary motions  must  be  expended in restoring the
excess of  force consumed in  voluntary  motion.  The
motions 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.   Paralysis of
the nerves  of voluntary motion  may exist without ema-
ciation ; but  frequently recurring attacks  of  epilepsy  (in
which vital force  is  rapidly wasted  in  producing me-
chanical effects) are always accompanied by remarkably
rapid emaciation.
   It ought to excite the highest admiration when we 
IN THE ANIMAL ORGANISM.
219
consider with what infinite wisdom the Creator has di-
vided the means  by which animals and  plants are quali-
fied  for their functions, for their peculiar vital  manifes-
tations.
   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 attractions, to de-
compose 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 ef-
fects  are not  propagated to  a  distance, owing to  the
absence of conductors of  force.
   The same vital force, which we recognise 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  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 tissue.   The expenditure of  force which the
living parts of  animals require,  in  order to reproduce
themselves from the  blood ; the  resistance of the chem-
ical  force which  has to be overcome  in  the  azotized
constituents of food by the vital agency of the organs
destined to convert them into  blood ;  these are  as noth-
ing compared to the force with which  the elements of 
220           THE PHENOMENA OF MOTION
carbonic acid are held together.   A certain  amount of
force would necessarily be prevented from assuming 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 diminished  by all obstacles.
But  the  conversion  of  the  constituents  of blood into
muscular fibre (into an organ which generates force) is
only a change of form.   Both have the same composi-
tion ; blood is fluid, muscular 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 op-
pose that force (cohesion),  which determines the form
of matter, in its manifestations.
   In what form or in what  manner the vital  force pro-
duces mechanical effects  in the animal body is altogether
unknown, and is as little to be ascertained  by experiment
as the connexion of chemical action with the phenome-
na of motion which we  can produce with  the galvanic
battery.  All the explanations which have been attempt-
ed are only representations  of  the  phenomenon ;  they
are,  more  or less, exact descriptions and  comparisons
of known  phenomena with  these, whose cause is  un-
known.   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 connex-
ion with the turning and  motion of a thousand wheels at
a distance from the piston-rod, appear incomprehensible. 
IN THE ANIMAL ORGANISM.
221
  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 phenomena
exhibited by living bodies.  The cause  of these  phe-
nomena  is not chemical force ; it is not electricity, 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  substances.  It is  a peculiar
force, because it exhibits manifestations which are found
in no other known force.
                         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  appear,
which the vital force  supplies to  leaves charged with
oil  of turpentine or tannic acid, when we consider the
affinity of oxygen for these compounds !
                   19* 
222           THE PHENOMENA OF MOTION
   This intensity of action or of resistance the plant ob-
tains by means of the sun's light; the effect of which in
chemical actions  may be, and is, compared to that of a
very high temperature (a moderate  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 conclusion
than 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  established, and that in
complete darkness all  those constituents of plants which,
during  the day, possessed the power of separating oxy-
gen from chemical combinations, and of resisting its ac-
tion, lose this power completely.
   A  precisely similar phenomenon is observed in ani-
mals.
   The living animal body exhibits its peculiar manifes-
tations of vitality only at certain temperatures.  When
exposed  to  a certain degree of  cold, these vital phe-
nomena 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  tempera-
tures, in the  same  ratio  in which  the tendency of the
elements of  the body to combine with  the oxygen of
the air increases. 
IN THE ANIMAL ORGANISM.
223
  By the combination of oxygen with the constituents
of  the  metamorphosed  tissues,  the temperature ne-
cessary to  the  manifestation of  vitality  is  produced
in the carnivora.   In  the herbivora,  again,  a  certain
amount of heat is  developed by  means of  those  ele-
ments of their non-azotized food, which  have the prop-
erty of combining with oxygen.
  It is obvious, that the temperature of  an animal body
cannot change,  if  the  amount  of inspired oxygen in-
creases in the same ratio as the loss of heat by external
cooling.
   Two  individuals,  carnivora, of  equal  weight, ex-
posed to unequal degrees of cold,  lose, in a given time,
by  external  cooling, unequal quantities of heat.   Ex-
perience teaches, that, if their peculiar temperature and
their original weight are  to remain unaltered, they re-
quire 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
proportional 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, aquan-
 tity of the constituents of the  body,  equal in weight to 
224           THE PHENOMENA OF MOTION
those of the food, has lost its condition  of life, and  has
been expelled in combination 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 combination
with oxygen ; and,  in consequence  of this  combination
with  oxygen, a  greater  amount of heat has been  lib-
erated,  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
there be a full supply of food and free access  of  oxy-
gen,  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 mechanical  purposes.
   With  the  external cooling, the  respiratory  motions
become stronger ; in a lower temperature more  oxygen
is conveyed to the blood ; the waste of matter increases,
and, if the supply be not kept  in equilibrium with this
waste, by means of food, the temperature 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 
IN THE ANIMAL ORGANISM.
225
of oxygen are in equilibrium together, that the tem-
perature  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 temperature must be consid-
ered as a  uniform condition of their manifestation.
   Now experience teaches, that, when the temperature
of the body sinks, the power of  the  limbs to produce
mechanical effects (or the force  necessary to the vol-
untary motions) is also  diminished.   The condition of
sleep ensues, and at last even the  involuntary 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, because,
with the abstraction of heat, as in the plant by abstrac-
tion of  light, the intensity of the  vital force diminishes.
It is obvious  that the  momentum of force  in a living
part depends on its proper temperature ;  exactly as the
effect of  a falling body stands in a fixed relation to cer-
tain other conditions  ; for example, to the velocity at-
tained in  falling.
   When  the temperature sinks, the vital  energy dimin-
ishes ; when  it again rises,  the momentum of force in
the living parts appears once more in all  its original in-
tensity.
   The  production of force  for  mechanical purposes,
and the  temperature  of  the  body, must, consequently, 
226           THE PHENOMENA OF MOTION
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 carri-
er's horse can  inspire in a given time are very unequal.
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 surrounding
medium, and the force   exerted  by a carrier'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 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 consequence
of the respiration of a highly  rarefied atmosphere, 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, unorganized compounds ; but the 
               IN THE ANIMAL ORGANISM.           227
whole of the inspired  oxygen  is not  applied to these
transformations ; the greater part serves to convert into
gas and vapor all matters which no longer belong to the
organism ;  and, as formerly mentioned, the combination
of the elements of such compounds with the oxygen
produces the temperature proper to the animal organism.
   The production of heat and  the change of matter 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 cannot  be
supposed  to  take  place   without the cooperation  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
vapor permeates animal membranes  and tissues, alcohol
can spread throughout the body in all directions.
   If the power of the elements of  alcohol to  combine
with oxygen were  not greater  than  that of the com- 
228           THE PHENOMENA OF MOTION
pounds formed by the change of matter, or that of the
substance of living tissues, they  (the elements of alco-
hol) could not combine with oxygen in the  body.
  It is, consequently, obvious, that by the  use of alco-
hol a  limit must  rapidly be put to the change of matter
in certain parts of the body.   The oxygen of the arte-
rial blood, which, in the absence of alcohol, would have
combined with the matter of the tissues, or with that
formed  by  the  metamorphosis  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 development of heat in
the body, after the use of wine, increases rather than
diminishes, without the manifestation of a corresponding
amount of mechanical force.
   A moderate quantity of wine, in women  and children
unaccustomed to its  use, produces, on the contrary, a
diminution of the force necessary for voluntary motions.
Weariness,  feebleness  in the  limbs, and drowsiness
plainly show that the force available for mechanical pur-
poses, 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 
IN THE ANIMAL ORGANISM.
229
nerves  of involuntary  motion,  and conveyed  to  the
heart,  lungs, and intestines.   In this case, the circula-
tion will appear accelerated at the expense of the force
available  for voluntary  motion ;  but, as  was before re-
marked, 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,
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 conse-
 quence of the low temperature and of the diminution of
 vital energy thus produced ; in others, the  involuntary
 motions continue, and the animal preserves a tempera-
 ture independent of the surrounding temperature.   The
 respirations go on ; oxygen, the condition which deter-
 mines  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 re-
 sistance.
    If we  now suppose that  the oxygen absorbed during
 the  winter  sleep combines, not with  the  elements  of
 living tissues,  but with those of the fat, then  the living
                    20 
 230          THE PHENOMENA OF MOTION
 part, although  a certain momentum of motion be ex-
 pended in keeping up the circulation, will not be  sep-
 arated and expelled from the body.
   With  the  return of the higher temperature,  the ca-
 pacity of growth increases  in the  same ratio, and the
 motion of the  blood increases  with the absorption  of
 oxygen.   Many  of these animals  become  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 hybernation,  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 such wise that no force  shall  remain avail-
 able for  the  involuntary motions.   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 becomes  uneatable.   The   con-
dition 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 destroyed.
   But, however closely the  conditions of the produc- 
IN THE ANIMAL ORGANISM.
231
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 considered as
in itself the only cause of these effects.
   All experience proves that  there is, in the organism,
only one source of mechanical power ;  and this 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 determined by
the mutual action  of opposed forces ; of which one class
must be considered  as  causes of increase (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  de-
pendent on heat; that is, on a  certain  temperature pecu-
liar to each specific organism.
   The cause of waste of matter  is the chemical action
of oxygen  ; and  its  manifestation is  dependent  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  absorp-
 tion 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 chemical action ;  and
 this  weaker resistance is determined by  the abstraction of 
232           THE PHENOMENA OF MOTION
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 necessary
for the manifestation  of vital activity is produced.
  From  the relations between the consumption of oxy-
gen on  the one hand, and the change  of  matter and
development on the other,  the following 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 purposes
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 ex-
pended,  this determines the absorption of corresponding
and unequal quantities of oxygen.
  For the conversion of living tissues into lifeless com-
pounds,  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 mechanical
force can be manifested, and  only a limited amount of
heat can  be liberated. 
IN THE ANIMAL ORGANISM.
233
  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 force produced in a 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,  intes-
tines, &c, require for their motions is lost to  the volun-
tary motions.
  The amount of azotized  food necessary  to restore
the equilibrium  between waste  and supply is directly
proportional to the amount of tissues metamorphosed.
   The  amount of living matter, which in  the  body
loses  the condition of life,  is,  in  equal  temperatures,
directly proportional to the  mechanical effects produced
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  proportional  to
the amount of nitrogen in their urine ; whether the me-
chanical force has been  employed in voluntary or invol-
untary 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 in-
cludes the conception  of an equilibrium  among all the
causes of waste  and  of supply ; and thus animal life  is
                 20* 
234           THE PHENOMENA OF MOTION
recognised 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  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, correspond-
ing to the sum of living particles.
  Growth,  or  the  increase  of mass, stands,  at every
age, in a fixed  relation to the amount of vital  force  con-
sumed as moving power.
   The  vital force,  which is expended for mechanical
purposes, is subtracted from the sum of the force avail-
able 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 produce  me-
 chanical effects.
   Hence it follows necessarily, that, when, as in child-
 hood, the supply exceeds  the waste  of matter, the  me-
 chanical  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 pro-
 portion.
   A perfect  balance between the consumption of vital
 force for supply of matter and  that for  mechanical ef-
 fects occurs, therefore, only in the adult state.   It is 
               IN THE ANIMAL ORGANISM,            235
at once recognised in the complete supply of the matter
consumed.  In  old  age more is wasted ; in childhood
more is supplied than wasted.
   The force  available for  mechanical purposes in an
adult man is reckoned, in mechanics, equal to |th 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 dis-
tance of 72,000 feet.   For  every second his  momen-
tum  of force  is= 30X2-5 =75  lbs.;  and  for  the
whole day's work, his momentum of motion is = 30 X
72,000 = 2,160,000.
   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  happens
that  the pressure of the engine, going at its  ordinary
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 gradually loses the  velocity it
had acquired.   What the wheel gained in velocity, the 
236
THE PHENOMENA OF MOTION
roller gained in force ; by this process force was ob-
viously collected, accumulated in  the velocity ;  but  in
this sense force does not accumulate in the Jiving or-
ganism.
   The restoration  of  force is effected, in the  animal
body, by the transformation of the separated parts, des-
tined  for  the production of force, and  by the expendi-
ture  of the  active  vital  force in causing formation  of
new parts ; and, with the restoration of the separated  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
waking 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 laboring  man, with sufficient
food, recovers, in seven hours' sleep, the whole  sum  of
force ; and, without reckoning the force necessary  for
the involuntary motions, which may be considered equal
in all men,  we may assume  that the mechanical force
available for work is directly proportional 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 
IN THE ANIMAL ORGANISM.
237
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  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 4 ;  the active force consumed  in  the formation of
new parts is, in this case, to  that consumed in mechani-
cal 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 available in
the  adult, then the mechanical  effects  are proportional
to  the number of waking  hours, the formation of new
parts to  the number of hours  of  sleep, and  we shall
have :
              Force expended            Force expended in
            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 equilib- 
238           THE PHENOMENA OF MOTION
rium  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 (24 : 286)
          In the old man  .  = 125 :  50 (118 :  43)
Or the increase of mass to the  diminution of waste :
          In the adult man  =100 : 100
          In the infant .  .  =100 :  10  (9)
          In the old man  .  = 100 : 250 (274)
  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 ve-
locity of 2\ feet in  the second ; but he  will  be able,
without  injury, to carry 6 lbs. to the same  distance.
  In the infant the increase is to the decrease as 10 to 1,
and consequently, if we in his  case increase the expen-
diture 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,  in-
deed, 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 
                IN THE ANIMAL ORGANISM.            239
 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 supervenes.
   With every hour of  sleep  the  sum of available  force
 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 labor, it will  be
 available for involuntary motions.  If the motion of the
 heart, of  the fluids, and of the  intestines (the circula-
 tion  of  the blood and digestion)  be  accelerated  in
 proportion  to  the  amount  of force not consumed   in
 voluntary motions,  the  weight of the  body will neither
 increase nor diminish  in 24 hours.   The body, there-
 fore,  can only increase in mass, if the force accumulated
 during  sleep, and available  for  mechanical  purposes, is
 employed neither for voluntary nor for involuntary mo-
 tions.
   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 temperature.
 In a different  temperature, and with deficient nourish-
ment, 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 oc-
curs, more or  less  quickly, in consequence of the  loss 
 240           THE PHENOMENA OF MOTION
 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
 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 admit
 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  equilibrium 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 movable, 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  pressure.   When this  excess of  force
has been consumed in motion, it cannot  be raised  high-
er ;  but, if new vapor 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 
IN THE ANIMAL ORGANISM.
241
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
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 disengagement
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 ele-
ments  of the metamorphosed  tissues, has recovered its
original temperature, the resistance  of its living  parti-
cles 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  continue to operate,  a  larger
amount of  vital force becomes available for mechanical
purposes.
   Let us  now  suppose that heat is abstracted  from the
whole  surface of the 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
                   21 
242               THEORY OF DISEASE.

