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A  LECTURE
PHYSIOLOGY OF  DIGESTION,
INTRODUCTORY TO
A COURSE OF LECTURES
 INSTITUTES OF  MEDICINE  AND  MATERIA MEDICA.




                  DELIVERED BEFORE THE




    MEDICAL CLASS OF THE UNIVERSITY OF THE CITY OF NEW VORK,




               AT THE SESSION OF 1844-5.




                       I BY    301 3&


         MARTYN PAINE, A. M.  M. D„


Professor of the Institutes of Medicine and of Materia Medica in the ™£^£2* °f
 New York ; member of the Royal Verein fiir Heilkunde in P«mssen.-, of the Med ca ^oc.et,
   of Leipsic; of the Montreal Natural History Society, a»d other Learned Associates.







                 FOURTH  EDITION.  ^   J








                  NEW  YORK:

      PRINTED FOR THE MEDICAL CLASS OF THE UNIVERSITY, B7

            JOSEPH H. JENNINGS, 111 FULTON STREET.


                     1844-5. 
                                      New York, November 4, 1844.
Prof. Paine :
  Dear Sir:—At a meeting of the Class of the University Medical College,
held on Saturday evening last, Mr. S. S. Satchwell, of North Carolina, being
in the chair, and Mr. Edmund R. Dabney, of Tennessee, acting as Secretary,
on motion, it was unanimously
  Resolved—That a Committee be appointed to solicit for publication, a copy
of the able  and eloquent Introductory Lecture delivered by Prof. Paine on
Thursday evening last.
  The undersigned  having  been  appointed the Committee to perform this
pleasing duty, allow  us to add our individual wishes to those of the Class, and
to hope that you will not refuse so unanimous a request.
  We need not assure you how truly we are yours, &c.,
                                 Philip A. Atlett,  Alabama.
                                 William J. Alexander, Virginia.
                                 Cyrus Arndt, New Jersey.
                                 John M. K. Alford, North Carolina.
                                 John W.  Albury, West Indies.
                                 W. A. Burleigh, Maine.
                                 J. Brown, New Hampshire.
                                 E. T. Currie,  Maryland.
                                 G. W. Clipping er,  Pennsylvania.
                                 R. H. Clarke, Delaware.
                                 Oliver Crooks,  Ohio.
                                 William  Edwards, Mississippi.
                                 G. G. Gaithek, Kentucky.
                                 W. M.  Huntingden,  Vermont.
                                 B. S.  James,  South Carolina.
                                 John McGregor, Rhode Island.
                                 Charles  T. Mount,  Canada.
                                 Valentine Mott, Jr., New York.
                                 Edward Perry, Connecticut.
                                 George W. Parkhill, Forida.
                                 Wm.  M. Ryer, Illinois.
                                 J. B.  Selby,  Wisconsin.
                                 George M. Tutt,  Georgia.
                                 T. D. Washburn,  Massachusetts.
                                 D. E.  Warren,  Tennessee.
                                     New York,  November 8, 1844.
Messrs. P. A. Aylett, and others, composing a Committee of the
                   Medkal Class of the University of New York, 4-c. :
  Gentlemen:—-In acknowledging the receipt of your very polite note, inform-
ing me of the  honor done me by the Medical Class, of soliciting for publication
a copy of  my late Introductory Lecture, I have  much pleasure in  acceding
to that request, and beg that you will convey to those gentlemen and accept for
yourselves my sentiments of respect and esteem.
                       Very truly,  and sincerely, yours,
                                                 MARTYN PAINE. 
THE   PHYSIOLOGY  OF   DIGESTION.
   I.  " Animal and vegetable physiologists institute experiments without being ac-
 quainted with the circumstances  necessary to the continuance of life,—with the
 qualities and proper nourishment of the animal or plant on which they operate,—or
 with the nature and  chemical  constitution of its organs.  These experiments are
 considered  by  them as convincing proofs,  whilst they  are fitted only to awaken
 pity."
   2. " All discoveries in physics and in chemistry, all explanations of chemists, [!]
 must remain without fruit and useless, because even to the great leaders  in  physi-
 ology, carbonic acid, ammonia, acids, and bases, are sounds without  meaning, words
 without sense,  terms of an unknown  language, which awaken no thoughts,  and no
 associations.  They treat these sciences like the vulgar, who despise  a foreign litera-
 ture in exact proportion to their ignorance  of it."—Liebig's  Organic Chemistry ap-
 plied to Physiology, etc.
   3.  " None of them (the most distinguished physiologists) had a clear conception of
 the process  of development and nutrition, or of the true cause of death. They professed
 to explain the most obscure psychological phenomena, and yet they were unable to say
 what fever is, and  in  what way quinine acts in curing it."   The oft-reiterated  con-
 clusion  follows, that  it  is reserved for chemistry to resolve these problems.—
 Liebio's Animal Chemistry.  [See 1st and 2nd paragraphs p. 15, left hand  column.]

   4.  " A writer, who can so contradict himself, scarcely needs to be exposed by us."
 —Carpenter's Review ofPaine's "Commentaries."   SeePAiNE's " Examination  of
 Revieivs" pp.  12, 86.

   5.  " For many centuries past a profitless system has been followed, the same  system
 that formerly obtained in natural philosophy, and the uncertainties and doubts of me-
 dical science are the best proofs of its value.   It is  the ruling principle of this system to
 satisfy  the inquirer for facts by the use of empty words,—words which mean nothing
 and prove nothing.   Life and vitality, with other sonorous epithets, figure away in
 these visionary speculations as though they were realities, and  change their forms
 without reason or rule, as do the images that we see in dreams."
   6.  " Just in  the same  way that I am willing to admit the existence of forty differ-
 ent simple metals, so, upon similar evidence, I am free to admit the existence of fifty
 different imponderable agents, if need be.  Is there anything which should lead us
 to suppose that the imponderables are constituted by Nature on  a pian that is elabo-
 rately simple,  and the ponderables on one that  is elaborately complex l   That the
 former are all modifications of one primordial ether, and the latter intrinsically diffe-
 rent bodies, more than a quarter of a hundred of  which have been discovered  during
 the present century ?"
   7. " We are thus forced to admit that rays of light, rays of heat, tithonic rays, phos-
 phoric rays, and probably many other radiant forms, have an independent  exist-
 ence, and that they can be separated, by proper  processes, from each other.''—Dra-
 per's  Treatise on  the Forces which produce the Organization  of  Plants,   pp. 41,
 70, 71.—New York,  1844.
   8. " The  inorganic and the organic world are blended together, depending both of
 them on common laws."—Draper's Introductory Lecture, 1844—5.
   9. " The  rays of the sun are the true nervous principle of plants."—Draper's Trea-
 tise on the Forces, &c. p. 102.
   10. " As soon as  the young plant  has exposed itself  to the  solar beam,  growth
 rapidly begins to take  place, and organized matter  to be condensed from the air," &c.
 —Draper's Introductory Lecture.
   11."  If, among plants light is the great agent of organization, electricity is the great
 motive force, which, under a specific modification, determines the movements of nutri-
 tious juices.   The imponderable agents are the vital  principle of organized  systems."
   12. " The oxygenizing action of the arterial blood is therefore the true cause of the
 systemic (general) circulation.   [See 2nd paragraph, p. 11, left hand column.]
   13. " The pulmonary circulation is therefore due to the oxydation of the venous
 blood."
   14. " The old medical aphorism,' ubiirritatio ibi affluxus,' translated into the pre-
cise language of modem chemistry, simply means, to the point where its deoxydation
is  taking place,  the arterial blood will flow."  [See 2nd paragraph, p. 11, left hand.]
   15. " By the aid of the principles here laid down, all the various physiological or pa-
thological conditions which are met with in inflammation, asphyxia, gangrene, &c. are 
4
presented as so many interesting chemical problems for solution."—[See 4th para-
graph, page 15th, right hand column.]
  16. " It is a vulgar error that a living being possesses a principle of resistance to ex-
ternal agents, while a dead one submits itself to them.  Both equally change, or of
the  two, the living one putrifies and changes the more rapidly."—Draper's  Treatise
on the Forces, &c pp. 23, 36, 41, 6.  [See 4th paragraph, p. 10, and 3rd p. 15, and
line 5th, &c. p. 12, right column.]
  17. " And now I hope to see this University, as it is the first to introduce these cap-
ital improvements, keep the first in the emulous race with all its sister institutions.   I
want to see it the great factory of Chemical discoveries and chemical doctrines in
the  western world."—Draper's Introductory Lecture.
  18. " Chemists and natural philosophers, accustomed to study the  phenomena over
which the physical forces preside, have carried their spirit of calculation into the the-
ories of the vital laws."—Bichat's General Anatomy, vol. 2, p. 54.
  19. " Let a man be given up to the contemplation of one sort of knowledge, and
that will become  every thing.   The mind will take such a tincture from a familiarity
with that object,  that every thing else, how remote soever, will be brought under the
same view.  A metaphysician will bring ploughing and gardening immediately to ab-
stract notions ;—the history of nature will signify nothing to him.  A chemist, on the
contrary, shall reduce  divinity to the maxims of his laboratory, explain morality by
sal, sulphur, and mercury, and  allegorize the  Scripture itself, and the sacred mys-
teries thereof, into the philosopher's  stone-"—Locke, on the  Human Understanding.
  20. " Mr. Locke, I think, mentions an eminent musician, who believed that God cre-
ated the world in  six days, and rested on the seventh, because there are but seven notes
in music.   I, myself, knew one of that profession who thought there were only three
parts in harmony, to wit: base, tenor, and treble, because there are but  three persons
in the Trinity."—Reid, on the Powers of the Human Mind, vol. 2 Essay 6. c. 8.
  21. " When education takes in error as a part of its system, there is no doubt that
it will operate with abundant energy, and to an  extent indefinite."—Burke.

