7    Js~#&fek  li>~,  &
         INTRODUCTORY ADDRESS,
DELIVERED AT THE
College of fjlptiaos anfo burgeons,
N E W YORK,
OCTOBER  16, 18 5 5.
JXO. C. DALTON, JUN. M. D
  PROFESSOR OF PHYSIOLOGY, AXD MICROSCOPIC ANATOMY.
2.^37^
       NEW YORK:
JOHN J. SCHROEDER, MEDICAL BOOKSELLER,
      BIBLE HOUSE, ASTOR PLACE.
          1855.
 
 
   At a  meeting of the Class of 1856  and 1856 held Oct. 17th, Mr. Jno. Ros<
Shiell in  the chair.  The following resolutions were adopted:

   1st. To appoint a committee to wait upon Prof. Dalton and solicit the manu-
script of  his Introductory Lecture, delivered Oct.  16th.
   2d. That Messrs. Eug.  Peugnet,  Geo.  F. Shrady, and Jno. T. Crook be ap-
pointed the Committee.

   Agreeably to the resolution, the following correspondence was entered into.

Dear Sir :
 •  We, the undersigned, a Committee appointed by the Class, would  respect-
fully solicit in their name, your permission to publish your Introductory Lec-
ture, delivered last evening.
                                  We remain yours, respectfully,
                                                 GEO. F.  SHRADY,
                                                 JNO. T. CROOK,
                                                 EUGENE PEUGNET.
  To Prof.  Jno. C.  Daltox, Jin.

   New York,  Oct. 11 th, 1855.
Gentlemen:
   Your polite note requesting permission to publish my recent Introductory
Lecture has been received.  The only return I can make for the honor you do
me, is to comply with your request.  Such as the Introductory is, I place it in
your hands, and remain,
                                           Your obedient serv't.
                                                JNO. C. DALTON, Jin.
To Messrs.  Geo.  F. Surady,
           Jno. T. Crook,
          Eugene Peugnet.
  New York, Oct. 18th, 1855.
   At a subsequent meeting, Mr. Walker in the chair, the report of the Com-
mittee being read.
   It was resolved, that the same gentlemen take charge of the publication. 
 
ADDRESS.
Gentlemen,—
  We welcome you to this School of Medicine.  No profes-
sion or association of men are united by more numerous and
important ties than the medical. None feel more constantly
and fully the close connection that results from common pur-
suits and common duties.  And, nowithstanding the accidental
differences and estrangements  that must occasionally result
from conflicting personal interests,'—I suppose there is no one
among us who would  not, at any time, meet a stranger with
more interest  and cordiality for knowing  that he also was a
physician.   That name is itself a  title which at once com-
mands our especial regard ;—and it naturally follows that just
in proportion to the respect we  are glad to pay to it and its
legitimate bearers, is the just aversion with which we regard
any one who assumes it falsely, or who degrades it by unworthy
practices.  You will  see  at once, then, that you who have
come here to commence or to continue the study of medicine,
must be regarded by us with feelings of no ordinary interest.
You have selected, for your occupation and pursuit through
life, the profession to which, years ago, we devoted ourselves.
You are preparing  yourselves  to  enter on the same field of
activity which we now occupy, and you will hereafter become
fellow  laborers in it  with us.   The character and position,
therefore, of the profession to which we belong, will certainly
be affected in no slight degree by the kind of spirit you infuse
into it.   It will be elevated or  depressed according as your
disposition, your  qualifications, and your acts tend to elevate 
6
ADDRESS.
 or depress it.   I need not say how much your future personal
 standing in the brotherhood of physicians, and the influence
 you are to exert on the profession itself, will depend  on the
 manner in which your preparatory studies are directed, and
 on the spirit and degree of activity with which you  pursue
 them.  This period of your pupilage must be regarded as the
 most important of  any in  respect of its influence  on your
 professional character.  When once you have passed through
 it, its influence is exerted,  for  good  or bad, and cannot be
 nullified or easily counteracted.  It cannot be  lived over again,
 nor its deficiencies, if  it have any, supplied.  Xot  only will
 the number of medical facts you  learn here  depend on your
 own diligence and the faithfulness of your teachers,—but what
 is of still more consequence, your future style of thinking in
 medical matters, and the manner in which you  are hereafter
 to observe and examine medical phenomena  will depend, in a
 very  great  degree on  the mode in which your studies are
 now to be carried on, and the train of ideas with which you are
 now to become familiar.  It is  no more  tban natural, then,
 that we should regard you, who are joining the ranks  of the
 students of medicine,  with  peculiar interest;  and  that we
 should feel  the importance of your understanding, as early
 as possible, the character and requirements of the study you
 have undertaken to pursue.
   There is probably but little occasion for me to speak of the
 worth and dignity of the medical profession.  If you were not
 already sensible of these, you would not have chosen it for the
 occupation of your lives.   Still it may not  be out of place
 here to say that further acquaintance with it will not  disap-
 point the expectations you have formed.   I do not know any
profession  whose membei's are more.thoroughly and sincerely
 attached to it  than  the medical;—there are  few where they
are so much so.  We sometimes, it is true, hear medical men
complain of the unpaid drudgery they are obliged to perform,
and the unjust slights and misconceptions to which they are
subject; and sometimes, disheartened by tbe  bluster and pre-
tensions of  some ephemeral but successful impostor, they for- 
ADDRESS.
7
get, for the time, that the Profession of Medicine has a dura-
tion  in the past and a security in the future, that raise it
above the level of temporary disaster, and protect it equally
from the passing attacks of ignorance and dishonesty.   And
whatever may be said of the practice of medicine by the dis-
appointed or the over-sensitive, all will agree that its study, as
a worthy pursuit for vigorous and cultivated minds, has no
superior in the whole field of  knowledge, open  to human
investigation.