brought to them in larger quantity than usual, will be
expelled from  the body in the form of oxidized com-
pounds.
                         III.
                THEORY  OF DISEASE.
  Every substance or  matter, every  chemical or  me-
chanical  agency, which changes or disturbs the restora-
tion  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 disturb-
ance (in other  words,  when the  resistance offered by
the vital  force),  is weaker than the  acting  cause  of
disturbance.
  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  con-
tinue 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  period
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. 
THEORY  OF DISEASE.
243
  It is evident  that one and  the same cause of  disease
will  produce  in the  organism very  different effects,
according  to  the period of  life ;  and that  a  certain
amount of disturbance, which produces disease in the
adult state, may be without influence  in  childhood or
in old  age.   A cause  of disease may, when it is added
to the cause of waste  in old age, produce  death (anni-
hilate  all  resistance on the part of  the  vital  force) ;
while  in the adult  state it  may produce only a dispro-
portion 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 matter
which  follows the  cooling  ; while  a  high  temperature,
which  impedes  the change of matter, is  followed by
disease.
   On  the other hand, we  see,  in  hospitals and chari-
table  institutions (in  Brussels, for example) in which
old  people spend  the last  years of life, when the  tem-
perature of the dormitory,  in  winter, sinks two  or three 
244
THEORY OF DISEASE.
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 symptons of dis-
ease, or of the usual recognisable causes of death.
   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  dependent 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 car-
ried  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. 
THEORY OF DISEASE.               245
   This state is called a febrile paroxysm.
   In consequence of the acceleration of the circulation
in the state of fever,  a greater amount of arterial blood,
and, consequently, of oxygen, is  conveyed to the dis-
eased  part, as well as to  all other parts ;  and, if the
active force in the healthy parts 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  re-
 sistance  offered  to  the  external  causes of change in
 these parts by the vital force.   The physician succeeds
 in putting  an end to the original diseased  condition,
                  21* 
246               THEORY OF DISEASE.
 when the disturbance, artificially excited,  (or  the dim-
 inution of resistance in another part,) exceeds in amount
 the diseased state to be overcome.
    The  accelerated  change of matter and  the  elevated
 temperature  in  the  diseased part show that the resis-
 tance offered  by the vital  force to the action of oxygen
 is feebler than in the healthy state.  But this resistance
 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,
fjeing 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 action of
oxygen,   by any  means, that it  becomes  inferior to  the
resistance offered by the  vital force, which,  although
enfeebled, has never ceased to act; for this proportion
between  these  causes of change is the uniform  and ne-
cessary condition of  increase of mass  in  the living or-
ganism.
   In cases of a different  kind, where  artificial exter-
nal disturbance produces  no  effect,  physicians adopt
other indirect  methods to  exalt the resistance  offered 
                  THE0RV OF DISEASE.              247
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.   They  diminish,  by blood-
letting, the  number of  the  carriers of  oxygen  (the
globules), and  by this means the condition of change of
matter ;  they exclude from the food all  such  matters as
are capable of  conversion into blood ; they give chiefly
or entirely non-azotized  food, which supports the respi-
ratory process, as well  as fruit and  vegetables, which
contain the alkalies necessary for the secretions.
   If they 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 they accomplish  this without arresting  the functions
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 
248               THEORY OF DISEASE.
 amount of oxygen acting  on them  in  the  blood is di-
 minished.   In the sensation of hunger, this  resistance,
 in a certain  sense, makes  itself known ;  and the  pre-
 ponderating vital force exhibits itself, in many patients,
 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  functions 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 ne-
 cessary to  the  performance of the functions  of the other,
 — then the diseased 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  reflect  that
 it behaves, in  all  its manifestations, exactly like other
 natural forces  ; that it is devoid of consciousness or of
 volition, and is subject to the action of a blister.
  The nerves, which accomplish  the voluntary and  in-
 voluntary  motions in the  body, are, according  to  the
 preceding  exposition, not  the producers,  but only the
 conductors of the vital force ;  they propagate  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 pre-
cisely analogous manner.   They permit the  current to
traverse them, and present, as conductors of electricity, 
                  THEORY OF DISEASE.              249
all the phenomena which they  exhibit as conductors of
the vital force.   In  the present state of our knowledge,
no one, probably, 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 con-
tact with  the  body,  produces  a current of electricity,
cannot  be denied.   For to the existing  force of motion
or of disturbance there  is added, in  the electrical cur-
rent,  a  new cause of motion and of change  in  form and
structure, which cannot be considered as altogether in-
efficient.
   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 con-
ditions 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 metamor-
phosis  of the brain.   When  this  condition  continues
beyond a certain  time,  experience  teaches that all mo-
tions  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 contin-
 ues ; the metamorphosis, which decides the issue of the
 disease, is limited to a short period.  We  must not for-
 get  that  the  ice melts  and  absorbs heat from the dis- 
250               THEORY OF DISEASE.
eased part;  that, if the ice be removed before the com-
pletion  of  the metamorphosis,  the  temperature again
rises ;  that far more heat is removed by means of ice
than  if we were  to surround the head with a bad  con-
ductor 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 deter-
mined  a more rapid change of matter.
   The self-regulating steam-engines,  in which, to  pro-
duce a uniform motion, the  human intellect has shown
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
steam  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 arrange-
ment  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 machine  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 vapor, or the force, so to speak, is  pro-
duced  by the  change  of matter,  by  the combustion
of coals in  the fireplace.   The  force increases  (the 
                  THEORY OF DISEASE.              251
amount of steam  generated, and  its tension increase)
with the temperature  in  the fireplace, which depends
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 diminished.  When the engine goes
slower, more steam is admitted to the cylinder, its ten-
sion  diminishes, the air passages  are opened, and  the
cause of disengagement of heat (or production of force)
increases.    Another  arrangement  supplies the  fire-
place incessantly with coals in  proportion as they are
wanted.
   Tf we now lower the temperature  at any  part of the
boiler, the tension within  is  diminished ;  this is immedi-
ately seen  in the regulators  of force,  which act precise-
ly as if we had removed from the boiler a certain quan-
tity of steam (force).   The regulator and the air  pas-
sages 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 respira-
tions become deeper  and  more  frequent ;  oxygen is
supplied in greater quantity and of greater density ;  the
change of matter is increased ; and  more food must be
supplied,  if  the temperature of the body is to  remain
unchanged. 
 252             THEORY OF DISEASE.
   It is hardly necessary to mention, that, in the  body,
 the tension  of vapor 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 preced-
 ing pages, it follows obviously that a diseased condition,
 once  established in any  part  of the  body, cannot  be
 made  to disappear  by  the chemical action of a remedy.
 A limit may be put by a remedy to  an  abnormal process
 of transformation ;  that process may be accelerated  or
 retarded ; but this  alone does  not  restore the normal
 (healthy) condition.
   The art of the physician  consists in the  knowledge of
 the means which enable him to exercise an influence  on
 the duration of the  disease ; and in the  removal of  all
 disturbing causes, the  action of which strengthens  or in-
 creases 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 inflammatory diseases,
and  in highly  muscular  subjects,  the   antiphlogistic
treatment has  a very high value ; while in other  cases
blood-letting produces unfavorable results.  The vivify-
ing agency of the blood must  ever  continue to be the
most  important  condition  in the  restoration of a dis-
turbed equilibrium,  which result is always dependent on
the saving of time  ; and  the blood  must,  therefore, be 
THEORY OF RESPIRATION.
253
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 exanthemata
is accompanied by fever, two diseased  conditions simul-
taneously  exist, and two processes are simultaneously
completed ;  and that the  blood, as it were by reaction
(that is, fever), becomes a means of cure,  as being the
carrier of that  substance (oxygen) without the aid of
which  the diseased products cannot be rendered harm-
less, 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 color ; and, with this
change of color,  oxygen  is absorbed  from the atmos-
phere.   Further, for every volume of oxygen absorbed,
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.
                22 
254            THEORY OF RESPIRATION.
  Whatever change the other constituents of the blood
undergo  in the lungs, thus much is  certain, that the
globules of venous blood experience a change of color,
and that this change depends  on the action of oxygen.
  Now we observe that the  globules of arterial blood
retain their color in the  larger vessels, and  lose it only
during their passage through the  capillaries.   All those
constituents of venous blood,  which are capable of com-
bining with oxygen, take up a corresponding quantity of
it in the lungs.  Experiments made with arterial  serum
have shown, 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 ab-
sorbed ;  and a  corresponding quantity of carbonic acid
is formed.
  It  is evident that  the change of color 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, Woh-
ler,  und  Liebig," p.  877.) 
THEORY OF RESPIRATION.            255
  Arterial blood, when drawn from the body, is soon
altered;  its florid color becomes  dark red.  The florid
blood, which owes  its color to the globules, becomes
dark by the action of carbonic acid, and this change of
color affects the globules, for florid blood  absorbs a
number of gases which do  not dissolve in the fluid part
of the blood when  separated from  the globules.   It is
evident, therefore,  that the globules have the power of
combining with gases.
   The globules of the blood change their color in dif-
ferent 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 color cannot, 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  carbonic
acid.  The same thing takes place  in nitrous oxide.  It
is clear  that they have here undergone  no decompo-
sition, and  consequently  they possess  the  power of
combining with gases, while the compound  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 color 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 unquestionably neces- 
256            THEORY OF RESPIRATION.
sary to  animal  life ;  and,  since physiology has  proved
that the globules take no  share in the process of nutri-
tion, it cannot  be  doubted that  they play a part in the
process of respiration.
   The compound  of iron in the globules has  the char-
acters of an oxidized compound ;  for it is  decomposed
by sulphuretted hydrogen, exactly in the  same way as
the oxides  or other analogous compounds 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 coloring matter of the blood.
   The characters of the compounds of iron  may, per-
haps, assist us to explain the share which that metal
takes in the respiratory process.   No other metal  can
be compared with  iron, for the remarkable properties of
its compounds.
   The  compounds of protoxide  of iron  possess  the
property of  depriving  other  oxidized  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 carbonate
of the protoxide.
   Carbonate  of protoxide of iron, in contact with wa-
ter and  oxygen, is decomposed ;  all the carbonic  acid
is given  off, and, by absorption of oxygen,  it passes in-
to  the hydrated peroxide, which may again be convert-
ed into a compound of the protoxide. 
THEORY OF RESPIRATION.
257
  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 organic ele-
ments 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 color.
  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 passage through
the  capillaries.    The same  thing  occurs when it  is
separated from the body,  and begins to undergo decom-
position  (to putrefy).  The compound, rich in oxygen,
passes, therefore, by the loss of  oxygen  (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 pos-
sesses 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 carbonic acid, combine with that substance.
   When  the  globules reach  the lungs,  they will again
take up the oxygen they have lost; for every volume of
oxygen absorbed, a corresponding volume of carbonic
acid will be separated ; they will return to their  former
state ; that is, they will again acquire the power of giv-
ing off oxygen.
                 22* 
258
THEORY OF RESPIRATION.
  For every volume of oxygen which  the globules  can
give off, there will be  formed (as carbonic acid con-
tains  its  own volume of oxygen, without condensation)
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  ab-
sorption  of oxygen,  passes into the hydrated peroxide,
there  are given off, for every volume of oxygen neces-
sary  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.  Con-
sequently,  the substance or compound, which  has  lost
its  oxygen, during  the passage of arterial into  venous
blood, must have been capable of  absorbing or com-
bining with carbonic  acid ; and  we find,  in point of
fact, that the living  blood is never, in any state, satu-
rated  with carbonic  acid ; that it is capable of taking
up  an additional  quantity,  without  any  apparent disturb-
ance  of  the function of the  globules.   Thus,  for ex-
ample, after drinking effervescing  wines, beer, or min-
eral 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 ex- 
THEORY OF RESPIRATION.             259
pended, otherwise  than in the  formation  of  carbonic
acid, the  amount of this  latter gas expired will corre-
spond exactly with that which has been  formed ;  less,
however, will be given out after the use of fat and of
still wines,  than after champagne.
   According  to the views now developed,  the  globules
of  arterial  blood, in their passage through the capilla-
ries,  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  com-
pounds, as  well as the formation  of the secretions and
excretions.   The greater  part, however,  of the  oxy-
gen is employed  in converting into oxidized 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 between this  carbonic
acid and the oxygen of the atmosphere.*

   * Since the publication of the first edition of this work,  the follow-
ing conclusions, from some researches by MM. Andral and Gavarret,
have been published in the Comptes rendus des Seances de  VAcade'mie
des Sciences for January 16th, 1843.  They tend to confirm the the-
ory of the formation of carbonic acid in the system, and  not in the
lungs.
   " 1st.  The  quantity of carbonic acid exhaled by the lungs in a given
time  differs  according  to age, sex, and constitution, in different
persons.
   " 2d. At all ages between eight years and the most advanced, there 
260              THEORY OF RESPIRATION.

   The organic  compound  of iron,  which exists in  ve-
nous 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
lungs,  like the globules, into more highly oxidized com-
pounds ; a  certain amount of  carbonic  acid is formed,
of  which a part always  remains dissolved in the serum
of  the  blood.

is a difference in the quantities exhaled by males and  females. Be-
tween the ages of sixteen and forty, man exhales about twice as much
as woman.
  " 3d. In man, the quantity exhaled increases regularly from eight
to thirty years of age, increasing very suddenly at puberty.  After
the age of thirty,  it commences decreasing, till the extreme of life,
when the exhalation is no more than at ten years of age.
  " 4th. In woman, however,  there is a marked exception after the
age of puberty, till which period she follows the same  law as man.
As soon as the catamenia appear, the exhalation of carbonic acid no
longer increases; and, while  the menstrual periods maintain  their
regularity, this exhalation is only a little more than in infancy.  As
soon, however, as the menses are suppressed, the increase of exhala-
tion is very remarkable; but, as  old age comes on, woman again fol-
lows the same rule as man.
  "5th. During pregnancy the exhalation of carbonic acid by woman
is increased.
  " 6th. In both sexes, and at  all ages, the quantity of carbonic acid
exhaled  by the lungs  is greater  in proportion to the strength of the
constitution, and the development of the muscular system."
  The experiments, from which  the  above conclusions were drawn,
were carefully performed at the  same hour of the day, between  one
and  two o'clock, and at a regular time after the subjects had  eaten.
— W. 
THEORY OF RESPIRATION.
261
  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 temperature  ;
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  evaporation
which  takes  place there,  the constant temperature  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
mis = 1-99 cubic mcn of  oxysen-
   In  one minute,  therefore, there are added  to the
constituents  of the  blood  18  X  1-99 = 35-8  cubic
inches of oxygen, which, at  the ordinary  temperature,
weigh  rather less than 12 grains  (12-2 Eng.).
   If we now assume, that in  one minute 10 lbs. of blood
pass  through the  lungs  (Muller,  Physiologie, vol.  i.
p. 345),  and  that  this  quantity of blood  measures 320 
262            THEORY OF RESPIRATION.
cubic  inches, then 1 cubic inch of oxygen unites with
9 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*44  grains of peroxide of
iron, in arterial blood, = 55*30 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*30 grains  of  protoxide  of  iron, in  passing
through the lungs, take up, in one minute, 6*14  grains of
oxygen (the quantity necessary to  convert it into perox-
ide).   But since, in the same time, the 10  lbs. of blood
have taken up 12 grains of oxygen, there  remain 5-86
grains  of oxygen, which combine with the other constit-
uents of the blood.
  Now,  55*30  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
carrying 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-
cess of respiration,  as far as it depends on  the  globules 
THEORY OF RESPIRATION.
263
of the blood.  It does  not exclude  the  opinion, that
carbonic 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 connexion 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,  indeed,  uninterest-
ing 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 action of
these compounds on those of iron, when  alkalies  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 the vital motions  will not be instantly
stopped.
   The  conductors  of force, the nerves, will convey,
as before, to the heart and intestines the power necessa-
ry for  their  functions.  This  power they will receive 
264
THEORY OF RESPIRATION.
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  process
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 show the
importance and probable advantage of an examination of
the blood in analogous  diseased conditions.  It cannot
be, in the slightest degree, doubtful, that the function as-
cribed to the blood-globules  may be considered 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 recog-
nisable by the  use of appropriate reagents.
  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  consid-
eration of certain puzzling 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




      METAMORPHOSIS OF TISSUES.
23 
  [The  Notes correspond with  the numbers in parentheses  in
the text.  All  the Analyses quoted, which have the mark * at-
tached,  have been made in the chemical laboratory of the Uni-
versity of Giessen.] 
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 composition
of aldehyde and acetic acid, of oil of bitter almonds and
benzoic acid.
                                               Oil of
            Acetic acid.     Aldehyde.   Benzoic acid,  bitter almonds.
Carbon         40-00      55-024       69-25      79-56
Hydrogen       6-67       8-983        4*86       5-56
Oxygen        53*33      35-993       25-89      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 ele-
ments.  This  important relation  cannot  be traced  in  the
mere numerical results of analysis as above given ;  but, if
the  composition of  the related compounds be expressed in
formulas, according to  equivalents, the  connexion in each 
268                    APPENDIX.
case becomes obvious, even  to him who knows no more of
chemistry than that C represents an equivalent or combining
proportion 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        Cl4H602.
  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 show, that acetic acid differs from alde-
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.
    C6N3H30e= (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
equivalent 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
order in which they are arranged.   The second formula  is
intended to express the  opinion, that  3 eq. of  cyanogen
(=6 eq. of carbon-j-3  eq. of nitrogen) having  united to
form a compound atom or molecule, have combined with 3 
                  ANALYTICAL EVIDENCE.              269
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 hydrated cyanic
acid, the whole  multiplied by 3.   Each  equivalent of cy-
anic acid  is formed of 1 eq. of cyanogen, 1 eq. of oxygen,
and 1 eq.  of water; and hence  the same number 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 differ-
ent ways ; yet in  each of these the  proportions of the  ele-
ments, calculated  for 100 parts, must of course be the same.
It is easy, therefore, to see the advantage we possess by the
use of formulae ; that, namely,  of  exhibiting the relations
existing between compounds of  different composition ;  and
that, also, of expressing the actual, probable,  or possible
differences between substances,  whose composition, 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 expressed
in a formula ; we shall only describe the  rule for calculat-
ing, from  a given  formula, the  composition in  100 parts.
For this purpose, it must  be  noted, that C, in a chemical
formula, signifies  a weight of carbon expressed by the num-
ber 76-437 (according to  the most recent determinations
75*8 or 75-0, a variation which has no  effect whatever on
the formulae here adduced, all of which  are calculated on
the number 76-437) ; that H signifies a weight of hydrogen
              23* 
270
APPENDIX.
= 12-478 ; N a weight of nitrogen = 177-04 ; and, lastly,
O a weight of oxygen := 100.
  The  formula of proteine, C48N6H36014, expresses, there-
fore,
          48 times   76-437 = 3668-98  carbon.
           6 times  177-040 = 1062-24  nitrogen.
          36 times   12-478= 449-21  hydrogen.
          14 times  100-000=1400-00  oxygen.
   The sum gives a weight of 6580-43  proteine.
Therefore, —
                                                 In 100 parts.
In 6580-43parts of proteine are contained 366898 carbon   55-756
In 6580 43            ditto           106224 nitrogen 16-142
In 6580-43            ditto            449-21 hydrogen  6-827
In 6580-43            ditto           140000 oxygen  21-275
                                                 100-000
   The  actual results of the  analysis, reduced to 100 parts,
when compared with the above  numbers, will show how far
the assumed formula is correct; or, supposing  the formula
ascertained,  they will  show the degree of  accuracy dis-
played  by the experimenter.  Thus the proportions in 100
parts,  calculated from the  formula, furnish an important
check to the operator ; and, conversely, the formula calcu-
lated from  his results, when compared with other  known
formulae, supplies a test of his accuracy, or of the purity of
the substance analyzed. 
ANALYTICAL EVIDENCE.
271
                 NOTE I.  P. 12.
CONSUMPTION OF OXYGEN BY AN ADULT, a
                 An Adult Man
->  Carbon contained
               consumes of oxygen  produces of carbonic        in the
According to        in 24 hours       acid in 24 hours       carbonic acid.
Lavoisier and
  Sesuin
               cubic in.  grains.   cubic in.   grains.    grains.
              | 46,037  15,661   14,930   8,584    2,820 French.

Menzies        51,480  17,625                          English.
Davy          45,504  15,751   31,680   17,811    4,853   do.
Allen and Pepys 39,600  13,464   39,600   18,612    5,148   do.t

              a Gmelin, — Brande's Manual, p. 1198.
  t The  experiments of Despretz (for which, see Thomson's '• Ani-
mal Chemistry," Edinburgh,  1843,  p. 635) lead to the conclusion,
that about l-10th of the oxygen gas absorbed combines with hydrogen
and forms water, and that 9-10ths of it go to the formation of carbonic
acid gas.   If this estimate be true, we  must, in order to get the true
volume of oxygen gas abstracted from air during respiration, augment
the volume of carbonic acid gas evolved by l-10th.  This would make
the average quantity of oxygen abstracted from the air inspired amount
to 4-092 per cent.
  Dr. Thomson examined the  air from his  lungs on  ten  consecutive
days, between eleven and twelve o'clock each day, and has given the
following table of the results.
                                   Carbonic acid gas.
            1st day       .      .       •  4-64 per cent.
            2d   "            .       •     4-70     "
            3d   " .       .      .       •  607     "
            4th  «...     3-27     "
            5th  « .       .       •       •  5-26     "
            6th  «...     205     "
            7th  « •       .       •       •  2-39     "
            8th  "...     3-85     "
            9th  " .       .       .       .  3-05     "
           10th  «...     7-16     «
The  mean of the whole was 4-24  per cent.  He has also given the 
272
APPENDIX.
               NOTE II.   P. 13.