  Differences of opinion on questions of great moment to  mankind
are apt to be strongly conveyed, and apparent error to be censured in
no measured terms.   This, perhaps, is often admissible,  considering
the obstinacy  of error, and so long  as it is the doctrine,  and not its au-
thor, which is assailed.   We  may revere the  names of Voltaire, of
Hume,  and of Gibbon, yield them a proud rank in the scale of intel-
lect,  and  gratefully  acknowledge the rich legacies they have left be-
hind.   But,   who  of  us would  hesitate to speak of their  infidelity
according to  its nature and  tendencies ?   This  is even demanded by
what we believe of the precepts of religion.   And so of the principles
of medicine, which hold as high a  relation to the temporal interests  of
man, as do the precepts of religion to his spiritual  welfare.   The high-
est order of intellect  is often devoted to the dissemination of error, and
perhaps more  frequently in religion and medicine than in any other ol
the great interests  of mankind.   This  must be fully and  firmly met,
not only by evidences of  the  truth, but by an exposure of  its  perver-
sions and  corruptions.
   In the discussion of my subject,  (the controverted physiology of diges-
tion,) I shall bring to your consideration the  misapplication of chemis-
try  to the  processes  of life ;  but in doing this, it will  be  only in the
defence of truth, and not with a view of diminishing  your  respect for
an important  science.   We must regard  its  defects  abstractedly, and
endeavor to eradicate  such impurities as tarnish its lustre.   We must
still yield to it all the  praise  to which  it is entitled by the devoted in-
dustry of its cultivators, by its elevated rank amongst the sciences, and
by its usefulness to man.   Indeed, as  a science of general usefulness, 
5
 as a source of  mental improvement and of pure and elevated enjoy-
 ment,  as opening to our view many of the most deeply interesting and
 stupendous institutions of  nature,  and often with that demonstration
 which no skepticism can resist,—I  say, with all these combined advan-
 tages, it is the most important of the sciences for the general purposes
 of life.   And I am mostly prompted in making  these remarks by the
 too common neglect of chemistry by the medical profession,  to whom
 it is farther recommended by its subserviency to the healing art.
   At  the outset of my subject,  it  will be necessary to premise a few
 statements as to the general  condition of medicine, and the auspices
 under which it is now cultivated.
   The physiological world, as you are probably aware, has been lately
 divided into three schools.   One of these sects virtually regards organic
 nature as a part only of inorganic, endowed with  the same properties
 and governed by the same laws.   It maintains, in short, that there is
 no real  difference  between a man and a stone.   At the  head of this
 school stands Liebig, the distinguished and able chemist.   It is a great
 and powerful school,  but  is falling, daily,  beneath the weight of  its
 vast errors and corruptions.  It is denominated  the chemical school
 of medicine.  Contrasted  with this is  the school of vitalism ;  and  to
 the interests of this  school, I may now say, the main efforts of my life
 have  been devoted.   Their doctrines will  be taught in the lectures
 which I shall have  the honor of laying at the foundation of your medi-
 cal education;  not,  however,  with  any concealment of adverse opinions,
 but with  an ample exhibition of their nature, and of their claims  to
 your consideration.   This school regards organic and inorganic nature
 as distinct in their most essential attributes; that each department is
 governed by properties and laws peculiar to itself.  It regards the or-
 ganic  being as fundamentally distinct from the inorganic in its elemen-
 tary constitution,  in the aggregation of its molecules,  in the structure
 of its parts, in its condition  as a whole, and in every phenomenon which
 it evinces.  It sees design in every part of  the living being,  eloquent
 even in the dry bones of a skeleton ; a design peculiar to every part,
 whilst all concur in harmony together to the common ends of one uni-
 versal  design.  On the contrary, also, this school discerns little of the
 nature of desio-n in the constitution, or  in  the  abstract condition  of
 inorganic matter.  It sees nothing, in  respect to power, but  mere vis
 inertia ; which,  however, is supposed by the  physical school to be capa-
 ble of evolving from simple matter every variety of organization,  with
 all  its  specific designs, even instinct and reason, whilst at the same  time
 we  hear from the  depth of materialism, that " organic nature  is the
 mystery of mysteries."
  Again, the vitalists, in consideration of the general facts now stated,
 maintain, in  the language of Liebig, the great head of the school  of
 mere physics, " the existence of a  power distinct from all other pow-
 ers of nature, namely, a vital principle ;"  which organizes and gov-
 erns all living beings, and  which is the fundamental cause of all their
 phenomena in health and disease.   I say, in the language of Liebig,
 " a  power distinct  from  all other  powers of nature,  namely, a vital
principle;" for this mere chemist, in his conflicts with living nature,
concedes the existence  of such a principle as  at the foundation of all
vital phenomena, yet in the same general manner, and on all specific
questions where he has introduced its direct and exclusive  agency, he 
6
as unequivocally declares that there is no such  principle, and that
every result of life, and disease, even thought itself, are entirely owing
to chemical agencies.  His whole system, as set forth in his " Organic
Chemistry applied to Physiology,"  and  in his "Animal Chemistry"
applied to Pathology and Therapeutics, is a tissue of similar contradic-
tions, of  the boldest  assumptions, and of stultifying doctrines.   Yet,
with deep mortification I  say it, he has  been hailed with an enthusi-
asm before unknown  in  the  annals of medicine, as the only true ex-
pounder of physiology and of medical philosophy.   The world, how-
ever, is fast awaking from its spellbound delusion,  and the doctrines
of this " reformer "  will  soon be mingled with the same  and  more
original chimeras which did  their part in " the dark ages of science."
   Finally, the  third  school,  or that of chemico-physiology, endeavor
to form, as it were, a bond of union between the schools of pure vital-
ism, and of pure chemistry, though such an  alliance be as unnatural
as human  brains in a block of granite.   The  chemico-physiologist
makes a compromise with  philosophy,  and  takes  for  his rule, " in
medio  tutissimus  ibis."    He  professes  to loathe all extremes; but
takes little trouble to ascertain  the fact whether  one doctrine or the
other be  fairly  entitled to  this appellation.    He sees  only the direct
opposition which exists, without  caring whether' one " extreme," as
he calls  it, may not be perfectly true, whilst the other is as perfectly
false.   He therefore mingles the doctrines of vitalism and of chemis-
try ; allotting to the  former  one half of the phenomena of life, and
the other half to the latter.   This is the  school to which you have the
greatest chance of becoming the victims; for it  is apparently recom-
mended  by the conciliatory principle which I have stated in the form
of its  motto,  and by many of the most distinguished members  of our
profession.
   I am  now prepared by these explanatory remarks, relative  to the
three schools of medicine, to  enter upon the consideration of the  philo-
sophy of digestion ; for each denomination  have interpreted that phi-
losophy  according to the general doctrines  of life  which are peculiar
to each.
   Beginning with pure chemistry, we find the great leader setting forth
the  process of  digestion in the  following language, in his late work on
Animal  Chemistry applied to Pathology  and  Therapeutics.   " Chymi-
fication," he  says, " is  independent of the vital force.   It takes
place in virtue of a purely chemical action,—exactly similar  to those
processes  of decomposition and transformation which  are known as
putrefaction, fermentation, or decay."   This  is exactly the  old doc-
trine of what are well denominated the  " dark ages."
   Now  you  will recollect that I have stated that  it is a remarkable
 characteristic  of the work which is assumed as the basis of the chemi-
 cal philosophy of life, that  it  abounds with  staring  contradictions ;
 and such is the fact in relation to the doctrine which I  have just quo-
 ted.  And how could it be  otherwise, seeing  that its author was con-
 stantly  employed about two  subjects that have no relation to each oth-
 er ; that is to  say, the philosophy of life and the philosophy of  chemis-
 try.  Rut I will go back, for a conflicting doctrine, to the " Reformer's"
 treatise on Organic Chemistry applied to Physiology, published a year
 or two antecedently to his work on  Animal Chemistry ; by which we 
7
shall learn  the  extent of the confusion which  pervades his writings,
and the tardiness with which it is discerned by his medical disciples.
   In that work, he says,  "the equilibrium in the chemical attractions
of the constituents of food is disturbed by the vital principle.  The
union of its  elements,   so as  to  produce  new combinations  and
forms,  indicates  the  presence of a peculiar  mode  of  attraction
and the  existence of a power  distinct from  all other powers of
nature, namely, the vital principle."   " If the food possessed life,
not merely  the chemical  forces,  but this vitality would offer resist-
ance to the vital force of  the organism it nourished."
   Such, then, was the opinion of this  Chemist  when discoursing of
life in his " Organic Chemistry applied to Physiology;" and passages
of a similar import occur in his late work on " Animal Chemistry,"—
ay, and  standing  in  connection  with  his  equally fundamental, and
hostile doctrine, which refers every living process and result to the me-
rest chemical agencies.
   The  work, however,  on Animal Chemistry  is  more of a distilla-
tion from the Laboratory than its predecessor; and  as many of the
most eminent physiologists in Europe,  who were  inclined to  mingle
chemistry with vitalism,  were nauseated by the dose which  was  last
administered, Liebig came out in his  lectures  for the session of the
present  year,  (1844) with the following placebo for the  vitalists and
the chemico-physiologists.  It is of some extent; but, as  it embraces
exactly the doctrines which I have been always employed in teaching,
and which  are  still fundamental  in my lectures, I shall  quote it, at
length;   so that,  should  there be  any present  who may  have be-
come imbued with the popular superstition in regard to  Liebig's  notions
in Physiology,  they may  rest assured that my lectures will  have for
their basis what will be allowed by their favorite Liebig to be the only
true foundation  of the  Institutes of  Medicine.   Thus, then,  the Ger-
man  Chemist, when, only six months ago, he was lecturing,  like my-
self, on  the  functions of life.
   "After the extinction* of the vital Principle," he says, "'in organic
atoms,  they maintain  their form and  properties, the  state into which
they have been  brought in  living organisms, only by  reason  of their
inherent inertia.    It is a  great and comprehensive law of  matter that
its particles possess  no self-acting,  no  inherent  power of originating
motion,  when at rest.   Motion must be imparted  by some  external
cause;  and, in like manner, motion once imparted to a body can only
be arrested by  external resistance."    So much for  simple  matter.
Now for matter in an organic state.   " The constituents of vegetable
and animal substances," he goes on, " having been formed under the
guidance  and power of the vital principle, it is  this principle which de-
termines the direction of their molecular attraction.   The vital princi-
ple, therefore,  must be a motive power, capable of imparting mo-
tion to atoms  at  rest, and of opposing resistance to other  forces
producing motion, such as the chemical force, heat  and  electricity.
We are able to  reliquify and redissolve albumen after it has been
coagulated by heat; but, the vital principle alone is capable of resto-
ring the original order and manner of the molecular arrangement in
the smallest particles of albumen.   Coagulated albumen is again con-