   Its antiquity cannot be estimated.  Among the civilisations
which may  have flourished before the  commencement  of
Egyptian and Indian records, and then disappeared from the
earth like the extinct mastodons  and mammoths, there is little
doubt that systems of medicine, more or less complete, perished
at the same time with other evidences of refinement and cul-
tivation.  Whenever, since then, the  human race has  made
any  intellectual progress, Medicine has always received its
due share of attention. The greatest and most ancient of Epic
poets that history knows* does not think it beneath the dignity
of his verse  to do homage  to the worth and  calling of the
physician.  Throughout the classical periods medicine was cul-
vated by the most active  and intelligent of the times, and
when the darkness of a Gothic night  settled down over the
face  of Europe, it was preserved from destruction in the
literature of the soberand  studious Arabs.  Since then, no
science has had brighter ornaments or more devoted followers.
Following  Hippocrates  and Galen, Celsus and  Pliny and
Avicenna, have come Morgagni and Malpighi, Spallanzani and
Vesalius, Ambrose Pare, Harvey and Hunter, and Boerhaave
and Bichat and Laennec. Do you think that such minds as these
can have labored in turn for two thousand  years in the field of
medical research without leaving us a legacy worth inheriting?
The subject that occupied them, enriched, as it is, by their suc-
cessive accumulations, cannot certainly be unworthy of culti-
vation by us.

       * 'hrpd$ yap dvr,p iro\r\<ov avrd^iog aAAwv,—Homer's Iliad, xi. 514. 
8
ADDRESS.
   If we are sometimes tempted to think that medicine has,
so far, made little progress, it is only because the subject is so
complicated and its extent  so  boundless.  The avenues that
it opens to us stretch out so far into the future that the space
already passed over seems small in comparison.  But it is
small in comparison only.  In every complicated department
of human knowledge progress is at first  slow and difficult,—
opposed by obstacles, retarded by unavoidable errors, which
must be corrected by subsequent examination.  The pioneers
of Medicine had no  royal road  to follow.  Their landmarks
were few,  and easily mistaken.   Their route led over intricate
passes or through close and tangled thickets. Sometimes they
were obliged to cross trembling and insecure  morasses ; and
sometimes, with laborious strokes of the hammer and crowbar.
they must force their way through ledges  of the solid  rock.
What wonder is it that they were sometimes misled by false
landmarks, and wandered off into impassable wastes, or were
misled into devious  by-paths, that .carried them backward
while they thought themselves advancing ?  Standing now on
the eminence to which they have  brought us, we can look
back and see the windings, and faults,  and doublings of their
track.  But if we had to begin where they begun, and to  go
over now the same ground, we should commit at least as many
errors as they.
   Let us not suppose, then, because we are  sometimes ob-
liged to discard as error what was a year ago held as truth, that
for that reason all previous  labors were fruitless, and we are
still beginning at the beginning.  That is not the case.  These
errors were only a part of  our previous acquisition.   They
were the  unavoidable  mistakes, made in first studying  an
intricate subject;—and by continued  perseverance they are
successively sifted out, while that  which  is absolutely true
remains behind, slowly but constantly accumulating.
   We are apt, also, to regard  those discoveries and achieve-
ments of Medicine which have been long the property of the
profession, as less valuable in themselves  than they really are.
As the schoolboy, drilled into detailed  familiarity with the
heroes of  Homer or the supernatural personages of ^Eschylus 
ADDRESS.
9
 and Sophocles, is incapable of appreciating the magnitude of
 the subject until  he recurs  to it  at some subsequent period
 when the effect of this constant familiarity has somewhat worn
 off, so we are  apt frequently to overlook the value and diffi-
 culty of many medical discoveries, because they now appear
 to us so simple and so  well-known.  Simple and well-known
 they undoubtedly are, now that they have been established ;—
 but they were not the less obscure beforehand, and difficult of
 acquisition.   " The most obvious thing in the world," says a
 French writer, " is  what was discovered yesterday ;—while
 nothing is so obscure as what will be discovered  to-morrow."
    The practice  of vaccination in Medicine, and of Etheri-
 sation in Surgery are discoveries still too recent and brilliant
 to have yet  been obscured, to any great extent, by the veil
 of  familiarity.  Yet even  these   have  already become  so
 thoroughly a part of modern Medicine, that we fully  appre-
 ciate them only when we recollect what would have been our
 condition without them.  Before the discovery of inoculation
 one out of every five, exposed to the variolous contagion, fell
 a victim to the disease. Now only one in fifteen hundred per-
 ishes from the same  cause. Before  the use of ether and chloro-
 form, surgical operations were a different thing from what they
 are at present.  The student who has commenced his career dur-
 ing the last few years, can form but a faint idea of what it was
 to do or even to witness a severe surgical operation previous
 to 1847.  Then the operating theatre, from the commencement
 to the end of the  surgeon's performances, was a scene of pain
 and terror.  The spectator's  mind  was half occupied in pre-
 serving an exterior of pretended indifference, and the air was
 filled with the patient's screams of  suffering or apprehension.
 Now the operating theatre is a quiet and noiseless room. The
 knife searches for morbid growths,  entangled among nerves
 and bloodvessels ;  or the pulleys drag, by main force, dislo-
 cated limbs from their  unnatural  positions, almost without
 producing a sound or a movement that  could excite the alarm
of the spectator, or shock his  sensibilities.  Older discoveries
than these seem now more common-place.  The  circulation 
10
ADDRESS.
of the Hood, for example, is no  longer the exclusive property
of medical science, but is  a part of the popular knowledge.
Almost every schoolboy is  taught something about it.  But
we have only to remember what must have been the difference
in the position of medical knowledge before and after Harvey's
discovery, to understand at once its true value.  Suppose, for
a moment, that anew discovery, of equal magnitude with that
of the circulation of  the blood, were  to  be made at the pres-
ent day.  What an enormous advance  would instantly be made
in every department  of medicine!
   These advances,  then,  have been continuous  since the
commencing history of our present civilisation.  Striking and
brilliant conquests in the  domain of discovery have been
made, of course, only at long intervals;  but some new facts,
well  worth all the  labor they cost, have  been constantly and
steadily accumulating, enabling us to correct previous misap-
prehensions, and opening the way to  similar acquirements in
the future.
