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The Progress and the Spirit of Medical Science.
AN
ANNIVERSARY  DISCOURSE,
DELIVERED BEFORE THE
NEW YORK ACADEMY  OF  MEDICINE,
NOVEMBER, 25, 1858.
                    BY
         E. li. PEASLEE, A.M., M.D.
PROFESSOR OF PHYSIOLOGY AND PATHOLOGY IN THE NEW YORK MEDICAL COLLEGE.
       [POBLISHJED BT ORDER Or THE ACADEMY.]
             .en/'-.



         NEW YORK:
PRINTED FOB THE ACADEMY BY W. H. TINSON,
        43 & 45 Centre Street.
              1859. 
 N/VZ.

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ANNIVERSARY  DISCOURSE.
Mr.  President  and  Fellows of  the New York
     Academy of Medicine :
  Standing in the  presence of so many of my pro-
fession whom  I  have been  accustomed to reverence,
I might feel some embarrassment, did I not remem-
ber that  I am placed here to-night by you and  in
your service; and that this is an occasion not in-
tended especially to call forth your criticism, but to
enkindle anew and  to expand our professional sym-
pathy.   I would gladly, therefore, render  the  exer-
cises of the present hour an  entertainment to you,
instead  of a  task.   But I  must select no  trivial
theme ;  and since the regular exercises of  this asso-
ciation are mostly of a kind in accordance with the
precept that—
           " That which before as lies in daily life
            Is the prime wisdom"—

I do  not  feel at  liberty to select  a  strictly practical
subject.   I will,  therefore, present  some  thoughts
upon the progress and the spirit of medical science, and
its claims upon medical men.
  "Hitherto," says a French  critic,*  "medicine—
* Louis Peisse : La M6decine et les Medecins, Pari?, 1857. 
4
ANNIVERSARY discourse.
both science and profession—has had only detractors
and  apologists, -believers  or skeptics.   It has been
attacked and  defended by  special pleadings only ;
there have been arguments on both  sides,  but  no
decision.  But where  is the Kant who can and will
tell us the fact ?   Shall we seek him in a  professor's
chair, or in an Academy?  Wherever he is, he should
show himself, for his time is  come."  It is with some
faint hope of calling out the  individual  so much need-
ed, that I  have selected my present  subject.   The
limited time allowed  me  on  this occasion will of
course compel me to  treat  some of its subdivisions
in a  very  cursory  manner ; and entirely to  omit
others.  But in what I may say, I will  hope to avoid
the errors both of the panegyrist of his own times,
and of the  "laudator temporis  acti."   I shall neces-
sarily adduce many facts familiar to all  medical men ;
though not, I will hope, for a trite purpose.
   The medical profession, like  the others, is some-
what inclined to cherish the idea of modern perfec-
tion.   Like the  other  professions  also, its members
generally adopt the principles and  acknowledge the
influence of their  predecessors without questioning
their correctness.   A candid inquiry  into the  real
progress, and  present  condition of our science will,
therefore, perhaps somewhat abate our complacency;
but it should stimulate our highest efforts to advance
it towards  that perfection  which  all invoke,  and
would witness for themselves.   We  are,  however,
during most of our  lives, too  much  immersed in
strictly professional labors, to give much attention to
these higher subjects;  and are too prone to feel that 
introduction.
5
they do  not particularly concern  ourselves.   But
there should be times, when our personal  responsi-
bilities in these respects  are presented to us ; and I
have assumed that this is appropriately an occasion
of that kind.
  There are those who assume that the human mind
itself has undergone a progressive increase  of power
and perfection in modern times; so that we now seize,
intuitively as it were, on what cost the ancients much
study and application ; and hence, know all they did
almost as a matter of course.  This  assumption  is,
however, opposed to all observation,  and to fact.  The
infant of 1858  requires as long a time to learn  to
talk  and to walk, or to acquire any other accomplish-
ment, for  aught we can conceive to the contrary, as
did the first-born of Cain.   And there are  no intel-
lects now-a-days superior  to  the  most  brilliant of
ancient times.  The advantage of the moderns con-
sists in  the improved facilities for  acquiring know-
ledge ; and  especially from  the art of printing.  A
few weeks  may now suffice  to acquire an amount of
knowledge it cost the ancients, perhaps,  a  thousand
years to  establish.   But-the power of acquisition is
no greater now, and its necessity no less, than it was
then.  Nor  is it by any means certain, or even pro-
bable, that the ancients  knew so much  less in the
aggregate than the  moderns,  as is so generally  as-
sumed.   They knew not  precisely what the moderns
know; but the world has not improbably  forgotten
quite as much as it  knows.  We have derived from
the ancients, but a small  part even of their recorded
knowledge.   But that little is calculated  to give a 
6
anniversary  discourse.
most exalted idea of the intellect and the learning of
antiquity, since it has impressed its character upon all
ages up to the present, and will impress all succeed-
ing ages to the  end of time.   And some  of  the re-
cently invented  instruments of our  art, and which
were supposed to indicate a degree of progress and
perfection never  dreamed of by the ancients, are now
known to have been  used at  least  1,800 years  ago.*
We, therefore, as truly as the ancients, can by labor
alone improve, or even acquire, our science.
                    PART  I.

  THE CONSTITUENTS AND THE  METHODS  OF SCIENCE.

  The following inquiries present themselves as pre-
liminary to my main, subject.

  I. What is the distinction between science and art ?
  II. What are the  elements constituting an  actual
science ?
  III. What is the true character of medical science as
compared with the  other sciences ?

  I. It is often asserted  that science is the basis of all
art.   But  it will be found in the majority of actual
instances, that  art is the forerunner, and  not the fol

  * Especially the speculum vaginas and speculum ani.  See drawings
of these and other instruments found in the ruins of Pompeii, in Amer.
Med. Monthly for August 1858. 
SCIENCE DISTINGUISHED FROM ART.        7
lower—the parent, and not the offspring—of science.
It is the province of science to know;  of art, to do.
Science inquires and ascertains what is ; art changes
what is to something different.   Science foresees and
predicts the  phenomena  around us;  art  forestalls,
controls, or  prevents them ;  science discovers ;  art
invents.  The immediate object of science is truth ;
of art, either pleasure or utility.  But  we must try,
before we can ascertain  and know;  the  tentative
must precede the positive : art in its primitive forms,
must  precede science.   It is true that every effort
of art  is made in accordance with certain facts and
principles ; but such efforts may be repeated for cen-
turies,  before the  facts or principles are discovered.
Meantime the art is improving, though the science
still remains unformed.  Some of the inventions of the
present  day  even, have  not yet  found a  scientific
basis.   Hence in the early ages of society there are
many arts, but no sciences.
  The art of medicine, therefore, dates back to the
earliest times ; while our  science is of comparatively
modern date.  The old adage—" Nusquam medicina
non est"—refers  to  the art  or practice of medicine
alone ;  and implies that there never has been a time,
in any nation, where the treatment of diseases and
injuries, has  not  in  some form obtained.   Much im-
portance has been attached to the assertion of Pliny
the elder, that Rome had no physicians for the period
of 600 years ; as if this city were an exception to the
general proposition just quoted.   It is, however, the
fact that in no age are physicians the sole practition-
ers ;  and I have also elsewhere shown that Pliny's 
8
ANNIVERSARY DISCOURSE.
assertion is  not correct.*  The  early  physicians of
Rome were  merely slaves, both male  and female ;
and therefore found no historian.  This was the case
indeed with the majority of them, until Caasar decreed
to all who practised medicine, the  rights  of citizen-
ship, f  In Athens, on the other hand, it was forbidden
by law, that a slave or a woman should practise phy-
sic ; and thus a dignity was imparted to our art which
secured its transmission to succeeding times.

           THE CONSTITUENTS^ OF  A SCIENCE.

   II. A science has been  said to consist of the facts,
ideas,  and principles of any  department of  know-
ledge—classified and arranged in a systematic man-
ner.}:
   1. Facts are something external to ourselves, and
therefore  existing independently of our own minds ;
e.  g.  the rising and the setting of the sun.  Facts
then, depend upon the nature of things;  and if actual
or real, are,  of course, true.  But we acquire facts by
the exercise  of our senses.  Whether  we  perceive
facts, therefore, as they are, depends upon our pow-
ers of observation  and their  use.   If  these  prove
deceptive, our supposed facts are not true, i. e. they

  * See Amer. Med. Monthly for April, 1859.
  t Subsequently, however, slaves were again allowed to practise medi-
cine. And the Code of Justinian, promulgated about a.d. 500, fixed the
price of physicians, male and female, at 60 solidi—or $257 12.
  X Sir William Hamilton's definition is too transcendental for our pur-
pose. "A  science is a complement of cognitions, having in point of
form, the character of logical perfection, and in point of matter, the
character of real truth.'1 
FACTS  AND IDEAS.                 9
 are  not real—are not facts at all, and are sometimes
 loosely termed "false facts."   With facts, then, sim-
 ple reality* is the test of truth; and no two facts can
 be contradictory, though our interpretations of them
 may be so.   Any doubtful proposition, adopted as a
 fact for the time being, is a mere assumption, or sup-
 position ; or if used to account for certain phenomena
 it becomes a hypothesis.   Theoretically, none but es-
 tablished facts should form part of a perfect science;
 but, during the formation of every science, hypotheses
 must be  more or less  used  as a substitute, for the
 time, for actual facts, and till the latter  can be veri-
 fied. A single  false fact being  once generally adopt-
 ed as  true, may retard  the progress of science for
 centuries ;  as did the  assumption that the earth is
 stationary, that the planets revolve  in circular orbits,
 and  that the blood passes directly from the right ven-
 tricle of the heart  into the left ventricle.   The last
 assumption apparently deferred the discovery of the
 circulation  of the blood for more than  1200 years.
   2. Ideas, on the other hand,  or notions, are the re-
 sults of our own  efforts of thought, and depend upon
 our  intellectual operations.  They  are  acquired by
 our  understanding and reason, as facts  are by our
 senses.   They may be acquired from or suggested by
 facts;  or indepedently of facts, or anything external
 to us—the imaginative faculty suggesting this  latter
  * In case of facts, reality is also the sole measure of possibility. "All
that is real is  possible; and all that is possible, exists."  We cannot,.
then, assume in advance, that an alleged fact is  impossible, unless the
terms in which it is expressed include an inconsistency; as when a came!
of the natural size is said to pass the eye of a needle—it being also un-
derstood to be of the ordinary dimensions. 
10
ANNIVERSARY DISCOURSE.
class of ideas.  Ideas, therefore, may be erroneous or
incorrect, though the facts suggesting them may be
true.   E. g. anatomists before the time of Galen knew
the fact of the existence of the arteries; but they held
the idea that they contain air and not  blood, and
hence their name.
  For scientific purposes, our ideas must be—1st, cor-
rect, or consistent with the facts suggesting them; and
2ndly, clear, definite and distinct. But the only demon-
stration of the correctness of an idea  in  natural sci-
ence is  the discovery of a new fact or principle cor-
responding in terms with it.   Meantime, however, an
idea must be received  as correct, if it is well esta-
blished;  i. e.  if it is consistent with known facts and
generally received  ideas, and is rationally adopted
by adepts in  the particular department of science  to
which it belongs.   But ideas require to be  reexam-
ined from time to time, and if possible, verified, even
to a demonstration.   But if it be said that the un-
derstandings  of men differ to such an extent that we
cannot  be  certain of the correctness of  our  ideas,
while we may be  of the reality of our facts, I  re-
mark, that the senses of men also differ in a scarcely
less degree, and may therefore deceive, as well  as
the reason.   The senses could never teach us that the
earth revolves round the sun, but led all men, up  to
Copernicus' time, to  adopt as a fact the assumption
that the  sun  revolves round the earth.   In science,
therefore, the senses and the  understanding have
mutual need  of each other.   Supposed facts must be
tested by reason ; and ideas  must be  verified by the
evidence of the senses    As a general rule, we may 
      CORRECTNESS AND  DISTINCTNESS  OF IDEAS.    11

be as sure of the correctness of well established ideas,
as of the reality of accepted  facts, though the con-
trary is often asserted  ; observation being as often
delusive as ratiocination.
   When however, an idea is demonstrated to be cor-
rect by the discovery of a new fact corresponding to
it, we cannot say that the idea has become a fact;  it
is merely proved to be correct.   The  idea  existed,
and still exists, in the mind alone; the  fact is exter-
nal.  Leverrier had the idea, founded on reasoning to
him quite  conclusive,  that there is a planet further
than Uranus  from the  sun; and, pointing his tele-
scope  in  its  supposed  direction,  he  discovered the
planet  itself.   The fact now takes its  place in the
science of  astronomy.   But in case he had not made
the discovery, the mere  idea, sustained by such argu-
ments as he  adduced, and being well established by
them, also deserved a place in his science, as a  guide
to a future discoverer.  Correctness of ideas, therefore,
implies, as Prof. Whewell remarks—" 1,  a  basis of
well known and clearly conceived facts; and 2, reli-
able reasoning, as based on invention, acuteness, and
correctness  of thought."
   On the  other hand,  the  distinctness  and  definite-
ness  of our ideas may be quite independent of facts,
or of truth.*  We may form quite as clear and defi-
nite an  idea of the sun's rising in the west and set-
ting in the east, as of its actual course.
   3. By a truth in science,  is meant a proposition
expressing the  exact  state of facts or  things.   The
  * By truth is meant an exact conformity with the actual state of facta
and things. 
12
ANNIVERSARY DISCOURSE.
statement of an  actual  fact or a correct idea, is  a
truth.   A general truth,  or a truth including several
minor ones of a similar  kind, and logically deduced,
is sometimes termed  a principle in science.  A prin-
ciple is  therefore not a general fact, as is sometimes
asserted.  All  facts  are  necessarily individual and
particular.   It is  simply a general proposition  pro-
mulgated as true.   But  since if our  ideas are incor-
rect our principles must also be erroneous, the latter
must, like the former, be tested in every practicable
way, before they  should be accepted as well estab-
lished, and admitted  into science.  A law in science,
is  merely  a  still  higher generalization embracing
several  principles; or a  still more^extended general
truth.   E. g. Schleiden observed  that the tissues of
various  plants are originally developed from  cells ;
and hence  deduced the law that all vegetable  tissues
are thus devolped.  And subsequently Schwann ex-
tended  this law to all animal tissues also.
  For scientific purposes, therefore, our facts must
be  true—i. e. real—our  ideas,  correct and  definite,
and our deduced  principles  well established.  Be-
sides, all these must be classified and arranged in a
systematic manner, before they constitute a science.
But this last proposition is too  evident to  require
illustration.
  I should therefore say that " an actual  science
consists of  the real  facts, the correct   and  distinct
ideas,  and  the established  general  truths  of any
department of knowledge, classified and systemati-
cally arranged."   The more  unquestionable the ele-
ments of any  particular department of science are 
        EXACT AND  DEMONSTRATIVE  SCIENCE.      13

from its very nature, the more  it deserves the name
of an exact or positive science.   In  this respect the
pure mathematics takes the lead, since it concerns
only  the  magnitude and the  quantity of  things.
Since,  also,  its conclusions  are  absolutely certain,
mathematics is termed demonstrative science,  in con-
tradistinction from the rest, which are termed sciences
of probability.  Natural philosophy and  chemistry
are regarded as exact sciences ;  but just so far as the
objects of a particular science can neither be meas-
ured, numbered, nor weighed, so far it is not capable
of becoming an exact science.   Medicine, therefore,
with the exception to a certain extent of anatomy,
cannot become an exact  or positive science.
  The division of the sciences  into the certain  and
the uncertain is a mere  contradiction.   Uncertainty
is associated  with certainty in all the sciences  of pro-
bability.   But the human mind  does not assent with-
out evidence  in one science more than in another,
and accepts only that which  it  believes, on the best
evidence attainable,  to be certain—i. e. true ;  though
it sometimes, " like  Ixion, embraces a cloud  instead
of a goddess."
  Some writers assert that  science  consists of facts
alone, since  this  term implies  what is known,  and
we  know  only facts ;  while our  ideas and general
truths, depending  on our reason, may be false  and
unreliable.  But we have seen  that  our  facts,  also,
may be false ; and  that, generally, our  ideas  and
deductions are as reliable as  our sensory perceptions.
E. g. we feel as certain as to the law of definite pro-
portions  in chemistry as we are respecting any one 
14
ANNIVERSARY DISCOURSE.
 of the facts on which it is based.   We may therefore
 say that science  consists of truths alone, but not of
 facts alone ;  and we have already seen that scientific
 truths include  facts, ideas, and  general  truths.  It
 should also be added that a fact has in itself no scien-
 tific value  whatever.   Its value  consists  entirely in
 the use we make of it, or the interpretation we give
 it.  In  other words, the mind alone  gives it value.
 Proclus tells us the Epicureans used to say that  even
 asses know the  fact that any two sides of a  triangle
 are together longer than the remaining one, and act
 accordingly ;  but they  are not, therefore,  acquainted
 with the science of geometry.   Many classes of  facts
 are acquired  by  the lower  animals; but not being
 interpreted they fail to contribute to scientific ends.
 Facts, then, have a mere "potential or  subsequent
 value, and  the only advantage of possessing them is
 the possibility of rising by a mental  process  to  the
 idea, the principle, or the law which governs them ;"
 or to the ideas in the Divine  mind, which are shad-
 owed forth by them.   Facts are  indeed the  " body
 of science," as Dr. Samuel Brown remarks ;  but  the
 " ideas " and conclusions they suggest " are its spirit"
 and its soul.  And " our real knowledge,"  says a
 recent writer,  " consists not in an acquaintance with
 facts,  which makes a pedant, but in  the use of facts,
 which makes a philosopher."
  But though facts are only the  'body of science,'
 while ' the ideas' and the conclusions they suggest are
 its soul, they are thus shown to be of primary and indis-
 pensable importance in the construction of a science
—like the bricks or blocks of stone of which an edi- 
         TRUE VALUE OF  FACTS  IN SCIENCE.       15

 lice is constructed.   But those who are satisfied with
 merely discovering and contributing facts, and leav-
 ing them for others  to use, are  the mere hewers of
 stone  and the brick-makers, in science ; while  the
 master masons are  those who assign to each fact its
 place and its value, and thus  really build up  the
 structure required.  Some of the most distinguished
 philosophers and discoverers did nothing themselves
 towards obtaining the facts on which their discoveries
 were based.   Newton, in  a letter to Flamstead, re-
 marked : " All the world knows I make no observa-
 tions myself;  and  if  I do not make  a handsome
 acknowledgment, they will reckon me an ungrateful
 clown."  Harvey did not himself discover a single
 one of the facts on which his discovery of the circu-
 lation of the blood reposed. To discover facts requires
 a high development  and much practice of the percep-
 tive faculties—of the senses ; to deduce conclusions
 requires superior and well exercised reasoning pow-
 ers ;  and  these  two diverse qualifications are  but
 rarely blended in the same mind.  Each  is, however,
 of great value in its place, and both are indispensable
 to the advancement of science ; though the latter per-
 forms the higher and the crowning function.