COMPOSITION OF DRY BLOOD (See Note 28).
Carbon
Hydrogen
Nitrogen
Oxygen
Ashes .  .
In 100 parts.  In 4
 .   51-96  .
 .    7-25  ,
 .   15-07  .
 .   21-30
 .    4-42  .
, Hessian = 36,864 grains.
  .  19154-5
  .   2672-7
  .   5555-4
  .   7852-0
  .   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
Deduct oxygen present
  in blood
=  7852-0
do.
do.
                   Remain  64103-3 grains of oxygen, required
for the complete combustion of 4*8 lbs. of dry blood, f
results of the examination of the air from the lungs of ten individu-
als, the average being 4-16 per cent, of carbonic  acid gas.  Dr. Prout
found that the proportion of carbonic acid expired is different at dif-
ferent periods of the day, being at its maximum nearly about noon, and
at its minimum about midnight.  It further appears, from his trials,
that the quantity begins to increase nearly at twilight.  The mean of
Dr. Prout's  trials was 3-45 per cent.  The mean of Mr. Coathupe's
trials, continued  for a week, was 4-02 per cent, t
   According to Mr. Coalhupe, if the population of Great Britain, Ire-
land, Scotland, and Wales be 26,500,000, (excluding the  army and
navy,) as quoted in Thomson's British Annual, 1839, we have no less
than 10,342,957,234 cubic feet of carbonic acid gas, or 147,072 tons of
carbon, as the present year's residuum from the respiration of the hu-
man beings now  existing within the circumscribed boundaries of Great
Britain and Ireland. — Mech. Mag., XXXI., 454.
   t Or 63685-6,  H = 12-478 and C = 76-437.
   MM. Macaire  and Marcet  analyzed  dried  arterial  and  venous
J Thomson's Animal Chemistry, Edin., 1843, p. 614. 
ANALYTICAL EVIDENCE.
273
  It is assumed, in  this calculation, that  24  lbs. of blood
yield 48 lbs. (20 per cent.) of dry residue.  The  remain-
der, 80 per cent, is water.
NOTE  III.  P. 14.
  DETERMINATION  OF  THE AMOUNT OF  CARBON
                         EXPIRED.
                     1.  Analysis  of
                          Fences.
  2-356 dry feces left 0-320 ashes (13-58 per cent.).
  0-352 dry faeces 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.
blood, and found  that venous blood contained more carbon  and less
oxygen than arterial blood.
                         Dried arterial blood.       Dried venous.
        Carbon      .    .    50 2    .    .     .    55-7
        Azote     •    •    ■   16*3  ....  16-2
        Hydrogen   .          6-6    ..     •     6'4
        Oxygen   .    .    .  26-3                •  217
                             "{KM                 ™0-°
_ Thomson's An. Chem., p. 619. 
274
APPENDIX.
             Black Bread  (Schwarzbrod).
0-302 dried black bread yielded 0-496 carbonic acid and 0-175
water.
  0-241
water.
do.
0-393
do.
0-142
  From the above, which  are the direct results of  experi-
ment, the composition in 100 parts  is  calculated  as in the
following table.

                      2. Composition
          Of Faeces.  Black Bread.        Potatoes.        Flesh.
Playfair.*   Boeckmann.*   Boussingault. Boeckmann.*
Carbon     45-24  45-09  45-41
Hydrogen    6-88   6-54   6-45
Nitrogen
Oxygen
Ashes      13-15   3-25   3-25
34-73  45-12  44-89
44-1  43-944   (See note
 5-8   6-222      28.)
45-1  44-919
 5-0   4-915
100-00 100-00 10000			100-0 100-00	
Water 300-00				
400-00				
		Of Pease.	Lentils.	Beans.
		Playfuir.*	Playfair.*	Playfair.*
Carbon	. .	. . 35-743	37-38	38-24
Hydrogen .		. . 5-401	5-54	5-84
Nitrogen *		. . 39-366	37-98	38-10
Oxygen				
Ashes	. .	. . 3-490	3-20	3-71
Water	•	. . 16-000	15-90	1411
		100-000	100-00	100-00
	Of Fresh Meat.		Potatoes.	Black Bread.
	Boeckmann.*		Boussingault.	Boeckmann.*
			*■ -\	
Water	75	74-8	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      100  100-010 
ANALYTICAL EVIDENCE.
275
                    3. Calculation,
with the help of the preceding data, of the  amount of car-
bon expired by an adult man.  The following  results  are
deduced from  observations made (see table) on the aver-
age daily consumption  of  food, by from 27 to 30 soldiers
in barracks for a month, or by 855 men for one  day.  The
food,  consisting of bread,  potatoes,  meat,  lentils,  pease,
beans, &c, was weighed with the utmost exactness, every
day during a month (including even pepper, salt, and  but-
ter) ;  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 approximate report  by the  sergeant-major, each soldier
consumes daily, on an average, out of barracks, 3 oz. of sau-
sage, | oz. of butter, \ pint  of beer, and Jg pint of brandy ;
the carbon of  which articles amounts to more than double
that of the fseces and urine  taken together.   In the soldier,
the fseces amount daily, on  an average, to 5| oz.  ; they con-
tain 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 the green
vegetables and of the food (sausages, butter, beer, &c) con-
sumed in the alehouse. 
276
APPENDIX.
  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
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  all, carbon 967-5 oz.
  With the bones, the meat, as purchased, contains 29 per
cent, of fixed matter ; 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,  v/hich 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. f of beans.
Assuming 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 15,976 oz. of potatoes consumed, there-
fore, the amount of carbon was 1936*87 oz.
   Bread. — 855 men eat daily 855 times 32 oz.,  besides
t According to the table, 222 oz. 
                  ANALYTICAL EVIDENCE.               277

36  lbs. of bread  in the  soup, which  in  all  amounts  to
27,936 oz.   100 oz. fresh bread  contain, on  an average,
30*15 oz. carbon; consequently, the  carbon  consumed  in
the bread amounts to 8422*7 oz.
  The total consumption, therefore, was

    In the meat   ....    967-50 oz. of carbon.
    In the fat.....44-80    ditto.
    In the lentils, pease, and beans    169-10    ditto.
    In the potatoes  .    .    .    1936-87    ditto.
    In the bread   ....  842270    ditto.
Consumed by 855 men     11540-97    ditto.
        Consumed by 1 man    .       13-5     ditto, f
   The faeces of a soldier weigh 5*5 oz., and contain, in the
fresh state,  11 per cent, of  carbon.  For  86 kreutzers
(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 48|
kreutzers (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.
  t  Taking the average composition of bread as given on page 273,
100 oz. contain  30-68,  which  would give 8570-76, increasing each
man's consumption  -17. — W.
  t  In the  original  table, the  quantities of these vegetables are en-
tered according to their  value in kreutzers, but they are here calculated
by weight  from the above data, as this appeared better adapted for
comparison  in this country than the prices would have been.— G.
  § According to the table, 2752.
                      24 
278
APPENDIX.
   For this reason, the carbon of the last-mentioned articles
of food has been assumed as equal to that of the fasces and
urine.   Sausages, brandy, beer, in short, the small quantity
of  food taken irregularly in the alehouse, has  not  been
included 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. 
                                                  TABLE I.  (to  Note III.)
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. November, in the period from the	No of men supplied witli food.	Beef.	Pork.	Potatoes.	Peas.	Beans.	Lentils.	Sour-krout.	Green Veget-ables.	Bread in Soup.	Salt.	Onions, Leeks, &c.	Pepper. Price in Kreutzers. 3kr.z=ld.	Fat or Lard.	Vinegar.
1st to 5th 6th to 10th 11th to 15th 16th to 20th 21st to 25th 26th to 30th	139 145 136 136 147 152	lbs. 36 37 36 37 39 30 215 lbs. 731 '37	lbs. 9 9 9 9 Pork Sau-sages. 63 lbs. Ol2 *57 OZ. 1153 •■■K5S	lbs. oz. 147 0 165 6 1C3 2 177 10 171 S 177 10	lbs. oz. 4 15J 3 5 3 5	lbs. oz. 3 7J 3 7J 3 74 3 74	lbs. oz. 3 54	lbs. 20 16 16 16 32	lbs. 12 70 42 12 36	lbs. 5 6 n	lbs. 44 5 4J 44 54 4	lbs. 4 34 34 54 3|	kr. 24 24 2 34 24 24	oz. 13| lOf 8 m	pints.
Total	855			992 4	11 94	13 14	3 54	100	172	36	28	24£	154	56	i*
The average No. of men daily fed • 855---Ofil IS 50 ---'4025 therefore each man had	r 1 Monthly In-, [Daily			lbs. oz. 34 13	oz. 6-8-7-	oz. 7375 171	oz. 1 150 1171	lbs. oz. 3 8&	lbs. "171	lb. 157	lb. 56 57	oz. 13f|	kr. 31 57	oz. 155 15f	pint. 3 57
		oz. 4_4_		lb. oz. 1 2|f	oz. 371 1710	oz. 222 855	OZ. 107 1710	oz. 1 149 *171	oz. 3122 "855	lb. 36 855	lb. 28 855	oz. 388 855"	kr. 31 1710	OZ. 56 855	pint. 3 3715
      N. B___As all the weights mentioned in the text of this work are Hessian pounds and ounces,  the different articles in this table have been reduced to the
same weights, excepting the Pepper and Vinegar, the amount of both of which is so small that they  may be omitted, without affecting the general result.   For
the benefit of those who may wish to reduce these weights to avoirdupois weight, it may here be mentioned, that 1 lb. Hessian = 16 oz. Hessian = 7680 grains
Hessian = 7712  grains avoirdupois.  Consequently, since  the  1 lb.  avoirdupois is = 7000  grains  Troy, 1 lb. avoirdupois : 1  lb. Hessian : : 7000 : 7712,  or as
1 : 11017; and 1 oz. Hessian = 482 grains Troy (1 oz. Troy is = 480 grains), while 1 oz. avoirdupois is = 437-5 grains Troy. 
280                      APPENDIX.


             TABLE II. — Note IV.,  page 14. a. f
FOOD CONSUMED BT  A HORSE IN  TWENTY-FOUR HOURS.
Articles of food.	Weight in the fresh state.	Weight in the dry state.	Carbon. 2961-0 977-0	Hydro-gen.	Oxy-gen.	Nitro-gen.	Salts and earthy matters.
Hay Oats Water Total	7500 2270 16000	6465 1927		323-2 123-3	2502-0 707-2	97-0 42-4	581-8 77-1 13-3
	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 and earthy mat-ters.
Urine Excrements	1330 14250	302 3525	108-7 1364-4	11-5 179-8	341 1328-9	37-8 77-0	109-9 574-6
Total	15580	3827	14731	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	2464-9	255-2	1846-2	24-0	12-3
							+ j
  a Boussingault, Ann. de Ch. et de Phys., LXX. 136.  The weights
in this table are given in grammes.   1 gramme = 15-44 grains Troy,
very nearly.
  f The discrepancy between the results of Table II. and those given 
ANALYTICAL EVIDENCE.               281
  TABLE II. —Note  IV., page 14 (concluded).

FOOD CONSUMED BT A  COW IN TWENTT-FOUR  HOURS.
Articles of food.	Weight in the fresh state.	Weight in the dry state.	Carbon.	Hydro-gen.	Oxy-gen.	Nitro-gen.	Salts and earthy mat-ters.
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	890-0
EXCRETIONS OF A COW IN TWENTT-FOUR HOURS.
Excretions.	Weight in the fresh state.	Weight in the dry state.	Carbon.	Hydro-gen.	Oxy-gen.	Nitro -gen.	Salts and earthy mat-ters.
Excrements Urine Milk	28413 8200 8539 45152	4000-0 960-8 1150-6	17120 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		6111-4	2601-6 3320		2082-7	174-5	920-6 890-0
Total of first part of this Table.	82500	104850	4813-4	595-5	4034-6	201-5	
Difference	37348	4373-6	2211-8	263-5	1951-9	27-0	30-6
							+
in the Agricultural Chemistry, page 176, arises from their being cal-
culated on  202 per cent, of nitrogen in hay, and 0-33 per cent, in
excrements. — W.
                       24* 
282
APPENDIX.
                    NOTE V.  P. 18.

TEMPERATURE OF THE  BLOOD  AND FREQUENCY OF
                      THE PULSE.
                         According to Prevost and Dumas,
                  The mean              The frequency
                 temperature ia     ,----------.«---------     s
                                 of the pulse    of the respiration
                     F.          in the minute.    in the minute.
In the Pigeon    .  107-6°          136            34
Common Fowl   .  106-7°          140            30
Duck   ....  108-5°          170            21
Raven   ....  108-5°          110            21
Lark.....117-2°          200            22
Simia Callitriche    95-9°           90            30
Guinea Pig    .  .  100-4°          140            36
Dog.....99-3°           90            28
Cat.....101-3°          100            24
Goat.....102-5°           84            24
Hare.....100-4°          120            36
Horse    ....   98-2°           56             16
Man.....98-6°           72             18
Man (Liebig)   .  .   97-7°           65             17
Woman (Liebig) .   98-2°           60            15

   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  (Magendie) is from  100*6°  to  101*6°.   As a
mean temperature, 99*5°  has  been adopted  in  this work,
p. 18. 
ANALYTICAL EVIDENCE.
283
                     NOTE VI.   P. 34.

  The prisoners in the House of  Arrest at Giessen receive
daily 1| lb. of bread (24 oz.), which contain 7J oz. of car-
bon.  They receive, besides, 1 lb. of soup daily, and,  on
each alternate day, 1 lb.  of potatoes.
     \h lb. of bread contains    .     .  7-25 oz. of carbon.
     1  lb. of soup contains   .    .    0-75     ditto.
     h lb. of potatoes contains  .     .  1*00     ditto.
                      Total   .     .    9-00    ditto.f
                   NOTE VII.  P. 42.

COMPOSITION  OF THE FIBRINE AND ALBUMEN OF
                       BLOOD, a.

          Albumen from Serum of Blood.           Fibrine.
                    Scherer.*                Scherer.*    Mulder.
                I.      n.      III.        I.       n.      I"-
Carbon  .   .  53-850  55-461   56097    53-671   54-454   5456
Hydrogen   .   6-983    7-201    6-880     6-878    7-069    6-90
Nitrogen   .  15-673   15 673   15-681    15-763   15-762   15-72
Oxygen    }
Sulphur     \ 23-494   21-655   22-342    23-688   22715   22-82
Phosphorus  )
  a Annalen der Chem. und Pharm., XXVIII., 74., and XL., 33, 36.

   For additional  analyses of animal fibrine  and  albumen,
see  Note  XXVII., which  also  contains analyses of  the
various animal tissues.
 " t At page 34 the carbon contained in the daily food of these pris-
oners is calculated at 8* oz., and the Appendix in the original makes
the number 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 0-25 oz. — G. 
284
APPENDIX.
                    NOTE VIII.  P. 47.

COMPOSITION  OF VEGETABLE FIBRINE, VEGETABLE
  ALBUMEN, VEGETABLE  CASEINE, AND VEGETABLE
  GLUTEN.

                      Vegetable Fibrine.         Gluten.
                                             As obtained from
                                               wheat flour.
                   Scherer.*a           Jones.*6 Marcet.c  Boussin-
             i.       n.      m.       IV.    i.     "n.
            53064   54-603   54-617    53-83   55-7   53-5
             7132    7 302    7-491     7-02   145   150
            15-359   15-809   15-809    15 58'    7-8    7-0
Carbon .   .
Hydrogen  .
Nitrogen   .
Oxygen
Sulphur
Phosphorus
24-445   22-285   22-083   23-56    22-0   24-5


a Ann. der Chem. und Pharm., XL., 7.
b Ibid., XL., 65.
c L. Gmelin's Theor. Chemie, II., 1092.
Vegetable Aleumen. a
Carbon .
Hydrogen
Nitrogen
Oxygen
Sulphur
Phosphorus
From Rye.
   Jones.*
 .  54-74
 .   7-77
 .  15-85

 t  21-64
From Wheat.
    Jones.*
    5501
      7-23
     15-92

    21-84
From Gluten.  From Almonds.
Varrentrapp & Will.* Jones.*
                 5703
54-85
 6-98
15-88

22-39
 7-53
13-48

21-96
Carbon
Hydrogen
Nitrogen
Oxygen, &c.
Boussingault.
   527
.    6-9
   18-4
.   22-0
Varrentrapp and Will.
15-70
a Ann. der Chem. und Pharm., XL., 66, and XXXIX., 291. 
ANALYTICAL EVIDENCE.
285
Vegetable Caseine. a.
Carbon
Hydrogen
Nitrogen  .
Oxygen, &c.
Scherer.*

54-138
 7-156
15-672
23034
Jones.*

5505
 7-59
15-89
21*47
Sulphate of Caseine
   and Potash.
Varrentrapp and Will.
51-41
 7-83
14-48
51-24
 6-77
13-23
a Ann. der Chem. und Pharm., XXXIX., 291, and XL , 8 and 67.

                 Vegetable  Gluten.
Boussingault.
Carbon .
Hydrogen
Nitrogen
Oxygen, &c.
54-2
 7-5
13-9
24-4
52-3
 6-5
18-9
22-3
                           Jones. *a
                            55-22
                             7-42
                            15-98
                         .  21-38
            a Ann. der Chem. und  Pharm., XL., 66.
  The pure gluten, analyzed by Jones, was that portion
of the raw gluten from wheat flour, which is soluble  in hot
alcohol.   The  insoluble  portion is  vegetable  fibrine,  the
analysis of which has been already given.
           NOTE IX.  P. 51.

COMPOSITION OF ANIMAL CASEINE. a
                          Scherer.*
Carbon
Hydrogen
Nitrogen
Oxygen  )
     lur  S
From fresh
  milk.
54*825
 7*153
15-628
22-394
From sour
  milk.
54-721
 7-239
15-724
From milk by
 acetic acid.
    IV.
   54-580
    7-352
   15-696
  in.
54-665
 7*465
15-724
22-146   22-372   22-910
Albuminous
 substance
  in milk.6
   V.
 54-507
  6-913
 15-670
                        22-316
Sulphi
  a Ann. der Chem. und Pharm., XL., 40 etseq.
  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. 
286
APPENDIX.
Carbon
Hydrogen
Nitrogen
Oxygen  .
Sulphur
Mulder.a
54-96
 7-15
15-80
21-73
 0-36
a For the analysis of vegetable caseine, see the preceding note.
NOTE X.  P. 63.
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  sawdust, 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 XI.  P. 68.