   Such, then, is  the science whose study you have  com-
menced or are  commencing.  Let us see what are  the meth-
ods we are to follow in its pursuit.
   Whenever  we  commence the examination of  a subject
which is entirely novel, and of unknown character, we almost
necessarily begin in the  middle.  Ignorant of its extent, un-
acquainted with its component parts,  we attack the question,
so to speak, at hap-hazard, knowing only that it is absolutely
necessary, at first, to make an  opening somewhere,—no de-
tailed plan of operations being possible, until an entrance, at
least, has  been  effected, and we are somewhat acquainted
with the nature of the ground.  Medicine having for its sub-
ject the causes and cure of  disease,  its cultivation was natur-
ally commenced by studying directly the effect of drugs on
the bodies of the sick.   Then, a patient who had recovered
from any illness, deposited in the  temple  of -Esculapius a
votive  offering, with  a tablet describing  his illness and the
means by which he  had been  restored to health  ;—so that
others, similarly affected,  might try  the effect of the same 
ADDRESS.
11
 remedy.  This was  a blind beginning; but necessarily the
 only one that could then be made.  In this, as in all similar
 cases, it gradually became manifest that such a plan of opera-
 tions, though necessary in the outset, was altogether inade-
 quate  to  the completion of the work.  The subject showed
 itself too vast, and the question  too  intricate.  The plan of
 the vEsculapian tablets might be followed for ages without pro-
 ducing directly any scientific result worth having;  because it
 proposes to itself the logical impossibility of a simple answer
 to a complicated question.  Instead of being homogeneous, the
 science of medicine is seen to be  composed of several differ-
 ent departments,—the simpler of which must be thoroughly
 understood before we  can approach the more  complicated
 with  any hope of success.  A certain method,  or order, in
 our studies therefore becomes necessary ;  for without it, pro-
 gress is impossible.  The study of medicine is divided accord-
 ingly into certain distinct departments or branches, which are
 under the charge of different teachers, and which follow each
 other in a pretty natural and connected series. These are
 Chemistry,  Anatomy,  Physiology,   Pathology,  Materia
 Medica, and Therapeutics.
    Chemistry lies so at the basis of medical science that it
 may be said to be rather a preparatory study than a part of
 medicine, strictly speaking.  It does not, in  fact, necessarily
 introduce us to medical  studies proper.   We  may study
 Chemistry thoroughly, without knowing anything about Medi-
 cine.   Still, it is so closely  interwoven with nearly every
 department that follows—with Anatomy, Physiology, Ma-
 teria Medica, and Therapeutics—it is  so  much  more neces-
 sary to the  physician  than to the student of most other
 sciences, that it is naturally and indispensably incorporated
 into the teaching of a medical school.   The physician is, par
 excellence, the student of nature. It is not his place to invent,
to theorise, to speculate.  His subject is the phenomena pre-
sented  by natural bodies, animate  and inanimate; and his
object  the modification of these phenomena, by combining
them to his own advantage.   The  inanimate substances, that
form so enormous a proportion of the mass of the globe, first 
12
ADDRESS.
claim his attention, and it is their properties and phenomena
that chemistry teaches him.  He sees them present two differ-
ent orders of qualities, under two distinct conditions (which
are common, indeed, to all natural objects), viz.: a condition
of rest, and a condition of activity.  In  a condition of rest,
he studies their weight, their form, their volume, their  color,
their consistency, their composition.   The drop of water pre-
sents to  him a globule of a certain color, transparency, and
fluidity.  He weighs  it and measures  it.  He separates its
oxygen and hydrogen, and weighs and measures them.  He
thus becomes acquainted with its properties in a state of rest.
Then another class of phenomena claim his attention—the
phenomena  of its  activity.  The  quiescent fluid  swells and
bubbles with the elevated  temperature.  It flies off in wreaths
of vapor that float through the air, and then condense again
on some stone jar or marble slab.  Or, subjected to the  oppo-
site condition of increasing cold, it becomes whitish an d opaque,
and solidifies into a network of interlacing crystallisation. Or.
dropped on a bar of iron, and suffered to remain there in con-
tact with the atmosphere, its oxygen seizes upon the metal, and
uniting with its substance, appears under a new form as a rusty,
brownish powder, that, united with muriatic acid, will  again
appear in a  new combination, as brittle, reddish crystals, en-
dowed with new properties, and susceptible of  new  trans-
formations.  Or, brought into contact with potassium, the ra-
pidity and violence of the combination, with its accompani-
ment  of  heat  and flashing flames,  presents  us with  the
remarkable  phenomena to which we have given the name of
combustion.  All the decompositions and re-compositions, and
the  phenomena of electricity and magnetism, crystallisation
and solution, vaporisation and solidification,—all these exhibit
to the chemical  student  the activity  of inanimate bodies:
that is to say—the phenomena which they are capable of
presenting when placed under the requisite conditions.   This
department of study is marked  by special characteristics.  It
bears everywhere a definite and  positive aspect,  and a char-
acter of  almost mathematical simplicity and certaintv.
    With Anatomy you cross the threshold of medicine proper. 
ADDRESS.
13
You commence here the examination  of that natural object
with which the physician is  more especially interested, viz.:
the living body.  In this first department of the science you
are to learn simply the parts  of which  that body is composed.