 COMPARATIVE CHARACTER AND QUALITY  OF  MEDICAL
                     SCIENCE.

  III. In respect to the comparative character and
quality of  the science  to  which  we are  devoted, it
has already been remarked that as a whole it is a
science of probability, and, with  the exception made, 
16
ANNIVERSARY DISCOURSE.
 cannot from its very nature become an exact or posi-
 tive science.  It is often repeated that medicine is
 an inductive science, and therefore to be classed with
 Astronomy, Physics, and Chemistry, and other mere
 physical sciences.  But of the several distinct depart-
 ments of medical science not one is exclusively induc-
 tive, and no two are equally so.
   Since, however, they are all in some degree induc-
 tive,  none of them but descriptive  anatomy made
 any considerable progress till the inductive  method
 of acquiring knowledge was distinctly recognized and
 began to be appreciated.  It therefore becomes neces-
 sary to inquire what is meant by the inductive method,
 and when and by whom its application to the advance-
 ment of the sciences termed  the  inductive, was sug-
 gested.

 THE METHODS OF  SCIENCE--INDUCTION AND DEDUCTION.

  I. An inductive science is one, it is said, which is
 advanced, or in which truth is obtained, by induc-
 tion.  What, then, is induction ? or, to use a synony-
 mous expression, what  is  the  inductive process?
 Some would reply that induction is a peculiar pro-
 cess of reasoning ; but  this is not the fact.  The
 peculiarity affects only the manner in which we ob-
 tain the data from which we reason, as will presently
 appear.
  There are but two scientific methods  of obtaining
truth:—1st. To  proceed from the external to the
internal, from facts  to conclusions,  from effects to
causes ;  2d. The  reverse  of this—to proceed  from 
INDUCTION AND DEDUCTION.           17
the internal to the external, from  principles to facts,
from causes to  effects.   The  first is  the inductive
process,  and is an  a posteriori mode of reasoning;
the  second, the deductive  or rational, or reasoning a
priori.   The inductive reasoner "rises from facts to
the  principle or law which governs them ;" the de-
ductive " draws the  principle or law from ideas  (not
facts) already in his mind, and explains the facts by
descending on them, instead of rising  from them."
The latter,  therefore, necessitates  a theory, or at
least a general proposition, to start with ; the former
excludes theory  entirely.   The  inductive method
gives the first place to facts;  the deductive, or ra-
tional, to ideas, or general propositions.   Both alike
include  a  reasoning process, neither of them being
mere investigation ;* and both are alike indispens-
able to  the  completion of every science,  since  each
has its own peculiar mission to fulfill; and they some-
times follow  each other  as  successive  steps in the
attainment of a particular scientific result.  The  rea-
soning process is the same in both ; the "induction"
consisting merely in the collecting and  bringing  into
the account, one  by one,  the facts on which we  rea-
son.  The inductive process, then,  consists of—1st,
the induction, as just explained ; and 2d, the deduc-
tion—i.  e.,  drawing the  conclusion from  the facts..
We therefore  reason from, but  not by, induction.
We can  never  attain to certainty,  but only to proba-
bility, by either of these methods.  Hence, the  con-

  * Investigation includes the various methods of ascertaining facts, as
observation, experiment, analysis, etc.
                          2 
18
ANNIVERSARY DISCOURSE.
elusions arrived at by both require verification; which
in the one case consists in repeating the  induction in
other circumstances, so as to collect a new series  of
facts ; and in the other, in testing the conclusion by
facts.
   The same conclusion may sometimes be arrived at
by both these processes, when  they confirm  each
other ;  e. g.  perceiving that  a certain number of
persons,  apparently not similarly  circumstanced in
other respects, have alike a  certain disease,  and also
work in lead, we may conclude inductively  that all
who work in  lead are liable to the disease, and that
lead is  a poison.   On the  other hand,  commencing
with the idea, or  theory, that all who work in lead
have a certain disease, we may deduce the conclusion
that lead is  a poison.  More  frequently, however,
the converse  proposition is arrived  at by the deduc-
tive process ; e. g. from the  idea or theory that lead
is  a poison, the conclusion is deduced that those who
work in  lead  will become  diseased.  The reasoning
in all these instances can be reduced to  the  form of
the syllogism, as  will  be seen further on.   But the
deductive method has far  the  wider  scope  ; since,
while the inductive  is confined  to  reasoning from a
class of  particular facts to  a general conclusion, the
other may  deduce  its  conclusions from ideas,  or
theories  even, or from  single facts, or a   number
confessedly too small  to justify an  inductive  con-
clusion. 
INDUCTIVE CONCLUSIONS.            19
         Reliability of inductive conclusions.

  The degree of  probability of an  inductive conclu-
sion depends, so  far as the facts are concerned, on
three conditions:
  1. They must  be true  or  real,  and therefore
reliable.
  2. They must  be comparable—*.  e. identical  in
kind.
  3. They must be sufficiently numerous.
  And, finally, these conditions being secured, the
conclusion deduced  must be logically correct.  But
this proposition applies equally to both the methods
under consideration.
  1. The reliability  of the facts must depend—1, on
our powers  of  observation,  natural  and acquired,
since we obtain facts by our senses merely ; and 2,
upon our invention in the way of aiding those powers,
whether by  instituting the most favorable circum-
stances, as in experiments, or  by Using the  best in-
struments.   Repeated  observation  and  experiment
are therefore the test of the reality of our facts ; " by
the former of which," says Sir Gilbert Blane, "we
may be said  to listen to nature, and by the latter to
question her."  If our facts be false, our conclusions,
if logical, must necessarily be  erroneous.
  2.  But the facts adduced must also be comparable
and therefore of the same kind.  We cannot, on find-
ing that of a certain number of persons  working in
lead  one  has colic, another typhus fever, a  third
pleurisy, and so  on—there being  as  many  different 
20
ANNIVERSARY DISCOURSE.
diseases as there are individuals—deduce the general
conclusion that this class of people  is liable to colic,
typhus fever, or pleurisy.   Evidently,  if we are to
deduce any general conclusion in regard to a  particu-
lar disease, the instances compared must  all be in-
stances of the disease in  question.   On  the other
hand, if we are to draw any general conclusion as to
the effect  of  a particular calling or avocation, the
instances adduced must all be examples of the same
avocation.
   Still, no one but an adept in the particular depart-
ment of science can judge accurately of the precise
nature and comparability of the facts pertaining to
it.  A physiologist alone can rightly collate  physio-
logical facts, preparatory to making a logical  deduc-
tion therefrom ; and the  chemist has the same exclu-
sive judgment in regard  to chemical facts.   And
neither can assume  the  place  of the  other  without
some  risk to the science on which he trespasses, un-
less he at the  same time  thoroughly understands the
latter also.
   3. But the probability of a conclusion obtained by
the inductive  method  also depends much  upon the
number of similar facts  adduced.   In general, we
may say  the  number must be  sufficient to warrant
the conclusion.  We must  have enough instances to
serve as a sample.   But different minds will  require
different numbers to satisfy them as a  basis for de-
duction ;   and different departments of science are
very diverse in this respect.  In physics or  natural
philosophy, a single instance will sometimes (though
rarely.) warrant a  conclusion;  in  physiology  and 
     BUT FEW CAN USE  THE INDUCTIVE METHOD.   21

pathology, many  instances will  be required;  for  in
the latter it is more  difficult to be sure  we have
ascertained  all the circumstances which bear on the
question, since the vital force  modifies the action  of
the merely physical forces.   The number of instances
required in  each particular  case, then,  is a mere
matter of judgment; and here, also, only the adept
in the particular  science is a competent judge.  The
expression of this judgment forms the major premiss
of the syllogism,  and is based  on a belief in the con-
stancy of nature's laws ; and whether the latter is or
is not intuitive, makes no difference.
  Such  being the  inductive  method  of acquiring
truth, it is  not singular that but very few can apply
it advantageously for the advancement  of science.
For, 1st, there are always  very few good observers
and experimenters ;  2d,  of these but a small propor-
tion can accurately discriminate and  collate the facts
they observe ; and 3d, most good observers cultivate
the perceptive faculties to the comparative neglect of
the logical.   Hence,  they  leave  their facts  quite
barren  of  scientific  results, till some  logical mind
completes the inductive process for which they af-
forded the materials, and thus makes a real addition
to  science.   Bacon  himself  remarked  that  it is  a
method  "difficult in  its operation," though  easily
explained.   There are,  however, a  very few,  who
can assign the true value to the facts  they observe,
and from them logically deduce the  general conclu-
sion.   Such possess  the really  inductive  mind,  or
that balance of the perceptive and the rational facul-
ties which  constitutes  the  good  observer and the 
22           ANNIVERSARY DISCOURSE.
good reasoner combined.   With the deductive mind
it however presents a very strong contrast.  While
it is plodding, cautious, non-committal and conserva-
tive, the deductive is impulsive, bold, frank, progres-
sive and reformatory ;  the former  is cold, rigid and
matter-of-fact; the latter is congenial, not exacting,
versatile and  imaginative ; the former  is intensely
and often  exclusively  practical;  the latter is theo-
retical rather, though it can adapt itself to practical
life.  The inductive philosopher says, " I have shown
it to be so ;" the deductive, "It must be so," or "it is
so,  a priori."  Children and most men are naturally
inductive ; poets, geniuses, and, I may add, most wo-
men, are naturally deductive, being more enthusiastic
and emotional than the majority of men, and  rather
impatient of  mere  facts and  details.   Of the  two
great nations of antiquity, the Greeks were emphati-
cally a deductive  people.   " In the art of experiment
and trying to find  his way with untripping step  among
details, the Greek was  as feeble as a child ; whereas,
in the sphere of ideas and vast general conceptions,
as well as in the fine art of embodying such universals
and generalities in beautiful and appropriate symbols,
it is not a  paradox to say that he was sometimes
stronger than a man."*   The  Roman mind was un-
scientific—and therefore had no decided deductive or
inductive tendency—vigorous,  stern, ambitious  and
practical. While Athens, therefore, was becoming the
centre of refinement and civilization to  the  world,
Rome was achieving conquests and mere material
* Eclectic Magazine, Oct. 1858, p. 198. 
bacon's novum ORGANUM.
23
 wealth; the former developed the individual, the latter
 looked mainly to  the  growth and the government
 of the state ; from the former,  therefore, we  have
 received  philosophy and  science ;  from the latter,
 jurisprudence alone.
   A comparison of the three most important nations
 of the present  day, in this respect, is not without
 interest in indicating the part hitherto  performed by
 each, and hereafter to be expected, in advancing our
 science—and would result nearly as  follows :   The
 English  mind is intensely  and  almost exclusively
 inductive ; and therefore slow, prudent, conservative
 and practical.  The German mind is  especially, but
 by no means exclusively, deductive ; hence it is pro-
 gressive,  theoretical, and  even  transcendental,  but
 less practical.  The French mind is especially ob-
 servant and  adaptive—inductive or deductive, prac-
 tical or  theoretical, as  may be  required—versatile,
 revolutionary, and highly aesthetic.  If I  may  also
 add the traits of American mind, I should say it is
 far more  deductive than inductive, but is  still prac-
 tical ;  though restless,  inventive  and  progressive.
 Compared with  the preceding, it evidently operates
 under a  "high pressure ;" but it is capable of  both
 observing and reasoning well, provided it can  only
 wait.

     The  inductive method as proposed by Bacon.

   II. The value  of the inductive method of acquiring
knowledge was first distinctly shown by Sir Francis
Bacon, in his remarkable work  entitled   "Novum 
24
ANNIVERSARY DISCOURSE.
 Organum ; or, True Suggestions for the Interpretation
 of Nature ;"  and which, after being twelve times  re-
 written and revised, was published in the year 1620.
 His doctrines had been rudely foreshadowed in the
 writings of Roger Bacon, about 350  years before,
 (1270).   "Each  science," says  Sir Francis, "has
 hitherto been  a light  and slender  thing ;"  and  he
 proposed a " reform in the system of human know-
 ledge, by advancing a new method  of using  the ra-
 tional faculties, and  showing  how  to  examine and
 interpret nature."  He did not, however,  himself
 term the new method the inductive ; but in contrast
 with the method of  the ancients, and especially the
 Aristotelian,  he called the latter method " The Anti-
 cipation of the Mind," and his own " The Interpreta-
 tion of Nature."
  The  "Organon"  of Aristotle  had  exercised  an
 almost exclusive sway over the human mind, in  re-
 gard  to  the  method  of acquiring  knowledge,  for
 nearly two thousand years (since B.C. 340).  It re-
 cognized logic as the fundamental science, and main-
 tained that we cannot, without the strict test of logic,
 observe facts in their true light.   Thus reasoning,
 with Aristotle, preceded observation ;  or rather all
 observation  was  tested  by  reasoning,   before  it
 could be accepted as reliable.  He held, in his philo-
 sophy, to the principle  of experience—i.e. that  all
 our thinking must be  founded on  the observation of
facts ;  but after all, facts could  not be recognized  as
 facts, unless they could be syllogistically established.
 Thus the Aristotelian has been called the  " speculative
 philosophy "—it being mostly  based on  ideas, not 
        VERBAL DIALECTICS OF  MIDDLE AGES.      25

facts ;  and being  a form of the  deductive  method
already explained.  For several centuries  prior  to
Bacon's time, however, this  method had been  much
abused.  Certain theologians had, in the eleventh cen-
tury, professed to represent Aristotle's method, un-
der the name of Nominalists, in a  controversy with
the Realists, who  believed with Plato, his master ;
and  the contest  was  prolonged,  each party  alter-
nately gaining the advantage, for about five hundred
years, till the Reformation (1517).  Thus, during the
middle  ages, " many ingenious but useless subtleties
were  passed off  for logic and  dialectics,"  under the
great name of Aristotle ; and the nicest distinctions
in words were accepted for conscientious accuracy.
This was by no means the  fault of Aristotle,  but it
brought him into disrepute ; and this  state of the hu-
man mind in regard  to  the  method  of acquiring
knowledge, still generally prevailing to Bacon's time,
he sought to substitute the new or  inductive  method
for the scholastic logic, and verbal dialectics,  then so
much abused and perverted from the Greek philoso-
pher.   The Baconian  philosophy is therefore usually
called  the  "inductive" in  opposition to  the  Aris-
totelian  or speculative ; and his work was called the
" Novum" Organon.
  But Bacon  did  not  assume  that his  " Organum "
should ever after  entirely displace that of Aristotle,
and  that we must  always  reason from  effects  to
causes, instead  of from causes to effects.  Admitting
the value of the deductive method in its legitimate
applications, he wished to institute a new method,
and as he believed, for the advancement  of science, 
26
ANNIVERSARY DISCOURSE.
a far better.  But the inductive does  not exclude
the rational method, as so many have supposed ; for
all  reasoning  is one  and the  same  process, as we
have seen,  and which may be clearly exhibited in the
form of syllogism.   Neither method alone is sufficient
in all cases, or in any science, and  each is invaluable
in  its proper place.  Three   errors,  however,  in
regard  to  the  inductive  method  have  been quite
prevalent,  and have produced  much confusion and
retardation of science.
  First—It has been understood to mean the pro-
cess of investigation and of collecting facts ; but in-
vestigation is merely a  term   to  include  observa-
tion, and experiment; is  not a reasoning process at
all, and, therefore, is not syllogistic.
  Secondly—It has been held to denote the mere de-
ducing of an inference from the facts collected.  But
this reasoning process is  only a part of the induc-
tive process, and also belongs  equally to the deduc-
tive.  Yet induction has also  erroneously been re-
garded as a distinct kind of argument from  the syllo-
gism ; though all  reasoning may  be syllogistically
expressed.
   Thirdly—It has  been generally taken for granted
since the time of Bacon, that certain sciences, called
the inductive, are advanced exclusively by the induc-
tive method;  the deductive or  rational method being
in every respect to them  entirely inapplicable.   No
science, however, is exclusively inductive ; those  so
called are  merely less deductive than  inductive—i.e.,
they are advanced to a greater  extent by the induc-
tive method than by the deductive.   Even astron- 
      ERRORS  RESPECTING  THE  INDUCTIVE METHOD.   27


 omy,* the most perfect of the inductive sciences, owes
 some of its sublimest discoveries to deductive reason-
 ing.   Newton's discovery of  the law of gravity—the
 greatest of scientific discoveries—is far more the re-
 sult of  the deductive than of the inductive process.f
 —This last error has greatly  arrested the progress of
 science, since the constant effort has been to advance
 the sciences  termed  inductive  by  induction  alone.
 For more than two hundred  years all deductive rea-
 soning  has been  decried, and especially in England,
 as  of no value in  the  advancement  of science ;  while
 inductive  reasoning  has alone  been  blindly wor-
 shipped  and encouraged.    All sciences,  however,
 require both  methods for their  advancement, as will
 appear.