COMPOSITION OF STARCH, a
		Stre	icker.*	
Calculated C12 Hio Oio	From Pease.	From Lentils,	From Beans.	From 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.
287
		Strecker.*		
	From maize.	From horse-chestnuts,	From wheat.	From rve.
Carbon	44-27	44-44	44-26	44-i6
Hydrogen	6-67	6-47	6-70	6-64
Oxygen	49-06	49-08 Strecker.*	49-04	49-20
		From	From	From
	From rice.	dahlia roots. unripe apples.		unripe pears.
Carbon	44-69	4413	44-10	44-14
Hydrogen	6*36	6-56	6-57	6-75
Oxygen	48-95	49-31	49-33	49-11
	From potatoes. Fror		n arrow-root. Prout.	From yams, a
	Berzelius.	Gay-Lussac & Thenard.		Ortigosa.*
Carbon	44-250	43-55	44-40	44-2
Hydrogen	6-674	6-77	6-18	6-5
Oxygen	49-076	49-68	49-42	49-3
  a The starch employed for the analyses, made by Strecker and Or-
tigosa, was prepared from the chemical laboratory at Giessen, from the
respective seeds, bulbs, and roots.
                   NOTE XII.   P. 69.

COMPOSITION  OF  GRAPE  SUGAR (STARCH SUGAR).
From grapes.a From starch.}
      De Saussure.
Carbon	36*71
Hydrogen	6-78
Oxygen	56-51
37-29
 6-84
55-87
From honey.e
    Prout.

    36-36
     7-09
   56-55
 Calculated
Cl2Hi4014.

   36-80
    7-01
   56-19
a Ann. de Chimie, XL, 381.
b Ann. of Philosophy, VI., 426.
c Philosoph. Trans. 1827, 373. 
2SS
APPENDIX.
                    NOTE XIII.  P. 70.

          COMPOSITION OF SUGAR  OF MILK.
       Gay-Lussac
       and ThSnard
Carbon   38-825
Hydrogen 7-341
Oxygen  53 834
Prout.
40-00
 6-66
53-34
Brunn.
40437
 6-711
52-852
Berzelius.
 39-474
  7167
 53-359
       Calculated
Liebig.* Ci2H12012.
         40-46
          6-60
         52-94
4000
 6-73
53-27
	NOTE XIV. P. 70.		
	COMPOSITION OF GUM.		
	Gay-Lussac		Calculated
	and Thenard.	Goebel. Berzelius.	C12HnOu.
Carbon	4223	42-2 42.682	42-58
Hydrogen Oxygen	6-93	6-6 6-374	6*37
	50*84	51-2 50*944	5105
                NOTE XV.  P. 72.
      ANALYSIS OF OATS  (Boussingault). a
100 parts of oats contain of dry matter
      Ditto                water
 84-9
 17-1

102-0
   100 parts of oats, dried  at 212° = 117*7 parts dried at
the ordinary temperature, contain
Carbon
Hydrogen
Oxygen
Nitrogen
Ashes .
Water
Oats dried in the air
 50-7
  6-4
 36-7
  2-2
  4-0

100-0
 17-7

117-7  contain in 100 parts,
         1-867 of nitrogen.
a Ann. de Chimie et de Phys., LXXI., 130. 
ANALYTICAL EVIDENCE.
289
                     Analysis of  Hay.
  100 parts of hay, dried in the air, contain 86 of dry matter.
                                          14 of water.
                                         100
   100 parts of hay, dried at 212°, = 116*2  parts  dried  in
air, contain
      Carbon       ....   45-8
      Hydrogen      ...      5-0
      Oxygen       ....   38-7
      Nitrogen       .    .    .      1-5
      Ashes        ....    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 3-096 oz. of nitrogen.
   72 oz. of oats     = 4<| lbs. contain 1-344     ditto.

                             Total    4-440
                  NOTE XVI. (a.)  P. 74.
  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
carbon.t
  t  By an error in calculation in the original, the amount of carbon
in 15 lbs. of meat is stated to be 27-64 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  suffi-
cient to affect the argument at p. 74. — G.
                25 
290
APPENDIX.
	NOTE XVI. (b.) P. 81. Composition of Hog's lard. Mutton fat. Chevreul. a	Human fat.
Carbon Hydrogen Oxygen .	79-098 78-996 . 11-146 11-700 9-756 9-304	79-000 11-416 9-584
a Recherches Chim. sur les corps gras.  Paris.  1823.
       NOTE XVII.   P. 81.
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 I
       Gay-Lussac Calculated
 Liebig.* &Th6nard. Ci2HnOn.
 42-301   4247   42-58
 6-384    6-90    6-37
51-315   50-63   51-05
  For the composition of gum and of starch, see Notes (14)
and (11).
        NOTE XVIII.   P. 82.
COMPOSITION OF  CHOLESTERINE.
		According to		Calculated
	Chevreul. a	Couerbe.i	Marchand.	C36 H32 O.
Carbon	85-095	84-895	84-90	84-641
Hydrogen	11-880	12099	1200	12282
Oxygen	3-025	3-006	310	3077
a Recherches sur les corps gras, p. 185.
6 Ann. de Ch. et de Phys , LVL, 164. 
ANALYTICAL EVIDENCE.
291
                   NOTE XIX.  P. 84.
     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 digested.
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 laminre 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 maturity, on the eight  spots, eight laminse
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 lamina ; and the
lamina?  of wax became as thick as four  under ordinary
circumstances.  The abdominal scales of the bees were,

  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. 
292
APPENDIX.
by means of the wax, distinctly raised, so  that the waxen
laminae projected between them.   On examination, I  found
that these thick laminae, which, under  the  microscope, ex-
hibited several lamellae, had  a sloping  surface downwards
near the head, and upwards in the vicinity of the tail.  The
first waxen lamina, therefore,  must have been pushed down-
wards by the second, because, where the abdominal scales
are attached to the skin, there is no  space for  two laminas,
the second by the third, and  thus the inclined surfaces  on
the sides of the thick laminae had  been produced.  I saw
distinctly from this, that the  first formed laminae are de-
tached by those which follow.  The sugar  had been con-
verted  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,
therefore, believe that pollen  furnishes food for  the  bees,
but I think  they only swallow  it in order, by  mixing it with
honey and water, to prepare  the  liquid food for the grubs.
Besides,  bees often starve in April,  when their  stock of
honey 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 
ANALYTICAL EVIDENCE.             293
really nourishment for bees, they ought to be able to sup-
port life on it, mixed with water.
  Bees never build honeycomb unless  they have a queen,
or are  provided with young out which of they can educate 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, volun-
tary, and dependent on certain  conditions ; but  the oozing
of wax is involuntary.
  One might suppose that a  large  proportion of  these
laminae  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 fiat 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 disappeared, and that a large  number
of laminae are lying on the paper.  It would appear as  if
the bees, which had carried 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 re-
main hanging to the top of the hive.  Repeated experi-
ments  of this kind have convinced me that the  bees, as
soon as their  laminae of  wax are mature, return to the hive
             25* 
294                    APPENDIX
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 revives, and its place  is occupied for the same
purpose by another.
   [From page 28 of the same work.]  In order to ascer-
tain 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, of this year (1841), at a  time
when the bees could obtain in this district  no further  sup-
ply 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 on the  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
evening 10 oz., and  on the 3d 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. 
ANALYTICAL EVIDENCE.
295
On the 5th of September  I  stupefied  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, but 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 [17 ?] oz.  of the 29 oz. of
honey given to them.  I next extracted the combs, and found
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
afterwards half an ounce daily, which was owing to the
circumstance,  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  confined  to  the  hive, weigh 4  oz. ; consequently
2,765 bees should weigh  9 oz.   But  they actually weigh-
ed 10 oz., and therefore  had within  them 1 oz. of excre-
ment, for  their honey  bladders  were  empty.   During  the
night  the weight of the box did  not diminish at all, because
the small  quantity 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  occurred 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 § of  an ounce of 
296
APPENDIX.
 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
 building of comb.  Cnauf has already  recommended this,
 although 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
 grains) will contain 4,166,666 laminae.  Hence, § 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 obser-
 vations.
   The  laminae,  when  formed,, are as  white as bleached
 wax.   The cells, also,  at  first,  are  quite white, but  they
 are colored 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 accumulated.
  P. 54.   Many believe  that bees  are hybernating ani-
 mals ;   but this  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- 
ANALYTICAL EVIDENCE.              297
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 development of
heat increased.   If, in summer, bees  without a" queen are
shut up in a glass box, they  become  uneasy and  begin to
hum.  So much  heat is by this means developed, 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.

           XX.  COMPOSITION OF BEES' WAX.
        Gay-Lussac  De Saus-                         Calculated
        and ThSnard.a  sure.6   Oppermann.c  Ettling.d   Hess.e  C20H20O.
 Carbon  81-784     81-607   81-291    81-15    81-52    81-39
 Hydrogen 12-672    13859   14073    1375    13-23    13-29
 Oxygen    5-544    4-534    4-636      509     5-25     532
       a Traite de Chimie, par Thenard, 6™ ed., IV., 477.
       b Ann. de Ch. et de Phys., XIII., 310.
       c Ibid., XLIX., 224.
       d Annal. der Pharm.,  II., 267.
       e Ibid., XXVII., 6. 
298
APPENDIX.
                NOTE  XXI. (a.)  P. 100.

COMPOSITION  OF HYDRATED CYANURIC  ACID,  OF
  HYDRATED CYANIC  ACID, AND  OF CYAMELIDE, IN
  100 PARTS, ACCORDING TO THE  ANALYSIS OF
                                       Wbhlcr and Liebig.* a
                                     Cyanuric  acid, cyanic
                                        acid, cyamelide.
        Carbon......2819
        Hydrogen.....230
        Nitrogen   .     .    .     .    .     .  32-63
        Oxygen      .....36-87

           a PoggendorfFs Annalen, XX., 375 et seq.
                NOTE XXI. (b.)  P. 100.

  COMPOSITION OF ALDEHYDE,  METALDEHYDE, AND
                    ELALDEHYDE. a
          Aldehyde. Metaldehyde.   Elaldehyde.        Calculated
           Liebig.*              Fehling.*             C4 H4 O2.
Carbon     55-024    54-511    54-620     54-467    55024
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, and XXVII., 319.
     NOTE XXII.  P. 101.
COMPOSITION OF PROTEINE.
      From the    From albumen.  From fibrine.
   crystalline lens.
		Scherer.* a	
Carbon .	. 55-300	55-160	54-848
Hydrogen .	6-940	7-055	6-959
Nitrogen	. 16-216	15966	15-847
Oxygen	21-544	21-819	22-346
 
ANALYTICAL EVIDENCE.             299
		Scherei	:*a	Calculated H36N6014.
	From hair. From horn. C48			
Carbon	54-746	55-150 55-408	54-291	55-756
Hydrogen	7-129	7-197 7-238	7*082	6-826
Nitrogen	15-727	15-727 15-593	15-593	16-142
Oxygen	22*398	21-926 21-761	23034	21-276
	a Ann. der Chem. und Pharm		u, XL., 43.	
	From vegetable From		From	From
	albumen. fibrine. albumen.			cheese.
	.	Mulder. <	i	
Carbon .	. 54-99	55-44	55-30	55-159
Hydrogen	6-87	695	6-94	7-176
Nitrogen	. 15-66	1605	16-02	15857
Oxygen	22-48	21-56	21-74	21-808
	a Ann.	der Pharm., XXVIII., 75.		
                NOTE XXIII.  P. 103.
COMPOSITION OF THE ALBUMEN OF THE YOLK AND
           OF THE WHITE OF THE EGG. a
	Froi	m the	yolk.	From the white,
		Jones.	*	Scherer *
	i.		n.	
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.
        NOTE XXIV.  P. 107.
   COMPOSITION OF LACTIC ACID.
                               CsHs06.
Carbon......44-92
Hydrogen.....6-11
Oxygen......48-97 
300                   APPENDIX.
                  NOTE XXV.   P. 111.

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  Pfliiger.

                                       Sulphuretted hydrogen.
                                       80 Vol. in 100 Vol.
Air.	Carbonic acid.	Inflammable gas.
a 5	5 —	15
6 25	— 27	48
c —	— 60	40
c —	— 20	80
                  NOTE XXVI.  P. 113.


 MAGENDIE  FOUND  IN THE STOMACH AND INTESTINES
               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
 execution : —
                              100 volumes of the gas contained
                          Oxygon.     Nitrogen.  Carbonic  Inflam-

 r From the stomach       11-00 Vol.
a <    —    small intestines  00 00
      —    large intestines  00-00
   From the stomach       0000
           small intestines  00-00
           large intestines  00-00
 r From the stomach       00-00
 c <    —    small intestines  0000
 C    —    large intestines  00-00
r From
	acid.	mable gas.
71-45	1400	3-55
2003	24-39	55-53
5103	43-50	5-47
00 00	00-00	0000
8-85	40-00	5115
18-40	70-00	11-60
00-00	00-00	0000
66-60	25-00	8-40
45-96	42-86	11 18
 
ANALYTICAL EVIDENCE.
301
 NOTE XXVII. (referred to in NOTE VII.  P. 42 and 121.)

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	
		Scherei	*a		Jones.* b	
	I.	n.	III.	IV.	X.	VI.
Carbon	53-850	55-461	55097	55000	53-72	53-45
Hydrogen	6983	7-201	6 880	7 073	7-55	7-66
Nitrogen	15-673	15-673	15-681	15-920	13-60	13-34
Oxygen						
Sulphur	i 23-494	21-655	22-342	22 007	2513	25-55
Phosphorus.						
a Ann. der Chem. und Pharm., XL., 36.
b Ibid., 67.
Jones.*
Scherer.*
Carbon
Hydrogen
Nitrogen
Oxygen
Sulphur
Phosphorus
 From    From
albumen  hydrocele.
of brain.
 VII.
55-50
 719
16-31
 VIII.
54-921
 7-077
15-465
 From
congestive.
abscess.
  IX.
54-757
 7171
15-848
From pus.
54-663
 7-022
15-839
 From
fluid of
dropsy.
   XI.    XII.
54101   54302
 6-947    7176
15-660   15-717
21-00   22 537   22-224   22-476    23-292   22-805
Mulder, a
 54-84
  7-09
 15-83
 21-23
  0-68
  0-33
Carbon......
Hydrogen......
Nitrogen......
Oxygen      ......
Sulphur......
Phosphorus......
         a Ann. der Pharm., XXVIII., 74.
26 
302
APPENDIX.
	2	. Fibrine. Scherer.* a		
	i. n.	III. IV.	V. VI.	VII.
Carbon	53-671 54-454	55002 54-967	53-571 54-686	54-844
Hydrogen	6-878 7069	7-216 6-867	6-895 6-835	7-219
Nitrogen	15-763 15-762	15-817 15-913	15-720 15-720	16-065
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.

                                       Mulder, a
Carbon.......54*56
Hydrogen......6-90
Nitrogen.......15-72
Oxygen.......2213
Sulphur.......0-33
Phosphorus......0-36

         a Ann. der Pharm., XXVIII., 74.


           3. Gelatinous Tissues.
                 Scherer.* a
		Tendons of the	Tunica	Calculated
	Isinglass. 50-557	calf's foot.	sclerotica. 50-995	C48H4iN7iOi8.
Carbon		49-563 50-960 50-774		50 203
Hydrogen	6-903	7-148 7-188 7-152	7075	7-000
Nitrogen	18-790	18-470 18-320 18320	18-723	18-168
Oxygen	23-750	24-819 23-532 23-754	23-207	24-629
a Ann. der Chem. und Pharm., XL., 46.
Mulder.
Carbon
Hydrogen
Nitrogen  .
Oxygen
50-048	50-048
6477	6*643
18-350	18-388
25-125	24 921
 
ANALYTICAL  EVIDENCE.
303
4. Tissues containing Chondrine.
Scherer.* a
	Cartilages of the		Calculated	
	ribs of the calf.	Cornea.	C48H40N6O20.	Mulder.
Carbon	49-496 50-895	49-522	50-745	50-607
Hydrogen	7133 6-962	7-097	6-904	6-578
Nitrogen	14-908 14-908	14-399	14-692	14-437
Oxygen	28-463 27-235	28-982	27-659	28-378
a Ann. der Chem. und Pharm , XL., 49.
5.  Composition  op the Middle Membrane  of Arteries.
Scherer.*		a	Calculated C48H38N6016. 54-10
1. Carbon . . . 53-750		II. 53-393	
Hydrogen . . 7-079 Nitrogen . . . 15-360 Oxygen . . 23-811		6-973 15-360 24-274	6-64 15-67 23-59
a Ann. der Chem. und Pharm		., XL., 51.	
6. Composition of Hornt  Tissues.
                  Scherer.* a
   External skin     Hair of
of the sole of the foot, the beard.
   Hair of the head.
Fair.    Brown.   Black.
Carbon    51-036  50-752  51-529   50-652  49-345  50-622  49-935
Hydrogen  6-801   6-761   6-687    6-769   6-576   6613   6-631
Nitrogen  17-225  17-225  17-936   17-936  17-936  17-936  17 936
Oxygen ) ^ g3g  252Q2  23.g48   24.643  26.143  24.g29  25.498
Sulphur 5
                             Scherer.*
             ________.____________________A________________________________.
Buffalo horn.
Nails.
                                    Wool.  Calculated
                        ---.              C48H39N7O17.
51-990 51-162 51-620 51-540   51-089  50-653   51-890
                             6-824   7029    6542
Carbon
Hydrogen  6-717  6-597  6-754   6779
Nitrogen   17-284 17-284 17-284  17-284  16901   17-710   17525
Oxygen  I  24.009 24-957 24-342  24397  25-186  24-608   24043
Sulphur  )
            a Ann. der Chem. und Pharm., XL., 53. 
304
APPENDIX.
  The composition of the membrane lining the interior of
the shell  of the  egg approaches  closely  to that of horn.
According to Scherer, it contains
                                            Scherer.* a
      Carbon.......50-674
      Hydrogen......6-608
      Nitrogen.......16-761
      °7f"  I......25-957
      Sulphur  y
            a Ann. der Chem. und Pharm., XL., 60.

  The composition of feathers  is also nearly the same as
that of horn.
                             Scherer.* a
	Beard of the	Q.uillofthe	Calculated
	feather.	feather.	C48H39N7Oi6.
Carbon .	. 50-434	52-427	52-457
Hydrogen .	7-110	7-213	6-958
Nitrogen	. 17-682	17-893	17-719
Oxygen	24-774	22-467	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 .	. 58*273	58-672	57-908
Hydrogen .	5-973	5-962	5-817
Nitrogen	. 13.768	13-768	13-768
Oxygen	21-986	21-598	22-507
a Ann. der Chem. und Pharm., XL., 63. 
ANALYTICAL EVIDENCE.
305
                  NOTE XXVIII.  P. 127.