Just as the mineralogist and the chemist study the forms and
substances met with in the crust of the earth, the water, and
the atmosphere, so you study the forms and substances enter-
ing into the composition of the  living frame.  You study
them by every available means.  As you wish to become ac-
quainted with all their different properties, you  make use, of
course,  of different methods applicable  to those  different
properties.  You use your eyes and your fingers for the parts
which are exposed and superficial, your knife and scissors for
those which  lie deep, or are so entangled with each other that
they require to be artificially separated.  You employ a mi-
croscope for those that are  too small for the naked eye, and
filters and evaporating dishes for those that are suspended in
a state of minute subdivision, or that present the liquid form
by mutual admixture and solution. Already without recourse
ro any  instruments, you gain  some  anatomical knowledge
from simply surveying the body.  You see some of its differ-
ent parts. You distinguish a head, a  neck, a trunk, and  ex-
tremities. You see the eyes and the ears, occupying distinct
positions; and by a little dissection, you become acquainted
with the integument, covering everywhere the exterior of the
body.   Going deeper, you find that in a single limb you can
distinguish  muscles and nerves, arteries,  veins, bones, liga-
ments, and tendons.   Examining  other regions, you see that
there are muscles there too, differing in shape from the first,
but similar in structure ; and you comprehend at last that all
these distinct but similar muscles, distributed throughout the
frame, when taken together, constitute a connected set,  or
order of parts—the muscular system.   So  with the tegumen-
tary system, or skin ; the bony system, or skeleton.   To exa-
mine  the muscle still  further,  you tear it into shreds with
needles; and as,  with  the naked  eye, assisted by knife and 
14
ADDRESS.
 forceps, you found an  entire limb to be made up of bones.
 ligaments, muscles, veins, &c,  so, aided by the  microscope,
 you separate the  entangled threads of which  the muscle is
 composed.   There are the  inosculating tubes of capillary
 blood-vessels,—the delicate, but  distinctly-marked  nervous
 filaments,—the white, wavy bundles of cellular tissue,—and
 the ruddy, prismatic,  muscular fibres, with their colorless and
 transparent sarcolemma, their elegant and regular striations,
 their concealed nuclei, and their bundles of beaded  fibrillse.
 When you have done this for the  rest of the tissues and or-
 gans, you have  done  all that can be accomplished by these
 means. Y^ou have  separated the body into the minutest forms
 of which  it  is composed.   But these forms, themselves, are
 not simple, but compound.  They are composed of a  mixture
 of different substances which cannot at once be recognised by
 the eye, because they have no definite size or shape, any more
 than the oxygen and nitrogen of the atmosphere, but which
 are mutually diffused  and united with each other.  Y'ou must
 then proceed to  study these more elementary constituents.
   If you take,  for example, a muscle, and cutting it into
 small pieces, soak it in distilled water, and then subject it to
 pressure, there will run from it a fluid with which the  fibres
 were bathed and moistened.  Heat this fluid to 160°, and it
 becomes turbid, depositing a curdy, flocculent substance, that
 was before in solution.  This is Albumen.  Separate  the pre-
 cipitate by  filtering, and you get a clear, acid fluid.  The
 acid is Lactic acid, which  you neutralise with Baryta-water.
 That forms a precipitate showing the presence of Phosphates
 of potass, magnesia,  ^c.  The remaining fluid you evapo-
 rate  slowly, till a substance  is deposited in  short,  needle-
 shaped crystals, with a brilliant lustre, a  sharp taste, and neu-
 tral in  reaction.  That is Creatine. There is another substance
 remaining, which is more soluble than the first, but which is,
 in its turn, compelled  to deposit  and solidify by the  advanc-
ing evaporation, or which must be seized upon and separated
by some salt oi' copper or zinc.  It crystallises in  prisms, has 
ADDRESS.
15
■a caustic taste, and is alkaline in reaction. It is called Creati-
nine.  Further on, Chloride of sodium is driven out also from
its fluid concealment, and  is exposed  at last, like  the  rest.
Then, with dilute muriatic acid you dissolve most of the re-
maining solid portion of the fibres, and neutralising with an
alkali, precipitate in  abundance the  semi-solid  Musculine.
One  or  two other substances  are extracted  by analogous
means, and our dissection  is then complete'.   We  have be-
come acquainted with the intimate structure and constitution
of the muscle—that is, we have studied its Anatomy.
    In pursuing this,  and similar examinations,  we must keep
clearly before our minds the object we have in view ; and al-
ways remember the distinction  that exists between  the  real
subject of our study, and the means used in its examination.
Let us not commit the error of regarding  our subject as diffe-
rent, because our methods of .investigation vary.  Thus, when
we use the microscope in  examining  the body, we  are not
studying optics, but  anatomy—we are not even  pursuing a
branch essentially  different  from  ordinary anatomy, but are
merely using an instrument, to gain  the same information
with regard to the smaller anatomical  forms that the naked
eye gives us  with regard to the larger.  So the chemical
manipulations used in examining the body are to be regarded
as  anatomical instruments  only,  of another sort;—and  they
may be used alternately, in chemistry or  anatomy, according
to the object we have in view.  Thus when the chemist takes
fibrine, and examines it as an isolated body, without reference
to its origin or physiological destination, as he might examine
sulphuret of iron or carbonate of magnesia ; when he separ-
ates its ultimate elements and ascertains  how much oxygen,
hydrogen, carbon, and nitrogen it contains;  when he  learns
what are the results of boiling it with potass, or decomposing
it with sulphuric acid,—then he is studying chemistry, and not
anatomy or physiology ; for his  whole  object and  aim in
examining  the substance, is the  investigation  of its purely  *
chemical phenomena.  But when he examines fibrine in its
relation to the organised frame, when  he  endeavors to learn 
16
ADDRESS.
   under what form and in what quantity it exists in the blood,.
   what are its  properties while circulating in the vessels, and
   what  are  the  modifications  of these properties in different
   parts of the body ;—then he is studying its anatomy, and not
   its chemistry.  For the chemical operations to which he has
   recourse are  resorted to, in this instance, simply as a means
   and not as an end.
      All the tissues and fluids of the body, therefore, are to be
   examined as we have examined the muscle. Take, for instance,
   the blood.—For the blood is as  much a part of the body as
   the bones and muscles, and therefore must be  examined first
   by the anatomist.   The albumen, the phosphate of lime, the
   chloride of sodium, in the blood  are  constituent parts of the
   frame, and therefore come within the domain of anatomy.  In
   point of fact, as a matter of convenience in  the arrangement
   of a course of  medical lectures,  the description of the fluids
   of the body usually falls to the lot of the teacher of Physio-
   logy ;—and such will be the arrangement in the course which
   we are now  commencing.   Anatomy and physiology are so
   interwoven, that it is not possible for the lecturer on anatomy
   to avoid referring occasionally to physiological matters ;—and,
   vice verad.  Still, this is of no consequence, so far as regards our
   present purpose.  Whether the fluids of the body be  treated
   of by one person  or another, their description is in reality a
   part of anatomy, and of anatomy alone ;—and it is necessary
   to recollect this, in order to avoid confusion in our ideas.