  * Kepler discovered his three great laws of planetary motion  and
 distances, published in 1609, not by the inductive process, as is usually as-
 sumed, nor by the deductive, but by the tentative method of investiga-
 tion merely ; which consisted in starting an hypothesis, as he remarks,
 and then  hunting it down.  Some writers have, however, erroneously
 included this mode of investigation under the inductive method.
  f Eclectic Magazine, June 1858, p.192, et seq.  The three great ques-
 tions which present themselves in our investigations in physical science,
 are  indicated by  the words,  " What ? Why 1 and How ?"—«.«. 1. What
 is the actual phenomenon—the fact.  2. Why  does it occur—the cause.
 3. How does it occur—the law.
  1. The fact of gravity, both terrestrial and celestial, might have been
 arrived at inductively from the fall of the apple, (if we accept the gener-
 ally received anecdote,) provided the apple was regarded merely as a
 mass of matter.   2. The cause of gravitation was assumed to be a pecu-
 liar force, from its effects, and called the force of gravity.  3. But the
 law of its action—it varying " directly with the quantity of matter, and
 inversely  with the square of the distance," was mainly a  deduction
 and which it required  seventeen subsequent years of Newton's life to
verify. 
28
ANNIVERSARY DISCOURSE.
        The deductive method also  vindicated.

  Since in  the  application of the deductive or ra-
tional method, we  draw  our conclusions from  our
ideas, while in case of the inductive method we rea-
son in a precisely  similar manner, but from estab-
lished facts instead of  ideas—it follows  that in the
formative epochs of all sciences,  the  deductive  or
theoretical must precede the inductive stage, from the
paucity of  established  facts.   Aristotle,  therefore,
lived too early to perceive clearly and to inculcate the
inductive method; though he also had some imperfect
idea of it  in  connection with the  deductive method.
But the deductive  method again becomes indispens-
able when,  in the  progress of science, the inductive
process has temporarily exhausted itself and is wait-
ing for new facts to be discovered, sufficient  to  war-
rant new  inductive  conclusions.    Several  of  the
sciences are precisely in this state  at the  present
time.  I shall therefore vindicate  the deductive, and
even the theoretical spirit, so generally and  so long
denounced and discarded.
   This servile worship of induction, and equally ser-
vile denunciation of all theorizing, has led to a blind
admiration  of mere observers, and a laborious accu-
mulation of heterogeneous facts; and which must re-
main entirely worthless till the deductive mind gives
them their true place and value.    Hence, the man
who finds a new chemical element or compound radi-
cal, though it were by mere  chance, and  though the
discovery promises no benefit whatever to the  race, 
    OBJECTIONS TO  THE SPECULATIVE PHILOSOPHY.  29

is, now-a-days, at once thought to be almost entitled
to a monument; while Dr. Marshall Hall  was, for
years after his discovery, denounced by many of his
profession in London, as a visionary theorist.  We, as
medical men, are also constantly reminded that  " ars
tota est in observationibus" and some of us thought-
lessly embrace  the common  error, and decry every
thing in the way of scientific effort but mere observa-
tion.   And yet we  know  that art does not consist
wholly in observations ; and, besides, that if it did,
science  does not.   For  though science cannot  be
formed or advanced without observation, we have seen-
that the observations  of but few, comparatively, are
of any scientific value ; and  that in all cases the value
is bestowed on  the facts acquired by observation,  by
the deductive mind  which gathers  them  up  and
uses them.
  The  real  ground of  objection to  the  method em-
ployed by the  ancients was,  not  that it  was the
deductive method—though it  alone cannot  accom-
plish everything in the  advancement of science,  as
we have seen, and they employed no other definite
method—but that in  its  application they reasoned
from their preconceived ideas,  and  not  from correct
ideas, or  ideas  based upon  actual facts.  But this
could not then be avoided, since  they  had not the
facts, and knew not how to acquire them.   But as
science  advances,  the conclusions  obtained  by the
deductive process  become more  reliable  in them-
selves,  and  also more easily verifiable by ever accu-
mulating facts.   Besides, the  objection does not hold
against reasoning from correct ideas ; and we  have 
30
ANNIVERSARY DISCOURSE.
seen that we may now very generally be as certain
as to the correctness of our ideas as we are of the
reality of our facts.  It was in its application, there-
fore,  that  the ancients failed, rather than in the
method itself, and for reasons which need not, at the
present day,  obtain.
  When, therefore, I vindicate a return to deductive
reasoning and  theorizing, in addition to the  induc-
tive method,  I mean not theorizing from ideas formed
independently of facts, but from ideas established upon
real facts.  I also include deductions from facts insuf-
ficient to warrant  an inductive conclusion.   I insist,
also, that all theories shall  be verified before their
promulgation, provided the necessary facts for their
verification or refutation are  afforded by  the present
state of science ;  and,  if not, that they be stated as
theories merely, for future reexamination.  On these
conditions, and these only, our theoretical conclusions
deserve a place in science.  Hence the greatest dis-
coverers have  ever been theorizers,  and not mere
observers ; though they, of course,  recognized as
indispensable  the  facts  obtained by observation,
whether by themselves  or  others.   For every dis-
covery,  unless accidentally stumbled upon—as Glau-
ber found the  sulphate of soda while  searching for
the philosopher's  stone—is but a theory in the mind
of its author till he verifies  it, and thus  shows it to
be strictly accordant with fact—or to be an  actual
discovery.  But I  shall  again return to  the subject
of theories before I close.
  I therefore conclude my remarks upon the  induc-
tive and the deductive methods in the words of Bacon 
     MEDICINE BOTH INDUCTIVE AND DEDUCTIVE.   31

himself, though I here  commend  the latter more
especially,  by the terms he  applied  to the former.
" Let there exist then, (and may it be of advantage
to both), two sources and two distributions of learn-
ing, and in like manner  two tribes, and, as it were,
kindred families  of  contemplators or philosophers,
without any hostility or alienation between  them,
but rather allied and united by mutual  assistance.
And as for those who prefer and more readily receive
the former, let us wish that they may prosper as
they desire in their undertaking,  and attain what
they pursue.   But if  any individual  desire, and is
anxious not merely to  adhere  to and make use of
present discoveries, but to penetrate still further, let
him, as a true son of  science (if such be  his wish),
join with us ; that when he has left the ante-chambers
of nature,  trodden  by the  multitude, an entrance
may at last be discovered to her inner apartments." *

 Medicine both  an inductive and a deductive science.

   Testing our own science by the preceding remarks,
we find all its departments both inductive and deduc-
tive, though in  some  the  inductive  element very
much preponderates.  But we find that into two of
them—Physiology and  Pathology—a  third element
is introduced, which is unknown to the mainly induc-
tive  and the merely physical sciences.  This  is  the
"doctrine of final causes,"  or " teleology," as it is
termed at  the present  day,  and which  will be  ex-
* Nov. Organum, Prsefatio, p. 3. 
32
ANNIVERSARY DISCOURSE.
plained further on.  The following arrangement of
the various departments  of  medical  science under
three subdivisions, will illustrate the  character  of
each.

1. Science of Structure,   ]   ,   .  '      [ Mainly inductive.
                    (   branches of.    )     J
                    C  pv>  • 1     A   (Inductive.
2. Science of Function,    •<    ^ Al  ,        ) Deductive.
                    \    Pathology,    |Teleological>
         . „         S Hygiene and ) Medical, j Mainly indue-
3. Science of Conservation, \ TherapeuticS) } Surgical) \   tim
                   PART  II.

THE  PROGRESS AND THE SPIRIT  OF  MEDICAL SCIENCE.

  Proceeding now to trace the progress of our  sci-
ence, its principal epochs are first to be designated.
  It  has been shown  (p. 7) that  art  naturally, in
point of time,  precedes science.   Certain rules or
maxims, however, become  current as art becomes
more common and better  understood;  these  being
the first attempts at formularizing  the results of  ex-
perience, and  preceding,  by a long interval,  any
attempt to reduce what is known to a scientific form.
These subsequently  accumulate, and  are  expanded
into definite precepts  or aphorisms ; then theories
are superadded and conclusions deduced ; and, finally,
facts are obtained in sufficient number to justify the
inductive process,  and  science  at  length  begins to
assume a definite form.   To its  completion, however,
the deductive method  still  continues to be as indis-
pensable as the inductive. 
THREE EPOCHS  OF MEDICAL SCIENCE.      33
   Auguste Comte states, in his  " Philosophic Posi-
 tive,"  that all  sciences  must  have  three principal
 epochs  of development:  1. The  childish religious ;
 2. The  boyish metaphysical ; and 3. The manly posi-
 tive.  I have shown (p. 13) that ours is not,  in any
 philosophical  sense  of the term,  a positive science ;
 and in tracing its progress I shall adopt as its three
 principal epochs, 1.  The superstitious ; 2.  The epoch
 of unsystematized medical learning ; and 3. The epoch
 of systematized learning, or actual science.  The first
 two epochs are of  course the  formative periods of
 our science, and during the second it consisted mainly
 of theories, aphorisms,  and  monographs.   There are
 also transitional and stationary, and  even retrogres-
 sive, periods ; but these need only incidentally  detain
 us.  I shall also pass rapidly through the two forma-
 tive periods—the superstitious and  the unsystema-
 tized—and consider  more  especially the more  recent
 and the  present condition of our science—its system-
 atized or actual state.   The period of time covered
 by each of the epochs just mentioned is seen below.
 1. Superstitious epoch—about 3600 i From the earliest times to Hippo-
    years,                  j  crates, or about b.o. 400.
 2. Epoch of unsystematized learn- ]
    ing—about 2000 years (theo- ' From Hippocrates (b.o.  400)  to
    retic,  aphoristic, and mono- J  Harvey (a.d. 1620).
    graphic epoch).           J
3. Epoch of systematized or actual) Since  Harvey (a.d.  1620) to the
    science—about 240 years.    )   present time.

            I.—THE SUPERSTITIOUS  EPOCH.

   The superstitious  epoch  extends  over  a  period
of about 3600 years—or from  the earliest times to
                         3 
34
ANNIVERSARY DISCOURSE.
Hippocrates (about B.C. 400 years).  It has been di-
vided into the primitive  and the  mystical periods;
the former ending, and the  latter commencing, with
the Trojan war,  B.C. 1184.  Of the medical ideas of
the antediluvians  we have  no reliable information.
It is  however pretty certain  that  their knowledge
was preserved in Egypt, the only portion of the world
which was not for a  long time after the deluge, in
darkness.  Still  later also, the most enlightened na-
tions  were the Egyptians, the  Babylonians, and the
Phoenicians.
   Of the Babylonians, we only know  that they had
the custom of carrying their sick to the public squares,
that the passers-by might suggest  such remedies as
they had known to be beneficial in similar cases. What
their ideas of disease were, we have  no  means of
knowing.  The  Phoenicians were  formerly the Ca-
naanites, the descendants of  Ham ; and were  con-
quered by the  Hebrews, the  descendants of Shem,
after the latter went out of bondage in Egypt.   The
latter did not  add to the learning obtained from
Egypt during their sojourn there;  and medicine is
least of  all the  professions  indebted to them.   And
as the art of medicine in Egypt consisted mainly, as
 will appear, of religious rites,  and incantations, even
 King Solomon was, among his countrymen, as  much
 distinguished for his knowledge of charms and incan-
 tations,  as for his general wisdom.  He was also  a
 necromancer of great power;  and his  use of super-
 natural  agencies  in the cure of diseases is yet  cele-
 brated in the traditions of the oriental nations.  As
 instances of the practice  of the Jews,  I will  remark, 
MEDICINE IN EGYPT.
35
that the egg of a grasshopper and the teeth of a fox
were employed by them as enchantments, especially
in diseases of the mind.  But to return to the Egypt-
ians.   They made very little addition to the know-
ledge they had received from the antediluvians.*  In
Egypt the occupations were hereditary, and the pro-
fessions were restricted  by law;  which prescribed
the precise information, facts, and principles, of which
the  science  Of medicine  should consist.  The only
medical book then extant, however, of which we have
any account, is  a treatise  on anatomy, by Athothis,
the son of Menes,  one of the Egyptian kings.  All
improvement by experiment was entirely prevented;
for if the  physician departed in the least degree from
the practice laid down in the books, and the  patient
died, his own life was forfeited. Each physician was
also confined in his  practice to a single disease ; and
human dissections were not permitted.
   The practice of our art must at all times be based
more or less upon the  prevalent ideas of the causes
of disease; and  it is natural for the human mind to
refer what is entirely  inexplicable, to supernatural
agencies.   Disease was  therefore at first attributed to
such  influences;  and hence  its treatment consisted
principally in charms,  incantations, and  religious
ceremonies; these  being also  used  quite as  much
with the intention of averting, as of curing, diseases.
Sometimes even human sacrifices were offered to ap-
pease the supposed anger of the gods.f  These  ideas'

  * The deluge occurred a.m. 1656, or b.o. 2348.
  t Long after those times, seven young men were annually sacrificed at
Athens for this purpose. 
36
ANNIVERSARY DISCOURSE.
of spiritual influence were also encouraged by the
priesthood, who exerted a controlling influence over
the popular mind.
  But Egypt, we have  seen,  was  merely the pre-
server, not the mother of the sciences, so far as they
were then understood.  And having at  last fulfilled
her mission in this respect, she transmitted her cher-
ished treasures to  the  Greeks.  The latter were a
mixed people, principally composed of Egyptians,
Phoenicians, and Phrygians.  Into Greece therefore,
the learning of the Egyptians was readily introduced,
and there took the form of science  and civilization.
Composed  of such  varied  intellectual elements,  the
Greeks were  a versatile, active, speculative, and pro-
gressive people;* experimentation was not prevented
by law  as  in Egpyt, and  our  own  art  and science
soon received important additions.
  It was also believed by the ancient nations, that
certain substances possess a health-preserving power;
as the jasper, and some other precious stones.  These
were therefore worn as amulets; and thus we discover
the original use of many of the trinkets  and  orna-
ments worn at the present day.
  In Chaldea, as well  as in  Egypt, the  heavenly
bodies were  also  supposed  to exert an  influence
upon diseases; and hence astrologers were consulted
to avert them.  The notion still extant in some parts
of this country, that a child must be weaned, or have
its ears punctured, only when the sign is right, is  a
relic of this very ancient pathology.  In the middle
 •■Hence in Greece the most honorable titles were expressive of wisdom
and knowledge, rather than of political station or wealth. 
             DOCTRINE OF  SIGNATURES.           37

ages a  somewhat  related idea, obtained in Europe,
viz.: that  the  remedies for particular diseases are
foreshadowed by their physical properties, as  their
form, color, etc.; and this has been called the " doc-
trine of signatures;"  e. g. the celandine was accepted
as a remedy for bilious derangements,  because  its
juice is yellow and  viscid, like the  bile ; the liver-
wort, also, was thought  beneficial in liver diseases,
and  the lungwort in those  of the lungs, from the
shape of their leaves. Some analogies were  carried
still  farther,  even  to a figurative signification ; and
the teeth of serpents, reduced to  a powder,  were
prescribed to despairing lovers, that they might thus
acquire the power to fascinate the other party.
   Of the ideas of  medicine entertained in Greece in
the earliest times, we have no knowledge; but may
safely assume that they were entirely derived  from
Egypt.   The first  Greek physician of whom we have
any account,  was Melampus, who cured the daughter
of King Proteus with black hellebore; and which is
named  from him,   " Melampodium."  Chiron, the
Thessalian, was the  next.  He was not,  however, a
practitioner, but a philosopher ; and merely taught
the science of medicine, as then understood.  And
here the primitive period ends.
   JEsculapius  flourished  during  the Trojan war—
(b.c.  1184), when commences the mystical period of
the superstitious epoch.   He was by the ancients  es-
teemed the father of medicine. Much, therefore, that
is mysterious and fabulous, in addition to his asserted
origin  from the gods, is associated  with his name.
Cicero  says he invented the pulling of  teeth.   His 
38
ANNIVERSARY DISCOURSE.
sons,  Machaon and Podalirius, were also famous  as
advancers of our art and science.   But  after the
Trojan war, and the  beginning of the troubles be-
tween Greece and Persia, medicine again degenerated
for nearly  800 years, into mere  superstitious rites
and the interpretations of oracles.  And thus closes
the mystical period and the superstitious epoch of our
science.