              * See my " Examination of Revkws," p. 26—28. 
8
verted into its original form ; it  is transformed into flesh  and blood in
the animal organism.
   " In the formation of vegetable and animal substances the vital prin-
ciple opposes, as a force of resistance, the action of the other for.
ces,—cohesive attraction, heat, and electricity,*—forces which render
the aggregation of atoms into combinations of the  highest order impos-
sible, except in living organisms.
   " Hence it is, that when  those complex  combinations which consti-
tute organic  substances are withdrawn from  the influence of the vital
force,—when this no longer is opposed to the action of the other dis-
turbing forces, great alterations  immediately ensue in their  proper-
ties, and in the arrangement of their constituents.   The  slightest
chemical action, the mere contact  of atmospheric  air, suffices  to cause
a transposition in their atoms, and to produce new arrangements; in one
word,  to excite decomposition.    Those remarkable phenomena then
take place which are designated  by the terms fermentation, putrefaction,
and decay.   These are the processes of  decomposition, and their  ul-
timate results are to reconvert the elements of organic bodies into  that
state in which they exist before they participate in the processes of life."
—London Lancet, May 18, 1844.
   Now, gentlemen, you are no  doubt astonished, and  well you may
be, to  hear such language, and the latest, too, that he has spoken, from
the chief of the school  who, in reality,  admit of nothing but  pure
chemistry in their system  of physiology.   The language which I have
just quoted from Liebig, should  place him amongst the unqualified vi-
talists.  It conveys the doctrines which lie at the foundation of my Medi-
cal and Physiological Commentaries, and which are opposed, in toto, to
the hallucinations of Chemistry.   And yet I have already  made other
quotations from the same writer, and on the same subjects, which you will
have observed contradict, in the broadest  and most absolute  manner
his doctrines as to the vital principle.  The latter seem to be thrown
out " as springes to catch woodcocks," or as others have it, as "a tub to
the whale."
   Such, then, are examples of the medley of contradictions in great fun-
damental principles, with  which the writings of this very extraordinary
and successful pretender in medicine, abound.  On the same  page we
meet a purely chemical and a purely  vital philosophy of digestion ;
and equally so of other important organic  processes.  Each is  laid
down  without qualification, and  with the dictum of a master who is con-
 scious that the preponderance he gives to the purely chemical philoso-
phy of life will establish his Empire in that philosophy with an age more
 prone than ever to the doctrines of materialism.  On the very subject
 of a vital principle itself he is asjlatly contradictory as on the cause of
 digestion; for at one moment he avows  the  existence of such a princi-

   * Heat, light, and electricity, are often absurdly supposed to constitute forces in their
 relation to living beings.  In that relation they are merely  vital stimuli, calling into
 action the properties of life.  These properties are the only  forces which have anv con-
 nection with the phenomena evinced by animals  or plants.  As to the doctrine of cap-
 illary  attraction, whether applied to the capillary circulation of plants or animals it
 is th<- vory worst of all the physical views of life; since it strikes a fatal blow at all or-
 ganic processes §.nd results, and at all the physiological and pathological doctrines which
 are founded upon them.  The doctrine, on the other hand, is contradicted by all the
 phenomena and results which appertain  to organic life; since they are all dependent
 on special modes of vital action carried on by the capillary system. 
9
pie, " distinct from all other powers of nature," and calls it " the vital
principle," which he says governs all the processes of living  beings,
and at the next moment  he avers  that " in the animal body  we re-
cognize, AS the ultimate cause of all force, only one  cause, the
chemical action which the elements of the food and the oxygen of the air
mutually exercise on each other.  The only known ultimate cause  of vital
force, either in animals or in plants, is A chemical process."  Thus,
also, he increases the medley of contradictions in relation to digestion,
by making that process to depend on a purely chemical  action, and to
evolve  that vital principle which  he had already avowed is the  only
power concerned  in chymification.
   But  be not  deceived; for,  however this  " reformer " may  beguile
you with words, and  seem to persuade rather than to rule, remember
that, at most,  he does but invalidate his own edicts  by countermands,
and that in the end he tells you that those apparently adverse decrees
 are,  in their absolute import, one  and the same; that they are consis-
 tent laws delivered from the laboratory, though apparently in  conflict
on account of the opposing forces, the attraction and repulsion, which
 preside in the  chemistry of nature;  that, however, in reality, there is
 no difference whatever in the seemingly two great principles which lie
 at the foundation, which are one  and identical,  since  " the mysteri-
 ous VITAL PRINCIPLE  CAN  BE  REPLACED BY THE CHEMICAL FORCES,"*
 and since, also, " the vital force unites in its manifestations all
 THE  PECULIARITIES  OF THE  CHEMICAL FORCES, AND  OF  THE NOT  LESS
 WONDERFUL CAUSE WHICH WE REGARD AS  THE  ULTIMATE ORIGIN  OF
 ELECTRICAL PHENOMENA, "fr !
    I dwell upon these absurdities, that you may the better realize the shal-
 lowness of that pretended philosophy which  has so lately swept, like a
 hurricane, over the intellectual  world ; that you may see, in this system
 of contradictions, the equal fallacy of that school  who endeavor,  with
 greater sincerity, to mingle the conflicting principles, and that you may
 the better cultivate and enjoy the simple and  consistent philosophy which
 nature teaches.  Nor will I yet leave that stupendous  system of assump-
 tion and contradiction which was so lately hailed by physiologists as the
 harbinger of a total revolution in  medical science,  ay, in the very  prac-
 tice of medicine,  without showing you the depth of the  materialism in
 which it was submerged.  I say nothing now of the avowed infidelity to
 which it has led.  Examples of that disregard of instinctive faith I have al-
 ready  placed in their proper  connection with  my present subject.:):
 But, I  will merely quote from  Liebig's revolutionary work a doctrine
 of the chemical school, from which, if I mistake not your ambition as
 intellectual and immortal beings, the very impulse of nature will turn
 you  with a loathing aversion.   You will see from it, also,  how utterly
degraded to the rank of the merest matter is every thing relating to or-
ganic life ; even  man  himself.   Thus, then, our author in behalf of
the school of chemistry.   " Physiology," he says, " has sufficiently
decisive grounds for the opinion, that every  motion, every manifestation
of force, is the result of a transformation of the structure or of its sub-

   * Liebig's Organic Chemistry applied to Physiology, &c.
   i Liebig's Animal Chemistry.
   t See my  "Medical and Physiological Commentaries," vol. 2, p. 122—140. Also
the Essay on the  Vital Powers. 
10
stance ; that every  conception, every mental affection, is followed by
changes  in the  chemical  nature  of the secreted  fluids; that  every
thought, every sensation, is accompanied by a change in the composi-
tion of the substance of the brain."—" Every manifestation of force is
the result of a transformation of the structure or of its substance."
   Many organic chemists,  however, are  disposed to admit the existence
of a spiritual  part, and  they should  therefore recollect that the exist-
ence of a principle of life  is substantiated by far more numerous facts
than the spirituality of mind, which they are so ready to concede when
inviting your attention to their physical doctrines of  life.  They should
be as ready to yield to one  series of facts as to the other, and especially
to the more cogent series when the minor is obtruded  upon your belief.
   Let us now observe the hostile attitude of some of the important doc-
trines which I have quoted  from Liebig, by  repeating them in direct
connection,  that  we may  the more distinctly  realize  the absurdities
which come to us from the  laboratory of the chemist, when its ambi-
tious  aim is turned upon physiology.  Examples of similar conflicting
views abound  in the writings of " the reformer."—Thus :—
  " Mi object has been, in the present
work, to direct attention to the points of
intersection of chemistry with physiology,
and to  point out  those parts in which
the sciences become, as it were, mixed
up together.  It contains a collection of
problems, such as chemistry at present re-
quires to be  resolved,  and a number of
conclusions drawn  according to the rules
of that  science.  These questions  and
problems will be resolved ; and we can-
not doubt that we shall have  in  that
case a new phtsiologt and a rational
pathology."—Liebig's  Animal  Che-
mistry.

  " 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 mutually  exercise on each other.
The only known ultimate cause of vital
force, either in animals or in plants,  is  a
chemical process. If this be prevented,
the phenomena of life do not mani-
fest themselves.  If the chemical action
be impeded, the  vital phenomena must
take new forms"   " All vital activi-
ty arises from the  mutual action of the
oxygen  of the atmosphere and  the ele-
ments of  the food."—Liebig's  Animal
 Chemistry.

  " Physiology has sufficiently  decisive
grounds for the opinion, that evert mo-
tion, every  manifestation of force,
IS the result of a transformation of
THE STRUCTURE OR OF  ITS SUBSTANCE;
that every conception, every mental affec-
tion, is followed by changes in  the che-
mical nature of the secreted fluids ; that
tvery thought, every sensation,  is accom-
  " A  rational physiology cannot be
founded on mere re-actions, and the liv-
ing body cannot be viewed as a chemi-
cal  laboratory."—Liebig's   Animal
Chemistry.
  " The^study of the  uses of the func-
tions ofrnfferent organs, and of their mu-
tual connection in the animal body, was
formerly the chief object in physiological
researches;  but lately this study has
fallen into the background."—Ibid.  [See
3rd motto.]
  " In the  animal ovum, as well as in
the seed of a plant,  we recognize a
CERTAIN REMABKABLE FORCE,THE SOURCE
of growth, or increase in the mass, and
of reproduction, or of supply of the mat-
ter consumed;  a force in  a state of
rest.*  By the action of external influ-
ences, by impregnation, by  the presence
of air and moisture, the condition of sta-
tic equilibrium of this force is disturb-
ed.  Entering into a state of motion
or activity, it exhibits itself in  the pro-
duction of a series of forms, which, al-
though  occasionally  bounded  by right
lines,  are yet widely distinct from geo-
metrical forms,  such as we observe in
crystallized minerals.  This force is call-
ed the vital force, vis vita, or vitali-
ty-"—Liebig's Animal Chemistry.—[See
my Essays on Vitality, &c. p. 13—18.]