      We examine, then, the blood as we have examined the
   muscles.—It  being  quite fluid, at least to the unaided  senses,
   the knife and the forceps are of no use to us here.  Instead,
   we first examine a drop with the microscope.—We then see
   that it  contains semi-solid globules, of two kinds, white and
   red, swimming  in a colorless and transparent liquid.  AVe as-
   certain the size, shape, color and consistency of these globules,
   and then, as in the  muscles, we  separate by various solvents,
v  the two amorphous substances,  globuline and haematine, of
   which the most numerous of them are composed.  Then we
   separate from the liquid portion, by appropriate means, first 
                      ADDRESS.                    x*
              c
the fibrine, then the albumen.  By successive  evaporations
and crystallisations, we get the water,  the chloride of sodium,
the phosphate of lime,  potass,  and magnesia, the urea and
other substances which, mingled together, made up its  mass,
Then we know the constitution of the blood, and have finished
its anatomy.

  Next in  order comes Physiology.—The Characters which
distinguish this branch from the preceding, are well defined
and important.  Anatomy is the description of the body in a
state of rest.   Physiology is the description of it in a state of
activity.  We see, then, that the order in which these branches
are arranged is not  an arbitrary one, but natural  and  neces-
sary. One must precede,—the other must follow. It is so with
all the departments.  But it is important to bear in mind this
fact:—that, although the first is always a necessary prelimi-
nary to understanding the second, the facts of the second
cannot be, in the least degree, inferred from those of the first,
but must be studied by themselves.  Thus, chemistry is essen-
tial  to  anatomy, because certain  substances,  belonging to
chemistry, such as chloride of sodium, occur as constituents of
the  human  body.   Chemistry teaches us the composition,
reactions, mode of crystallisation, solubility, etc. of chloride of
sodium, and if we did not know these we could not extract it,
or recognise  it when extracted from the body.  But  if  we
knew its chemistry  ever so well, we could not, on that account,
infer its presence as a constituent of the body, nor in what
quantities, nor in what situations it would present itself.  These
facts must be ascertained for themselves, as a part of anatomy
proper.  So, again, the structure  of the  body in a state of
rest, or its anatomy, is  to be  the first understood; but its
active phenomena, or its physiology, must then be ascertained
by direct  observation and experiment.   No knowledge of
anatomy, however minute and thorough, could  ever teach us
that the muscular fibre was contractile, or  the nervous  fila- '
ment sensitive.  Those bodily  phenomena,  even,  which  are
purely mechanical  in their nature, require the same  direct
            2 
18
ADDRESS.
examination.  The structure  of the heart may be learned
by dissection;  its rythmical and  complicated  movements
baffle  all a  priori hypotheses, and  must be actually seen to
be understood.  This is not because they are at all obscure
or mysterious in their nature ; for they are, as I have already
said, purely mechanical in character; but because their condi-
tions are so peculiar, owing to the tortuous course of the fibres,
their arrangement in interlacing layers, their attachments and
relations, that their combined  action produces an effect alto-
gether peculiar, and not similar to that which is observed
anywhere outside the living body.  Many of the  phenomena
of life are chemical in their character:  There  are combina-
tions and solutions, decompositions and  re-compositions ; but
these, again, cannot be  inferred from any previous chemical
knowledge, but must  be ascertained for themselves, as they
take place in the organised frame.  ]\o other plan of investi-
gation  will succeed, because many of these reactions  do not
take place, and  cannot be made  to  take place anywhere
else.  This,  again, is not because there  is  anything particu-
larly mysterious  or extraordinary  in their  nature, but be-
cause  the conditions, necessary for  their accomplishment,
are met  with in  the  body, and not elsewhere.  A  differ-
ence in  the surrounding  conditions will modify the  sim-
plest chemical phenomena.  If a hot concentrated solution
of sulphate of soda be  allowed  to  cool in contact with the
atmosphere, it chrystallises; covered with a film of  oil it
remains fluid.   Sulphur, which solidifies at a temperature of
232°, crystallises in oblique prisms ;  below that point, it crys-
tallises in rhombic-based octahedra.  It is plain, then, that we
cannot foretell, from our knowledge  of the chemical reactions
of a substance outside the body, what will be its reactions  in
the body; since the conditions under which it is placed are new.
  Ferrocyanide of potassium and perlactate of iron, by mutual
decomposition, produce  Prussian blue.   But if the lactate of
iron, be injected into the right jugular vein of an animal, and
ferro-cyanide of potassium into the left, so  that  they mav
meet in the blood, no Prussian blue  is produced.   The serum 
ADDRESS.
19
 of the blood holds both salts in solution, and yet they do not act
 on each  other;  because there exists also in  the serum an
 organic substance,  which by its presence prevents their  usual
 reaction.   If this organic substance be destroyed by  a few
 drops of sulphuric  aoid, then the two salts are at liberty to act
 on each other, and the Prussian blue is immediately produced.
    If a solution of cyanide  of mercury be injected into  the
 femoral artery, it returns unchanged by the femoral vein, and
 the animal suffers no inconvenience.  But if injected into the
 vein, and carried through the heart to the lungs, it destroys
 life in less than a minute; because in the tissue of the  lungs
 it meets with a substance by which it is decomposed with the
 production of hydrocyanic acid, that poisons at  once the nerv-
 ous system, and stops the action of the heart.
    Such facts as  these give us an idea of the peculiar delicacy
 and complexity  of the phenomena which we meet  with in
 studying  Physiology.  Singular  as it may seem, there is a
 tendency in some minds to ignore this complexity in the phe-
 nomena of life,—to push it  out of the way, even, and  cover
 it up, as if it were  a stumbling-block in the path of science,
 instead of being, as it  is, an essential fact, to  be recognised
 and studied  like any other.  I could name more than one
 physiological writer, whose whole endeavor seems to be  to re-
 duce the  science, as it  were, by force of arms, to a series of
 simple  propositions, which do not express its real character.