      II.--EPOCH OF UNSYSTEMATIZED LEARNING.

   The second  epoch of  our science—that of un-
systematized knowledge—begins about B.C. 400, with
Hippocrates, and extends  over a  period of about
2000 years, to the discovery of the circulation of the
blood by  Harvey in  1620.  This  is subdivided  by
Renouard into four periods.
   1st. The Philosophic, which he dates however from
Pythagoras, B.C. 500,  to the foundation of the Alex-
andrian Library,  B.C.  320.
   2d. The Anatomical—from  last date to  the death
of Galen, a.d.  200.
   3d.  The  Transition period—from Galen to the
revival of letters, a.d. 1400.
   4th. Period of Renovation—a.d. 1400, to Harvey,
1620.

   The Philosophic and Anatomical periods are, how-
ever,  only two  phases of the theoretical  or  mono-
graphic; the transition, is  only a  stationary period;
and the period of renovation, the theoretical period
again returning with  a new impulse. 
PYTHAGORAS AND HIPPOCRATES.        39
             The works of Hippocrates.

  This  e*poch was really initiated by the  labors of
Hippocrates, about the year B.C.  400; and to which
the teachings of Pythagoras, and his followers about
100 years before, must be regarded as the prelude.
Pythagoras, however, merely taught what was known
of medicine,  as  a philosopher, not  being  himself
a  physician.   Hippocrates  removed  from  medical
knowledge its uncertainty and its mystery.   Pytha-
goras had shown that the labors of JGsculapius were
but  human;  Hippocrates  taught his contempora-
ries  rightly to appreciate their value, and first gave
to medicine  a cyclopedic, or rather a monographic
form.   Of the many works attributed to him, per-
haps  the following only can, without  any doubt, be
admitted to be genuine ; though it does not comprise
one-fourth part of the Hippocratean collection.
The Prognostic.               On Articulations, or Luxations.
The Aphorisms.               On Fractures.
The Epidemics—(Lib. 1st and  2d.)  Treatise  on Instruments for Re-
On Regimen, in Aeute Diseases.      duction.
On Airs, Waters, and Places.
  These works, considering the  time when they were
written, are remarkable for their practical value,  and
for nearly 1800 years exerted a paramount  influence
on medical men.   But they are now found to  abound
in mere theories, and  to contain very little true  sci-
ence.
  Most, even of the aphorisms, so  long  blindly ex-
tolled and admired, as the  sublimest  effort of medi-
cal genius, and a certain number of which the faculty 
40           ANNIVERSARY DISCOURSE.
of Paris, till within a few years, required all candi-
dates for the doctorate to insert in their theses—are
now found to  contain  "exceptional truths, vulgar
reflections, and even  errors  and  contradictions."
(Renouard,  p.  116.)   Hippocrates  was,  however,
everywhere  accepted  as a  supreme  authority, in
medicine, up  to the 16th century, though somewhat
objected toby Galen, 600 years after his own time;
and  the  science and the art of medicine have been
transmitted to modern times by him.
  The foundation of the  Alexandrine Library, about
forty years after the death of Hippocrates (or, B.C.
320), gave a great impulse to medical studies.  There
Erasistratus and Herophilus taught, and somewhat
advanced the  science of anatomy ; but  their works
are lost.   The principal works of which we have any
remains, for  500 years  after Hippocrates,  are the
two  books of  Aretaeus,  on semeiology  (about a.d.
200); the treatise  of Coelius Aurelianus, on  chronic
diseases ; the eight books of Celsus  " de Medicina;"
and  the works  of  Galen on hygiene, anatomy,  and
physiology.
  The time from the foundation of the Alexandrine
Library  (b.c.  320) to the  death  of Galen,  in  a.d.
203, has been designated as the  anatomical  period.
And from this date to the discovery  of the circu-
lation of the blood, in 1620, a period of  1400 years,
and  exten'ding  through what I have before  termed
the  stationary, and the return  of  the  theoretical
period, but slight additions were made to our science.*
* See Appendix, note I. 
STATIONARY PERIOD.
41
                   Medical sects.

  Several sects  arose during the anatomical period,
which should be mentioned here.  1. The Dogmatists
trusted  to theory, assuming  to be  the followers of
Hippocrates.   2. The  Empiricists  (Empirics),  who
adopted  the  opposite extreme of relying on obser-
vation and  experiment  alone.   3. The Methodists,
who  combined   theory  with  experience.   4. The
Pneumatists (or  Spiritualists), who asserted the influ-
ence upon the  body of an ethereal element, or the
animal  spirits.   5. The  Eclectics,  the  last  sect
before the dark ages, who professed  to select and
combine all that was valuable, from the preceding.
But none of these made any essential addition to the
theories of Hippocrates.  And during the 1200 years
ensuing after the death of Galen  (i. e. a.d. 200  to
a.d. 1400),  we  find only commentators upon, and
servile imitators of, Hippocrates and Galen ; the art
and the science  of medicine having, throughout Eu-
rope,  during  this  period,  again relapsed  into the
hands of the priests.  Among the Arabs alone  medi-
cine was still preserved, after the  destruction  (a.d.
640)  of the  Alexandrine  Library to a.d.  1400.
But the Arab writers are also scarcely more  than
mere commentators on Hippocrates and Galen.
  From a.d. 200 to 1400 is, therefore, the station-
ary period of our  science, or rather the retrograde
period ; for it actually retrograded, instead  of ad-
vancing— except in Arabia,  where it barely  main-
tained its former condition. 
42
ANNIVERSARY DISCOURSE.
  But if we  must admit that the medical mind was
entirely servile during  that  long, dark period,  all
mind was in the same condition ; and  no important
advance was made in any science.   For the writings
of Roger Bacon, published about the year 1260, on
various departments of science, were  two or three
centuries in  advance of his  age; were regarded as
heresy, and therefore suppressed, and he was im-
prisoned on their account.
  During this period, and indeed for  a century after-
wards (to 1500), skepticism was as  rare, and intole-
rance  as severe,  in philosophy and medicine as in
religion ; and the "infallibility of Aristotle,. Hippo-
crates, and Galen,  was as implicitly admitted,  as that
of St. Paul and St. Angustine."  Hence it was that
so many medical  errors were  taught  and defended
with entire conviction, by minds of the loftiest intelli-
gence.  In the present age  of freedom of thought
and expression, this seems truly astonishing.
  During the 14th century,  however,  the spirit of
religious freedom and commercial enterprise revived
the cultivation of the arts and sciences in Italy ;  and
in 1315. Mondini,  Prof,  of Anatomy at Bologna, first
publicly  dissected two  human bodies,  and  is re-
garded as the father of human anatomy.   On all ana-
tomical questions, however, medical men were  still
accustomed to swear by Galen, even to the time  of
Harvey.
  From 1400 to 1620 (termed the erudite period  by
Renouard), great  progress was  made in anatomy by
the labors  of Fallopius (1560), Eustachius (1570),
Yesalius, Fabricius, Caesalpinus, and others ; and the 
THE OCCULT  SCIENCES.
43
absolute authority of Galen  began to wane.   The
great work of Vesalius, on  the  structure of the
human  body,  was  published  in  1543 ;  and in the
same year Copernicus published his discovery that
the sun is the  centre of the solar system, which " fell
like a bomb " upon the stagnant intellect of the  time ;
and in the last part of this  period  (about 1600), the
early writings of Bacon had  been published.   This
period is, therefore, the prelude to  the last epoch of
our science—its systematized  or actual state—which
commenced with  the  discovery of the circulation  of
the blood.
   It was during the first part  of this period that the
separation of medicine  from  the  priesthood,  com-
menced in the 14th century, was  consummated ; and
during  the  last  century of  it (the  16th) celibacy
ceased in France to be obligatory on  physicians, and
they no longer obtained  ecclesiastical benefices.
   But a revolution at once  from  superstition to true
science was impossible ; there  must be—1st, a denial
of the doctrines before blindly admitted ; and,  2d, a
substitution of something entirely new,  and which
should seize at once upon the imagination, in order,
secondarily, to interest the  intellect.  It was, there-
fore,  during  the  16th  century that  the " occult
sciences," as they were called, engaged so much atten-
tion, and were applied to medicine  ; and which were
the  most remarkable forms  of  pseudo-science the
world has ever seen. 
44
ANNIVERSARY DISCOURSE.
                The  occult  sciences.

  The first  step towards the revolution—the denial
of the doctrines hitherto implicitly believed in—was
taken by Cornelius Agrippa,  about the year 1520,
in his work on the " uncertainty, vanity, and abuse
of the sciences."  In it he maintained :  " That there
is nothing more pernicious and injurious  to com-
mon life, and nothing more  pestilential  to the salva-
tion of souls than  the  arts and sciences."   He ex-
cepted only laborers and shepherds.  Even alchemy,
which he had practised a good deal, he berates in the
following terms : "In fine, having lost the time  and
the money which you have  devoted to it,  you will
find yourself old,  ragged,  hated, famished,  always
smelling of  sulphur, soiled with sweat and charcoal,
paralytic with frequent manipulations of quicksilver,
and gaining nothing but a running nose ; in a word,
so unhappy that you will  be willing  to sell your
body and even  your soul."
  The " occult philosophy," so  called, was divided
into four branches.   1st. Theurgy or theosophy, to
which  a man  raises himself by prayer, meditation,
and ecstasy;  and  which enables  one  to  produce
supernatural phenomena,  by  the intervention of
God.   2d. Magic, or the art of controlling  demons,
and, through  them,  imitating  true miracles.  3d.
Astrology, or the art of reading future events, in the
case of individuals,  nations,  or diseases,  by the stars.
And 4th. Alchemy,  the object of which was to  find—
1st, the philosopher's  stone, which should transform
the other metals into gold ; and 2d, the  elixir of life, 
             CARDAN AND PARACELSUS.           45

which should cure all diseases.  The practice of these
was termed the " cabalistic  art," and their applica-
tion  to medicine  was  termed  cabalistic  medicine.
Agrippa was a cabalistic physician.
  The second  famous cabalistic  doctor was Jerome
Cardan, who flourished from 1530 to 1576.  Para-
celsus was, however, the boldest, and the most influ-
ential of  them all;  his career  extending from 1525
to  1541.   He  quarrelled with  the  whole medical
faculty, and praised the chemists and  the alchemists,
though  both disowned him.  He  introduced  anti-
mony into the practice  of  medicine, and was the
father of spagyrism,  or the use of chemical remedies.
He professed  at last to have discovered the elixir of
life, and  died  at the age of 48, with a bottle of it,
as is said, in his pocket.
  Soon after  Paracelsus' death,  the ideas  of the
chemical  sect he  had founded, who held that all the
functions  are  mere chemical action, were  exploded.
But medical science, in its early doubting state, always
took its phases, for the time, from the prevailing  in-
tellectual  direction.  Hence, as in the 15th and 16th
centuries, it turned to alchemy, and sought the elixir
of life, in the 17th it leaned for support upon me-
chanics  and mathematics ; and hence arose the sect
of iatro-mathematicians—who, led by Borelli (1690),
assumed that the  human body is a machine, and  all
its functions are due to mechanical force. But Hoffman,
about 1720, recognized  the  influence of the nervous
system and the vital force ;  and  thus exploded Bo-
relli's system, and laid  the  foundation for the true
science of physiology and pathology. 
46
ANNIVERSARY DISCOURSE.
                 Medical doctrines.

   Subsequently, however,  to the  adoption of the
Baconian method,  we  find no more  medical sects ;
but  the  elements of our science were progressively
consolidated into an indivisible  unity.   Particular
doctrines have been put forth, from time to time, but
with very little influence on its progress.   Such were
1. The chemico-theosophical doctrine of Yan Helmont
(about 1610),  who,  though  a chemist,  maintained
that the functions  of the body are controlled by an
immaterial  principle, which he termed the Archaeus.
2. The chemico-material doctrine  of Sylvius (1690),
who held that all diseases are due to chemical changes,
producing an excess of acid or of alkali.  3. The psy-
chiatric doctrine (about  1710) of Stahl, who,  deny-
ing  all chemistry,  asserted that  the  living soul is
the only moving force in the human body.   4. The doc-
trine of Solidism—i. e. that diseases are located in the
soft  solids,  especially the nerves,  proposed (about
1778) by Cullen; for all had been humoralists to his
time.  6.  The  doctrine of Brown,  that all  diseases
are sthenic or asthenic.   7.  And last  of all, Hahne-
mann's doctrine  of " similia similibus  curantur," in-
finitesimal  doses, and the  psoric origin of diseases.
All these doctrines,  but  the  last,  have been entirely
exploded ;  and  this, as announced  by Hahnemann,
has nearly or quite  died out in the land of its origin,
and  still retains a distinct name among us also, only
by gradually approximating more and more nearly to
the established  principles of our science. 
BACON'S ESTIMATE OF MEDICAL  SCIENCE.    47
      State of medical science  in  Bacon's time.

  Taking now our standpoint with Bacon—the time
being 1600 to 1620—we must admit with him that
our science, like all the other sciences, had hitherto
been  a "light and  slender thing."   Little  had been
added to the science  of conservation since the writ-
ings of Hippocrates, Celsus, and Galen.  Instead of
acquiring facts  as  a  basis of advancement,  physi-
cians had given their attention to generalities, to the
neglect of nature, though the  " philosophies" where-
on  they  depended were trifling, and " medicine  not
founded  on philosophy is a weak thing."   Hence, he
considered that our  art at that .time  stood  among
" the most conjectural ones," and that " great pains
had been bestowed upon the cure of diseases, but to
small purpose."  He  adds, " medicine, therefore, has
been rather professed than labored, and  yet more
labored than advanced, as the pains bestowed thereon
were rather  circular than progressive ;  for I  find
great repetition and but little  new matter in the
writers of physic."*
   A rapid glance,  therefore, at the recent additions
to anatomy and surgery, at some  of the  inventions
of  the  two  preceding centuries, and  at  the  rude
physiology of the  circulation which then existed—
must introduce us to the third and  last epoch  of
our science,  which  dates from the great discovery of
Harvey.
               * De Angmentis, lib. iv. cap. ii. 
48
ANNIVERSARY DISCOURSE.
  I. Anatomy, though having  received  an impulse
from Mondini, as  already explained, in 1315, first
acquired any  important  accessions  from Vesalius ;
and during  the century preceding Bacon  (1500 to
1600),  it had been advanced by him and Varolius in
Holland, by  Sylvius  in  France, and by Fallopius,
Eustachius and Fabricius  in Italy.  Pare, the father
of French surgery, had also  taught  to  heal wounds
by  the  first intention, had revived  the use of the
ligature  to  arrest  hemorrhage, and first  used  the
twisted suture in hare-lip.   Tagliacotius had invented
the rhinoplastic operation  ; and Fabricius the modern
trephine and the use of the tube  after tracheotomy.
Wiseman, the Pare of England, was the contemporary
of  Bacon.   Sanctorius  had  called  attention to the
cutaneous and pulmonary transpirations ;  and Ser-
vetus had suggested the pulmonary circulation.