  "The vital principle must be a mo-
tive power, capable of imparting mo-
tion TO atoms at rest, and of opposing

  * See  my " Examination of Reviews,'  p.
7—24. 
11
panied by a change in the composition of
the substance  of the  brain" !—Liebig's
Animal Chemistry.

  " In the processes of nutrition and re-
production, we  perceive the passage of
matter from the state  of motion to that of
rest,  (static equilibrium.)  Under the in-
fluence of the nervous system, this matter
enters again into a state of motion.   The
ultimate causes of these different condi-
tions of the vital force are chemical  for-
ces."
   " The cause of the state of motion is
to be found in a series of changes which
the food undergoes in the organism, and
these are the results of processes of de-
composition, to which either  the food it-
self, or the structures formed from it, or
parts of organs, are subjected."—Liebig's
Animal  Chemistry.   [See 6th and 7th
 paragraphs, page 13, left hand column,
 and right  hand column, page  11-12, and
 12th, 13th, and 14th mottos.
    This summary principle, were it  true,
 would be truly beautiful. But it appears
 to be not only deficient in every necessary
 element, but to be contradicted by all the
 phenomena of sympathy and by all that is
 known of pathology  and therapeutics;
 and  this,  too, according to  the author's
 own repeated and fullest affirmations and
 doctrines  to the contrary.]

    " The  power  to  effect transforma-
 tions does not belong to the vital princi-
ple.   Each transformation is  owing to a
 disturbance  in the attraction of the ele-
 ments of a compound, and is, consequent-
 ly, A PURELY CHEMICAL  PROCESS."—LlE-
 big's Organic Chemistiy applied to  Phy-
 siology, &c.—[See,  also 1st  paragraph,
 page  14, and  6th paragraph, page 14,
 right hand  column, and others equally
 contradictory.]

   [I occupy this space to indicate to the reader
 that he will find that Liebig considers the  " che-
 mical action which the elements of the food and
 the oxygen of the air mutually exercise on each
 other," to  be the effect  of life and the cause of
 life, and the cause of death, and the cause of
 animal heat, and that respiration is the essential
 cause of the whole,—even of death itself.  Thus
 we have all the phenomena of  organic beings,
 from the cradle to the grave, referred to a single
 chemical process.]

    "  Every thing in the animal organism,
 to which  the name of motion can be ap-
 plied, proceeds from the nervous appa-
 ratus.   The phenomena of motion in ve-
 getables, the circulation of the sap,  for
 example, observed in many of the chara-
 ceae,and the closing of flowers and leaves,
 depend on physicaL and  mechanical cau-
 ses.   Heat and light are  the remote
resistance to other forces producing
motion, such  as  the  chemical force,
heat and electricity."—Liebig's Lec-
tures for 1844.  [See 16th motto.]
  " In the animal organism we are ac-
quainted with only one cause of mo-
tion ;  and this is the same cause which
determines  the groiolh of living tissues,
and gives them the power of resistance to
external  agencies.  It  is  the  vital
force."
  " 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 arrangement
or form.  This supposition takes from the
vital phenomena nothing  of their wonder-
ful peculiarity. It may, therefore, be con-
sidered 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
dependent on a certain luminiferous mat-
ter or  other, which has  no farther con-
nection with the  laws ascertained by in-
vestigation."—Liebig's  Animal   Chem-
istry.
  " Our notion of life involves something
more than mere reproduction, namely, the
idea of an active power exercised by vir-
tue of a definite form, and production and
generation in a definite form. The produc-
tion of organs, and their power not only
to produce their component parts from
the food presented to them, but to gen-
erate themselves in their original form
and with all their properties, are charac-
ters belonging exclusively to organic
life,  and constitute a form of reproduc-
tion independent of  chemical powers.
The chemical forces are subject to the
invisible cause by which this form ia
produced.   Of  the existence of  this
cause itself we are made aware only by
the phenomena which it produces.   Its
laws must be investigated just as we in-
vestigate those of the other powers which
effect motion  and  changes  in matter."
"The vital principle is only known to us
through the peculiar form of its instru-
ments ; that is,  through the  organs  in
which it resides.   Hence, whatever kind
of energy a substance may possess, if it is
amorphous and destitute of organs from,
which the impulse, motion,  or change,
proceeds, it does not live.  Its energy
depends, in this case, on a chemical ac-
tion.  Light, heab> electricity, or other 
1
1
causes of motion in vegetables ; but in
animals we recognize in the nervous ap-
paratus a  source  of power,  capable of
renewing itself at every moment of their
existence."—Liebig's Animal Chemistry.
—[See, also, 3rd paragraph, page 10,right
hand column.]
  Nevertheless, although—
  " Plants require light,  and,  indeed,
sun light,  it is not necessary that the di-
rect  rays  of the sun reach them.  Their
functions certainly proceed with greater
intensity and rapidity in  sunshine, than
in the diffused light of day ; but it mere-
ly accelerates in  a greater degree the
action already existing."—Liebig's Or-
ganic Chemistry applied  to Physiology,
&c.   [See note p. 8,  and opposite para-
graph.]
  " The vital force unites in its mani-
festations all the peculiarities of che-
mical forces, and of the not less wonder-
ful cause which we regard as the ultimate
origin of electrical phenomena."—Lie-
big's Animal Chemistry.   [See, also, 4th
paragraph,  page  10, right hand column,
and first  paragraph, page 8, and note.]

  " The  mysterious vital principle can
be replaced by the  chemical forces."—
Liebig's  Organic  Chemistry applied  to
Physiology, &c.
   " 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 or-
ganism is, to a certain extent, independ-
ent of those external influences, just be-
cause the animal body can produce with-
in itself that source of motion which
js indispensable  to the vital process."
—Liebig's Animal  Chemistry.

   " Neither the emission of carbonic acid
n or the absorption of  oxygen (by plants)
has any  connection with  the process of
assimilation ; nor have they the slightest
relation  to  each  other.    The one is
purely a mechanical, the other a  purely
chemical process.   A  cotton wick, in-
closed in a lamp, whjgh contains a liquid
influences [justly considered here by Lie-
big as vital stimuli and not forces] may
increase, diminish, or  arrest  this ac-
tion ;  but  they are  not  its efficient
cause."  " The vital principle opposes
to the continual action of the atmosphere,
moisture, and temperature, upon the orga-
nism, a resistance which is, in a certain
degree, invincible.  It is by the constant
neutralization  and renewal of these ex-
ternal influences that life and motion are
maintained."—Liebig's Organic  Chemis-
try applied to Physiology, &c.
  " An abnormal  production of  certain
component parts of plants presupposes a
power and capability of assimilation,
to which the most powerful chemical ac-
tion cannot be compared.  The bestidea
of it may be formed, by considering that
it surpasses in power the strongest galva-
nic battery,  with which we are not able
to separate the oxygen from carbonic acid,
as  is  done by  the leaves of plants,"
" and without the direct solar rays."
  " All that we can do is to supply those
substances which are adapted for assimi-
lation by the power already present in
the organs of the plant."—Liebig's Orga-
nic Chemistry applied to Physiology, &c.
—See,  also, third quotation in this col-
umn, page 10.
  " The living part of a  plant  acquires
the whole force and direction of its vital
   " In what form or  in  what manner
the vital force produces mechanical
effects  in the animal body  is altoge-
ther  UNKNOWN,  AND IS AS LITTLE TO BE
ASCERTAINED  by experimfnt as the con-
nection  OF   CHEMICAL   ACTION  WITH
THE  PHENOMENA  OF   MOTION,   which
we can produce  with  the   galvanic
battery.  We know  not how  a  certain
invisible something, heat, gives to certain
bodies the power of exerting an enormous
pressure  on  surrounding  objects.   We
know not even how this something itself ia
produced when we  burn wood or coals.
  " So it is with  the vital force,  and
with  the phenomena exhibited by living
bodies.  The cause of these phenomena is
not chemical force ;  it is not  electrici-
TY,nor magnetism. It is a peculiar force,
because it exhibits manifestations  which
are formed by no other  known force."
  " In regard to the nature and essence
of the vital force, we can hardly deceive
ourselves, when we  reflect, that it  be-
haves, in all  its manifestations, exactly
like other natural forces ; that it is de-
void of consciousness or of volition, and is
subject to the action of a blister."—Lie-
big's Animal  Chemistry. 
13
saturated with carbonic acid, acts exactly
in the same manner as a living plant in
the night."—Liebig's Organic Chemistry
applied to Physiology, &c.