  According to the analyses of Playfair and Boeckmann,

0-452 parts of dry muscular flesh gave 0-836 of carbonic acid.
0*407......0-279 of water.      [of water.
0-242......0-450 of carbonic acid and 0-164
0-191......0-360    .    .    .     0-130
0-305 of dried blood gave 0-575 of carbonic acid and 0-202 of water.
0-214    .    .     .    0-402  ....    0138
1-471 of dried blood, when calcined, left 0-065 of ashes = 4 42 per cent.
   The dried flesh was found to contain     of ashes  4-23 per cent.
   The nitrogen was found to be to the carbon as 1 to 8 in equivalents.

   Hence, —
	Flesh	i (beef).	Ox-blood.		Blood.
					Mean of 2
	Playfair.	Boeckmann.	Playfair.	Boeckmann.	analyses.
Carbon	51-83	51-89	51-95	51-96	51-96
Hydrogen	7-57	7-59	717	7-33	7-25
Nitrogen	1501	15-05	15-07	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 composition
of the organic part is,
Carbon
Hydrogen
Nitrogen
Oxygen  .
This corresponds to the formula
    4
    C48  •
    H39
    N6   .
    01S      ••       *
                 26*
54-12	54*18	54-19	54-20
7-89	7-93	7-48	7-65
15-67	15-71	15-72	15-73
22-32	22*18	22-31	22-12
54-81
 6-91
15-87
22-41 
306
APPENDIX.
       NOTE XXIX.  P. 128.
COMPOSITION OF CHOLEIC ACID, a
Carbon	Demar^ay. . 63*707	Dumas. 63-5	Calculated C76H66N2022. 63-25
Hydrogen Nitrogen Oxygen .	8*821 . 3*255 24-217	9-3 3-3 23*9	8*95 3-85 23-95
a Ann. der Pharm., XXVII., 284 and 293.
               NOTE XXX.  P. 128.
COMPOSITION OF TAURINE AND CHOLOIDIC ACID.
                   1. Taurine, a
Carbon	Demar^ay.* . 19-24	Dumas. 19-26		Calculated C4H7NO10. 19-47
Hydrogen	5-78	5-66		5-56
Nitrogen Oxygen .	. 11-29 6369	11-19 63-89		11-28 63-69
	a Ann. der Pharm.,	, XXVII., 287	and 292.	
	2. Choloidic Acid, a			
	Demar^ay.*		Dumas. 73-3	
Carbon	I. . 73-301	n. 73-522		C72H56O12. 74-4
Hydrogen Oxygen .	9-511 . 17-188	9-577 16-901	9-7 17-0	94 16-2
          a Ann. der Pharm., XXVII., 289 and 293.
  In reference to the researches  of Demar^ay on the bile,
I would make the following observations.
  The matter to which I have  given the name of choleic
acid is the bile itself, separated  from  the inorganic constit-
uents (salts, soda, &c.) which it contains.   By the action of 
                 ANALYTICAL EVIDENCE.              307
subacetate of lead aided by ammonia, all the organic con-
stituents of the bile  are made to unite with oxide of lead,
with which  they  form  an insoluble resinous precipitate.
The substance here combined with oxide of lead contains
all the carbon and nitrogen of the bile.  The substance which
I have  named choloidic acid is that which is obtained, when
the bile, purified by alcohol from the substances 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  separated  in the form of
taurine  and ammonia.   The cholic acid contains the ele-
ments of bile, minus those  of carbonate of ammonia.
   These three compounds, therefore, contain the products
of  the  metamorphosis  of  the entire bile ; their formulae
express 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
combined 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  influence on  the deter-
mination  by analysis  of  the relative  proportions  of the
elements.  In  the formula? themselves, therefore,  is in-
volved no hypothesis ;  they are simply expressions  of the
results of analysis.   It  signifies  nothing that the  choleic
or choloidic 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
bile by the  action of the  atmosphere,  or of chemical re- 
308
APPENDIX.
 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  burden which
 impedes  his  progress.   It cannot be maintained  of any
 one  of the 38 or 40  substances,  into which the  bile has
 been divided  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
 reagents  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 insoluble 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  in-
 stantly separated by other acids.   Yet diluted acids  cause
 no such separation of stearic and margaric acids in  bile. 
ANALYTICAL EVIDENCE.
309
  It is possible, that,  in  the course of new and repeated
investigations, the composition of substances obtained from
bile may be found different from that which  has been given
in our analytical  development 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  development  of  our  views in  formulae, only to
assume  that  more  water  and oxygen,  or less water and
oxygen, have  taken a share  in  the metamorphosis of the
tissues ; but  the truth  of  the  development  of the process
itself will not be  by this means affected.
                 NOTE XXXI.  P. 129.
           COMPOSITION OF CHOLIC ACID, a
                            Dumas.       Calculated C74H60O18.
Carbon.....68-5            68-9
Hydrogen   ....     9-7             9-2
Oxygen      ....  21-8            21-9
              a Ann. der Pharm., XXVIL, 295.
                 NOTE XXXII.  P. 131.
COMPOSITION OF THE CHIEF  CONSTITUENTS OF THE
            URINE OF MEN AND ANIMALS.
                      I. Uric  Acid.
              Liebi»*a       Mitschcrlich.6  Calculated C10H4N4O6.
Carbon  .    .  36-083          35-82          36-01
Hydrogen  .     2-441           2-38           2-35
Nitrogen     .  33-361          34-60          33-37
               28.126          27-20          28-27
             a Ann. der Pharm., X., 47.
             b Poggendorff's Ann., XXXIII., 335.
Oxygen 
310
APPENDIX.
                  2. Alloxan, a.
A PRODUCT OF THE OXIDATION OF URIC  ACID.
	Wbhler and Liebig.* Calculated C8 H4	
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.
				Calculated
	Prout. a	Wbhler and Liebig. b		C2 H4 N2 02.
Carbon .	. 19-99		20-02	20-198
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.			
				Calculated
	Liebig.* a	Dumas, b	Mitscherlich. e Cjg	Hs N05 +HO.
Carbon	60-742	60-5	60-63	60-73
Hydrogen	4-959	4-9	4-98	4-96
Nitrogen	7-816	7-7	7-90	7-82
Oxygen	26-483	26-9	26-49	26-49
a Ann. der Pharm., XII., 20.
b Ann. de Ch. et de Phys., LVIL, 327.
c Poggend. Ann., XXXIII., 335.
	5. Allantoine. a.	
	Wbhler and Liebig.*	Calculated C8 H6 N4 06.
Carbon	. 30-60	30-66
Hydrogen	3-83	3-75
Nitrogen	. 35-45	35-50
Oxygen	30-12	30-09
a Ann. der Pharm., XXVI., 215. 
ANALYTICAL EVIDENCE.
311
6.  Uric or Xanthic Oxide, a
Carbon	Wbhler and Liebig.* . 39-28	Calculated Cs H2 N2 02 39-76
Hydrogen	2-95	2-60
Nitrogen	. 36-35	36-84
Oxygen	21-24	20-80
	a Ann. der Pharm., XXVI.,	344.
	7. Cystic Oxide, a	
Carbon	Thaulow.* . 3001	Calculated C« H6 N04 S2. 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.
  Tho cystic oxide  is  distinguished from all the other
concretions occurring in the urinary bladder by the sulphur
it contains.  It can be shown with  certainty,  that the sul-
phur is present neither in the oxidized  state,  nor in com-
bination 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- )
  ted hydrogen   $
7 atoms water  .  . .
C10N4H4O6
C14   H6 03
      H8   S8
      H,0,
4 atoms cystic oxide = C24N4 H24016S8 = 4 (C6 NH6 04 S2). 
312
APPENDIX.
  An excellent method  of detecting the presence of cystic
oxide 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
solution.   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 products, oxalic acid.
	NOTE XXXIII. P. 131.	
apositiop	I OF OXALIC, OXALURIC,	AND PARABi
	NIC ACIDS.	
	1. Oxalic Acid (hydrated).	Calculated
Gay-Lussac & Thenard. Berthollet.		C2 Oa + HO.
Carbon	26-566 25-13	27-04
Hydrogen	2-745 3-09	2-21
Oxygen	70-689 71-78 2. Oxaluric Acid, a	70-75
	Wbhler and Liebig.*	Calculated
	A.	C6 H4 N2 Og. 27-59
Carbon	27-600 27-318	
Hydrogen	3-122 3072	3-00
Nitrogen	21-218 21-218	21-29
Oxygen	48-060 48-392 a Ann. der Pharm., XXVI., 589. 3. Parabanic Acid, a • Wbhler and Liebig.*	48-12
Carbon	31-95 31*940	31.91
Hydrogen	2-09 1-876	1-73
Nitrogen	24-66 24-650	24-62
Oxygen	41-30 41-534	41-74 f
a Ann. der Pharm., XXVI., 286.    t Calculated C3 Hi N, 03. 
ANALYTICAL EVIDENCE.              313
                  NOTE XXXIV.  P. 132.

          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 oFroedeer (1).   Flesh of beef (2). Flesh of veal (3).
                Boeckmann.*               Playfair.*
    Carbon        52-60          52-590          52^52
    Hydrogen      7-45           7-886            7-87
    Nitrogen      15-23          15-214          14-70
    Oxygen
Ashes
24-72          24-310          24-91
                 NOTE XXXV.  P.  135.
   The formula C108 H84 N18 O40, or  C^H^N^,  gives,
when reduced to 100 parts,
             CJ4.....50-07
             H42 .....     6-35
             N9.....19-32
             020.....24-26
Compare this with the composition of gelatine, as given in
Note (27).
         NOTE XXXVII.  P. 146.
COMPOSITION OF LITHOFELLIC ACID, a
                                          Calculated
           Ettling and Will.*         Wbhler.  C40 H36 Oa
Carbon        71-19    70-80    70-23     70-83    70-99
Hydrogen      10-85    10-78    10-95     10-60    10-44
Oxygen        17 96    18-42    1892     18-57    18-57
    a  Ann. der Chem. und Pharm., XXXIX., 242, XLL, 154.
                   27 
314
APPENDIX.
               NOTE XXXVIII.  P. 168.

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 XXXIX.  P. 168.

           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 nitro-
gen.   The picrotoxine employed for these analyses was partly ob-
tained from the manufactory of M. Merck, in Darmstadt, and was
partly prepared by M. Francis  himself;  it was perfectly white, and
beautifully crystallized.   Regnault, as is well known, found no nitro-
gen in this compound.
NOTE XL. P. 168.	
COMPOSITION OF QUININE	
Liebig.* Carbon .... 75-76	Calculated C20 H12 N02. 74.39
Hydrogen . . . 7-52 Nitrogen . . .8-11 Oxygen ... 8-62	7-25 8-62 9-74
 
ANALYTICAL EVIDENCE.
315
      NOTE XLI.  P. 168.
COMPOSITION  OF MORPHIA, a
Carbon
Hydrogen
Nitrogen
Oxygen
 Liebig.*

72340
 6-366
 4-995
16-299
Regnault.
72-87
 6-86
 501
15-26
72-41
 6-84
 501
15-74
a Ann. der Pharm., XXVL, 23.
 Calculated
C35 H20 N06.
  72-27
   6-73
   4-78
  16-22
                NOTE XLII.  P. 168.
COMPOSITION OF CAFFEINE, THEINE, GUARANINE,
        THEOBROMINE, AND ASPARAGINE.
Carbon
Hydrogen
Nitrogen
Oxygen  .
  Caffeine.a  Theine.6
Pfaff and Liebig.*  Jobst.
 .  49-77     50-101
     5-33      5-214
 .  28-78     29*009
   16-12     15*676
Guaranine.c
   Martius.
   49-679
   5-139
   29-180
   16-002
Calculated
C8HSN202.
 49-798
   5-082
 28-832
 16-288
               a Ann. der Pharm., I., 17.
               6     Do.        XXV., 63.
               c     Do.        XXVL, 95.

  Guaranine is the name given to  the crystallized principle
of the guarana officinalis, till it was shown to  be identical
with caffeine and theine, as the above analyses demonstrate.

          COMPOSITION OF THEOBROMINE, a
Woskresensky.
Calculated C9H5 No Oz.
Carbon	47-21	46-97	4671	46-44
Hydrogen	4-53	4-61	4-52	4-21
Nitrogen	35-38	35-38	35-38	35-84
Oxygen	12-88	13-04	13-39	13-51
a Ann. der Chem. und Pharm., XLL, 125. 
316
APPENDIX.
         COMPOSITION OF ASPARAGINE. a
                      Liebig.*   Calculated Cs Hs N2 06 + 2 HO.
Carbon  .    .        32-351              32-35
Hydrogen   .     .      6-844               6-60
Nitrogen .     .     .   18-734              18-73
Oxygen    .    .     42-021              4232
             o Ann. der Pharm., VII., 146.
                NOTE XLIII.  P. 143, 167.
     ON THE CONVERSION OF BENZOIC ACID INTO
                     HIPPURIC ACID, t
                   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 ex-
pressed  the  opinion, that benzoic acid,  during  digestion,
was probably 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
  t To the evidence produced by A. Ure, of the 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-azotized substance taken  in the
food can take a share, by means of its elements, in the act of trans-
formation 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 remedies;  and, if the influence of caffeine on the formation
of urea or uric acid should admit of being  demonstrated in  a similar
way, we shall then possess the key to the action of quinine and of the
other vegetable alkalies. — /. L. 
ANALYTICAL EVIDENCE.
317
acid with  his  food, an  acid  crystallizing in needle-shaped
prisms, which had  the  general properties of benzoic acid,
and which he  then  took for benzoic acid.   (Tiedemann's
Zeitschrift fiir Physiologie, i. 142.)   These crystals were
obviously  hippuric acid, as  plainly appears from the state-
ments, that they had the aspect  of  nitre, and, when sub-
limed, left a residue of  carbon.  But  at that time hippuric
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 ac-
tually found hippuric acid in the urine of a  patient who had
taken benzoic acid, recalled  this relation, so remarkable in
a physiological point of view, and induced me to undertake
the following  experiments, which, at the suggestion of Pro-
fessor Wohler, I made  on myself. The supposed conver-
sion of benzoic acid into hippuric acid  has, by these  exper-
iments, been unequivocally established.
   I took, in the evening, before  bedtime, 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 trans-
pire profusely.  I 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
               27 * 
318
APPENDIX.
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-
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 colorless prisms, an inch in length.
  These 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 crys-
tals, which I  found to be 60*4  per cent.   Crystallized hip-
puric  acid, according  to the  formula Clg H8 N05 -j- HO,
contains 60-73 per cent,  of carbon ;  crystallized benzoic
acid, on the other hand, contains 69*10 per cent,  of carbon.
  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 examine 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 the muriatic acid, yielded, on  the  addition of 
                  ANALYTICAL EVIDENCE.             319
nitric 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 color characteristic of uric  acid.  This observation
is opposed to the statement of Ure ; and he is certainly too
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
conversion of benzoic acid  into  hippuric acid ;  but, as his
observations 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.   Finally, it is  clear that the  hippuric acid  existed in
the urine in combination with a base, because it only sep-
arated after the addition of an acid.

  In  the London, Edinburgh, and  Dublin  Philosophical
Magazine, for June, 1842, is a paper by Mr.  Garrod,  con-
firming Dr. Ure's fundamental observation.  When from
a scruple to half  a drachm of benzoic acid was swallowed,
a copious crop of crystals of hippuric acid was. obtained,
amounting to from  fifteen  to twenty-nine grains,  by the
addition of hydrochloric  acid  to the  urine passed  three or
four hours  afterwards.  Mr. Garrod states,  that  he  was
always able to obtain a distinct trace of uric acid  from a
drop or two of the urine.
  The London Chemist, for March, 1843, contains a paper
by Erdmann and Marchaud, on the conversion of cinnamic
acid into hippuric  in the animal  organism,  by the  sim-
ple  oxidation of a portion of its carbon and its hydrogen. 
320
APPENDIX.
                   NOTE A.   P. 14.

               EXCRETION OF CARBON.

  Berzelius considers the quantity of carbonic acid in all the
calculations, as given in note (3), p. 273, to be too great, for
the solid food taken into the body contains f ths of its weight
of water, and of the other Jth, seldom more than £ is carbon ;
consequently 6\  lbs. of solid food would be necessary to
supply the quantity of carbon  which, according to these
estimates, is  excreted  from the  body by the lungs in 24
hours, independent  of what is got rid  of  in other ways.
Muller, 1*303.
         ACTION OF THE HEART.  See Page 57.

  The contraction (systole) only of the heart is an active
state; the dilatation  (diastole) is  the moment of  repose, in
which  the  fibres are  relaxed,  and in which the blood is
poured from  the  contiguous veins into  the cavities of the
heart, to fill the vacuum  consequent on  the  relaxation of its
fibres; the valves of the  heart  being so arranged  as to
allow the  influx of the blood  from the veins.  (Miiller's
Physiology, Vol. I. p. 173.)  See also the experiments of
Sir David Barry, ibid. 234, and  those of  Poiseuille, ibid.
Muller,  although not  admitting to their full  extent the in-
ferences of Barry, admits, that, by the sucking of the heart,
and  by  the action of the valves, a  part of  the  resistance
which opposes the course of the venous blood is overcome. 
ANALYTICAL EVIDENCE.
321
                   NOTE (B.)  P. 165.

             ENDOSMOSE AND EXOSMOSE.

  If we place the  lower end of an open tube, which has
been covered with a thin membrane, such as a  piece of
moistened bladder, in a vessel of water,  and pour a solu-
tion of sugar into  the tube,  the  water  from the  vessel will
shortly be found to pass into  the tube, and the  column of
liquid  will  increase  in height.   At  the  same  time, the
water in the vessel will become  slightly  sweet; a small
quantity of syrup having passed through the pores of the
bladder into the water  without, while a much larger por-
tion of water has  entered the tube.   The  water will con-
tinue to enter the tube,  and the  syrup to leave it, until the
two liquids are  nearly of the same density.  A solution of
gum, salt, or other substances may be employed instead of
sugar.  If two solutions  be employed,  as,  for  instance,
sugar or gum within the tube, and potash or  soda without,
a circulation will  in like  manner take  place.  Instead of
animal membrane, any vegetable  matter  with  fine pores,
such as a thin piece of  wood, or any porous mineral sub-
stance, may be substituted  without  affecting  the result.
Dutrochet,  the discoverer of these phenomena, gave  the
name of Endosmose to tire inward, and that of Exosmose to
the outward  movement.   He  supposed  them to be due to
two opposite currents of electricity. —Dutrochet's  hypo-
thesis  has  not been confirmed.  It  does not  constantly
happen that  the denser  fluid attracts more of the thinner
than the latter  does of the  former;  in  the case of gases,
especially, the contrary  is seen to be sometimes  the case. 
322                   APPENDIX.
But the chemical constitution of the fluid, and its physical
and chemical relation to the  animal  membrane  which it
permeates, seem to have an  important influence  on the
phenomenon. — The  phenomenon of the endosmosis  of
gases, on  which M. Faust  (Amer.  Med. Jour., Vol.  VII.
Froriep's  Not. N.  646) has  instituted  experiments,  are
very remarkable.  A bladder  half filled with  atmospheric
air, being  placed  under a  jar  containing carbonic acid,
becomes more distended ;  and, if the bladder which  is
placed in the carbonic acid gas  contains hydrogen, it be-
comes distended to  bursting.   If, on the contrary, the jar
contains the lighter, and the bladder  the denser gas,  the
bladder becomes collapsed.   (Miiller's Elements of Physi-
ology,  p.  245.)   Gases also permeate  moist  animal  tex-
tures, and will be absorbed  by fluids  within  them.  This
explains how  gaseous matters  can enter  into the blood
without the globules of the blood escaping. 
INDEX. 
 