  II. Several important  inventions had,  however,
been made during  the  15th and 16th  centuries, in
accordance with a previous statement, that  art natu-
rally precedes the  science on which it is based.   Of
these, I specify only a few.  The 15th  century had
produced the  invention of oil painting on canvas
(1410), wood engraving (1423), printing (1442)—pa-
per having been used over a century previously (since
1312)—the establishment  of the  post-office (1464),
and aquafortis and line  engraving (1480,  twelve
years before America was  discovered).  As belonging
to the 16th century,  the  following inventions may
be noted.  The pocket-watch (1500), the spinning-
wheel  (1530), the padlock (1540),  the  use of pins 
     INVENTIONS OF  15TH  AND  16TH CENTURIES.   49

(1543), sealing-wax (1550),  public carriages  (1571),
bombs and mortars, and telescopes (1588).*
   III. The notions of the physiology of the circulation
entertained by the medical men of Bacon's time in-
cluded three fundamental errors, which demand some
explanation in this connection.
   1.  The arteries were supposed to contain  air and
blood ; the air passing into them from the trachea.
   2.  The two ventricles of the heart  were believed
to communicate, by holes  through the septum which
divides them.
   3.  The veins were supposed to carry the blood to
the various parts of the body.f
   1.  The ancients  held that the  arteries contain air
only, but Galen had shown that they contain blood ;
still maintaining that they also  contain air, which
enters the blood  to cool  it, from the  trachea, and
then passes out again.  The fact that the blood con-
tains oxygen could not of  course be known till after
the discovery of the latter by Priestley ; so that the
discovery of the aeration of the blood,  as now under-
stood, is of but recent date.  Galen, therefore, termed
the blood in the arteries " spirituous blood," and held
that it nourishes the lungs and  other delicate organs;

  * Entering upon the 17th century, we find that glass* was first manu-
factured in France in 1608; naval telescopes  in 1610; barometers and
thermometers in 1620; printing of colored engravings, 1626; the pendu-
lum, 1636; the streets of  Paris were first lighted and swept in 1666, the
year of the plague in London; the first opera in Paris, 1669.
  t Flourens: Histoire de la decouverte de la circulation du sang.  Bul-
letin de l'Academie de Medecine, Paris, 1855, tom. xx. p. 648 et suiv. ^
                 * Plate glass was not made till 1688.
                         4 
50
ANNIVERSARY DISCOURSE.
while the venous blood nourishes the coarser organs,
such as the liver.
  2. So deep was the conviction for 1300  years, of
the communication between the two ventricles, as-
serted by Galen, that anatomists at  length actually
saw the holes they believed in.  But at last, Berenger
de  Carpi, who  preceded Vesalius  as  Professor  of
Anatomy at Padua, ventured to admit that  they are
seen with very great  difficulty ("cum maxima diffi-
cultate videntur ").  But not till 1543 was this error
overthrown by Vesalius,  who, daring to use his own
eyes,  positively asserted that there is no  such com-
munication as Galen had  described; and  thus, for
the time being,  excited the animosity of the whole
medical profession against him.
  3. Michael Servetus, not  a physician but a theo-
logian, had,  in 1566,  made a lucky  guess,  and as-
serted that the venous and arterial  blood are mixed
in the lungs ; or, in  other  words, had asserted the
pulmonary circulation, in a theological work entitled
" Christianismi Restitutio."  He was, however, burned
as a heretic, six  years afterwards, and since only two
copies of his  book  escaped the  flames, but little
importance was attached to this  correct assertion,
blended as it was with many physiological absurdities.
The pulmonary  circulation was, however, reasserted
by Realdo Colombo, a pupil and successor of Vesa-
lius at  Padua,  in  1572 ;  and  by  Caesalpinus, the
botanist, in  1593.  The  latter was the first to use
the phrase "circulation of the blood."
  But of the general circulation, no one but Caesal-
pinus had yet even a suspicion.  It was now  believed 
harvey's discovery.
51
that the arteries commence in the heart and the veins
in the liver, and that the latter carry the blood from
the liver to every part of the body.  Fabricius had
discovered the valves  of  the  veins in 1574,  and
noticed that they point  towards the heart;  but this
he  supposed was merely to prevent  the blood from
unduly accumulating in the lower parts of the body.
The barber-surgeons must, of course, have seen that
on applying a ligature to the arm, preliminary to
venesection, they must  have stopped the course of
the blood through the veins towards the hand ;  and,
therefore, that the venous blood, which flowed, must
have  been flowing from the  hand  and towards the
heart.   But they merely saw, they  did not give any
value to  the fact (p. 14).
   But even the pulmonary circulation was not rightly
understood by Caasalpinus and  his  two predecessors,
just mentioned ;  so that, as understood, it was a bar-
rier rather than an aid to Harvey's  discovery.   They
had no idea that  all the blood passes through the
lungs, but only so much as was  necessary for the
reception of the vital spirits—i. e. the same  quantity
which Galen had supposed to pass  from the right to
the* left ventricle through the holes in the septum.


       Harvey's discovery of the circulation.

   Such then were the  ideas of  the  circulation  when
Harvey commenced his investigations. Born in 1578
(four years after Fabricius' discovery), and being four-
teen years the junior of Galileo, he became the pupil
of Fabricius, then Prof, of Anatomy at Padua,  about 
52
anniversary discourse.
the year 1615.   His attention was directed to the
discovery of the valves of the veins by his preceptor,
and  the  question occurred whether the blood does
uot,  after  all,  pass through the  veins  towards the
heart, instead of the opposite direction.  He insti-
tuted experiments  in 1616 to  1618, in order to de-
cide that question ; and in 1619, being then 41 years
of age, he first publicly taught his discovery of the
true circulation of the blood.  Thus,  Fabricius' dis-
covery had lain a barren and  useless fact for forty-
five years.
   When this grand deduction—for it was not an in-
duction—was once made,  it seems  so  simple that we
are now astonished that it was not made  before, or
that it found such violent opposers.  Aristotle is, in-
deed, said  almost to have discovered the true circula-
tion, nearly 2000 years before.  But there are in the
history of  all the sciences  "stray passages of mean-
ingless  vagueness, wherein older  authors  indicated
something like the truths afterwards  established on
the firm basis of experience and reasoning ;" and we
award to Aristotle, as to Servetus, merely the merit
of a lucky conjecture.  Very likely both would have
opposed Harvey's discovery, had they been living at
the  time.   Indeed,  an extreme  difficulty is expe-
rienced, even by the most eminent  men, in  seeing
the  plainest facts when they contradict all  their  pre-
conceived  notions, and are opposed to the dominant
opinions of the  age.  And we have seen that the
most striking characteristic of  the human mind,  dur-
ing  the preceding  1300 years,  had been an unques-
tioning and acquiescent servility.   No one, then, but 
               harvey's  discovery.             53

a man of genius  could have coordinated  and inter-
preted the discoveries of the preceding half century ;
and no one but an independent thinker could have
made and defended the deduction therefrom.  Others
were on the verge of Newton's discovery of the law
of gravity, but he alone had  the  talent to make it.
Harvey did not publish his  discovery till nine years
afterwards (1628). His ideas were,  for the  most
part, readily adopted by his  countrymen; but abroad
he was attacked from all quarters as a mere theorist;
Riolan, a most famous teacher of anatomy, and profes-
sor in the College of France, being his most violent
and eminent opponent; while Guy Patin employed his
caustic satire  against him ; and Moliere and Boileau
ridiculed the whole faculty,  thus disagreeing among
themselves.  Descartes, Swammerdam, Sylvius  and
Malpighi, however, adopted the discovery with en-
thusiasm.  Harvey replied  to his opponents  in  a
spirited but  dignified  manner, but retained  an un-
pleasant  recollection of his  opposition.  He  himself
admits that  after the  publication of  his work his
practice  essentially diminished, he being thought a
crazy visionary.   After the  death of his  patron,
Charles I., and during  the  civil war, his  house  was
plundered  in his absence of all his furniture, and of
what he most of all valued, the records of his  experi-
ments.  He also lost all his  labors on the  generation
of insects.  He published his work  on the Generation
of Animals in 1651 ; and to Harvey we also owe the
first announcement of the law " Omne  vivum ex
ovo."
  Thus Harvey discovered the fact of the circulation 
54
anniversary discourse.
of the blood.  He,  however,  could not discover the
whole course of the circulation, since he could know
nothing of the capillaries.  Neither did he under-
stand  the function  of the  lacteals, discovered  by
Aselli,* in 1622 ; or  of the receptaculum chyli, dis-
covered,  in 1648, by Pecquet.   He  maintained that
the lacteals  contain milk  and  not chyle.  He sup-
posed the office of the lungs is to cool the blood, and
prevent it from boiling up.  He supposed the blood
passes  from the arteries  to  the veins in two paths :
1st, the  two kinds  of vessels  (arteries  and  veins)
directly communicating ;  and  2d, through porosities
of the part.
   The  simple microscope was  invented in 1621, but
the  capillaries  were  not discovered  till  1661, four
years after Harvey's death, by Malpighi.   Leuenhoek
also described the capillary circulation in 1668, as if
it had been  previously  unknown.  And  thus the
course of the circulation was demonstrated.  Bichat
was,  however,  the first to recognize the capillaries
as a distinct system, nearly sixty years ago; and Henle
first investigated  their  structure so recently as 1841.
The cause or forces of the circulation could not be
ascertained till histology took a scientific form, and
the precise action of the different parts of the  circu-
latory apparatus had been ascertained. Harvey, how-

  * The lacteals had been discovered by Erasistratus about b.o. 300, and
were afterwards forgotten.  Aselli's work, printed at Milan in 1627, is
the first  containing colored anatomical figures—the arteries and veins
being in red, and the lacteals in black.  It was supposed that the lacteala
oarry the chyle to the liver, till Pecquet traced it to the thoracic duct
and the subclavian vein. 
harvey's discovery.
55
ever,  described  the  motions of the  heart far more
accurately than most subsequent writers.*
  The 240 years which  have already elapsed since
Harvey's discovery have  not sufficed to complete it,
and to demonstrate all its relations  and  its import-
ance  to our  science.  It is not  strange, therefore,
that we have no very important advance to report
in our science during the remainder of this century
—i. e. up to 1700—in consequence of if.  Forty years
had passed after its promulgation before all opposition
to it had ceased, and  its  true value began to be con-
sidered ; " a  certain succession of time and of persons
being generally necessary to familiarize men  with
one thought  before  they can advance to that which
is next in order."  (Whewell.)
  I should not,  however, omit the following names
of eminent men in our profession who honored it in
the different  countries of Europe, and improved our
science  by their labors,  in  the  17th century.   In
Great Britain—Sir  Thomas  Browne ; Dr. Darwin ;
Wiseman, the father of British surgery ;  Sydenham,
the English Hippocrates ; Lower,  who first suggested
the idea of transfusion of the blood ; Wharton, Willis,
and Glisson,  whose names are  incorporated into the
nomenclature of the  science  they  advanced ; Drs.
Goulston  and  Radcliffe,  and  the  celebrated John
Locke.  In  France  were Pecquet,  Vieussens,  and
Tourneforte.   In Germany, Wirsung and Schneider.
Stenon  in  Denmark.  In Holland this  period  was

  * See an account of Harvey's discovery in Blackwood's Magazine for
July, 1858. 
56           ANNIVERSARY discourse.

distinguished by the names of Bidloo, Graaf, Ruysch,
the best of minute anatomists,  and who  sold his
museum, made by himself, to the czar of Russia for
30,000  florins ;  Nuck and Tulp ;  Leuenhoek, the
originator of microscopical anatomy, though not  a
physician ; and  Swammerdam, the  most ingenious
of all dissectors of insects.  In Italy, I can only men-
tion Bellini, Borelli, Malpighi, distinguished in minute
anatomy,  and who first saw the  circulation under
the microscope ;  Lancisi, physician to three succes-
sive popes;  and Ramazzini, distinguished  for his
varied learning.

          Advancement of physical science.

  Meanwhile, however, in physical science, which had
presented an almost entire blank for 1000 years after
the fall of the Roman empire (a.d.  400)—and espe-
cially in  astronomy—an astonishing advance was
being made in the  17th  century.   Galileo made his
telescope  in 1609,  and  applying  it to the heavens,
almost  at  once  discovered the  moons of  Jupiter,
and confirmed by direct observation the doctrine an-
nounced a century  before by Copernicus.   He also
invented the  pendulum,  in 1636;  the  idea having
been  suggested to him while  a medical student, on
seeing a chandelier swinging in a  church at Pisa.
Kepler published his discovery of the laws of the plan-
etary motions and distances, in 1609.   Newton,  born
in 1642, discovered  the law of gravitation—the most
splendid scientific deduction ever made—in 1665, or
46 years after  Harvey's discovery; and his Principia 
epoch  of actual science.
57
were  published in 1687.  The science of mechanics
had also been greatly advanced meantime, especially
by Galileo's discoveries.

  III.—EPOCH OF SYSTEMATIZED OR  ACTUAL SCIENCE.

  Thus it appears that though the  third epoch of our
science dates from the discovery of the circulation of
the blood, about 1620, it  may for all practical  pur-
poses be regarded as  commencing  with the last cen-
tury, when the influence of that discovery began to
be felt;  and when it became finally emancipated from
the control of systems and doctrines, and rapidly as-
sumed a systematized form.  It must serve my pur-
pose to give a very  brief abstract of its  progress,
therefore, during  the  last  150 years, under the three
subdivisions before mentioned,  (p. 32.)

         Progress of anatomy since 1700.

  I. The science of descriptive anatomy, has been ad-
vanced since 1700, by the labors of Cheselden, John
Hunter,  the  Monroes, the  Bells, Astley  Cooper,
Grainger, Sharpey, and Quain, in  Great Britain ; of
Petit, Bichat, Cloquet, Cruveilhier and  others, in
France; Malpighi, Scarpa, Galvani, and Pacchioni, in
Italy; Albinus, and De Haen, in Holland; Schmucker,
Zinn,  Meckel, Soemmering, and Rosenmuller, in Ger-
many; and by Winslow, a Dane.
  General anatomy was originated by  Bichat, who
published his  great work in 1801; it having been
written  within a single year.  He  first attempted to 
58           ANNIVERSARY DISCOURSE.
reduce the complex  structures of the body to their
peculiar tissues, and to introduce a systematic order
into the study of anatomy and physiology, not known
before his time.  Upon the basis laid down by Bichat,
the science of histology, or minute general anatomy,
has arisen during the last  fifteen years;  and which,
advanced by the labors of Schwann, Todd and  Bow-
man, Queckett, Kolliker,  Robin, and many others, at
length underlies the  whole  domain of anatomy, phy-
siology,  and  pathology;  and promises  the  grandest
results, as the starting-point of future discoveries in
the departments just mentioned.
  Microscopical anatomy may be said to have  origi-
nated with Leuenhoek, about the year 1668. But it
made but slow advancement, on account of the  de-
fective instruments used.   Great improvements were
however made in the construction  of the compound
microscope in 1832,  and since that time it has  ad-
vanced at a rapid rate.
   Comparative anatomy,  or the study of the  struc-
ture of the lower animals,  was the first department
of anatomy  in point of  time.  We  have seen that
dissections of the lower animals only were  allowed by
law, till the time of  Mondini,  or about five hundred
and forty years ago.   After human dissections were
permitted, comparative anatomy  was neglected, till
again resorted to  by naturalists, and  especially by
Cuvier,  as a  basis of classification  of the animal
kingdom.  It was also studied by Hunter, as a basis
of general physiology, and is still cultivated by many
in all the countries  of Europe, in its relations more
especially to  human  structure and function. 
       THE SCIENCE  OF FUNCTION SINCE 1700.     59

  Pathological anatomy was  initiated near  the end
of the last century,  and has  been advanced by the
labors of Hunter, Baillie,  Carswell, Hodgkin,  Aber-
crombie,  Cooper, and Paget,  in  England ; Bichat,
Pinel, Andral, and Cruveilhier  in France; by Engel,
and above all, by Rokitanski, in Germany.
  Of transcendental  anatomy,  Geoffroy  St. Hilaire
was  the  originator, some  thirty years  since.  It is
still  receiving some  attention, especially  in  Ger-
many.

  Progress of physiology and pathology since 1700.

  II.  The  science   of function—including  physio-
logy and  pathology—has been  advanced since 1700,
mainly by the following  individuals :   1.  Frederic
Hoffman, who became a professor in the university of
Halle in 1700, and was the first to establish the true
basis  of these two departments.*  2.  Boerhaave, who
became a professor at Leyden, in  1710.   He is the
author of the humoral pathology, as now generally un-
derstood  after half a century of disrepute from the
ridicule of Dr. Cullen ; and he proposed a theory of
inflammation more consistent with the present state
of physiology and pathology than most which have
followed it.  His aphorisms and institutes of medicine
were  translated into every European, and also into
the Arabic,  language.   3.  Haller, a pupil  of Boer-
haave, has been styled the father of physiology.   He

  * His scientific and literary labors were immense.  The mere titles of
the folio volumes written by him, as detailed by Haller, in his " Bibli-
otheca Medica," extend to thirty-eight quarto pages. 
60
ANNIVERSARY DISCOURSE.
first maintained,  about 1740,  that  sensibility  and
irritability are inherent in the nervous and  muscular
tissues respectively; an opinion opposed for nearly a
century  afterwards,  and  now  entertained  by  all
physiologists.   He wrote,  between  thirty-five  and
forty volumes,  varying from octavos  to folios,  on
anatomy,  physiology,  pathology,  botany,  surgery,
and other departments of medical science.
   Goethe also, though a poet, gave a new impulse to
the  science  of  function, by  the  announcement, in
1790,  of  his brilliant  deduction,  the principle  of
" developed and metamorphosed symmetry "—or the
doctrine  that all the different  parts of plants are but
modifications of the same  structural form.   4. But
John Hunter has done more for comparative anatomy,
and human physiology as  illustrated by the former,
than any  other individual; and holds  the highest
rank as an anatomist, physiologist and surgeon.  His
ideas of  inflammation,  announced  about  seventy
years ago, have been  implicitly  adopted  by most
writers to the present time, though quite at variance
with the  present state  of  pathological   science.
5.  Sir Charles Bell discovered the motor and the sen-
sory function of the  anterior and  posterior roots,
respectively,  of the spinal nerves in 1807, and pub-
lished  his  discovery  in pamphlet  form  in 1810.
Blumenbach,  Hufeland,  Treviranus,  Valentin, Pro-
chaska,   Miiller, Burdach,   the  Wagners,  and  the
brothers  Weber, must also  be mentioned  here; and
Adelon, Berard, Foville, Flourens, and Bernard.  And
last, Dr. Marshall Hall, the discoverer, in 1832, of the
reflex,  or  diastaltic, function  of the spinal cord— 
        PRESENT STATE OF MEDICAL SCIENCE.      61

the greatest physiological  discovery  since  that  of
Harvey.
  In  the  department  of  general pathology alone, I
only mention the  labors  of Williams,  Chomel, and
Henle;  though the list might easily be made a long
one.