   " At night, a true chemical process com-
mences, [though  every process is either
purely mechanical or purely chemical, by
night or by day, according to the last quo-
tation] in consequence  of the action of the
oxygen of the air  upon the substances
composing the leaves, blossoms, and fruit.
This process is not at all connected with
the life of the vegetable organism, because
it goes on in the dead plant exactly as in
a living one." !
   Nevertheless,—
   ■" What value can be attached to experi-
ments, in which  all those matters which
a plant requires in the process of assimi-
lation, besides its mere nutriment, have
been excluded with the greatest care ?
Can the laws of life be investigated in
an organized being which is diseased or
dying ?" — Liebig's Organic Chemistry
applied &jc —Or, can those laws be inves-
tigated in  " a Cotton wick, inclosed in a
lamp" ?
  " Analogy, that fertile source of error,
has unfortunately led to the very unapt
comparison of the  vital  functions  of
plants with those of animals."—Liebig's
Organic  Chemistry  applied  to Physiol-
ogy, &c.—[See, also, right hand  column
p. 12.]
  Plants, when properly placed in glass
vessels containing distilled water,  will, by
means of their roots, decompose the glass,
and absorb its silex and alkali, and assim-
ilate those substances to themselves, and
in despight of any chemical  affinities; yet,
  "All substances  in solution  in a  soil
are absorbed by the roots  of plants, ex-
actly as a sponge imbibes  a liquid,  and
all that  it contains, without selection,"
and "their assimilation is a purely chem-
ical process."—Liebig's Organic Chem-
istry applied, &c,
  " 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 PURELY CHEMICAL action,  EXACTLY SIM-
ILAR to those  processes of  decomposition
or transformation which are known  as
PUTREFACTION,   FERMENTATION,   or  DE-
CAY."—Liebig's Animal Chemistry.
  " Those remarkable phenomena, fer-
mentation, putrefaction, and decay, are
the processes of Decomposition, and their
ultimate  results are to reconvert the ele-
energy from the absence of all conductor*
of force.  By this means the leaf is ena-
bled to overcome  the strongest chemical
attractions, to decompose carbonic acid,
and to assimilate the elements of its nou-
rishment."—Liebig's Animal Chemistry.
   " In vegetable physiology,  a leaf is re-
garded  in every  case merely as  a leaf,
notwithstanding that leaves generating oil
of turpentine or oil of lemons, must pos-
sess  a  different  nature from  those in
which oxalic acid  is formed.  Vitality,
in its peculiar operations, makes use of a
special apparatus for each function of an
organ.   Vegetable physiologists,  in the
study of  their science,  have not directed
their attention to that part of it (the laws
of vitality) which is most worthy of inves-
tigation."—Liebig's Organic Chemistry
applied to Physiology, &c.
   " 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 ; and that it is given
out in the gaseous form, without exerting
the  slightest  action on the juices of
the plant."
  " The animal  organism is a higher
kind  of vegetable."
  " Assimilation, or the process of ror-
mation  and growth, goes on in the same
way  in animals and in  vegetables.   In
both  the same cause determines  the in-
crease of mass. This constitutes the true
vegetative life."—Liebig's Animal  Chem-
istry.                       ,

   " The constituents of vegetable and
animal substances  are formed under the
guidance   and  power  of   the  vital
principle, which determines the direction
of their molecular  attraction."  " In  the
formation of vegetable  and animal sub-
stances,  the vital principle opposes, as
a force of resistance,  the action  of the
other forces," &c.—Liebig's  Lectures
for 1844.

  " The equilibrium in the chemical at-
tractions of the constituents of food is dis-
turbed by the vital principle ";  and
"the union of its elements,so as to produce
new combinations and forms, indicates a
peculiar mode of  attraction,  and the ex-
istence  of a  power distinct  from  all
other powers of nature, namely, the vi-
tal principle."—Liebig's Organic Che-
mistry applied to Physiology, &c.

   " The vital force causes  a  decompo-
sition of the constituents of food, and de- 
14
ments of organic bodies into that state in
which they exist before they participate in
the processes of life."—Liebig's Lectures
for 1844.

  " In the action  of the gastric juice on
the food, no other element takes a share
except the oxygen of the atmosphere."
" This air by means of the saliva, reaches
the stomach with the  food, and there its
oxygen enters into combination."—Lie-
big's Animal Chemistry.
  " The power of  elements to unite to-
gether,  and to form peculiar compounds
which are generated in animals and vege-
tables,  is  CHEMICAL AFFINITY."--LlEBIG'S
Organic Chemistry applied to  Physiolo-
gy,  &c .  [See, also, as to elements,  the
6th, page  12, and 2d paragraph, page 13,
and 3rd paragraph, page 10, and the 3rd,
4th, 5th, and  6th  paragraphs, page  14,
right hand column ; and other places. ]
  " We should not permit ourselves to be
withheld, by the idea of a vital principle,
from considering in a chemical point of
view, the process of transformation of
the food, and its assimilation by the  va-
rious organs.  This is the more necessary,
as the views, hitherto held, have produced
no results, and are quite incapable of use-
ful application."—Liebig's Organic Chem-
istry applied &c.—[See third paragraph,
page  11, right hand column, and other
contradictory quotations in same column.]
  " In the natural state of the digestive
process, the food only undergoes a change
in its  state of cohesion, becoming fluid
without any other change of properties."
—Liebig's Animal Chemistry.

  Although—" the process of chymifica-
tion is independent of the vital force, and
takes place in virtue of a purely chemical
action, exactly similar to those processes
of Decomposition which are known as pu-
trefaction, fermentation, or decay";—
nevertheless, " Inorganic compounds dif-
fer from organic in as great a degree as
in their  simplicity  of  constitution."—
Liebig's Animal Chemistry, and Organic
Chemistry. [See next quotation, this col-
umn, and 1st and 2d paragraphs page 22.]
  " By chemical agency we can produce
the constituents of muscular fibre, skin,
and hair"!  "We are  able  to form, in
 stroys the force of attraction which is con-
 tinually exerted between  their molecules.
 It  alters  the direction  of the  chemical
 forces in such wise, that the elements of
 the constituents  of  the  food  arrange
 themselves  in another  form,  and com-
 bine to produce new compounds.   It for-
 ces the new compounds to assume forms
 altogether different from those which
 are the result of the  attraction of cohe-
 sion when acting freely, that is, without
 resistance."
   " The vital force appears as a moving
 force or cause of motion, when it over-
 comes  the chemical forces, cohesion and
 affinity, which act between the constit-
 uents of food, and when it changes the
 position or place in which their  elements
 occur.   The vital force is manifested as
 a  cause of motion  in overcoming the
 chemical attraction of  the constituents
 of food, and is, farther, the cause which
 compels them  to combine in a new ar-
 rangement,  and to assume new forms."—
 Liebig's Animal Chemistry.
   " When a chemical  compound of sim-
 ple constitution is introduced into the sto-
 mach,  its chemical action is,  of course,
 OPPOSED BY  THE VITAL PRINCIPLE.   The
 results produced depend upon the strength
 of  their respective actions.   Either an
 equilibrium  of both powers is attained, a
 change being effected without the destruc-
 tion of the vital principle ; in which case
 a  medicinal effect is occasioned.  Or,
 the acting body yields to the superior
 force of vitality, that is, it is digested.
 Or, lastly,  the  chemical action  obtains
 the ascendency and acts as a poison."—
 Liebig's Organic Chemistry applied to
 Physiology,  &c.
   " The individual organs, such  as the
 stomach, cause all the organic substances
 conveyed  to them, which are capable of
 transformation,  to assume new forms.
 The stomach  compels the elements of
 these substances to unite  into a  compound
fitted for the formation of the  blood."—
 Liebig's Organic Chemistry, &c

   " The first substance capable of afford-
 ing nutriment to animals  is the  last pro-
 duct of the creative  energy  of veget-
 ables."—Liebig's Animal Chemistry.
   " The special characters of food, that is
 of substances  fitted for assimilation, are
 absence of active chemical properties,
 and the capability of yielding to trans-
 formations."—Liebig's Organic  Chemis-
 try applied to Physiology, &c.

   " The constituents  of  vegetable and
 animal substances having been  formed
 under  the  guidance  and tower of the 
15
our laboratories,  formic acid, urea,  &c.
We see, therefore,  that this mysterious
VITAL PRINCIPLE CAN BE REPLACED BY THE
chemical  forces " !!—Liebig's  Organic
Chemistry applied to Physiology,  &c—
[See page 22d, second paragraph.]
  "The influence of poisons and of reme-
dial agents on the living animal body evi-
dently shows that the chemical decompo-
sitions and combinations in  the  body,
WHICH MANIFEST THEMSELVES IN THE PHE-
NOMENA of vitality, may be increased in
intensity by chemical forces of an analo-
gous  character, and retarded or put an
end to by those of  opposite  character;
and  that we are enabled to exercise an
influence on  every  part of an organ by
means of substances possessing a well de-
fined chemical action."—Liebig's  Ani-
mal Chemistry.  [See 3d motto.]

   " With respect to the  action of qui-
nine, or the  alkaloids of opium, &c,
physiologists and pathologists entertain no
doubt that it is  exerted  chiefly on the
brain and nerves.   If we reflect that this
action is exerted by substances which are
material, tangible  and ponderable ;£hat
they  disappear in  the organism; that a
double dose acts more powerfully than a
single one ; that, after a time, a fresh dose
must be given if we wish to produce the
action a second time; all these  conside-
rations, viewed chemically, [.'] permit on-
ly one form of explanation; the supposi-
tion,  namely, that  these compounds, by
means of their elements,  take a share in
the formation of new or the transfor-
mation of existing brain and  nervous
matter "!!—Liebig's Animal Chemistry.

   " It is impossible to mistake the modus
operandi of putrefied sausages, or muscle,
urine, cheese, cerebral   substance,  and
other matters, in a state of putrefaction."
"It is obvious that they communicate their
OWN  STATE   OF  PUTREFACTION  TO  THE
sound blood, from  which they were pro-
duced,  exactly in  the same  manner as
gluten in a state of decay or putrefaction
causes a similar transformation in a so-
lution of sugar ".'
   " The mode of action of a morbid virus
exhibits such  a strong similarity to the
action of yeast upon liquids containing
sugar and gluten, that the two processes
have been long since compared to one an-
other, although merely for the purpose  of
illustration.   [They have often been rep-
resented as  identical.]   But, when the
phenomena attending the action of each
 respectively are considered more closely,
vital principle, it is this principle which
determines the direction of their molecu-
lar  attraction." —" The  vital  principle
alone is capable of restoring the original
order and  manner  of the molecular ar-
rangement in  the  smallest  particles of
albumen."—Liebig's Lectures for 1844.