INDEX.
                               A.
Acid.
— Acetic.   Composition; and relation to that of aldehyde, 267, 268.
— Benzoic.  Composition, and relation to that of oil of bitter almonds,
    267, 268.  Converted into hippuric acid in the human body, 143,
    316.
— Carbonic.  Is the form in which the inspired oxygen and the car-
    bon of the food are given  out, 12.  Its formation in the body the
    chief source of animal heat, 11-21.  Occurs, combined with pot-
    ash and soda, in the serum of the blood, 39.  Formed by the action
    of oxygen on the products of the metamorphosis of the tissues, 59.
    Its  formation may also be connected  with the production of fat
    from starch,  82-87.  Generated by putrefaction of food  in  the
    stomach of animals,  110.  Also by the fermentation of bad wine
    in man, when it causes death by penetrating into the lungs, 111.
    Escapes through both skin and lungs, ib.  Produced, along with
    urea, by the oxidation of uric acid, 133.  Produced, with several
    other compounds, by the oxidation of blood, ib.  May be formed,
    along with choleic acid, from hippuric acid, starch, and oxygen,
    145.  Also, along with choleic acid, urea, and ammonia, by the
    action of water and oxygen on starch and proteine, ib.  Produced,
    along with fat and urea, from proteine, by the action of water and
    oxygen, in the absence of soda,  146.   Combines  with  the com-
    pound  of  iron  present in venous blood, and  is given  off when
    oxygen is absorbed,  257.  Is absorbed by the serum  of blood in
    all states, 258. Researches of Andral  and Gavarret on the exha-
    lation of, 259.  Coathupe's estimate of the quantity from respira-
    tion, 273.
— Cerebric. Its composition, 174.  Its properties, 176.
                      28 
326                         INDEX.
Acid.
— Choleic.  Represents the organic portion of the  bile, 127.  Its for-
    mula, 128.  Its transformations, ib.  Half its formula, added  to
    that of  urate of ammonia, is equal to the formula of blood 4- a
    little oxygen and water, 129.  Produced in the oxidation of blood,
    133.  Views which may be taken of its composition, 141.  May
    be  formed by the action of oxygen and water on proteine and
    starch, 144.  Products of its oxidation, 146.  Various ways  in
    which it may be supposed to be formed  in the body, 152.  Its
    composition, 306.  Cannot be said  to exist  ready formed in the
    bile, 308.
— Cholic. Its composition, 309.  Derived from choleic acid, 127,129.
    Possible relation to choleic acid, 141.
— Choloidic.  Its composition, 306.  Derived from choleic acid, 128.
    Possible relation to choleic acid, 141.   Possible relation to starch,
    150.  Possible relation to proteine, 134.
— Cyanic.  Its formula, 268.
— Cyanuric.  Its formula, 268.
— Hippuric.  Its composition, 310.  Appears in the urine of stall-fed
    animals, 80.  Is  destroyed  by exercise,  80,  132.   Is probably
    formed  in the oxidation of blood, 133.  Is found in  the human
    urine after benzoic acid has been  administered, 143, 316.  May
    be  derived  from proteine when acted on by oxygen and uric
    acid, 144.  With starch  and oxygen, it may produce choleic and
    carbonic acids, ib.  May be derived from the oxidation of choleic
    acid, 146.
— Hydrocyanic or Prussic.   Its poisonous action explained, 263.
— Lactic.  Its composition, 299.  Its origin, 107.  Does not  exist in
    the healthy gastric juice, ib.
— Lithofellic.  Its composition, 313.  Probably derived from  the  ox-
    idation  of choleic acid;  is the chief constituent of bezoar stones,
    146.
— Margaric.  Exists in bile, 308.
— Muriatic.  Exists in the free  state in  the gastric juice, 107, 108.
    Is derived from common salt, 108, 153.
— Oxaluric.  Analysis of, 312.
— Parabanic.  Analysis of, 312.
— Phosphoric.  Exists in the  urine of the  carnivora in  considerable
    quantity, 76, 155.  Its  proportion very small in that of  the gra-
    minivora, 76.  Derived from the phosphorus of the tissues,  ib.
    It is retained in the body to form bones and nervous matter, 77. 
INDEX.
327
Acid.
— Sulphuric.  Exists in the urine of the carnivora, 76, 155.  Derived
    from the sulphur of the tissues, 76.
— Uric.  Its composition, 309.   Products of its oxidation, alloxan,
    oxalic  acid, carbonic  acid, urea, &c, 131, 133.  Is probably de-
    rived, along with choleic acid, by the action of oxygen and water
    on blood or muscle, 130.  Disappears almost entirely in the sys-
    tem of men and of the higher animals, 54, 130.  Appears as cal-
    culus, when  there is a deficiency of  oxygen, 131.  Never  occurs
    in phthisical cases, ib. Yields mulberry calculus when the quan-
    tity of oxygen is somewhat increased, but only urea and carbonic
    acid with a full  supply of oxygen, ib.  Uric  acid calculus  pro-
    moted by the use of fat and of certain wines, 133.  Unknown on
    the Rhine,  ib.  Uric acid and  urea, how related  to allantoine,
    134 ; to  gelatine,  135.  Forms the  greater part of the urine of
    serpents, 53.  Yields, with the elements of proteine and oxygen,
    hippuric acid and urea,  144.  How related to taurine, 148, 149.
    Calculi of it never occur  in wild carnivora, but often in men who
    use little animal food, 139.
Action.  Of the heart, 120.
Affinity, Chemical.  Is  the ultimate cause of the vital phenomena,
  10.  Is active only in the case of contact, and depends much on the
  order in which the  particles are  arranged, 194.  Its equilibrium
  renders a compound  liable  to transformations, 196.  In producing
  the vital  phenomena, it is modified by  other forces, 198.  It is not
  alone the vital force or vitality, but is exerted in subordination to
  that force, 221.
Air.  Introduced into the stomach  during digestion with the saliva,
  109.  Effects of its temperature and density, dryness, &c, in respi-
  ration, 15, 16.  Thomson's examination of air from the lungs, 277.
Albumen.   Animal and vegetable albumen identical, 47, 48.  Their
  composition, 283, 284, 299.   Vegetable albumen, how obtained,
  45.  Is a compound  of proteine, and  in organic composition iden-
  tical with  fibrine and caseine,  47,100, 102.  Exists in the yolk as
  well as the white of eggs, 103.   Also in the serum of the blood, 39.
  Is the true starting-point of all  the animal tissues, 102, 103.
Alcohol.  Is hurtful to carnivorous savages, 170.  Its mode of action ;
  checks the change of matter,  228.  In cold climates  serves as an
  element of respiration, 21.
Aldehyde.  Its composition; how related to that of acetic acid, 267,
  268.
Alkalies.   Mineral alkalies essential  both to vegetable  and  animal
  life  156.   Vegetable alkalies  all  contain nitrogen, all act  on the 
328
INDEX.
  nervous  system,  and are all  poisonous  in a  moderate dose, 172.
  Theory of their action ; they take a share in the transformation or
  production of nervous matter, for which  they are adapted by their
  composition, 173-179.  Action of caustic alkalies on bile, or cho-
  leic acid, 127.
Allantoine.  Is found in the urine of the  fetal calf.   How derived
  from proteine.   How related to uric acid and urea, 134.  How re-
  lated to choleic acid, 141.  Its composition, 310.
Allen and Pepys.  Their calculation of the amount of inspired oxy-
  gen, 271.
Alloxan.  Formed by the oxidation of uric acid, 129.   Converted by
  oxidation into oxalic acid and urea, oxaluric and parabanic acids, or
  carbonic acid and urea, 131.  How related to taurine, 148.  Seems to
  act as a diuretic, 149.  Recommended for experiment in hepatic dis-
  eases, ib. (note).
Almonds, Bitter.  Oil of.  Its composition ; how related to benzoic
  acid, 268.
Ammonia.  Combined with uric acid, it  forms the urine of serpents,
  birds, &c, 53.   Its  relation  to choleic, choloidic, and cholic acids,
  123.   Is one of the products  which may be formed by the oxidation
  of blood,  133;  or  of proteine, 145.  Its relation  to uric acid, urea,
  and taurine, 147.  To allantoine and taurine, 148.  To alloxan and
  taurine, ib.   To choleic and choloidic acids and taurine, 150.  To
  urea, water, and carbonic acid, 151.  Is found in combination with
  acids in the urine  of the carnivora, 155.
Analysis.  Of dry blood, 272, 305.  Of dried flesh, 305.  Of fasces,
  274.   Of black bread, ib.  Of potatoes, ib. Of pease, 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, 283, 301,
  302.   Of vegetable fibrine  and  albumen,  vegetable caseine  and
  gluten, 285.  Of  animal  caseine, 285, 286. Of  starch, 286, 287.
  Of grape or starch sugar, 287.  Of sugar of milk, 288.  Of gum, ib.
  Of oats, ib.  Of hay, 289.  Of  fat, 290.   Of cane-sugar,  ib.  Of
  cholesterine, ib.   Of wax, 297.  Of cyanic acid, cyanuric acid, and
  cyamelide,  298.  Of aldehyde, metaldehyde,  and elaldehyde, ib.
  Of proteine, ib.  Of albumen from the yolk and white of egg, 299.
  Of lactic acid, ib.  Of gas  from the stomach of cows after eating
  to excess, 300.  Of gas from the stomach and intestines of executed
  criminals, ib.  Of gelatinous tissues, 302.  Of tissues containing
  chondrine, 303.  Of arterial  membrane,  ib.  Of horny  tissues, ib.
  Of the lining membrane of the egg, 304.  Of feathers, ib.  Of the
  pigmentum nigrum, ib.  Of choleic acid, 306.  Of taurine,  ib.  Of
  choloidic acid, 309.  Of  cholic acid, ib.  Of uric acid, ib.   Of al- 
INDEX.
329
   loxan, 310.  Of urea, ib.   Of hippuric acid, ib.  Of allantoine, ib.
   Of xanthic oxide, 311.   Of cystic  oxide, ib.   Of oxalic  acid, 312.
   Of oxaluric acid, ib.  Of parabanic acid, ib.  Of roasted flesh, 313.
   Of lithofellic acid, ib.  Of solanine, 314.   Of picrotoxine, ib.  Of
   quinine, ib.  Of morphia, 315.  Of caffeine,  theine, or guaranine,
   ib.  Of theobromine, ib.  Of asparagine, 316.
 Andral and Gavarret.  Their researches on carbonic acid, 259.
 Animal Heat.  Derived from  the combination of oxygen with the
   carbon and hydrogen of the metamorphosed tissues, which proceed
   ultimately from the food, 16, 17.  Is highest in those animals whose
   respiration is most active, 18.   Is the same in man in all climates,
   18, 19.  Is kept up by the food in proportion  to amount of external
   cooling, 21.  Is not produced either by any direct influence of the
   nerves, or by muscular  contractions, 28-32.  Its  amount in  man,
   32.   Chemical  action the sole source of it, 36.  The formation of
   fat from starch  or sugar must produce heat, 88 - 90.  The elements
   of the bile, by  combining with oxygen, serve chiefly  to produce
   it, 59.
 Animal Life.  Distinguished from vegetable life  by the  absorption
   of oxygen, and the production of carbonic acid, 2.  Must not be
   confounded with consciousness, 6, 7.  Conditions necessary to an-
   imal life,  9, 11.  Depends upon an equilibrium between waste and
   supply, 233-242.
 Antiseptics.   They act by putting a stop to  fermentation, putrefac-
   tion,  or  other  forms of  metamorphosis,  162.  Their action  on
   wounds and ulcers, 116.
 Arterial  Blood.  Conveys  oxygen to every part of the body, 59,
   257.   Contains a compound of iron, most probably peroxide, 257.
   Yields oxygen in passing through the capillaries, 59, 259.  Contains
   carbonic acid dissolved or combined with  soda, 261.
 Arteries.  Composition  of their  tunica media, 303.  How derived
   from proteine, 121.
 Asparagine.   Its composition, 316.  Its relation to taurine and  bile,
   170.   Theory of its action on the bile, 171.
 Assimilation.  In animals it is independent of external influences,
  3. Depends on the presence  in  the blood of compounds of  pro-
  teine, such as fibrine, albumen, or caseine, 38- 103.  Is more ener-
  getic in the young than  in the adult animal, 65.  Is  also more  en-
  ergetic in  the herbivora  than in the carnivora, 78.
Atmosphere.  See Air.
Azotized Products.   Of vegetable life, 44, 167, 173.  Of the meta-
  morphosis of tissues.  Necessary  for the  formation  of bile in  the
                       28* 
330
INDEX.
  herbivora, 150.   In man,  157-160.   May be replaced by azotized
  vegetable  compounds, 161.   Theory of this,  168-172.  Of the
  transformation  of the  bile, or of choleic acid ; how  related to the
  constituents of urine, 147.

                               B.

Beans.   Composition of, 274.
Beer.   Forms part of the diet of soldiers  in Germany, 275-278.
Bees.  Their power of forming wax from  honey, 291 - 297.
Benzoic Acid.  See Acid, Benzoic.
Berthollet.   His analysis of oxalic acid, 312.
Berzelius.   His  analysis of potato  starch, 287; of sugar  of milk,
  288; of gum, ib.; of cane-sugar, 290.  On excretion of caibon, 320.
Bezoar Stones.  See Acid, Lithofellic.
Bile.  In the carnivora is  a  product of  the metamorphosis of the
  tissues, along with urate of ammonia, 130.  May be represented by
  choleate of soda, with which, however, it  is  not identical, 308.
  Products of its transformation, 126, 307.  Remarks on these, 306-
  308.   Origin of bile, 60, 137.   Starch,  &c, contribute  to its  for-
  mation in  the herbivora, 141, 148, 150, 152, 157.  Soda essential to
  it, 146, 153, 155.  Relation of bile to urine,  148.  To starch, 150.
  To fibrine,  130.  To caffeine, Sec., asparagine,  and  theobromine,
  170, 171.  For the acid substances derived from bile, choleic, choloid-
  ic, and cholic acids, see Acid, Choleic, &c.  Yields  taurine, 128.
  Contains cholesterine, 82, 308.   Also  stearic and  margaric  acids,
  ib.  Its function ; to support respiration, and produce animal heat
  by presenting carbon and hydrogen in  a very  soluble form to the
  oxygen of the arterial blood, 59-63.   Amount  secreted by the dog,
  the horse, and man, 62.  It returns entirely into the circulation, and
  disappears completely, 59-61.
Blanchf.t.   His analysis of solanine, 314.
Blood.  The fluid from which every part of the body is  formed, 8.
  Its chief constituents, 38.  How formed from vegetable food, 44.
  Can only be formed from compounds of  proteine, 47.   Is, therefore,
  entirely derived from vegetable products in the herbivora, and indi-
  rectly, also, by the carnivora, which feed on the flesh of the former,
  48.  Its composition identical with that  of flesh, 127.  Analysis of
  both,  305.  The secretions contain all the elements of the blood,
  126.    Its relation to bile and urine, 129.  Products of the oxidation
  of blood,  133.  Excels of azotized food produces fulness  of blood
  and disease, 139.  Soda is present in the blood, 153 -155.  Impor- 
INDEX.
331
  tant properties  of the  blood, 163-166.  Venous blood contains
  iron, probably as protoxide ;  arterial blood, probably as peroxide, 259
  - 262.   Theory of the  poisonous  action of sulphuretted hydrogen
  and Prussic acid; they decompose  the  compound of iron  in  the
  blood,  263.   The  blood, in  analogous  morbid states, ought to be
  chemically examined, 264.  Analysis of, 272.
Blood-letting.  Theory of its mode of action, 247.  It may produce
  opposite effects in different cases, 253.
Boeckmann.  His analysis of black bread, 274 ; of potatoes, ib.; of
  dry beef, 305; of dry blood, ib.; of roasted flesh, 313.
Bones.   Phosphoric acid  of the food  retained to  assist  in forming
  them, 77. Gelatine of bones  digested  by dogs,  93.  See, further,
  Gelatine.  Cause of brittleness in bones, 96.
Boussingault.  His analysis of potatoes, 274.  His comparison of the
  food and excretions in the horse and cow, Table, 280.  His analy-
  sis  of gluten, 284;  of  vegetable  albumen,  ib.;  of vegetable glu-
  ten, 285;  of oats, 288 ;  of hay, 289.
Braconnot.  On the presence of lactic acid in gastric juice, 107; of
  iron in the gastric juice  of the dog, 108.
Brain.  See Acid, Cerebric, and Nervous Matter.
Bread.   Analysis  of, 274.
Brunn.   His analysis of sugar of milk, 288.
Buckwheat.  Analysis of starch from, 286.
Burdach.  His statement of the  amount of bile secreted by ani-
  mals,  62.
Butter.   Forms a part of the food of soldiers in Germany, 275.
Buzzard.  Its  exciements consist of urate of ammonia, 53.

                               c.