  Progress of hygiene  and therapeutics since 1700.

  III. The third department, or the science of con-
servation,  includes  two subdivisions, viz. :  hygiene,
public and private,  and therapeutics.  The number is
so great of those who have  advanced the  science of
therapeutics, that  I cannot undertake to enumerate
them.   It would   include  every  eminent  practical
writer—medical, obstetrical, and surgical—from Hoff-
man to the present time.   I need  only say, that the
science of therapeutics, or the treatment of diseases, in
the three  departments  of practice just mentioned, has
kept pace with that of pathology, on which all true
advancement in therapeutics must be  based; and
that the science of hygiene, or the  preservation of
health, has also advanced together with physiology.
  And at length the question presents itself, what is
the present state of our science ?  And I will attempt
as brief a reply as possible.


        PRESENT STATE OF  MEDICAL SCIENCE.

  I. We  may regard  descriptive and surgical anat-
omy as nearly complete in their development.   Patho-
logical anatomy, also, so far as its facts are concerned, 
62
ANNIVERSARY DISCOURSE.
may be regarded as  susceptible of no  very great
additional  advancement,  unless  some  new aids to
observation are adopted.   The  120,000 bodies in-
spected post mortem by Rokitanski  alone, we may
well suppose, presented almost every structural lesion
cognizable  by our present means  of observation, that
the human body is liable to.  But deductions of great
importance and value  are yet to be made from this
vast array of facts.   Rokitanski, like most patho-
logical  anatomists,  is  merely the cautious observer
and the accurate  reporter.   Some deductive mind
will yet give these observations  their true scientific
value.
  In histology many facts are yet wanting, and will
be  supplied.  Here also the labor  of a deductive
intellect is required to  coordinate the facts ; which
promise future discoveries  not inferior to  those  of
Harvey and Hall.
  Microscopic anatomy, aside from histology, which
is a particular phase of it, needs,  and  will  acquire far
greater definiteness, and advancement.  Of compara-
tive anatomy also the same may  be  remarked, from
its importance in elucidating human  physiology and
pathology.

     Present  state  of physiology and pathology.

  II. On the recent  rapid advancement  of the
science of function, we  have much reason for congra-
tulation. But we  must  still affirm that the physi-
ology and the pathology of the present day are alto-
gether  too intensely chemical; and  simply because we 
PRESENT  STATE OF PHYSIOLOGY.        63
implicitly receive  our physiology, at the  hands of
chemists.  Certainly the science of physiology cannot
be formed without the aid of chemistry; but chemists
should not, therefore, claim the whole field for them-
selves, nor should  physiologists to such an extent have
surrendered it.  Chemistry conducts us to the thresh-
old of physiology ;  but it can carry us no further.
It is, therefore, a valuable and an  indispensable guide
thus far, but can be nothing more.  But the chemists
assuming, as did Paracelsus 300 years ago, that all the
functions of  the living body are merely the result of
chemical actions,* virtually include physiology within
their own domain.  They next assume  that  a  man
weighs  a certain number  of pounds,  say 140, and
proceed to tell us  how many ounces of  food,  both
solid and fluid, he  requires  daily and  per  annum ;
just how much  oxygen  he  consumes, and  how much
carbonic acid he exhales, and just what proportion of
his weight he secretes in bile  or gastric juice ; and
this they call making  physiology a positive  science. •
Physiologists, on  the other hand, assert  there is a
distinct vital force ;  but still admit that possibly, after
all,  this force may be correlated  with, or convertible
into, chemical force, which is practically yielding the
point to  the chemists.  Besides, we are  reminded,
that physiology  is an  inductive  science, like chem-
istry ;  and  therefore  to be  advanced  in a similar
 way, and of course  equally well,  if not best of all, by
 chemists, from  mere chemical facts.
               *

   * Liebig, however, asserts distinctly that  the vital force is  a force
 " sui generis." 
64
ANNIVERSARY  DISCOURSE.
  But against this we enter our protest, for the fol-
lowing reasons :
  1st. It is a principle to which there should be  no
exception,  " never to attempt to solve the problems
of one science, by the order of perceptions peculiar
to another ;"  since each  science has its own  canons
of interpretation and investigation and reasoning.
   2d. If  Physiology  were mainly  an  inductive
science, like chemistry, I have  shown  that physiolo-
gists alone can judge of the value and the true bear-
ing of physiological facts, and they alone can collate
them for the inductive process (pp. 20-21).

           The doctrine of final causes.

  But while chemistry  is  merely an inductive sci-
ence, in the sense already assigned  to that  term
—it  being  far  more inductive  than  deductive—
physiology  is something more  than  an inductive
science.  It is at the same  time both inductive and
teleological.  In other words, it is partly inductive,
and partly relies for its advancement on the assump-
of  final  causes.    Prof.  Whewell asserts that the
" assumption of final causes has  given rise  to the
science of  physiology;" but if so,  it consists, also, of
principles  obtained  by the  inductive  process.  The
phrase " final cause "  originated with Aristotle,* and
is merely synonymous with the word "purpose."  The
doctrine of final  causes has recently been expressed

  * Aristotle's expression is, rb ov eveaev—nal rb dyadov, as indicating this
kind of cause.  See his Metaphysics. 
DOCTRINE OF  FINAL CAUSES.          65
by the  word '' teleology ;"  this word having  refer-
ence, from its  derivation, to the end, object, or pur-
pose,  of the  part or  organ  under  consideration.
E. g. In order to ascertain the function or use of a
part, we begin by assuming that it has some purpose—
was formed  for some particular end ;  and reasoning
out that end or purpose from the structure and other
circumstances, is applying the doctrine of final causes
or  reasoning  teleologically.   Bacon*  regarded  the
"philosophy of final causes as sterile,"  and so does
Geoffroy St. Hilaire.  But it is the  fact, that the use
of every organ  has been discovered by starting with
the  assumption that it  must have  some end.f  The
discovery of the circulation was due  to the persuasion
of a purpose in every part of the  circulatory appa-
ratus.   In the science of function, we  must, as Kant
has remarked, " adopt the  maxim,  that nothing is in
vain ;  and proceed upon it in the same way, in which
in natural philosophy, we proceed upon the principle
that nothing happens by chance."
   Practically, therefore, the physiologist must adopt
the  principle of  final causes ;  a  principle entirely
unknown to chemistry, or any other merely physical
science, and peculiar to the physico-vital sciences—
or physiology  and  pathology.   He mayo say,  with
Geoffroy St. Hilaire, " I take care  not to ascribe to
God any intention ; for I mistrust  the feeble powers
of my reason.  I  observe  facts merely, and  go  no
further.   I only pretend to the character of the his-

  * " It is so far from being beneficial, that it even corrupts the sciences,
except in the intercourse of man with man."—Xov. Organum, book ii.,
Aphorism ii.                          t Appendix, note ii.
                         5 
66            ANNIVERSARY DISCOURSE.

torian of what is."   But after all, he cannot advance
a step without the aid of the very principle  he con-
demns.
  All departments  of  science  ask  the  question
"why."*  But while  the physical sciences mean by
this word,  "through what cause?"  the  physico-
vital mean by it,  " for what purpose ?"   E. g. if the
question be,  " why do sulphuric  acid and soda unite
to form  a salt ?" the  answer is  a statement of the
efficient  cause, viz.:  "because they have a  chemi-
cal affinity for each  other."  But  if the question be,
" why have all animals a stomach ?"  the reply is, "in
order to  digest their food," and consists in  a mere
statement, not of the cause, but of the object, or pur-
pose of that organ.  While, therefore, chemistry is an
inductive, physiology is a teleological science.
   But physiology is also in many respects inductive.
If we find that arsenic, administered in a certain dose
to  several animals  of the same  species, and  in all
respects alike as nearly as can be ascertained, proves
invariably fatal—and deduce from these similar facts
the general conclusion that arsenic is a poison to that
whole species of animals, we are pursuing an induc-
tive process.  While, therefore, chemistry is merely
an  inductive science,  physiology is both teleological
and inductive ; and  the blending thus of efficient and
final causes is peculiar to this subdivision of medical
science.f
   There is,  indeed,  a " tendency in all  recent re-

  * See note, page 27.
  t That it is also deductive has already been shown by some of the
discoveries adduced. 
        CHEMISTRY AN  AID TO PHYSIOLOGY.       67

search," says a  recent writer, " to impugn the doc-
trine of vitality, both in animal and vegetable life, as a
distinct force and  power ;  and to merge its alleged
functions, whether of organization,  maintenance, or
reproduction, in those same physical forces, which act
on the inorganic matter of the world around us."  It
is high time this tendency were checked ;  since phy-
siology (as he  continues,)  " though closely  encir-
cled round by  physical laws and  phenomena,  and
approached only  through  these, has still  a  secret
region within—the law and principle of life, hitherto
inaccessible by any  method of human inquiry"—
though we are " moving  onward  to those truths,
which are the certain  reward  of all legitimate  in-
quiry.*   " The notion of life and  vital force," may
still "be  too  obscure to be steadily held," as Prof.
Whewell remarks ; but it  may gradually become so
clear and definite, as to be available in  science ; and
then, as  Cuvier  suggested,  "natural  history may
have its Newton."
   We,  therefore,  accept chemistry "as a means of
exploration, not of deduction—as a pillar, not a  pinna-
cle—as an instrument, not  an  aim.  Chemical laws
are quantitative, chemical actions resulting in definite
combinations ; physiological laws can never become
quantitative, but  only qualitative,  since living  sub-
stances or tissues have not a  definite  composition.
No analysis of  a  nerve will ever throw any light on
sensibility ; no arrangement of chemical formulas will
ever explain the form and properties of a cell."
* Edinburgh Review, July, 1858. 
68
ANNIVERSARY DISCOURSE.
Chemistry may tell us '' what an organism is made
of; but it cannot tell us how it is made, nor  how it
manifests its  vital attributes."—Blackwood's  Maga-
zine, March, 1858.
   Perhaps  I  can adduce no  better  instance of the
barrenness of chemical labors as applied to the expla-
nation of physiological phenomena than the positive
physiology, so called, which chemists have conferred
upon us, in respect to the subject of food and diges-
tion ; and which are familiar to most medical  men.
   During the last twenty years, the most extensive
and laborious researches have  been made by chem-
ists in respect to food ; and in a chemical point  of
view, merely, they are doubtless of very great value,
for all this must precede the true physiology of food
and digestion.  But no important  and reliable phy-
siological result has  yet  been obtained from them.
We are  assured by the chemists that the nutritive
properties of the various kinds of aliment are  in pro-
portion to the amount of nitrogen they contain ; and
that while the nitrogenized elements of our food are
alone histogenetic, or tissue-producing, the  non-nitro-
genized  elements  are simply calorific, or  heat-pro-
ducing, and not  in the least histogenetic.  But phy-
siological observation  shows that the body may  be
nourished for a time, by the calorific elements of the
chemists  alone ;  and that the so-called histogenetic
elements are also calorific.   According  to the chem-
ists, fat  being non-nitrogenized,  should be calorific
merely j  but not a cell nor  a fibre can  be formed
without a certain amount of fat, and  it is, therefore,
also histogenetic.  Common  salt, also, and the phos- 
   ACTION OF STIMULANTS CHEMICALLY EXPLAINED. 69

phates of lime and magnesia are as truly histogenetic
as the nitrogenized compounds, albumen and caseine ;
for not a tissue nor a fluid in the human body can be
formed if either of them is absent.
   I  will adduce  only one more illustration of the
positive physiology which is formed in the laboratory.
In explanation of the  fact,  that  all  the  different
varieties of the human race are inclined to the use of
some form of stimulant, the  chemists have assumed,
that the  active principle of coffee, tea, and spirituous
liquors, increases the  functions of  the  nervous and
muscular systems,  without,  or  with greatly dimin-
ished, waste.  I say, have assumed this, for no proof
whatever of this  position has  been adduced.  All
admit that  the vital phenomena in all ordinary cir-
cumstances  are accompanied by waste  of the tissue
manifesting them.   A  muscle  cannot  produce the
least motion without a corresponding loss of its sub-
stance ; not an idea flits through the mind, without
carrying away some molecules of the brain-tissue.
But chemists  assure us  that  if we first introduce  a
quantity of alcohol, or caffeine, or theine  into the
circulation, we may then move and think, ad libitum,
without  any sensible waste of the active tissues.  A
mere mechanic would doubtless explain this propo-
sition, by saying  that  these  three  substances are oil
to the corporeal machinery, and diminish the friction ;
and this explanation  is as  valid  as the  preceding,
though it assumes,  as did the  iatro-mathematicians
(p. 45) that the human organism is a mere  machine.
We  use coffee, and tea,  and  alcohol, not to prevent
waste, and, therefore,  save  the expense of food  to 
70
ANNIVERSARY DISCOURSE.
supply it;  but simply because  they are stimulants,
and  produce a  certain well-known  physiological
effect; because they excite the nervous and muscular
systems,  especially, to a higher degree of activity for
the time being ; though the waste is here, as always,
proportional to that activity.   It is the waste conse-
quent on action, that exhausts a tissue or organ ; and
if alcohol,  coffee  and tea, could enable  us to think,
and  feel, and move, without waste  of the cerebral
substance and the muscular system, habitual drinkers
would  be  the most intellectual of men ; and their
brain, never feeling the  effects of exhaustion, would
be superior to the necessity of sleep  and repose.   I
am not  here speaking in derogation of these  sub-
stances properly used and administered ; I am  only
objecting to the chemical explanation of their action,
as totally at variance with all physiology, though it
is unhesitatingly accepted by some physiologists.
   Now,  the errors  before mentioned in  regard  to
food, result from the fact that chemists  merely look
to the composition of the substances which  nourish
the organism ; while the physiologist looks also, and
more especially, to the organism which is to be  nou-
rished;  and remembers that the latter acts upon, and
changes, as truly as it is acted upon by, the  food.
Belladonna, hemlock, mix vomica, and  aconite, are
fatal poisons to most animals  ; but the rabbit takes
the first, the goat the second,  a kind  of buzzard the
third, and the horse, aconite, with impunity.   Bread
and milk, taken as food by a kitten, in time develop
a full-grown cat;  but taken  by an  infant, develop
human tissues.  It is especially the  organism, then, 
       THE "PHYSIOLOGY OF PROBABILITIES."     71

and  not  merely  the chemical  composition of  the
food, which determines and controls the result.


           Positive physiology objected to.

   We then accept the chemical ideas of food with much
hesitation ; and especially when  we  also remember
that, as Mulder and Lehmann have admitted, "che-
mistry is  still in too imperfect a state to give clear
and  satisfactory answers to its own  appropriate ques-
tions in this direction."  The " positive physiology," I
am considering, is, at most, nothing more than what
Berzelius happily termed, the " physiology of proba-
bilities."   It is an attempt to erect the science of life
on a basis of mere analysis. *. e. of death and decom-
position ;  and  the result  only too  nearly resembles
that  achieved  by  the  alchemist, as  shown by  the
following epitaph, supposed to have been written by
himself.
            " God his almighty power displayed,
             When he from nothing all things made;
             With crucible, to work I went,
             And in the fire a fortune spent;
             Reversing just what he had wrought,
             I everything to nothing brought.

   I  have confined my illustrations to the physiology
of the present time ;  but pathology is merely morbid
physiology, or  physiology modified  by disease, and is
at present equally amenable to the  strictures I have
applied to the department  on  which it is based.
And  it is  high time  that both  physiologists  and
pathologists, while grateful for the aid which analyti- 
72
ANNIVERSARY DISCOURSE.
cal chemistry has  conferred, at length assume the
control of their appropriate domains.


     Present state  of hygiene and  therapeutics.