 They attempt to square physiology on the pattern of  other
 sciences, instead of taking it as it really presents itself, and
 in  studying  it as  chemistry  and  physics,  they  forget to
 study it as  physiology.  A single example will make my
 meaning in this  respect more easily understood.  It is well
 known that a certain amount of sugar is constantly introduced
 into, or produced in the body; and that, as it enters the blood,
 it is destroyed and disappears as sugar, passing through  a  se-
 ries of transformations, the details of which are not altogether
understood.  In Diabetes, this sugar, for some cause or other,
is  not destroyed  as it  is in  health, and accumulates in the
blood—making its  appearance, consequently, in some of the 
20
ADDRESS.
secretions.  Some  years  ago,  the  chemist Mialhe  observed
that when sugar was boiled with a solution of pota-s, it was
destroyed under the influence of the alkali, losing the proper-
ties of suo-ar,  and becoming  converted  into a  brown sub-
stance, known as  melassic acid.   Observing also that  the
serum of the blood was alkaline, he concluded that it was by
this  alkali that the sugar w;>> naturally destroyed  in  the
circulation;  and' that when the alkalescence of the  serum,
from any cause, was  insufficient, all the sugar could  not be
destroved by  it, and therefore accumulated, producing  the
condition of Diabetes.   He observed, in this instance, what
took place in the test-tube,  and from that  inferred what took
place in the blood—forgetting, by some inconceivable fatality,
the essential difference between a solution of caustic potass,
at the  temperature of  212°, aud the slightly alkaline blood,
composed of twenty  different ingredients,  at the  temperature
of 100°, and  circulating in the vessels of the living body.
His  conclusion was worthless, as the expression of a physio-
logical fact, for the simple reason that, in the body, the sugar
is not boiled with caustic  potass, but is  subjected to other
influences.  The destruction of sugar by boiling  potass, on
which  he based his theory, is a purely chemical fact, of a
certain  degree of importance, and extremely interesting to
know ; but it is not a physiological fact, and he was not, as
he supposed, studying  Physiology.
    Lot us not, then, commit the mistake too commonly inade^
of taking it for granted that things will be in  the body as
they are in  the  test-tube and  crucible.  We cannot  tell
whether they  will be so or not, until we look and see.  If we
persist in regarding the organised frame as a furnace or a
filtering-jar, and its actions as identical with combustions and
liltrations,  we may  amuse ourselves with introducing  into
Physiology an imaginary simplicity, but we shall make no
progress in positive knowledge.  If we  wish to  study the
structure and  growth of sea-weed, we  do not look for  it in
fresh water.   If we  wish to  study the functions and  pheno-
mena of life, we must search for them in the living body, and 
ADDRESS.
21
in the living body alone—take them as they are, and not com-
pare them with other things which are dissimilar.
   Pathology is the natural  history of disease.  It is  the
study of the unnatural phenomena  of the living  body pro-
duced by the operation of morbid influences.  It is almost a
truism, then, to say that we must first be acquainted with the
natural processes, before we can understand their deviations.
But beside this we  must study independently the deviations
themselves, without attempting to deduce them from the  na-
tural phenomena.   Physiology throws no light on pathology.
It is very true, as I have already said, that  it is a  necessary
preliminary, and if we try to  get on without it, we shall suc-
ceed only in wasting our time.  But it is a necessary prelim-
inary only.  It  brings us up to the  threshold  of pathology;
—it does not carry us over it.  The pathologist must study
the body in disease, just as the anatomist and the physiologist
have  studied it in health.  His means and methods are the
same, his subject only is' different.  There is no  organ or
function of the diseased body which is not subject to his scru-
tiny ; no solid or fluid that he is not to dissect and analyse.
All this is to be done without reference to any future and dif-
ferent order of studies.  The disease is first to be investigated
without the least reference to curing it.  It is to be studied as
a natural phenomenon, like the eclipses  and the  spring-tides.
I cannot too much ask your attention to this fact, for it is one
that has exerted, and is exerting, much influence on medical
science.  There  is no particular in which the medical profes-
sion have  made more rapid  and satisfactory  improvement
during the last twenty years than in their way of thinking on
this point.  Physicians are now awake to the necessity of
knowing something: about the  disease in its  natural, undistur-
bed course, before they undertake to treat it.   Formerly, a
sick man was a man who required to take  medicine.  Fever
was  defined to  be something that demanded  bleediug  and
sulphate of magnesia ; and, in  the mind of the student, cholera
infantum was instantly associated with calomel or hydrargyrum
cum creta.  Physicians, however, began to see at last  that 
22
ADDRESS.
 this was a confused and unsatisfactory method;—and that the
 smoke of this senseless cannonading blinded their own  eyes*
 and really prevented their seeing what they might have learned
 by simply keeping still.  Then pathology  began to take  its
 proper place as one of the departments of medicine.   Medical
 men soon comprehended that diseases have a natural history,
 like the different ages of man, or the different species of ani-
 mals.  They originate  at certain times, in certain places,
 under certain conditions.  They announce themselves by cer-
 tain symptoms, insidious or  violent.  They pursue a certain
 course,  steady or fluctuating, tedious or rapid.  They are
 liable to certain accidents, relapses, and complications. Many
 of them terminate in a certain number of days, or weeks, or
 months.   A few are as deadly as  poison,  some imply no dan-
 ger to life,—most of them are distinguished by a certain pre-
ponderance of the favorable  or unfavorable  chances, which
 are now in a great measure estimated for  each one.
   These are the topics which will occupy you as pathologists.
 AVe  must recollect, also,  that what we mean by a disease is
 only a morbid condition of the functions, as health is a natural
 condition of the functions.   It is these functions, therefore,
 the active phenomena of the diseased body, which  deserve
 and  require our attention; and not  any  imaginary force,  or
 entity, which will always necessarily elude our  observation.
There is no  such thing  as  a pneumonia, properly speaking.