Caffeine.  Identical with theine, 170.  Its relation  to taurine and
  bile, 171.  Theory  of its mode of  action,  171.  Its composition,
  315.
Calculus.  Mulberry ; derived  from the imperfect oxidation of uric
  acid, 131.  Uric  acid calculus is formed in consequence  of de-
  ficiency of inspired oxygen, or excess of carbon  in the food, 131.
  See Acid, Uric.   Bezoar stones composed of lithofellic acid, 146.
Cane Sugar.  Its  composition, 290.
Carbon.  Is accumulated in the bile, 59. Is given off as carbonic
  acid 12.  Excess of carbon  causes  hepatic diseases, 23.  By com-
  bining with oxygen, it yields the  greater part of the animal heat.
  See Animal Heal, Bile, and Acid,  Carbonic.  Amount of carbon
  oxidized daily in the body of a man, 14.  Calculations on which 
332
INDEX.
  this statement is  founded, 273-290.  Amount  consumed  by the
  horse and cow, 14.  Different proportions of carbon in different
  kinds of food, 16.  Carbon  of flesh  compared with that of starch,
  showing the advantage of a mixed diet, 73.  Calculation on which
  this statement is founded, 273.  Amount of carbon in dry blood
  calculated, 272.   Quantity of, from  respiration, 278.   Amount in
  the food of prisoners calculated, 283.  Excretion ol carbon, 320.
Carbonates.  They occur in the blood, 39.
Carbonic Acid.  See Acid, Carbonic.
Carbonic Acid Gas.  Quantity of, in  air from the lungs, 277.
Carnivora.  Their nutrition  the most simple, 43.  It is ultimately
  derived from vegetables, 47, 48.  Their young, like  graminivora,
  require  non-azotized compounds in  their food,  49.  Their bile is
  formed from the metamorphosis of their tissues,  57, 59.  The pro-
  cess of assimilation in  adult and young  carnivora compared, 65.
  Their urine, 76.  The assimilative  process in adult carnivora less
  energetic than in  graminivora, 78.   They are  destitute  of fat, 80.
  They  swallow less air with their food than graminivora, 113. Con-
  cretions of uric acid are never found in them, 139.  Both soda and
  ammonia found in their urine, 155.
Caseine.  One of the azotized  nutritious products of vegetable life,
  46.  Abundant in  leguminous  plants, 46.  Identical in organic
  composition with fibrine and albumen, 47.  Animal caseine  found
  in milk and cheese;  identical with vegetable caseine, 50.  Fur-
  nishes blood to the  young animal, 51.  Is one  of the plastic  ele-
  ments of nutrition, 92.   Yields proteine, 101,102.  Its relation to
  proteine, 120.  It contains sulphur, ib.  Potash essential to its pro-
  duction, 156. Contains more of the earth of bones than blood does,
  51. Its analysis, 285.
Cerebric Acid.  See Acid, Cerebric.
Change of Matter.  See Metamorphosis of Tissues.
Chemical Attraction.   See Affinity.
Chevreul.   His researches on fat, 81.  His analysis of fat, 290.  Of
  cholesterine, ib.
Chloride of Sodium. See Salt, Common.
Choleic Acid.  See Acid, Choleic.
Cholesterine.  See Bile.
Cholic  Acid.  See Acid, Cholic.
Choloidic Acid.  See Acid,  Choloidic.
Chondrine.  Its relation  to proteine,  120.   Analysis of tissues con-
  taining it, 3l)3.
Chronic Diseases.  The action of inspired oxygen is the cause of
  death  in them. 26, 27. 
INDEX.
333
Chyle.  When it has reached the  thoracic duct, it is alkaline, and
  contains albumen coagulable by heat, 138.
Chyme.  It 13 formed, independently of the vital force, by a chemical
  transformation, 165.  The substance which causes this transforma-
  tion  is derived from the  living membrane  of the  stomach, 165.
  Chyme is acid, 138.
Clothing.   Warm clothing is a substitute for food to a certain ex-
  tent, 21.  Want of clothing accelerates the rate of  cooling, and the
  respirations, and thus increases the appetite, ib.
Coathupe.  His estimate of the quantity of carbonic acid from respi-
  ration , 278.
Cold.   Increases the appetite by accelerating the respiration, 21.  Is
  most judiciously employed as a remedy in cerebral inflammation, 249.
Concretions.  See Calculus, and Acid, Uric; also, Acid, Lithofellic.
Constituents, Azotized.  Of blood :  see  Fibrine and Albumen. 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.
Corn.   Experiments on oil in, xxix.
Couerbe.  His analysis of cholesterine, 290.
Cow.  Amount of carbon expired by  the, 14.   Comparison of the
  food  with the excretions of the cow, 281.
Crum.   His analysis of cane-sugar, 290.
Cultivation.  Is the economy of force,, 75»
Cyamelide.  Its  formula, 268.
Cyanic Acid.  See Acid, Cyanic.
Cyanide of Iron.  Its remarkable properties, 257.
Cyanuric Acid.   See Acid, Cyanuric.

                               D.
Davy.   Oxygen consumed by an adult man, 271.
Death.  Cause of, in chronic diseases, 26. Caused  in old people by
  a slight depression of temperature, 243.   Definition of it, 242.
Demarcjay.   His analysis of choleic acid, choloidic acid, and taurine,
  306.   Remarks on his Researches on Bile, ib.
Denis.  His experiments on the conversion of fibrine  into albumen,
  39, 40.
Despretz.   His calculation  of the heat developed in the combustion
  of carbon, 32.   His experiments on respiration, 271.
Diabetes Mellitus.  The sugar found in the urine in this disease
  is grape sugar,  and is derived from the starch of the food, 92. 
334
INDEX.
 Diastase.  Analogy between its solvent action on starch, and that of
   the gastric juice on coagulated albumen, 106.
 Diffusion of  Gases.  Explains the fact that  nitrogen is given out
   through the  skin of animals, 113;  and the poisonous  action of
   feather-white wine, 111.
 Digestion.   Is effected without the aid of the vital force, by a meta-
   morphosis derived from the  transformation of a substance proceed-
   ing from the  lining membrane of the stomach, 105.  The oxygen
   introduced with the saliva assists in the process, 109.   Lactic acid
   has no share  in it, 107.
 Disease.   Theory of, 242 et seq.  Cause of death in chronic disease,
   25.  Disease  of liver caused by excess of carbon or deficiency of
   oxygen, 22.  Prevails in hot weather, 23.
 Dog.  Amount of bile secreted  by, 62.   Digests  the gelatine of the
   bones, 94.  His excrements contain  only bone earth, 95.  Concre-
   tion of urate of ammonia said to have been found by  Lassaigne in a
   dog, doubtful, 139 (note).
 Dumas.  His analysis of choleic acid,  306; of choloidic acid, ib.; of
   taurine, ib.; of cholic acid, 309;  of  hippuric acid, 310.   His  views
   borrowed from Liebig, 41.

                               E.

Eggs.  Albumen of the white and of the yolk identical, 103.  Analy-
   sis of both, 299; of lining  membrane, 304.  The fat of the yolk
   may contribute to the formation of nervous  matter,  103.  This fat
   contains iron, ib.
 Elaldehyde.  See Aldehyde.
 Elements.  Of nutrition, 92.  Of respiration, ib.
 Empyreumatics.   They  check transformations, 162.  Their action
   on ulcers, 116.
 Equilibrium.   Between waste and  supply of  matter  is  the abstract
   state of health, 233, 246.  Transformations occur in compounds in
   which the chemical forces are in unstable equilibrium, 104.
 Ettling.  His  analysis of wax, 297.
 Ettling and Will. Their analysis of lithofellic acid, 313.
 Excrements.   Contain little or no bile in man and in  the herbivora,
   none at all in the dog and other carnivora, 62.   Those of the dog
  are phosphate of lime,  95.  Those of serpents are urate of ammo-
   nia, 53.   Those of birds also contain that salt,  54.  Those of the
  horse and cow compared with their food, 280, 281.
 Excretion.   Of carbon, 320. 
INDEX.
335
 Excretions.  Contain, with the secretions, the elements of the blood
  or of the tissues, 126, 130.  Those of the horse and cow compared
  with their food, 280, 281.  Bile is not an excretion, 62.

                               F.

 F.«ces.  Analysis of, 274.
 Fat.  Theory  of its production from starch, when oxygen is deficient,
  80 et seq.; from other substances, 83. The formation of fat supplies
  a new source of oxygen, 86; and produces heat,  86 et seq.  Maxi-
  mum of fat, how obtained, 91.  Carnivora have no fat, 80.  Fat in
  stall-fed animals, 86.  Occurs  in some diseases  in the blood, 92.
  Fat in the women of the East, 96. Composition compared with that
  of sugar, 81, 82. Analysis of fat, 290.  Disappears in starvation, 24.
  Is an element of respiration, 92.
 Fattening of Animals.  See Fat.
 Featherwhite Wine.  Its poisonous action, 111.
 Febrile  Paroxysm.   Definition of, 244.
 Fehling.   His analysis of metaldehyde and elaldehyde, 298.
 Fermentation.  May be produced by any azotized  matter in a state
  of decomposition, 115.  Is arrested by empyreumatics, ib.   Is anal-
  ogous to digestion, 114.
 Fever. Theory and definition of, 244.
 Fibre, Muscular.  See Flesh.
Fibrine.   Is an element  of nutrition,  92.  Animal and vegetable
  fibrine are identical, 47.  Is a compound of proteine, 102.  Its rela-
  tion to proteine, 121.  Convertible  into albumen, 40.  Is derived
  from albumen during incubation, 103.   Its analysis, 283, 284, 302.
  Vegetable fibrine, how obtained, 45.
Fishes.  Yield phosphuretted  hydrogen, 18 (note).
Flesh. Consists chiefly  of fibrine, but, from the mixture of fat and
  membrane, has  the same formula as blood, 127.   Analysis of flesh,
  305. Amount of carbon in flesh compared with that of starch, 74,
  289.
 Food.  Must contain both elements of nutrition and elements of res-
  piration, 92.  Nutritious food, strictly speaking, is that alone which
  is capable of forming blood, 38.  Whether derived from animals or
  from vegetables, nutritious food contains proteine, 38, 101 et seq.
  Changes which the food undergoes in the organism of the carniv-
  ora  52 et seq.   The  food of the  herbivora always contains starch,
  sugar, &c,  68.   Food, how dissolved, 104  et seq.  Azotized food
  has no direct influence on the formation of uric acid calculus, 131. 
336
, INDEX.
  Effects  of superabundant azotized food,  138,  139.  Non-azotized
  food contributes to the formation  of bile, and thus to  respiration,
  140 et seq.   Salt must be added to the food of herbivora, in order
  to yield soda for the bile, 154.   Caffeine, &c, serve as food for the
  liver, 178.   The vegetable alkalies may be viewed as food for the
  organs which form the nervous matter, 179.  Amount of food con-
  sumed by  soldiers in Germany, 275.   Its  analysis, 279.  Food of
  the horse and cow compared with their excretions, 280, 281.
Formula.  Explanation of their  use, 268.   How  reduced to  100
  parts, 269.   Formula? of albumen, fibrine, caseine, and animal tis-
  sues, 120.  Formula  of proteine, 116; of blood and flesh, 127; of
  fat, 82; of cholesterine, 82; of aldehyde,  acetic acid, oil of bitter
  almonds, and  benzoic acid, 268;  of cyamelide, cyanic acid,  and
  cyanuric acid,  268;  of choleic  acid, 128; of choloidic  acid  and
  cholic  acid, 128; of gelatine, 135; of hippuric acid, 143;  of litho-
  fellic acid, 146 ; of taurine, 148; of alloxan, 148.  See Analysis.
Francis.  His analysis of picrotoxine, 314.
Fremy.  Lameyran and Fremy ;  their analysis of gas from the ab-
  domen of cows after  excess in fresh food, 300.  His researches on
  the brain, 43, 174.
Frequency of the pulse and respiration in different  animals, 18, 282.
Fruits.  Contain very little carbon,  and hence are  adapted for food
  in hot climates, 16.

                               G.

Gas.   Analysis of gas from abdomen of  cows after excess in fresh
  food, 110, 300.  Analysis of  gas from the stomach and intestines of
  executed criminals,  111, 300.   Carbonic acid,  quantity of in air
  from the lungs, 277.
Gastric  Juice.  Contains  no solvent but  a substance in a state of
  metamorphosis, by the presence of which the food is dissolved, 104.
  Contains free acid, 105.  Contains no lactic acid, 107.  In the dog
  has been found to contain iron, 108.  See Digestion, Chyme, Food.
Gay-Lussac  and Thenard.  Their analysis of starch, 287 ; of sugar
  of milk, and  of gum, 288; of cane-sugar, 290;  of wax, 297; of
  oxalic acid, 312.
Gelatine.  Is derived from proteine, but is no longer a compound of
  proteine, and cannot form blood, 122 et seq.  May serve as food for
  the gelatinous tissues, and thus spare the stomach of convalescents,
  95, 124.  In starvation the gelatinous tissues remain intact, 93.  Its
  relation to proteine, 125.  Its  formula, 135.  Its analysis, 302, 303. 
INDEX.
337
Globules of the blood are the carriers  of oxygen to all parts of the
  body, 163 -166.   They contain iron, 253 et seq.
Gluten.  Contains vegetable fibrine, 45.  Analysis of it, 284, 285.
Gmelin.  On the sugar of bile, 140.
Goebel.  His analysis of gum, 288.
Goose.  How fattened to the utmost, 91.
Graminivora.  See Herbivora.
Grape-sugar.   An element  of respiration, 92.   Is  identical  with
  starch-sugar and diabetic sugar, 72,  Its composition, 73.  Its anal-
  ysis, 287.
Growth, or increase of mass, greater in graminivora than in carniv-
  ora, 77.  Depends on the blood, 38; and  on compounds of pro-
  teine, 102.  See Nutrition.
Gum.   An element of respiration, 92.  Its composition, 71.  Is related
  to sugar of milk, ib.  Its analysis, 288.
Gundlach.   His researches on the formation of wax from honey of
  the bee, 291-297.
                              H.

Hair.   Analysis of, 303.   Its relation to proteine, 120.  Analysis of
  proteine from hair, 299.
Hay.  Analysis of, 289.
Hays, A. A.   His experiments on corn,  xxix.
Heart.  Action of the, 320.
Hepatic Diseases.  Cause of, 22.
Herbivora.  Their blood  derived from compounds  of proteine in
  their food, 47.  But they require  also for their support non-azotized
  substances, 68.  These last assist in the formation of their bile, 140
  et seq.  They retain the  phosphoric acid of their food to  form brain
  and nervous matter, 77.  Their urine  contains very little phospho-
  ric acid, 76.  The energy of vegetative life in  them is very great,
  78.  They become fat when stall-fed, 79.
Hess.  His analysis of wax, 297.
Hippuric Acid.  See Acid, Hippuric.
Horn.   Analysis of, 303.   Contains proteine ; its relation to proteine,
  120.   Analysis of proteine from  horn, 299.
Horse.  Amount of carbon expired by, 14.  Comparison of his food
  with his excretions, 280.  Force exerted by a horse in mechanical
  motion compared to  that exerted by a whale, 226.
Hybernating Animals.   Their  fat disappears  during  the winter
   sleep, 24.  They secrete bile and urine during the same period, 60.
 Hydrocyanic Acid.  See Acid, Hydrocyanic.
                       29 
338
INDEX.
Hydrogen.  By combining with oxygen contributes to produce the
  animal heat, 23.
                               I.

Ice.  Is judiciously employed as a remedy in cerebral inflammation,
  249.
Inorganic constituents of albumen, fibrine, and caseine, 39, 116,120.
Iron.  Is an essential constituent of the globules of the  blood, 253 et
  seq.   Is found in the fat of yolk  of egg, 103,  Also in the gastric
  juice of the dog, 108.  Singular properties of its compounds, 256.
Isomeric  Bodies. 99, 268.
                               J.
Jobst.  His analysis of the"ine, 315.
Jones, Dr. Bence. His analysis of vegetable fibrine, 284 ;  of vegeta-
  ble albumen, ib. ; of vegetable  caseine, 285;  of gluten, ib.; of the
  albumen of yolk  of egg, 299,301;  of the albumen of brain, 301.

                               K.

Keller.   His researches on the conversion of benzoic acid into hip-
  puric  acid in the human body, 316.
Kidneys.  They  separate from  the arterial blood  the  nitrogenized
  compounds destined for excretion, 76.

                               L.

Lactic  Acid.  See Acid, Lactic.
Lavoisier.  His  calculation of the amount of inspired  oxygen, 12,
  271.
Lehmann. On the presence of lactic  acid in gastric juice, 107.
Lentils.   Contain  vegetable caseine, 46.  Analysis of, 273, 274.
  Form part of the diet of soldiers in Germany, 276.  Table, 279.
Liebig.  His analysis of sugar of milk, 288 ; of cane-sugar, 290; of
  aldehyde, 298; of uric acid,  309; of hippuric acid,  310; of qui-
  nine,  314 ; of morphia, 315 ; of asparagine, 316.  His calculation of
  the carbon daily expired as carbonic acid, 13, 273 et seq.  Table,
  279.  His remarks on Demarqay's researches on bile, 306 - 309.
Liebig and Pfaff.   Their analysis of caffeine, 315.
Liebig and Wohler.  Their analysis of alloxan,  310;  of urea, ib.;
  of allantoine, ib.; of xanthic oxide, 311 ; of oxaluric acid, 312; of
  parabanic acid,  ib.
Light.   Its influence on vegetable  life analogous to that of heat  on
  animal life, 222. 
                              index.                        339

  Lime.  Phosphate of.  See Bones.
  Liver.  It separates  from the venous blood the carbonized constitu-
    ents destined  for respiration, 57.  Diseases of the liver, how pro-
    duced, 22.  Accumulation of fat in the liver of the goose, 91.
  Lungs.  Carbonic acid from the, 259.

                                M.

  Macaire and Marcet.  Their analysis of blood, 272.
  Maize.  Analysis of starch from, 287.
  Marcet.   His analysis of gluten, 284.
  Marcet and Macaire.  Their analysis of blood, 272.
  Marchand.   On the amount  of urea in the urine of the dog  when
    fed on sugar, 60.  His  analysis of cholesterine, 290.
  Martius.  His analysis of guaranine, 315.
  Mechanical  Effects.  See Motion.
  Medicine.  Definition of the objects  of, 245 et seq.  Action of medi-
   cinal agents, 161 et seq.
 Menzies.   His calculation of the amount of inspired oxygen, 12  271.
 Metaldehyde.   See  Aldehyde.
 Metamorphosis of Tissues, 99 et seq.   In  other  parts of the vol-
   ume, passim.
 Milk.   Is the only natural product perfectly fitted to sustain life, 50.
   Contains caseine, ib.;  fat  (butter),  ib.; sugar of milk, ib.; earth
   of bones, 51 j and potash, 156.
 Mitscherlich.  His analysis of uric acid, 309 ;  of hippuric acid, 310.
 Momentum.  Of force, 191.  Of motion,  192.
 Morphia.  Contains less nitrogen than quinine, 168.  Its analysis, 315.
 Motion.  Phenomena  of  motion in  the animal body, 186 et  seq.
   Different sources of motion, 189.  Momentum of motion, 191.  Mo-
   tion propagated by nerves, 208.  Voluntary and involuntary mo-
   tions accompanied by a change of form  and  structure in living
   parts, 209. Motion derived from change of matter, 210 et seq.  The
   cause of motion in the animal body  is a peculiar force, 220.   The
   sum of the effects of motion in the body proportional to the amount
   of nitrogen in the urine, 233.
Mulberry  Calculus.  See Calculus.
Mulder.  Discovered proteine, 101. His analysis of fibrine of blood,
  283 ;  of animal caseine, 286;  of proteine, 299;  of fibrine, 302;
  of gelatine, ib.; of chondrine, 303.
Muscle.  See Flesh.
Muscular Fibre.  Its  transformation depends  on the amount of
  force expended  in producing motion, 209. 
340
INDEX.
                               N.