   III.  I cannot delay to do justice to the present
advanced state of the science of conservation, i. e. of
hygiene and therapeutics.
   1. Public hygiene has of late received especial atten-
tion in all  civilized countries ; and  the results have
been apparent, in  the  greatly diminished mortality
in those cities and States where its principles have
been best applied.  We have, however, yet seen but
the beginning of what can  be  accomplished in the
saving of human life, and the prevention of  disease ;
and we never can fully realize it until the laws per-
taining to  the public  health are  administered  and
enforced by medical men.   So long as health officers
are selected  on merely political grounds,  and to the
exclusion of medical men,  just  so long  will  perish
multitudes  annually of those who  might have been
saved by timely precautions.  Nothing  short of  a
thorough acquaintance with the various departments
of medicine can render one familiar with the compli-
cated relations of  the great subject of the public
health; and not till every  city inspector, coroner, and
health warden, is a well educated medical man, can
the  people enjoy the  sanitary advantages to which
the present state of science  entitles them.
   Private  hygiene, on the  other hand, though well
understood  by medical men, can be  to no great 
          NATURE IN THE CURE  OF DISEASE.       73

 extent enforced ; since it is set at defiance by many
 of the predominant fashions of  the day.

           Nature in the  cure of disease.

   2. Of the present progressive and rapidly improv-
 ing state of the science  of therapeutics also, I  must
 but briefly speak.   We are  approaching the period,
 and, I trust, are very near it, when it will be generally
 admitted that the first question proposed to himself by
 the physician  on examining a  patient and  deciding
 the nature of the case, should be, not " what remedy
 shall I prescribe ?" but " shall I in this case prescribe
 any medicine ?"   For if nature, aided by repose  and
 appropriate diet, is sufficient in any  case, promptly
 to accomplish the cure, surely all medication  is unne-
 cessary,  and probably injurious.  If  nature is  not,
 thus aided, sufficient, then occurs the second question,
 " what remedy shall be given, and what  is the  least
 amount  that will accomplish the  required object?"
 And he is the  best  practitioner  who knows,  both
 when to decide to give  no medicine,  and also what
 and how much to administer,  when a remedy is
 required.  To  precisely this kind of discrimination
 the  science of  therapeutics is   now  tending.  The
 result is, that far less  medicine  is  administered  now
 than twenty years  ago,  by the  best practitioners,
 though with an increased,  instead of a diminished
 faith in its effects.  We sometimes hear it remarked
 that the  older a practitioner becomes,  the less is his
faith in the efficacy of medicine.   It would,  I think,
be  more  correct  to  say, the  older   a  practitioner 
74
ANNIVERSARY DISCOURSE.
becomes, the  greater is  his  faith  in the  curative
powers of nature.  This will lead him to administer
less medicine on the whole, for he will have  learned
to distinguish  the cases requiring medical aid from
those  which  do  not.   But  his  faith  in  medication,
applied  in cases  requiring it, will be  found actually
to increase with age, and an increasing skill in apply-
ing it.  As Richter has said, " He that is not growing
wiser, has never been wise ;"  so I  should say, that
the practitioner whose faith in  medication, properly
applied, does not increase with  his  experience,  has
never had any faith based on his own proper applica-
tion of it*
   The science  of therapeutics has  also  been much
advanced of late by improved/bnras of therapeutical
agents.  The vegetable alkaloids, possessing a defi-
nite chemical composition and therapeutical power,
have vastly increased the  certainty and reliability of
our  prescriptions;  and much  more  remains to  be
done in this  direction.  We therefore welcome any
effort, from  any and  every source,  to increase  the
certainty of the materia medica; and though we object
for reasons  before  assigned  (p.  13)  to the  term
" positive," as applied to remedial agents, we consi-
der  that  podophyllin,  leptandrin,   hydrastin,  and
several  other  remedies of  this class, are  already

  * The work entitled, "Nature  in Disease," by Sir John Forbes, who
has had a medical experience of over half a century, has by many been
entirely misunderstood. It merely inculcates a greater reliance upon
nature in the management of disease, than has hitherto been manifested ;
while it asserts an undiminished faith in remedies, properly applied.  It
cannot fail to be productive of much benefit to the profession. 
THE  NUMERICAL METHOD.
75
proved  to  be highly valuable contributions to our
therapeutical means.

              The numerical method.

  And another recent effort to render therapeutics a
positive  science  I must not  entirely pretermit,
since it still  exerts a sensible, though much dimin-
ished influence.   I allude to the "numerical method,"
initiated by Louis about twenty-five years ago.   The
aphorism " Ars tota est in observationibus " I have
already called in question; and Morgagni added the
remark  about 200 years ago:  " Non  numerandae
sed perpendendas sunt  observationes."   Louis, how-
ever, insisted that the  enumeration  of  observations
is the principal thing necessary ; and that without
this method, nothing valuable can  be established  in
anatomy, pathology, or therapeutics.  And Bouillaud,
in his essay on medical philosophy,* travesties Mor-
gagni as follows : "Non solum numerandae,  sed etiam
perpendendae,  sunt  observationes;"  thus entirely
reversing the meaning of the Italian medical philoso-
pher.   The  science  that does  not  count, say the
numeralists,  is never sure of anything, and therefore
is not  science  ;  and,  hitherto, medicine  has not
 counted, or what amounts to the same  thing, it has
counted badly.  It  has  said "very many, a  few,
several, often,  rarely," and the like ; it should say
five,  twenty, or some  definite  number, and  five,
 twenty, or some other  precise per cent.
   No one  fails to appreciate accurate counting in  all
                     * Paris, 1836. 
76
ANNIVERSARY DISCOURSE.
cases of statistical details ; and so far as the  nume-
rical method  merely counts, its  value  is not ques-
tioned.    But  when it  also applies the  inductive
process, or the deductive, to its numerical results, and
claims to  be an  infallible guide in medical expe-
rience, it  simply attempts what, from the nature  of
the case, it can never fulfill.   But it has promised its
greatest  triumph  in its application  to therapeutics ;
and I will specify some  of its actual results in this
department.
   In the first  place,  the results  of  the  practice
adopted   by  the  numeralists  themselves,  do  not
demonstrate a more reliable  knowledge or an im-
proved  state  of therapeutics on their part, since the
mortality has not been  less  than that  occurring  in
the practice of others. E. g. according to a report on
typhoid  fever, by Andral, of those  treated by the
expectant method,  all  recovered ;  while  of those
treated by purgatives  and  bleeding,  by Bouillaud
and Louis, one-eighth to one-sixth died.
   But,  secondly,  the  figures  obtained by  different
partisans  of the numerical method, entirely disagree ;
e. g. Louis, treating  typhoid  fever by free bleeding,
lost one-half  of his patients, and we  should infer
that it is  a very dangerous practice ; but Bouillaud,
adopting the same treatment, lost only one in seven-
teen patients  ; from which we  must infer precisely
the reverse.   Which of the two  shall we follow, if
our therapeutics is  to be rendered  positive  in this
way?  Is blood-letting, in typhoid fever positively
injurious,  or, on the  whole, beneficial ?
   Thirdly, the therapeutical result  arrived at  by 
THE NUMERICAL METHOD.
77
the numerical method  are mere averages,  and there-
fore of no practical value in particular cases.  Bou-
illaud treated 57 cases of pneumonitis by successive
bleedings and other remedies ;  though I here notice
the results only  so far as the amount of blood taken
from the patients is concerned.  On counting accu-
rately, he found the 57 patients had lost 259 lbs. of
blood,  or on an average 4 lbs. 8i oz. each.   But not
a single patient  had lost precisely 4 lbs. 8£ oz., for a
patient is never an average, but a case by and  of itself.
The greatest  amount taken from a patient had been
10 lbs ; and  the  least, 1 lb. 12 oz.   Finally,  of these
57 patients  53 recovered, and  4, or about Tv, died.
Now, what  is the  therapeutical principle herefrom
resulting ?   That if we treat pneumonitis by repeated
blood-letting, we shall  lose only 1  patient  in  14?
By no means, for much depends on the  quantity of
blood  taken.  Does it then follow that  if we take
4  lbs.  SI oz. of blood in cases of  pneumonitis, we
shall cure 53 out of  57 cases?  Certainly  not, for
that treatment was not adopted in the cases adduced,
and would probably have led  to a  different result if
it had  been.  It, then, neither proves  that blood-
letting is or  is not a proper remedy in pneumonitis,
nor how much blood should be taken, if  bleeding be
decided upon.  From the cases adduced, we  can  only
infer that if 57 other  cases  of  pneumonitis,  indi-
vidually like the 57 before mentioned, should  be again
individually  treated in the same way—the amount of
blood taken varying from 1 lb. 12 oz. to  10  lbs., and
 averaging 4 lbs. 8i oz.—53 of the 57 cases would
 recover.  But we know we can never again collect 
78
ANNIVERSARY DISCOURSE.
57 cases precisely like the preceding ; and, therefore,
though this conclusion may be very positively asserted,
it is positively worthless, except as a mere statistical
fact.
  The numerical  method can therefore never  add
essentially of itself to the department of therapeu-
tics.  It can count, and count well; and should pre-
tend  to nothing more.   But when it oversteps its
appropriate  domain of mere statistics, and essays to
deduce  conclusions, it ceases to be a reliable guide.
Its facts, as obtained, are too heterogeneous to warrant
an  inductive conclusion, and can  only be conducive
to science in this way when obtained under precisely
similar conditions—the most difficult of all things for
the observer in this  department to be sure of—and
when collated  by an adept  in pathology  and  thera-
peutics.   It  may be  also added, as a matter of fact,
that not a single important discovery in therapeutics
has by this method been made, while meantime the
anaesthetic effects  of  ether have been discovered by
a mere deduction and  its verification ; and subse-
quently, those of chloroform and amyline, by deduc-
tion also  from  the  known  similarity of action in
other respects of chloric and  sulphuric ether, and the
highly carbonized composition of them all.  Of course
all  knowledge of therapeutics must proceed at first
from direct  experiment; but  as science  advances,
deduction will become more  and  more useful in the
way of discoveries  in this department; our deductions
being verified by experiment, as in the instances just
given.  For as our  methods of  diagnosis  become
more certain, we  shall be able, more and more, to 
THERAPEUTICS  MAINLY INDUCTIVE.       79
deduce  the  therapeutics required in each particular
case from its pathology and our knowledge of the
action  of remedies.   Sydenham,  who was contempo-
rary with Bacon, Harvey,  and John Locke, recog-
nized this principle in our science over two hundred
years ago.   "As truly," says he, "as the physician
may collect  facts of diagnosis from the minutest cir-
cumstances  of disease, so truly may he elicit indica-
tions in the  way of therapeutics.   I have  often
thought  that, provided with a thorough insight into
the history  of any disease whatever,  I could invari-
ably apply an equivalent remedy.   These phenomena
of the disease, if carefully collated with each other,
lead, as it were by the hand, to those palpable indica-
tions of treatment, which  are drawn, not from the
hallucinations of our  fancy, but from the  innermost
penetralia of our nature."
  But I have stated that  therapeutics is mainly an
inductive department of our science.  Facts alone,
therefore, well assorted and in sufficient number, war-
rant, in  most instances, a  practical deduction ;  and
hence the most rigid  observation and experiment are
here indispensable.   But it  is in  this department
especially that we realize  the force of Hippocrates'
maxim, " Experientia fallax—judicium difficile ;" since
the action of therapeutical agents is constantly modi-
fied  by  the ever-varying  conditions of the  living
organism.   Besides, the testimony of the  observer's
senses are quite liable to be biased  by some precon-
ceived opinion,  if not compromised by some  defect
in his method.  Hence it  is generally far safer to
wait till a  second observer  has verified the  so com- 
80
ANNIVERSARY DISCOURSE.
mon  announcements  of wonderful  properties of new
remedies, or new applications of old  ones, before we
adopt them in our practice.  Too generally have the
novelties in this department been found to depend on
some dominant hypothesis or theory; as the elephant
seen  by the  too credulous astronomer in the moon,
turned out to be a mouse in the  distal portion of his
telescope.
            The spirit of medical science.

   The facts  and ideas  which have been  presented,
show that we may very safely abate some  of the pre-
tensions  often put forward, in regard to the present
perfection of our science ; though we cannot still say
with  Bacon,  that it is "a light  and  slender  thing."
On the other hand, we have cause for admiration and
astonishment at the vast and  imperishable structure
which has  been erected during the last one hundred
and fifty years ; and may confidently anticipate  at
least  an  equally rapid advance  in future.  We have
found its progress thus far, interrupted by long sta-
tionary periods, and that  it has  at  times even retro-
graded.  In the  future  we can  hardly expect such
interruptions.  We have  seen that in its  spirit our
science was mystical to the time  of  Hippocrates; ex-
clusive thence to Galen; servile and acquiescent from
Galen's  time to Harvey; and uniformly progressive
since  Harvey's discovery became  generally accepted,
to the present time.   That the present philosophical
and progressive  spirit will still  continue to advance
and ennoble our science, we cannot entertain a doubt. 
EVERY  ONE A DEBTOR TO  HIS PROFESSION.   81
                  PART  III.

THE CLAIMS  OF MEDICAL SCIENCE UPON-MEDICAL MEN.

  And, finally, the  question  occurs, what  are the
claims of our science upon us as medical men ?
  This  question vwould  be answered very differently
by different members of our profession, since  they
cherish very different kinds of attachment to science,
as is expressed by a German poet:

             " To some she is a goddess great;
                To some a milch cow of the field:
              Their business still to calculate
                The butter she will yield."

  But our science has  claims upon us all alike  ; and
I may indicate  the manner in  which we should
respond to  them, in the words of the  author of the
" Novum Organum : " "I hold every man a debtor to
his  profession ; from the which, as men do seek and
receive countenance and profit, so ought they of duty
to endeavor themselves to be a help  and an  orna-
ment thereto."   It is often repeated that ours is a
noble  science  ; then we can become an " ornament
thereto " only so far as we are individually  scientific
and noble  men.   But we maybe a "help" to our
science in  two ways ; 1,  by our own  labors, and 2
by encouraging the labors of others.
                         6 
82
ANNIVERSARY DISCOURSE.
    How improve our  science  by our own labors.

   I. There are three  principal methods of improv-
ing our science by our own labors : 1, by ascertaining
and correcting existing errors ; 2,  by collecting and
arranging  established facts  in a  scientific form, in
monographs, treatises,  etc. ; and  3,  by making new
additions to it, or actual discoveries.
   1. In order  to  ascertain  and to correct  existing
errors, it is necessary to question  and  reexamine all
ancient  opinions.  We  have  seen that men  often
continue " acquiescent in errors so  baseless, that they
vanish immediately they are challenged."  We  must
then challenge old opinions.  I do not inculcate skep-
ticism ; that is usually the offspring of ignorance.   I
bespeak that rational and temperate doubt, which an
acquaintance with the history and development  of all
science  cannot fail to cherish.  "  He who seeks for
truth,"  says Descartes, "must, once in his life, doubt
of all he believes."  I would encourage the habit of
scrutinizing the  doctrines and opinions of others ;
and, above all,  of  forming our own opinions,  upon
data which we possess in common with them ; in a
word,  of being  " Nullius addictus jurare in verba
magistri."  The habit  of  thinking  for ourselves may
seem  to imply that  of observing for ourselves  ; for
we have seen that in the formation of science, sense
and  reason—observation  and  deduction—have   a
mutual need of each other.  But we are to remember
the difficulty of observing correctly ; and that while
" the  knowledge of the senses is the best of  know- 
         INDEPENDENT THINKERS ARE RARE.       83

ledge, delusions  of the senses are the worst of delu-
sions." *   Each,  therefore,  should ask  himself if he
has t"he qualifications for a good observer, and the
leisure for making observations ; and, if not, he may
rely on  others for  facts, and  restrict himself to the
interpretation of them, as we have seen was the case
with Harvey and Newton.  In respect to independ-
ence of opinions, it will,  however, always be true of
the vast  majority of even  educated  minds, as in the
time of the  author of the " Praise  of Knowledge."
'' They learn nothing at the universities but to believe.
They are like a burdened ship, they never move, but
by the wind of other men's breath, and have no oars
of their  own to  steer withal!"  We wonder  at the
poverty and servility  of the human mind in the mid-
dle ages.  But  the number is comparatively very
small in every age, of those who, thinking and  rea-
soning  independently, advance their  science,  and
compel the rest to follow, though with lagging and
unequal steps.   Without the independent thought of
Vesalius, Caasalpinus,  and Harvey, the circulation of
the blood might have remained undiscovered  to the
present time.  There are  now many important  sub-
jects in the various departments of our science which
require to be investigated entirely de novo.   Diges-
tion is one of them, as we have seen.  And none
should  be deterred  by  their  obscurity,  from the
expression of their well-formed  opinions.   Every
man  is obscure  in science  till he makes himself
otherwise ; and  young  men have  ever done more
* Dr. Latham. 
84
ANNIVERSARY DISCOURSE.
for science than those far advanced.  Vesalius pub-
lished  his  great  work on  anatomy when twenty-
nine years  of age ; Andral published his on Patholo-
gical Anatomy when but twenty-seven years of age ;
and Bichat had completed all his immense labor at
the early age of thirty years.
   2. After reexamination of  the received facts and
principles of our science, and the rejection of such as
are found to be false or untenable, we may contribute
much to its future advancement by others, or by our-
selves, by collecting the established facts and princi-
ples, and arranging them in a systematic order in the
form of a compendium, a monograph,  or a treatise on
the particular  subject or  department concerned.
Thus  the labor of acquiring that department,  up  to
the present time, is vastly abridged ; and the student,
and even the practitioner who has but  little leisure,
can gain that amount  of knowledge which is indis-
pensable, in  no other way.   The  compendium, or
treatise, however, affords only a panoramic  view,  as
it were, of  the particular department of science ; the
details must  be subsequently sought in the mono-
graphs on the particular topics it includes.
   3. To those who would advance our science by actual
discoveries, whether of facts or principles, the follow-
ing considerations are of importance.
   First. Those who would become discoverers, should
evidently commence their preparation  by accurately
acquiring all that  is  already known in the depart-
ment they  propose to  advance.  Many an individual
who prides himself upon his talents for original inves-
tigation, has found, after arriving with much labor at 
          DISCOVERIES ARE OF TWO KINDS.        85

a particular result, that another  had already done,
and  perhaps  much better,  precisely what  he had
accomplished.  A vast amount of intellectual power
is  absolutely thrown  away, from  this kind of igno-
rance.  When we have acquired all that others have
achieved,  or have  learned where, why, and  in what
way,  others have failed, then, and only then, may we
exert  our own  powers with the best  prospect of
success.
   Secondly. If we would make additions to our science,
we should have a definite idea of the precise object
we wish to accomplish.  Thus alone can we  propose
a  definite question to the mind ; which is the only
way to achieve a  definite result.  For  " rightly to
state  a problem, is no inconsiderable step towards its
solution."                                 -.  .?,.-• *

       Discoveries are of two distinct classes.