  " From the theory of disease developed
in the preceding pages, it follows, obvi-
ously, that a diseased condition once es-
tablished, in any part of the body, cannot
be  made to  disappear by the  chemical
action  of a  remedy."—Liebig's Animal
Chemistry.
   " The vital force  is subject to the
action of a blister."—Ibid.
   " The vital force  in a living animal
tissue appears  as a cause of growth in the
mass, and of resistance to those external
agencies which tend to alter the form,
structure,  and composition  of the  sub-
stance of  the  tissue in which the vital
energy resides."—Liebig's Animal Chem-
istry.  [See 16th  motto, and  4th para-
graph, p.10, and 5th line p.12, right hand.]
   The following unscrupulous declaration ap-
appears to be addressed to that class of readers
to whom' 1 have adverted in the 3rd paragraph.
p. 8. Thus:
  " It is not the true chemist who has end eavored
to apply to the animal organism his notions de-
rived from purely chemical  processes.  He has
not  had the remotest intention of undertaking
 the explanation of any really vital phenomenon,
upon chemical principles.  The only part which
chemistry now, or for the future, can take in the
explanation of the vital processes,  is limited to a
more precise designation of the phenomena, and
to the task of controlling the correctness of infe-
 rences, and ensuring the accuracy of all obser-
 vations  by number and weight.  Although the
 chemist is able  to analyze organic  bodies, and
tell us their ultimate elements, he does not claim
 the  power of  synthesis, or of producing them
 again by the union of these elements " !!!—Lie-
 big's Lectures for  1844.—[See, particularly, 3d
 paragraph, p.10,6th paragraph, p.14, left column,
 and 3rd and 15th mottos.   Alto,  the opposite
 paragraphs.]
   " The vivifying  agency of the blood
 must ever  continue to be the most impor-
 tant condition in the restoration of a dis-
 turbed equilibrium, and the blood must,
 therefore,  be  considered  and  constantly
 kept  in  view, as the ultimate and most
 powerful  cause  of lasting  vital re-
 sistance, as well in the diseased as in the
 unaffected parts of the body."—Liebig's
 Animal Chemistry.
    Nevertheless,—
    " No other  component part  of  the or-
 ganism can be compared to the blood, in
 respect of the feeble resistance which it
 offers  to  exterior  influences." — "The
 chemical force and the vital principle hold
 each other in such perfect equilibrium,
 that every disturbance, however  trifling,
 or from whatever cause it may proceed, 
16
 it will in reality be seen that their influ-
 ence defends upon the same cause." " Or-
 dinary yeast  and the  virus of human
 smallpox, effect a violent  tumultuous
 transformation, the former in vegetable
 juices, the latter in the blood".'  " The
 action of the virus of  cowpox is  analo-
 gous to that of low yeast [.']  It commu-
 nicates its own state of decomposition to
 a matter in the blood, and from a second
 matter is  itself regenerated" !  "The
 susceptibility of infection by the virus of
 human smallpox must cease after vacci-
 nation, for the  substance to the pres-
 ence of which this susceptibility is  owing
 has  been removed from the body by a
 peculiar process of decomposition artifi-
 cially excited "  !  " Cold meat is always
 in a state of decomposition.  It is  possi-
 ble that this state may be communicated
 to the system of a feeble individual, and
 may  be one of the sources of consump-
 tion" ! '.—Liebig's Organic  Chemistry
 applied to Physiology, &c

  " In all chronic diseases, death is
 produced by the same cause, namely,
 the  chemical  action  of the   atmo-
 sphere."  And so, also, of death  from
 acute diseases; breathing, in all the cases,
being the cause of death.—Liebig's Ani-
mal Chemistry.
EFFECTS A  CHANGE IN THE BLOOD."—LlE-
big's Organic Chemistry applied, &c

  But, again, nevertheless,—

  " It  is obvious,  moreover, that in all
diseases where the formation of conta-
gious matter and  of exanthemata is ac-
companied by fever, two diseased condi-
tions simultaneously exist, and two pro-
cesses are simultaneously completed \ and
that the blood, as it were, by re-action,
that is, fever, becomes a means of cure."
—Liebig's Animal Chemistry.