A man with pneumonia is a man whose  skin is hot, whose
pulse is rapid, whose lung  is inflamed, whose respiration  is
hurried, and whose expectoration rusty and  adhesive.  Pneu-
 monia, so far as its derivation is concerned, means inflammation
 of the lungs.  But inflammation of the lungs is  only one  of
the morbid conditions under which the patient is laboring.__
There are also the alterations of the pulse, the temperature
of the skin, the secretions, &c.  You will say, perhaps, that
these are secondary, and all dependant on the inflammation ;
—but that is the very  thing of  which we are ignorant__
whether the  alterations referred to are so  dependent on the
inflammation, or whether they are all dependent, inflammation 
ADDRESS.
23
as well as the rest, on some other cause, not yet known to
us.  The name, pneumonia, which we  give  to this collection
of morbid conditions does not represent anything positive. It
is simply an intellectual artifice, by which we keep these con-
ditions associated in our minds, and are enabled  conveniently
to communicate them to others.  Do  not suppose  that  these
are fanciful distinctions, interesting to the metaphysician, but
of no practical importance to the medical  man.   They are
real distinctions, of the first practical importance.  That they
are real we can see at once, by referring to the history and
nomenclature of  various  other  diseases.   Dyspepsia, for
example, means only a collection of symptoms, the most con-
stant and prominent of which is a disturbance of some  kind
in the process of digestion.  No intelligent physician supposes
it really to represent any distinct disease.  Every one knows,
on the contrary, that it comprehends several different morbid
actions, of which one may  have its seat in  the  stomach, an-
other in the duodenum, another in the jejunum,  and a fourth,
perhaps, in the ileum.  AVe are not yet sufficiently acquainted
with the distinctive characters of these affections, to give them
their  proper  titles; and it is  therefore from our ignorance,
and not from our knowledge, that we name them all Dyspepsia.
Before Laennec and Louis lived and  wrote, all inflammatory
affections of  the thoracic organs were known by the name of
inflammation of the chest;—simply because physicians were
unable to  distinguish them during the life  of the patient.—
Now, with better means of diagnosis, we know the difference
between pleurisy, pericarditis and pneumonia.   But shall we
stop here, and rest satisfied, thinking we have  followed the
thread to  its termination?   Yes,—if  we believe the  term
" pneumonia" means something positive and definite, and ex-
presses the real character of the disease.  But  not so,  if we
take it for what it really is,—a word, used for the sake of
convenience,  and nothing  more.   AVe always find  that the
simpler departments of medicine, preceding in the natural
course of study the more complicated, are actually farther
advanced than they at  any one period  of time. Thus, ana- 
24                    ADDRESS.

tomy is now more complete than physiology,—physiology than
pathology,—pathology than therapeutics.  And as pathology
itself has  two parts, one corresponding to anatomy, the other
to physiology, it  is not surprising  that its  anatomical part
should be the more complete of the two. The actual changes that
go on in disease,—the unnatural combinations and decompo-
sitions, we know little or nothing about.  AVe do know some-
thing of the alterations in the constitution, i. e. the anatomy,
of the fluids.  AVe know that in some diseases the blood has
more fibrine than is natural, in others less globules.  In some
that it  contains an  abundance of sugar, in  others that it is
deficient in salts.  But we are much better acquainted  with
the altered structure, or the morbid  anatomy of the  solids.
These,  being more easily examined  than the fluids, naturally
first received the attention of pathologists ;  and in this par-
ticular our knowledge is already remarkably complete.  As
the alteration  of the solids, then,  in color, consistency and
texture, is apparently the most essential element of disease
with which we happen to be acquainted, we naturally derive
our nomenclature, whenever it is possible, from these data of
morbid anatomy.  AYe have consequently induration and soft-
ening of the brain, pulmonary tuberculosis, cancer, local and
general, gastritis, nephritis, hepatitis, etc.  AVe call a disease
pneumonia, because  in it the lung has undergone  the inflam-
matory induration.   But in all probability there are other
changes, particularly in the constituents of the blood,  dating
anterior, perhaps, to the pulmonary inflammation, which are
not yet understood, but which are certainly indispensable to
a real  knowledge of  the disease.  These will also be  under-
stood in time, as pathology continues to advance, and then we
may hope to learn something of those active changes, those
disturbances in the continuous movement of union and decom-
position, of nutrition and disintegration, incessantly going on
in every solid and fluid of the body, that really constitute the
essential processes of disease.

    We come at last to Tiierapeitics. or the cure of disease. 
ADDRESS.
25
This is the end and aim of all our studies, the goal of all our
exertions.  We are  to learn  to  accomplish this  by every
means and  appliance  in our  possession.   And as  these
means and appliances consist largely of medicines, vegetable
and mineral, our  first care is to study these medicines by
themselves, so as to become thoroughly acquainted with the
instruments we are to use.  This branch is Materia Medica.
—Men  have always had, and always will have  an instinc-
tive faith  in the power of drugs.  This power is not to be
questioned.  Drugs will excite or depress the nervous energy.
They will paralyse or irritate the muscles.  They will modify
profoundly the nutrition of the whole body or of particular
parts.  One, rubbed on the skin of the forehead, will  dilate
the pupil.   Another, taken into the stomach, will depress and
retard the movements of the  heart.  Another,  introduced
gradually into the system, will  produce a pustular eruption
about the face and neck ;  and a fourth will relax the extensor
muscles  of the hand, and  send  neuralgic pains through the
trunk and extremities.  Nothing is more natural, then, than
to  believe that substances which act so powerfully on the
healthy frame, may be used to advantage in modifying the
processes of disease.  But we must in the first place, learn
their physical and chemical  properties, their commercial
history, the adulterations to which they are subject, and the
means of  detecting them. It is particularly indispensable>
too, to know their action on the healthy body, in different
quantities, and under all the varying conditions of age, sex,
temperament and  constitution.  Once thoroughly acquainted
with our instruments, we can then passto the study of their use.