 Nerves.  Are the conductors of the vital  force, and of mechanical
  effects, 208.  Effects of the disturbance of their conducting power,
  218.  They are not the source of animal heat, 28.
 Nervous Life.  Distinguished  from vegetative, 36.
 Nervous Matter.  Contains albumen, and fatty matter of a peculiar
  kind, 43.   Vegetables  cannot  produce  it, 49.  The fat of yolk of
  egg probably  contributes to its formation,  103.  The phosphoric
  acid and phosphates, formed in the metamorphosis of the tissues of
  the herbivora, are retained to assist in  the  formation of nervous
  matter, 77.  The  vegetable  alkalies  affect  the nervous  system,
  172-174.   Composition  of cerebric  acid,  174.   Theory  of the
  action of the vegetable alkalies, 175.
 Nitrogen.   Essential to all organized structures, 42, 43.  Substances
  in the body which are destitute of it not organized, 43.  Abounds
  in nutritious vegetables, 45. Nutritious forms in which it  occurs,
  ib. el seq.   Occurs in all vegetable poisons, 167; also in a few sub-
  stances which are neither nutritious nor poisonous, but  have a
  peculiar effect on the system, such as caffeine, 167 et seq.
 Nitrogenized.  See Azotized.
 Non-Azotized.  Constituents of food.  See Starch.
Nutrition.   Depends  on the blood,  38;  on  albumen, fibrine, or
  caseine, 38 et seq.  Elements of nutrition, 92.  Compounds of pro-
  teine aloue are nutritious, 101.   Occurs when  the  vital force is
  more powerful than the opposing chemical forces, 188.   Theory of
  it, 199.  Is almost unlimited in plants from the absence of nerves,
  201.  Depends on the momentum of force in each part, 216.  De-
  pends also on heat, 231.

                               0.

 Oats.  Amount required to keep a horse in good condition, 72.  An-
  alysis of, 288.
 Oil.   In corn, experiments on, xxix.
 Oil of Bitter  Almonds.   Its  composition.   How related to  ben-
  zoic acid, 267, 268.
 Old  Age.  Characteristics of 236 el seq.
 Oppermann.  His analysis of wax, 297.
 Organized Tissues.  All contain nitrogen, 42, 43.   All  such as are
  destined for effecting the change of matter are full of small vessels,
  212.  Their composition, 120.  The gelatinous and cellular tissues, 
INDEX.
341
  and the uterus, not being destined  for that purpose, are differently
  constructed, 213. Waste of organized tissues rapid in carnivora, 73.
Organs.  The food of animals always consists of parts of organisms,
  2.  All organs in the body contain nitrogen,  42, 43.  There must
  exist organs for the production  of nervous  matter, 179; and  the
  vegetable alkalies may be viewed as food for these organs, ib.
Origin.  Of animal heat, 16, 29.  Of fat, 78 et seq.  Of the nitrogen
  exhaled from the lungs,  109 et seq.  Of gelatine, 121 et seq.  Of
  uric acid and urea, 129 et seq.  Of bile, 128, 136, 139 et seq.,  150.
  Of hippuric acid, 143, 316 et seq.  Of the  chief secretions and ex-
  cretions, 145.  Of the soda of the  bile,  153 et seq.  Of the nitrogen
  in bile, 160.   Of nervous matter, 173 et seq.
Ortigosa.  His analysis of starch, 287.
Oxalic  Acid.  A product, along with urea, of  the partial oxidation
  of uric acid, occurring in the form of mulberry calculus, 131.   Its
  analysis, 312.
Oxygen.  Amount consumed by man daily, 12, 271.  Amount con-
  sumed daily in oxidizing 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,
  24 - 26.   The amount of oxygen inspired  varies  with the tempera-
  ture, dryness, and  density  of the  air, 16.  Is carried  by arterial
  blood  to all  parts of the body, 163.   Fat differs from sugar and
  starch only in the amount of oxygen, 81.  It also contains less oxy-
  gen than  albumen,  fibrine,  &c, 83.  The  formation of fat de-
  pends on a deficiency of oxygen, 85 et seq.; and helps to  supply
  this deficiency, 86.   Oxygen essential to digestion, 108.  Relation
  of oxygen to some of the tissues formed from proteine, 120.  Oxy-
 .gen and water, added  to blood or to flesh,  yield the  elements  of
  bile and of urine,   128.  Action  of oxygen  on uric  acid, 129;
  132; on hippuric acid, 79,133;  on blood, ib.;  on proteine, with
  uric acid, 144 ;  on proteine and starch, with water,  ib.; on choleic
  acid, 146; on proteine,  with water,  147.  By depriving starch of
  oxygen  and water, choloidic acid  may be formed,  150.  Oxygen
  is essential to the  change  of matter, 164. Its action on the  azo-
  tized  constituents of plants  when  separated, 202.   Its  action on
  the muscular fibre essential to the  production of force, 209-215.
  Oxyo-en is absorbed by  hybernating animals, 229.  Is the cause
  of the waste  of matter, 231 ; and of animal heat, 232.   Blood-
  letting acts by  diminishing  the  amount of oxygen  which acts on
  the body, 247.   Its absorption is  the cause of the change of color
  from venous to arterial blood, 253.   The globules probably contain
                       29* 
342
INDEX.
  oxide of iron, protoxide in  venous blood, peroxide in arterial, 255
  et seq.  All parts of the  arterial blood contain oxygen, 164,  165,
  254, 259.   Quantity of abstracted from air by respiration, 271.

                               P.

Pears.  Analysis of starch  from unripe, 287.
Pease.  Form part of the diet of soldiers in Germany, 276.  Abound
   in  vegetable caseine, 46.  Analysis of pease, 273, 274 ; of starch
  from pease, 286.
Pepys and Allen.  Their calculation of the amount of inspired oxy-
  gen, 271.
Peroxide  of Iron.  Probably exists in arterial blood, 255 et seq.
Pfluger.  His analysis of the gas obtained by puncture from the ab-
  domen of cattle after excess in  green food, 300.
Phenomena of motion in the animal body, 185 et seq.
Phosphates. See Bones.
Phosphoric  Acid. See Acid, Phosphoric.
Phosphorus.  Exists in albumen and  fibrine, 39, 43, 120. It is not
  known  in what  form,  116  et seq.  Is an  essential constituent of
  nervous matter, 174, 180.
Phosphuretted Hydrogen.  Occurs  among the products of the
  putrefaction of fishes, 180, 181.
Picrotoxine.  Contains nitrogen, 168 (note).  Its analysis, 314.
Plants.  Distinguished from animals by fixing carbon and giving out
  oxygen, 2,202; by the want of nerves and of locomotive powers, 3.
  Their capacity of growth almost unlimited, 219.  Cause of death in
  plants, 203.
Playfair, Dr. L.  His  formula for  blood,  127.  His  analysis of
  faeces, of pease, of lentils, of beans, 274;  of flesh and of blood,
  305;  of roasted flesh, 313.
Poisons, Vegetable.   Always contain  nitrogen, 167 et seq.  Differ-
  ent kinds of poisons, 161.  Theory of  the action of Prussic  acid
  and of sulphuretted hydrogen, 262.
Polymeric Bodies, 99.
Potash.   Essential to the production of caseine or milk, 156.
Potatoes.   Amount of carbon in, 276.  They form part of the  diet
  of soldiers in Germany, ib.  Analysis  of, 274 ;  of starch from, 287 ;
  of solanine from the  buds  of germinating potatoes, 314.
Pregnancy.  Exhalation of carbonic acid during,  260.
Prevost and Dumas.  On the frequency of the pulse and respira-
  tions, 282. 
INDEX.
343
Products.  Of the metamorphosis of tissues found in  the bile  and
  urine, 126.  Of the action of muriatic  acid on bile, 127.   Of the
  action  of potash on bile, ib.  Of the action of water and oxygen on
  blood or fibre, 129.  Of the oxidation of  uric acid, 130.  Of the ox-
  idation of blood, 133.   Of the action of  water on proteine, 135.  Of
  the action of urea on lactic and bezoic acids, 143.   Of oxygen  and
  uric acid on proteine, 144.  Of oxygen on starch and hippuric acid,
  ib.   Of oxygen and water on proteine and starch,  145.  Of oxygen
  and water on proteine, when soda is absent, 146.  Of the separation
  of oxygen from starch, 159.  Of the  action of  water on urea,  151.
  Of the action ofwater and oxygen on caffeine or theine, asparagine,
  and theobromine, 170.
Proteine.   Discovered by  Mulder, 101.   Its composition, 102.   Pro-
  duced alone by vegetables, ib.  Is the source of all the organic
  azotized constituents of the body, 103.   Its formula, 116.   Its rela-
  tion to fibrine,  albumen, caseine, and all the  animal  tissues,  120.
  Gelatine no longer yields it, although formed from it, 123.   Its re-
  lation to  bile and  urine, 130.   Its relation  to allantoine  and  cho-
  loidic acid, 134; to gelatine, 135; to  hippuric acid,  143;  to the
  chief secretions and excretions, 144, 145; to fat, 146.   Analysis of
  proteine from the crystalline lens, from albumen, from fibrine, from
  hair, from horn, from  vegetable albumen and  fibrine, from cheese,
  298 et seq.
Prout.  His analysis of  starch, 287 ; of grape sugar from honey, ib.;
  of sugar of milk, 288 ;  of cane-sugar, 290; of urea, 310.   His  dis-
  covery of free  muriatic acid in the gastric juice, 107.  On  the
  effect of  fat food on the urine, 132.   On carbonic  acid expired,  272.
Prussic  Acid.  See Acid, Hydrocyanic.
Pulmonary Diseases.   Arise from excess of oxygen, 22.  Prevail in
  winter, 23.
Pulse.  Its frequency in different animals, 282.
Putrefaction.   Is  a process  of transformation, 104.   Membranes
  very liable to it, 105.  Effects of the putrefaction of green food in
  the stomach of animals,  110.  Is analogous to digestion, 114.  Pu-
  trefying animal matters  cause the fermentation of sugar, 115. Is
  checked by empyreumatics, 116,162.

                               Q-

Quinine.  Contains nitrogen, 168.  Its analysis,  314. 
344
INDEX.
                               R.

Regnault.   His analysis of morphia, 315.
Reproduction of the Species, 37.
Reproduction of Tissues.  See Nutrition.
Respiration. Theory of, 253 et seq.  Quantity of oxygen abstracted
  from air during, 271.  Its connexion with the food and with animal
  heat,  11 et seq.
Rhenish Wines.  Contain so much  tartar, that their use prevents
  the formation of uric acid calculus, 133.

                               s.

Salt, Common.   Essential to the formation  of bile in the  herbivora,
  and to that of gastric juice, 153 et seq.
Saussure,  De.  His analysis  of grape sugar and of starch sugar,
  287; of wax, 297.
Scherer, Dr. Jos.   His analysis of albumen from  serum  of blood,
  283; of fibrine of blood, ib.;  of vegetable fibrine, 284 ; of vegeta-
  ble caseine, 285; of animal caseine, ib.; of proteine from different
  sources, 298; of albumen from white of egg, 299; of albumen from
  different  sources, 301; of fibrine, 302; of gelatine  from different
  sources, ib.; of tissues containing chondrine, 303 ; of the tunica
  media of arteries,  ib.; of horny  tissues,  ib.; of the lining mem-
  brane of the egg, 304; of feathers, ib. ; of the pigmentum nigrum
  oculi, ib.   Results of his researches, 120,121.
Secretions.   See Bile and Urine.
Seguin  and  Lavoisier.  Calculation of the amount of inspired oxy-
  gen, 271.
Serpents.  Their excrements consist of urate of ammonia, 53.  The
  process of digestion in them, 53.
Sleep.  Theory of, 217.  Amount of sleep necessary for the adult, the
  infant, and the old  man, 236 et seq.  Induced by alcohol or wine,
  228.
Soda.   Essential to  blood and bile, and derived from common  salt,
  153 et seq.
Sodium, Chloride of.  See Salt.
Solanine.  Contains nitrogen, 168.  Its analysis, 313.
Starch.  Exists in  the food of the  herbivora,  68.   Is convertible
  into sugar,  69.   Its relation to gum and sugar, 71.   Its function in
  food, ib. et seq.  Amount of carbon in starch compared with that in
  flesh, 73, 74.  Its  composition compared with that  of fat, 81,  86. 
INDEX.
345
  Is the source of diabetic sugar, 91.  Is an element of respiration,
  92.   Dissolved by diastase,  107.   Its relation to choleic acid, 144.
  Its  relation to the principal  secretions  and excretions, 145;  to
  choloidic  acid, 149; to bile, 150,  153,155, 157.  Its  analysis from
  fifteen different plants, 286, 287.
Starvation.  Process of, 24.  Cause of death, 26.
Strecker.   His analysis of starch from 12 different plants, 286, 287.
Sugar.  Analysis of grape-sugar, 287;  of sugar of milk, 288; of cane-
  sugar, 290.  Is an element of respiration, 92.
Sulphur.  Exists in albumen, and caseine, 39,120.
Sulphuretted  Hydrogen.  Theory of its poisonous action, 263.
Sulphuric Acid.  See Acid,  Sulphuric.
Supply of matter.  See Nutrition.
Supply and Waste. Equilibrium  between them constitutes the ab-
  stract state of  health,  242, 243.  Effects of its disturbance, ib. et seq.
  Means for restoring the equilibrium, 236, 245 et seq.

                               T.

Table of the food consumed  by soldiers in Germany, 279.  Of the
  food and excretions of the horse and cow, 280, 281.
Taurine.  How  produced from  bile,  127.   Its relation  to  choleic
  acid, 123.  Its relation to uric acid and urea, and to allantoine, 147;
  to uric acid, 148; to  alloxan, ib.; to choloidic and  choleic acids,
  and  ammonia, 150; to caffeine, or theine, 170; to asparagine, ib.;
  to theobromine, ib., 171.
Temperature.  Its effects  on the amount of inspired oxygen,  16,
  and on the appetite, 17 et seq.   A slight depression of temperature
  causes death in aged people, 255.  Temperature of the blood in
  different animals, 282.  Temperature of the body constantly kept
  up by internal causes, 18-22.
Tendons.  Analysis of, 302.
Thaulow.  His analysis of cystic oxide, 311.
Theine.   Identical with caffeine, 169.  And with guaranine, 315.
  Theory  of its action, 171  et seq.   Its relation  to bile, 170.  Its
  analysis, 315.
Theobromine.   Analogous to  theine, 169.  Theory  of its  action,
  171  et seq.  Its relation to bile, 170,171.   Its analysis, 315.
Theory.  Of animal heat, 16 et seq.  Of digestion, 104 et seq.  Of
  respiration, 253 et seq.  Of the motions  in the  animal  organism,
  185 et seq.  Of disease, 242 et seq.  Of the action of caffeine, &c,
  172 et seq.  Of the action of the vegetable alkalies, ib.   Of health,
  242,243. 
346
INDEX.
  Thomson.  His examination of air from the lungs, 271.
  Tiedemann and Gmelin.  Their attempt to support a goose upon al-
   bumen alone, unsuccessful, 102.
  Tissues, Metamorphosis of.  See Metamorphosis.  Analysis of the
   animal tissues, 301.  Formulae of, 120.
  Tobacco.  Arrests or retards the change of matter, 170.
  Transformation.  See Metamorphosis.
  Turnips.  Juice of, contains vegetable fibrine and albumen, 46.

                               u.

  Urea.  Derived from uric acid, 130,133.   Also from the oxidation
   of blood, 133; from allantoine,  134.  Its relation to choleic acid,
   141; to hippuric acid, 143; to proteine, ib.; to proteine and starch,
   145; to proteine and fat, 146; to taurine, 147; to carbonate of am-
   monia, 151; to theobromine, 171.  Its analysis, 310.  Occurs, in the
   urine of those who have taken  benzoic acid, along with hippuric
   acid, 318.
 Uric Acid.  See Acid, Uric.
 Urinary Calculi.  See Calculus.

                              V.

 Varrentrapp and Will. Their analysis of vegetable albumen, 284.
   Of sulphate of potash and caseine, 285.
 Vegetable Life.  Distinguished from nervous life, 36.   Predomi-
   nates in the early stages of  life, ib.   Also in the female,  37.
 Vegetables.  Alone produce compounds of proteine, 102.  Azotized
   constituents of, nutritious, 44 ; medical or poisonous, 167.  Analy-
   sis of those vegetables which are used for food, 273 et seq.
 Venous Blood.  See Blood.
 Vital Force, or Vitality.  Definition of, 1 et seq. Theory of, 185
   et  seq.
 Vogel.  His analysis of gas from the abdomen of cattle after excess
  in  green food, 300.

                              w.

Water.  Is one of the two constituents  of the  body which contain
  no nitrogen, 43.  Its use as a solvent, ib.  Contributes to the greater
  part of the transformations in the body, 130, 133- 135,  141, 145-
  149,151,170,171. 
INDEX.
347
Wax.  On its production  from honey by the bee, 291 - to 297.  Its
  analysis, 297.
Wheat.   Contains vegetable  fibrine, 45.  Analysis of fibrine, albu-
  men, and gluten, from wheat, 284.
Will and Ettling.   Their analysis of lithofellic acid, 313.
Wine.  The wines of the south promote  the formation of calculus,
  133.  But not Rhenish wines, ib.  Theory of its action, 228.
Woskresensky.  His analysis of theobromine, 315.

                              Y.

Yams.  Analysis of starch from, 287. 
 
 
NATIONAL LIBRARY OF MEDICINE
nlm D3nstn  a
NLM031926190