  " We can have no very high idea of
experiments made by gentlemen, (chem-
ists, with reference to digestion,)  who, for
want of anatomical knowledge, have not
been able to pursue  their reasoning even
beyond the simple  experiment itself."—
John Hunter's Observations on Diges-
tion.
  *** The quotations from "Liebig's Organic
Chemistry applied to Physiology," are derived
from Mr. Playfair's edition, London, 1840 ; those
from " Liebig's Animal Chemistry,"  are  taken
from  Professor  Gregory's  edition,  reprinted
Neve York, 1842.  The italics and capitals are
mine.
   It only remains now to say of the foregoing contradictions (hitherto
 unnoticed,) that,  whenever and wherever they, or  their resemblances,
 occur in any department of science, we may of course rely upon it that
 the  writer is in pursuit of any thing but truth, or is most inexcusably
 ignorant of his subject.   In  medicine,  too,  we  may readily  suspect
 that every thing is spurious which comes to us upon  the wings of the
 imagination, or where  we  meet with tropes and  metaphors instead of
 crucibles and  acids, or  with  harmonious  words  instead of obstinate
 facts and hard thinking.
   It follows, therefore,  from what I have stated of the incongruities of
 the  chemical school on the philosophy of digestion, as well  as of all •
 other  functions of life, that I  need not say   much of the groundless
 nature of that  mingled system  of  contrarieties by which the chemico-
 physiologists interpret the same  functions.   Their doctrine of digestion
 is thus laid down  by  the distinguished  chemist, Dr.  Prout;  for you
 should understand that chemists, not physiologists and  physicians  not
 the students of organic nature,  are the great  leaders in  the  medical
 schools of pure chemistry and of chemico-physiology.   " First " says
 Dr.  Prout, " the stomach has the power of dissolving alimentary sub-
 stances, or, at least, of bringing them to a  semi-fluid state.  This ope-
 ration seems to be altogether chemical.
   "  2d.  The stomach has, within certain limits, the power of changing
 into  one another the simple alimentary principles," and " this part of the
operation  of the stomach appears, like the  reducing process, to be
 chemical; but  not so easy  of  accomplishment.  It  may be termed the
converting operation of the stomach. 
17
 '  " 3d.  The stomach must have, within certain  limits,  the power of
 organizing and vitalizing the different alimentary substances."   " It is
 impossible," he says, " to imagine  that this organizing agency of the
 stomach can be  chemical.   The agency is vital,  and its nature com-
 pletely unknown."
   Such, then, is the doctrine of digestion as entertained by the chemico-
 physiologists.  But, from what we have already  seen of the absolute
 contradictions which abound in the writings of those who attempt the
 application of pure chemistry to the  functions and results of organic
 life, we  may expect  that the chemico-physiologist will be equally in-
 consistent when he  applies himself, at  one time, to  the  phenomena of
 living beings, and, at another, reasons from the results  of the labora-
 tory to those phenomena.   Accordingly, we find  within a  few pages
 of the foregoing doctrine of the chemico-physiologist,  that he broadly
 affirms that " there is no relation whatever between the mechanical ar-
 rangements and  the chemical  properties to  which they administer."
 " There is no reason why the chemical changes of organization should
 result from the mechanical arrangements by  which they are accom-
 plished,  neither is there the slightest reason, why the mechanical ar-
 rangements in the formation  of organized  beings should lead to the
 chemical changes of which they are the instruments."
   Here, then, in a single sentence, are not  only the strangest contra-
 dictions, but a full admission that there is not the " slightest reason" for
 the application of chemistry to  any process, function, or result of living
 beings.
   Nor is  this  all.  For the chemico-physiologist, the same eminent
 chemist  whom I have just quoted, goes on to say, that " with the living,
 the animative properties of organic bodies, chemistry has not the small-'
 est alliance; and  probably  will never, in any  degree, elucidate  those
 properties.  The phenomena of life are not," he says, " even remotely
 analogous to anything we know in chemistry as exhibited among inor-
 ganic agents."  And, as if to complete the overthrow  of the chemical
 part of the philosophy of digestion, the  same  reasoner observes  that,
 " The means by which the peculiarities of composition  and structure
 are produced, which  is so remarkable in all organic substances,  like
 the results themselves, are quite peculiar, and  bear little or no resem-
 blance to any artificial process of chemistry ;" that  " nature will not per-
 mit the chemist to officiate as her journeyman in  the most trifling de-
 gree."   So, also, Dr. Roget, alike distinguished in the school of chemi-
 co-physiology.   " Vital chemistry,"  he says,  " is too subtle a power
 for human science to detect, or for human art to imitate." And to the
 same effect may be quoted Dr.  Carpenter, one of the  foremost in the
 school of pure chemistry.   " The agency of vitality," says this rea-
 soner,  who generally ridicules  the term  and all that is supposed to re-
 late to it, " the agency of vitality," he says, " as Dr. Prout justly re-
 marks, does not change the properties of the elements, but simply com-
 bines the elements in modes which we cannot imitate." And thus might
 I go on with one  after another, till I should have exhausted  the whole
 that have attempted  to confound the science of life with the science of
 chemistry, and show you by their own statements  that there is not the
 slightest  intelligible connection  between them.   Indeed, I  have already,
on a former occasion, pointed out  this universal admission.
                                 2 
18
  The ground of chemistry  being thus virtually abandoned to the vi-
talist, it would seem superfluous to pursue an adversary who is always
upon the retreat.   But, as he flies, he is for ever shooting from behind,
and his Parthian  weapons fall thickly and heavily upon the vast  mul-
titude.  He must therefore  be subdued into a practical acquiescence
with those consistent principles  of nature which exact his consent, but
not his compliance.
  The subject of  digestion supplies one of the numerous  opportunities
of pushing the  chemico-physiologist  upon open ground, and of exhib-
iting truth in its unadulterated  purity.   It is here, too, especially, that
chemistry has reared its batteries, and whence it sends forth its  artil-
lery into the various dominions  of the organic world.   Yet  it is  here,
that vitality  is exemplified in its  most impressive and astonishing as-
pects, and  where unequivocal demonstrations abound that fluids, as
well as  solids,  are endowed with the principle of vital  operations.—
It is here,  especially, that  nature has illustrated  her distinction be-
tween the animate and inanimate world, and established her  chain of
connection.   It is here, in the incipient change of dead into living mat-
ter, that we witness a full display of those powers which operate in the
most elaborate organization, and an equal exclusion of the forces which
appertain to dead matter.  It is here the line of separation  begins ab-
ruptly ; but where analogies are preserved in the  conversion of dead
into living matter, through new  modes of combining the same elements ;
and doubtless our admiration would  increase,  should we  mount along
the entire functions of assimilation, and find, at each step of the ascend-
ing series, that the whole agency has  been committed to forces that
have no existence in the inorganic world ;  that the whole is the har-
monious result of a principle which may form  an  intermediate link be-
tween spirit  and matter; and that there is no power within our control
by  which we can determine  the  nature of the changes.   Casting a
glance at the vegetable world,  we find the connection continued,  by
other analogous links, with elementary matter itself;  but here,  as in
the higher department of nature,  the line of separation is equally de-
fined, however low in the scale  of analogy may be the properties of life
which have their  beginning in vegetable organization.
  It is here, then, at the threshold of life, as in the propagation of the
species, that we especially witness a substitution for Creative Power;
and as all that appertains exclusively to the organic world was per-
fectly distinct in its Creation from the inorganic, so are the  substituted
processes of generation, and of  the conversion  of dead into living mat-
ter, equally  distinct from the causes and results of inorganic  processes.
   However, also, we may scrutinize the process of digestion in either
of the organic kingdoms, we  find that nature has provided intricate
means for the purpose, and established analogies in their organization
as well as their phenomena, that  are unknown in the inorganic world.
And if we carry  the analysis through  the  whole labyrinth  of animal
and vegetable creation,  we meet, at every step, with so much Unity of
Design, such gradual modifications of structure and functions, and all
conspiring to a specific end, we must conclude that the whole are gov-
erned by forces peculiar to themselves.
   But,  notwithstanding  the astonishing Unity of Design, and the gra-
dation of analogies which connect together the most  dissimilar of the 
19
  systems which are designed for digestion, there are peculiarities at-
  tending each in every species of animals,  which place at a remote dis-
  tance the laws of chemistry.  " An alimentary Canal  is observed in
  every class of animals, and  almost  in every species, but its form  and
  structure  vary according to the situation of animals in the  scale, or
  according to the kind of food on which they are destined to subsist, and
  the extent of the elaboration  it requires to  undergo.   The  peculiarities
  presented by the digestive organs are, therefore, intimately  connected
  with the  diversities of form manifested  by the organs  of animal  life,
  and with all the living  habits and instincts of animals."   We see, also,
  an extension of this principle in relation to certain periods of life.   In
  ruminating animals, for instance, the fourth stomach is alone employed
  during dentition.  And yet, with all this variety, there is but one com-
  mon result, one homogeneous chyle.  The same principles, the same
  vital impulses which ultimately develope and call into action  the three
  first stomachs of the ruminantia, appear to be not less concerned in the
  consummation of their final cause.
    One of the most important arguments in favor of vital  digestion  con-
  sists in the remarkable endowments of the stomach, as manifested by its
  vital signs, and by the  sympathies which  prevail between this organ
  and all other parts.   The final  cause of  this  peculiar constitution of
  the stomach, this lavish supply of the properties of  life,  this subservi-
  ence of other organs to  its dominion, must  be sought in  its adaptation
  to the generation of a fluid that may bestow the first and most difficult
  act of vitalization upon dead matter.   There  would  also  have been
  something harsh and abrupt in nature, to have admitted into the recesses
  of her living organization  mere dead matter.   It is opposed to all anal-
 ogy, and is, therefore, opposed to all reason.  But,  that  a fluid should
 perform this astonishing office, this first and great step in the ascending
 series, it must possess in a high degree the principle of life.   Mysteri-
 ous as it  may be represented, we must all of us  come at last to the  ad-
 mission of the existence of a  vital  principle; yet far less mysterious,
 and far less difficult of comprehension than the human soul.  It is fair,
 then, to  conclude that an organ destined for such a high function should
 possess that principle, in  common with all other parts,  as the means
 on which its function depends; and  the best evidences in favor of (his
 analogical inference are to be seen  in its diversified manifestations of
 life.   To deny the dependence of vital  results  upon specific  powers,
 necessarily involves an exclusion of  all the evidence  by which we infer
 the existence of gravitation, or of the intangible properties of matter.—
 As well  may we doubt the reality of spirit, " or the  Maker of the eye,
 because  it cannot see Him that made it."
   We have seen, also, that it is conceded by philosophers who defend,
 in extenso, the chemical hypothesis of life, that there  may be something
 appertaining to the stomach totally distinct  from the  chemical powers,
 and which is capable of imbuing the chyme with vitality and an or-
ganic condition ; and it is, therefore,  quite a philosophical  conclusion,
that this vital something has an important  agency in  preparing the ma-
terial for the admitted exercise upon it of the  vivifying  or organizing
power.   Nor can there  be any  valid objection to the supposition that
this vitalizing power, which so far transcends  the chemical forces in
the organizing effect it  is allowed to exert,  may be  fully adequate 
20
to any transmutations the food may undergo;  and this inference is the
more corroborated by the consideration that matter already in an or-
ganic state must be better fitted  for the process of vivification,  than  it
can possibly be after its  elements  are broken up  and recombined by
forces with which those of life are  in absolute opposition.  Besides, the
vitality of the  gastric juice, or the  vital influence  of the stomach itself,
being fully admitted, and even capable  of organizing the food anew,
this, in itself, should protect the  alimentary matter against any chemi-
cal agencies which have been supposed to operate.  That this counteract-
ing power, indeed, prevails to the full extent which I have alleged, ap-
pears to be rendered certain  by  the ordinary absence of any of those
chemical changes which take place where numerous substances are
mixed together out of the stomach,—substances  which  often  possess
strong chemical affinities for each other, and whose operation within the
stomach would be promoted by its high temperature.   On the contrary,
whatever the variety, it is uniformly resolved  into  one and the same
homogeneous substance, utterly  unlike  the results  of chemical reac-
tions of one kind of food upon other kinds ; and what is also  as conclu-
sive  as it is astonishing, the chyle is apparently the same substance in
all animals.   Chemistry must here  be  consistent with itself, and not
renounce, for the sake of hypothesis, those precise laws  by which, in
its legitimate pursuit,  it lays open, with  astonishing exactness, what
had appeared the arcana of nature.  Here, too, upon the chemico-phy-
siological hypothesis, is presented an instance  in which it must be ne-
cessarily assumed that the properties of life and the forces of chemis-
try must act together in concert  in  converting dead into living  matter,
—one destroying, and at the same  moment the other vitalizing ; whilst
the assumption is contradicted by  all that is known of the  relation of
these forces to each other.
  It will be also readily conceded  that it is the demand of philosophy
not to multiply causes, where one is perfectly adequate ;  and especially
where it is admitted that all the others are of themselves wholly inade-
quate.
  This remark may be also equally applied to a  common  assumption
which is set forth in the following apparently plausible manner.   "The
vitalists," says one of their opponents, "are loth to admit the operation