   In commencing Therapeutics proper, we  are more deeply
sensible than ever of the necessary connection and enchain-
ment of the different departments of medicine.   AVe have
arrived now at the most complicated ; and we see how all the
others form a basis upon which it rests.  AVe know the struc-
ture of the healthy body, and have studied its active pheno-
mena.  AVe understand to a certain extent, its morbid actions:
and we are familiar with the effect of drugs on it in a state of 
26
ADDRESS.
health.  Now we are to study the mode in which these drugs
modify its  morbid actions, so as to bring them back to  a
healthy condition.  Plainly, this is a problem, complicated
though  not inextricable;  and one which demands that we
should bear constantly in mind all the necessary preliminaries.
Keeping these in view, we proceed farther on, to the study of
Therapeutics by themselves.  The results, again, of this study
must  be worked  out by direct  observation, and  cannot be
deduced from any knowledge previously acquired. AVe must,
it  is true, know the  action  of drugs on the healthy body;
because, without such  knowledge, our direct  study of their
action on the morbid functions would be blind, and lead to no
definite result.  But this direct study is not the less indispens-
able.  Because a particular drug produces atrophy in a healthy
organ it does not follow that it will  produce atrophy in that
organ when inflamed; because the actions on which it operates
are different in the  second  case from what they are in  the
first. Therapeutics, then, presents no exception, in this respect,
to  the rule  that governs the other departments.
   We  see the necessity, also, in Therapeutics, of regarding
the disease as  what it is, viz.: a group  of morbid actions
only,—and of studying the effect of  drugs on these morbid
actions.  Otherwise  we shall run  the risk of mistaking the
value of certain facts and methods, and of making them use-
less or injurious, when, properly estimated, they might have
been sources of advantage.  Take, for instance, the numerical
method, at  one time so  much in vogue as a means of investi-
gation—valuable if confined to its legitimate  objects,  but  a
source of error if it be taken, as it sometimes is, as an  unde-
viating formula, by which all questions in Therapeutics are
to  be settled.  According to this plan, to learn how to treat
pneumonia, we collect  a thousand, or, if possible, five thou-
sand cases  of it, and count the  results of a certain mode of
treatment; adopting or rejecting it accordingly. This would
all be right if "pneumonia" were really the  subject of our
study in any particular case. But it is not.   The subject of 
ADDRESS.
27
our study is a particular group of morbid actions, and it is
upon these our treatment is to operate.   Do not suppose,  be-
cause two men have inflammation of the lungs, that they  are
necessarily in the  same condition.  And  if they are not in
the same  condition, the  effect  of drugs upon them will be
different.  Let us attend, then,  to the real  actions of disease,
and not be misled by a name which only represents them.
Otherwise we shall be obliged,  as the French would express
it, to  take  our pay in words, and the realities  will  es-
cape us.
   We see, then, why it is that so much judgment and cau-
tion  are required  in the practice of Therapeutics, and why
the careless observer is liable to so many mistakes and disap-
pointments.  Medicine is said to be an uncertain science, and
the action of drugs variable.  That, however, is not the case.
Under the same conditions, a drug will always have the same
effect, just as surely as the sun rises and sets.  It is the condi-
tions which vary in different cases, and these conditions re-
quire to be distinctly understood and  compared with each
other; for in no other way can we arrive  at any definite
result.
   You will find, in continuing the study of Therapeutics,
that physicians at the present day give  but very little medi-
cine,  in comparison with what was customary many years
ago.   This is not, as I have already intimated, because they
have lost, in any degree, their confidence in the  power of
drugs, but because they have become convinced that the pre-
vious methods  of  investigation were,   to a  certain extent,
erroneous, and not likely to produce a  satisfactory result, so
long as every unknown  disease was at  once attacked with a
multitude of unknown  remedies, the  operation of  which
tended rather to perpetuate our ignorance than to dispel it.
Now, retracing our steps so far  as they have been made in a
wrong direction, we are endeavoring to  attain the same  end
by a different and more practicable route.  We now feel  the
necessity,  on undertaking the care of a patient, of making 
28
ADDRESS.
our diagnosis, clear—complete, including every circumstance
that shall throw light on the actual  condition of  the patient.
This is, at present, the most important work that the practi-
cal physician has  to do; and it is his way of doing it that
more than anything else distinguishes the good from the infe-
rior  practitioner.   That done, his next object is to be sure
and not injure the  sick man by unnecessarily meddling with
him, or by allowing him to be exposed  to accidents and im-
prudencies that would tend to aggravate his original difficul-
ties.   Beyond that, he uses few drugs, because what he does
employ he wishes  to use in an understanding manner, and
with his eyes open—not blindly, or at hap-hazard.
   Such, gentlemen, is the plan we  are  to follow in the
course which begins  at present.  I have occupied your time
in discussing it somewhat in  detail—being fully convinced
that the  method according to which scientific studies are  to
be pursued, far from  being a matter of indifference, is of real
and  practical importance.  A good method will do much to
simplify  and facilitate the student's labors; a bad one will
certainly be the source of delay and perplexity.  Especially
necessary is  it  to  have a distinct idea of the true direction
and limits of ourstudy in any particular department, so that
we may not  be led to demand of it more than it can accomp-
lish, or apply it to purposes for which it is not appropriate.
   Nothing  now remains for me to say but to repeat the wel-
come with which I commenced, both to vou who will engage
with us in the labors of the coming winter,  and to those also
who have come here this evening to encourage us by their
presence, and to testify their interest  in the great science of
Medicine.  These halls, which for eighteen  years have been
devoted to the pursuit and teaching  of that science, are about
to be abandoned now for a more convenient and  appropriate
situation.    The Institution that  occupies  them,  however,
while changing its locality, will in its character remain the
same.    That Institution claims to be catholic  and liberal.
Devoted to no clan, or sectarian idea—jealous only of move- 
ADDRESS.
29
ments that threaten the  purity and dignity of medicine—its
highest ambition is to represent the feelings and maintain the
interests  of the Profession.  May it  continue in the same
ambition. And may it always remain hereafter, as it always
has been, in character as well as in name, the

          College of Physicians and Surgeons. 
•