of chemical agents at all, and would seem to consider it derogatory to
suppose that any changes, save the subtle ones effected by the  powers
of life, are worked upon the aliment."  " The vital principle," he says,
" whatever it may be, incessantly makes use of chemical  and mechani-
cal agents for  its purposes ; and  it  is no more degrading to it to  employ
an acid liquid, and a triturating  process, in order to digest the aliment,
than it was to  have recourse to bony levers, cartilaginous pulleys, and
tendonous ropes."
  Here, in the first  place, you will observe an entire begging of the
question as to  digestion by an acid, since that has never been  shown,
and is the main point at issue.   It  is a perfectly unfounded and extor-
ted inference from the factitious  analogy supposed to be seen in the ad-
mitted mechanical movement of the food in the stomach,  bony levers
cartilaginous pulleys, dec.  But the pretended analogy,  I say,  is utter-
ly inapplicable, were it admissible  to reason from better premises of
this nature  to  the existence of  important facts  which  have no other 
21
foundation.   The bony levers, muscles, tendons, heart, and large blood-
vessels, are mere instruments acted upon by the vital principle, and have
no part in the vital results, except as they are the passive instruments
of the properties of life.  You  will observe  the same distinction be-
tween the process of digestion, and the mechanical movement  of the
food in the stomach, or the "trituration" of the food, as it is erroneous-
ly called by the writer just quoted; since food is not triturated  by the
stomach excepting where that organ is designed to supply the place  of
teeth.   You will observe, I say, the total  want of analogy between that
mechanical movement of the food, and the assumed action of an acid ;
since, in the latter case, a radical change  is supposed  to be wrought
in the alimentary mass, whilst no such change is wrought by the mere
movement, or even by the trituration or grinding of food in the stomach.
The contractions of the stomach,  which are purely of a vital nature,
facilitate the process of digestion ; but they do no more than to expose
the food  freely to the  action of the gastric juice, by which, alone, the
conversion into chyme  is performed.  The contractions, or " trituration,"
are exactly on a par, as auxiliaries to  digestion, with the teeth, or with
the knife, which divide the  food.   The acid  alone applies  to the sup-
posed chemical process of chymification.   This  is the  only  agent, in-
volving the  only force distinct from the vital principle  that is supposed
to operate, and to take part with the properties of life in the functions
which belong to those properties.  Nor is  this  all.  Those chemical
forces, or an equivalent agent, are supposed to appertain to  the gastric
juice, (a product of the most  highly endowed organ in  the animal sys-
tem) ;  and through  that product, and by that product, to operate inde-
pendently of the  vital  properties, or,  under their control.   But, here
it may be again affirmed  that throughout  nature there is not an  analo-
gical fact to warrant the conclusion ;  and with equal truth it may be
said that there is nothing to aid our conception of the cooperation of the
chemical and vital forces, whilst all that is known of their relations  to
each other proclaims their absolute independence.
   But, again, it is the  admitted final cause of the gastric juice  to be-
stow life upon  dead  matter, whilst it is incontrovertible that inorganic
matter  is insusceptible of any  such  influence from gastric action.—
Every fact proclaims that nature has  provided  the vegetable kingdom
for the purpose, especially, of determining organic combinations  out  of
inorganic substances for  the sustenance of animal life.  In  the lan-
guage of Liebig, " The first  substance capable of affording nutriment
to animals is the last product  of the creative energy,"—ay, " the
creative energy,"  he says,  " of vegetables."—(Animal Chemistry.)
It is manifest,  therefore,  that it would be an absurdity on the part  of
nature to have ordained that  chemical  agencies should operate even  at
the very threshold of life, at the very fountain for which she had pro-
vided elaborate means to subvert the combinations of chemistry,  and  to
bring them into those entirely new arrangements that approximate the
changes they are destined to undergo in the animal stomach.   And far
less probable is it, that this fundamental principle should be lost as we
ascend from vegetable  to animal organization; since  every  chemical
result within the stomach  would tend to reduce the aliment to the state
of that inorganic matter whose complete  reduction into organic com-
pounds was  effected by the vegetable kingdom for the uses of the ani- 
22
mal.  Such chemical results, therefore, would  counteract  the great
final cause of nature, in either organic  kingdom; and, in the animal,
would render the means of sustenance more and more indigestible, and
progressively liable to the condition of inorganic matter.  This is fully
allowed by the chief of the school of pure chemistry ; as shown in the
foregoing parallel quotations.
  But again I say, if the vital principle  be " capable of making use of
chemical agents," no reason can be assigned why it  may not be equal
to the whole work of digestion, and of every other process of living be-
ings.  The simple construction may be comprehended, whilst the other
is utterly unintelligible.  The former alone is agreeable to  the rules
of philosophy, and abolishes the inextricable confusion which attends
the chemical hypothesis.   What,  indeed, can be  meant, by  the vital
properties making use of chemical  forces 1  Can there be a more glar-
ing absurdity ? more  absolute nonsense ?  How are those chemical for-
ces brought into use, how held in subjection, how for ever maintained
in one exact  operation in each particular organic process, of which
there  are multitudes, distinct from each other, going on in the same in-
dividual ?  How do  they  elaborate  from one common,  homogeneous
fluid,  either the blood, or the sap, all the various, unique, unchanging,
secreted products of the whole organic being ?  Products, for ever the
same  in every part, yet differing from each other according to the  na-
ture of the part ?  Did you ever hear or dream of any thing analogous
to this in that inorganic world where chemistry  holds its empire ?—
When do those chemical forces begin to operate, in the living body,
what  part do they perform, and what is the allotment of the properties of
life ?  Is there any known concert of action between the two species of
forces 1   On the contrary,  is it not every where demonstrated that the
properties of life are  in direct opposition  to the forces  of chemistry ?
  Whatever be the construction, by uniting the two forces, (as is done
by the only chemical school that is entitled to a respectful notice,)  we
convert  what is a simple problem,  like  all other processes of nature,
into the  greatest paradox that has been yet devised by the ingenuity of
man.   It  is in vain to say that some one or two of the products of or-
ganization, such as carbonic acid, and urea,  are  such as result from
chemical affinities, since these are excrementitious;  whilst  chemistry
assures us that all organic compounds are utterly different in  their ele-
mentary combinations from any compound of a chemical nature.
  Thus  might I go  on to argue this subject  upon general principles
alone ; whilst at every step of the argument, we should see the whole
chemical hypothesis of life taking its proper rank as a dream of the im-
agination, or as a project of ambitious minds.
  But, I must hasten to the specific  facts which are brought by the
chemical and the chemico-physiological schools to the support of their
preconceived hypotheses;  for  you must understand  that digestion was
regarded as a chemical process, and  according even to its present in-
terpretation, whilst chemistry  was yet in its  infancy.
  Digestion having been assumed  to be  more or  less,  or  altogether, a
chemical affair, it rationally followed that it might be imitated by  art.
Accordingly, when this ambitious science had  succeeded in turning
the whole inorganic  world into the laboratory, it set itself at the manu-
facture  of organic compounds, and  even at the entire animal.  It did 
23
 not, like Alexander, sit down and weep because it had no more worlds
 to conquer; but, like Shakspeare, having  " exhausted worlds, it then
 imagined new."  Even eminent physiologists,  who should look with
 jealousy upon any invasions upon the  laws of nature,  especially upon
 such as it is their peculiar province to illustrate, began  the manufac-
 ture of gastric juice by fire and acids, and metallic salts.   We are thus
 presented by these philosophers  with  artificial  compounds, of a most
 incongruous nature, and we are told that each one is the gastric juice ;
 that each is capable of the  same precise results as that universal pro-
 duct of animals, apparently the same in  all, and elaborated from the
 blood by an organ of the highest vital  endowments, and to which  there
 is nothing analogous in all the^other products of living beings, each pro-
 duct being, also, equally unique, and all derived from one common source.
    A diversity of opinions exists as to the real nature  of the chemical
 agent supposed to be employed by nature  in  the process of digestion.
 Free muriatic acid having been found,  or supposed to exist, in the  stom-
 ach, it has been concluded by many that this must be the great agent;
 whilst  Dr. Prout, and  others,  affirm that  "  free muriatic acid more or
 less retards the  process of reduction."  Dr. R.  Thompson, however,
 states that, by digesting muscular fibre in dilute muriatic acid, he pro-
 duced  a substance " exactly  resembling chyme."  This experiment
 was pretty widely repeated, and  many were  equally  successful with
 " dilute muriatic acid" as was Dr. Thompson.   Others, on the contra-
 ry, declared  their failure, and others, like Dr. Prout, maintained that
 this acid retarded digestion.   Eberle had already advanced the hy-
 pothesis that mucous membranes, no matter whether of the stomach  or
 the bladder, dissolved either in  muriatic or acetic acid,  would  form
 the true gastric juice, and perform its wonderful operations.   There is
 now a  general bias in  favor of one of these compounds, though other
 preparations are supposed by many to form very good gastric juice.
 Again, it is said that the " digestive mixture," as it has been well de-
 nominated by the manufacturers, " retains its solvent properties for
 months," whilst the gastric juice loses its solvent power soon after its
 abstraction from the  stomach.  And what equally establishes a  total
 difference between the " mixture" and the gastric juice is the no small
 circumstance that the chemist may torture and extinguish the artificial
 " digestive principle"  in a variety of ways, and then transmute it  back
 in  all its vigor.  Thus, according to Schwann and Miiller,  the artifi-
 cial " digestive principle" may be neutralized  by an alkali,  and after-
 wards " precipitated from its neutral solution by acetate of lead, and ob-
 tained again in  an active state from that precipitate by means of hydro-
 sulphuric  acid."  This precipitate, we  are told, when  thus treated,
 and thus compounded  of principles radically different from the original
 mixture, is essentially  the same as the gastric juice, and that the results
 of such artificial preparations must be taken as the test of the physiolo-
gy  of natural  digestion; that, abandoning nature, we must look to the
 resources of the  laboratory  for any satisfactory  account  of  her  vital
 processes.   Nor do I at all exaggerate ; for it is distinctly avowed that
 we knew nothing of digestion till the invention of the artificial mixtures.
 Thus, it is said of Schwann by one so  able  and distinguished as Miil-
 ler, that he, (Schwann) " having discovered that  the infusion of dry
mucous membrane with dilute acid, even after it is filtered, still retains 
24
its digestive power, the digestive principle, therefore, is clearly in solu-
tion, and the theory of digestion by contact falls to  the ground."  Here,
a  most important physiological induction is wholly founded upon a pro-
cess which has not the most remote connection with organized matter ;
and as to the paradox which involves the combined agencies of muri-
atic acid, alkalies, acetate of lead, hydro-sulphuric acid, and mucous
membranes, it  is  certainly a burlesque  upon the  science of chemistry.
   I have said that the experimenters took the hint of manufacturing
gastric juice from the occasional discovery of an acid in the stomach.
But, this is undoubtedly a rare phenomenon in a healthy stomach, and
where the  food has  been at  all  appropriate in quality and quantity.—
The chemical hypothesis, as I have said, was long ago  in vogue,  and
was put at rest  by demonstrative proof.   Distinguished observers, Hun-
ter, Haller,  Willis, Spallanzani, Fordyce, and more recently Dumas,
Schultz, and others, insist that the reputed acid  is  the result of a true
chemical decomposition of vegetable matter.   Spallanzanf, whose ex-
periments were almost endless, Scopoli,  Chevreuil, and  others, rarely
succeeded in finding it at all, and in some animals never.   Spallanzani,
indeed, affirms  that the gastric juice is  neither acid nor alkaline in its
natural state.
   As far back  as  Haller's day,  when this subject was  agitated, it is
said by this illustrious  and  accurate observer,  that, " although there
may be some rare signs of an  acid in the stomach, it does  not, there-
fore, become us to suppose that  food is animalized by a  chemical pro-
cess;  much less  to  compare this process with the action of an acid."
And, anticipating  the modern experiments with  the  " digestive  mix-
ture," he declares of analogous proceedings  at his own era,  " frustra
etiam quisquam, imitatus liquores acres  chemicos, liquorem corroden-
tem invenerit, qui carnem in pultem resolvat."  And there can be  no
doubt that Hunter's prophecy holds good to this day, that—
   " If ever any matter is formed in any of the juices secreted in any
part of a vegetable or animal body  similar to what arises from fermen-
tation, we may  depend on it,  it arose from that process ; but we may also
depend on it, that there is a defect of the living  principle in these cases."
   These are not the mere speculations of genius, but the facts and the
conclusions of genius after a long,  and wide,  and  experimental survey
of nature.* And are  these observations,  nay,  our  own experience, our
own senses, to  be  set aside to accommodate a hypothesis of life which
identifies dead,  even inorganic, with living beings ?
   I might thus  go on to multiply proofs of the foregoing nature, not a lit-
tle of which is  supplied by distinguished observers of the present day ;
and a variety of  other facts  might  be brought in opposition to the che-
mical hypothesis of digestion.  But time presses, and I  must come to
a conclusion ; but not without expressing the  conviction that it is here,
especially-,  that the physiologist must raise his principal defence against
the invasions of chemistry.   Defeated upon this ground, the adversary
may be easily expelled  from the  whole domain of organic life.

  * See mottos, 1st,  2nd, 3rd, 5th and  16th  paragraphs.  Yet is it said that the
chemical speculations " must command the respect of their opponents."
,.**,* Paine's Medical and Physiological Commentaries, in 3 volumes, may be had only at the Au
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