   Thirdly. The future discoverer in our science must
remember at  the  outset,  that  in respect  to  the
methods  for  achieving  them, discoveries  may be
arranged  in  two  classes :  the observational  and the
rational.  The first are discoveries of facts alone, and
are made by the use of the senses merely—by observa-
tion ; the second  are discoveries of principles or laws,
and are made by the  use of  the reason, by deduction,
and are afterwards verified by facts.   In  the first, the
discoverer merely  sees; in  the  second,  he foresees.
The   discovery of a continent, an island, a comet, a
new  chemical element or  compound, of a muscle,
or of any  anatomical or  histological element, are
instances  of the  first  class  of discoveries ; those of 
86
ANNIVERSARY DISCOURSE.
Harvey,  Kepler,  Newton,  Dalton,  and Hall,  belong
to the second class.  The former may sometimes
be made even accidentally, or  by one  of inferior
intellectual capacity, if favorably situated ; the latter
demand  a philosophical  and logical mind of a high
order, with habits of intense and continuous thought.
This continent was actually discovered by Columbus
because it lay in his course while he was intending to
go  to  Asia,  and  really  supposed  he  was doing  so.
Besides,  the discovery was really made by the sailor
at the mast-head of Columbus'  ship  ; but then  its
commander had placed him there to keep a look-out
for land.  Not all facts  can, however, be discovered
by  the senses alone ; and when the  reason is also
required to ascertain them, they belong to the second
class.  Such  is the  fact that the earth moves round
the sun,  and that  its orbit is elliptical, and not circu-
lar.  I do no injustice, therefore, in adding that the
authors of the first class of discoveries—those by mere
observation—are  mere finders ; while the others are
the true discoverers.   Both are equally seekers after
truth,  except in the instances in which facts are acci-
dentally ascertained ; and both must institute definite
investigations in  order  to accomplish their  object.
But those who seek for facts  alone have ever made
the greatest  parade respecting their  investigations ;
and this  too, generally, whether they lead  to any posi-
tive result or not.  So  that now-a-days it seems to
be by some accounted a greater glory to be said to be
engaged in original investigations, though they never
report a new fact discovered, than to have actually
discovered a  new law in  science. 
"original investigations."          87
   And here I will devote a few lines of criticism to
this phrase, " original investigations," so often used
in a somewhat towering sense at the present time, by
those who profess to be engaged in them.  Investiga-
tion means "the  action, or  process,  of searching
minutely for truth, facts, or principles"  (Webster).
Of course, its methods are various, but they all imply
the use of the senses alone, as in the  search for facts,
and sometimes for truths ; or  of the reason more
especially; or  of both combined. The most facile
method  is that which  exercises the senses  alone,
and this everybody can profess  at least, though very
few will achieve discoveries even of facts.   On the
other  hand, but few can exert the combined influ-
ences  of the senses and  the  understanding  in their
investigations.   The other party will, therefore, from
their number,  raise the  greatest clamor  respecting
their own labors ; while,  at the  same  time, the mind
of larger grasp and rational tendencies, usually waits
till it can modestly state what it has  done,  instead of
proclaiming what  it  is  doing.  Besides,  the mere
seekers after facts, can display to the uninitiated their
instruments of brass and of glass, packed in rosewood
cases,  or arrayed upon  the walls of a laboratory;
while the rational discoverer carries the main part of
his apparatus  for  discovery  entirely out of sight,
within his cranium.  But the word  '' original" has,
also, to some, a sort of talismanic and exclusive sig-
nification, as  applied  to  their own scientific labors.
Indeed,  some  gentlemen seem to attach far more
importance to the originality,  than to the  investiga-
tions themselves, or their results.   To be engaged in 
88
anniversary discourse.
"original investigations," is, forsooth, the plenum of
their scientific aspirations; though their labors prove
as barren  as  the observations of the  eastern fakir,
who spends his days  in the  contemplation of his
omphalos.  Original means "first in order; preceding
all others."  But whether mere priority confers any
special merit upon our investigations,  depends upon
their objects, their methods,  and,  above  all,  upon
their results.  The greenhorn who should attempt to
ascertain  the dimensions of the  man in the moon
through a telescope  of  his own construction, would,
so far as is recorded, be engaged in an original inves-
tigation.   But,  should  any especial  renown accrue
therefrom?  The  alchemists   made  many original
investigations in search of the philosopher's  stone,
and  the  universal solvent;  and they also sometimes
boasted of their labors.  But all others, at the time,
and  even since,  have derided them as visionary, ridi-
culous, and without results.   He who first institutes a
legitimate scientific investigation,  deserves  all com-
mendation and encouragement, that he  may attain to
some important result;  and  when  the  latter  is
achieved, he may expect the  praise  of all scientific
men ; but  it is sufficiently out of character for the
true scholar to  boast  of  a thing, even when  it is
already done.  The  less, therefore, we  think  of the
originality, and the more of the objects of our inves-
tigations, and their results, the better is the prospect
of advancing our science.  The mere seekers for facts
have, however, no exclusive claim to originality.  To
say that the investigations of Harvey were not as ori-
ginal as those of Fabricius, is simply absurd. 
FALSE ORIGINALITY.             89
            Originality falsely so called.

   There are, however, two  very cheap methods of
 acquiring a reputation for originality to which I may
 here  allude.   The  first  consists in the  repetition,
 under  some  modification of circumstances,  of the
 observations of others, and tacitly allowing or actually
 aiding  them  to  pass  for " original investigations."
 The other is adopted generally by those who boast of
 writing " original works" in the  various departments
 of our  science.   Of course, two persons may make
 the same investigations, neither being aware that an-
 other had ever made them ; and in  such a case, both
 are entitled to  the merit of originality, if  that is of
 any account, though he  only who preceded in point
 of time will retain  it.   But I am  now  alluding to
 what is at best but a mere imitation, and often a very
 lame  one,  of the experiments of others.   On the
 other hand,  upon most of the  departments of our
 science, it is folly to pretend, at the present day, to
 write an  original work.   To assume  that the facts
 and principles contained in such a work have all been
 obtained first, or originally, by the author, is assuming
 that they were before unknown; and therefore assert-
 ing that the work  is one  upon an  entirely new
 department  of science.   An original work, therefore,
 at the  present day, on  descriptive  anatomy,  phy-
 siology, pathology, or  either of the  practical depart-
 ments of medicine, is an impossibility. A new work on
 either of these departments may  contain new facts or
principles acquired by the author's original investiga- 
90
ANNIVERSARY DISCOURSE.
tions, perhaps ; or it may possess originality of plan
or object, or arrangement, or in the manner of pre-
senting the various facts and principles to the reader's
mind.   Indeed,  if it is not original—"the  first  in
order,  preceding  all  others"—in  some  of  these
respects, it should never see the light, and will be
very certain not long to enjoy it.  Yet such a work is
not, as a whole and  unqualifiedly, an original  work ;
or, if it be still asserted to be such, then a treatise or
a compendium may be as deserving of this distinction
as a monograph or an essay.  A truly original scien-
tific  work is  one in  which original  investigations,
ideas, or principles—or all these together—predomi-
nate.   Tested thus,  it is true that original works are
very  rare.   There  is  much writing with  compara-
tively little new matter.  Most that is done is '' ver-
tiginous, or in the way of perpetual rotation;" * and
most  authors who profess  the most  originality,  fill
their  works with  egotism  instead.   But original
works, as just defined, are by no means indispensable
to the advancement  of science ; while new works are
so, in order to  incorporate  into it, in a permanent
form, the new facts and truths which are successively
ascertained.   On the  other hand,  also, an original
work, like original investigations, as has been shown,
may be  entirely barren and useless.  The question,
then,  suggested  by the announcement of  each new
scientific work should be not,  "is it original ?" but "is
it truly useful ?"   i. e. will it conduce more than its
predecessors to the advancement of science ?

                 * De Augmentis, p. 1. 
    PERSEVERANCE NECESSARY TO TnE DISCOVERER.  91


      Moral qualities required in  a discoverer.

  Fourthly.  Certain moral elements  are also  de-
manded in the future discoverer of scientific truth. I
first mention faith, as opposed to skepticism and infi-
delity.  He must constantly remember that
            " There is more in heaven and earth
             Than is dreamt of in his philosophy,"

or that of his times.  And a  higher faith is a very
essential aid ; and hence, as Prof. Whewell has re-
marked,  "discoverers  in science  have generally had
a belief in an intelligent Creator." *
  Fifthly.  Another important moral  element  is a
patient perseveranee.  Habits of intense and continu-
ous thought are indispensable to  the real or rational
discoveries, and hence they are not rapidly or  easily
made.  When Newton was asked how he made his
discoveries, he  replied,  " by constantly thinking of
them."   He also thought and labored for seventeen
years after his discovery of the law of gravity, before
it  could  be said to be demonstrated and completed.
Harvey's work cost him a labor of twenty-six years;
and Marshall  Hall states that he devoted to his dis-
covery  of  the  reflex  or  diastaltic  function of  the
spinal cord, not less than 25,000  hours of intense
thought, and as many more to its applications to diag-
nosis  and pathology.  Hence  it  is that the greatest
discoverers  have generally been men of the  highest
intellectual  endowments, and of extensive  general, as
* Vol. iii. p. 477. 
92
ANNIVERSARY DISCOURSE.
well as professional,  acquirements.  Harvey, Newton,
Haller, Jenner, and  Sir Chas. Bell are examples.
  Finally.  Courage  and independence  are  invaluable
aids.  He who would hope to make any real  discov-
ery in our science must, at all events, have no dread
of being  called a  theorist.   We have  seen that a
rational discovery is  necessarily preceded by a theory,
and which, on being verified, becomes the  discovery
itself.  Newton's discovery of the law of gravity was
a mere theory, based on Kepler's law, till it was veri-
fied  by facts applied by Newton's intellect; Kepler's
discoveries  were also,  till  verified  by him, mere
theories,  based  on  Copernicus's discovery, that the
sun  is the centre  of the solar  system ; and Coper-
nicus's discovery,  too, was  in like manner  at  first
a theory.   It is, of  course, only rarely that a theory
leads to  a discovery ; but it is  always true  that a
rational discovery is first  shadowed forth  in the dis-
coverer's mind as a mere theory, and which he subse-
quently tests, and   verifies  if  true.    The  greatest
philosophers and discoverers have therefore  always
been theorizers ; and it would be interesting to know
how many diverse theories had been adopted  for the
time, and  afterwards rejected,  by Harvey and by
Newton, before  the  true theory, as  verified in the
discovery, presented itself  to their minds.   Kepler's
account of his own experience in this respect, consti-
tutes one of the most interesting chapters in the  his-
tory of science.   It has very rarely been the  case
that the true theory is the first  suggested to the dis-
coverer's mind; or if so, false theories have  almost
invariably  been  previously   suggested  by  others. 
WHO IS  THE ACTUAL  DISCOVERER?
93
Hence, almost  all discoveries are preceded by, and
associated with, less clear  and definite speculations,
as Newton's was by Kepler's  fiction of magnetic
virtue ;  and sometimes, when  the  discovery is  at
length actually made, it may be  very doubtful who is
really entitled  to  the merit of being the actual dis-
coverer—the preceding theories having approached so
nearly to, or having actually suggested, the true one.
That he who proves or verifies the theory is the real
discoverer  is, however, the  only  rule  to decide such
cases.  Hence  it  is very  common to  remark  that
others were on the way to  the discovery, though they
did not make  it.  This was the case with Dalton's
law of definite proportions.   Hence,  also,  two  or
more persons, at a distance  from  each other, may actu-
ally make the  same  discovery,  neither being aware
of the labors of the other.   " II  est tout simple," says
Dutrochet, " que l'on se rencontre, dans le chemin de
la science."  Hence, also,  we may be on the thres-
hold of a discovery, without being aware of it.   Let
no one, therefore, fear to be called a theorizer.   His
theory may suggest a discovery  to another, if not to
himself.   Only let him  know that he is theorizing,
and not mistake his theories for actual discoveries—
which they  can never be till verified.
   In theorizing we  reason from ideas, not facts ; or,
in other words, we adopt the  deductive, and not the
inductive  process.   I  have already shown that some
of the greatest discoveries—the real discoveries as
opposed  to  mere  findings—even in the physical  sci-
ences, and more still in our  own science, have been the
result far more of deduction than of induction.  And 
94
ANNIVERSARY DISCOURSE.
 this will probably be true to a still greater extent,
 we have seen, as science  advances in the future.   I
 have, therefore, insisted  on  deduction, as a not less
 important  method,  henceforth,  of progress in our
 science ; though induction is by no means to be laid
 aside.   We are  evidently now in an age of transition.
 " Changes affecting the whole condition of mankind
 are  occurring more rapidly, as well as more exten-
 sively, than at  any other prior time in human his-
 tory ;"  the grand agent in this change being the
 wonderful   progress,  more  especially, of  physical
 science, and particularly of mechanics and  electricity,
 and its modifications.   " Inductions of a higher grade
 have been  reached,  and generalizations attained,
 going far beyond those subordinate laws in which
 science was formerly satisfied to rest." *  And all this
 has  been accomplished mostly by  deduction.  Our
 own science  is  also  responding to  this progressive
 impulse of. the  physical sciences ; and the  more  it
 advances, the  greater will be the need of the tran-
 scendental  views furnished by the deductive method.
 Great has been  the progress of the last 150 years,
 but  what is already  known is "but  a speck com-
 pared with what  will be added."  Medical science
 will  be  complete only when "the  structure and the
 functions of all  the tissues and organs in the body
 shall be understood, and all the counteracting agents
to all abnormal structures and diseased functions, are
 ascertained ;"  and the still  unfulfilled  objects of
science will be achieved, we believe, more by the rea-
* Edinburgh Review, ut sup. 
DEDUCTION  VINDICATED.
95
son than the senses—more by deduction  than by
induction.   " In that field which  we  and our  pos-
terity have yet to traverse," says a profound writer,
" I firmly believe that the imagination will effect
quite as  much  as the understanding ;"  this faculty
suggesting the ideas on which the understanding may
reason.  And  "we have every reason  to believe,
that when the human mind once  steadily combines
the whole of its forces, it will be more  than a match
for the difficulties presented by the external world."
   But the preceding qualifications for  making scien-
tific discoveries imply labor, and of course time.  Can
a physician command the time required ?  That will
depend  upon his habits.  If he fully appreciates the
value of minutes, he may do so ; otherwise not.
      " Sands make the mountain—moments make the year."

   I have often  thought that the practising physician,
 to accomplish his duty to his profession,  must realize
 in his own busy life, the stanza in  Faust:
                 " Geburt und Grab,
                  Ein ewiges Meer,
                  Ein wechselnd Weben,
                  Ein gltmend Leben." *

   To accomplish much in aid of science, we must
 possess some of the  industry of John Hunter, who,
 for thirty years in succession, rose before daylight to
 pursue  his favorite labors.  We must even somewhat
                * " Birth and the grave—
                  An eternal ocean,
                   A changing motion—
                   A glowing life." 
96
ANNIVERSARY DISCOURSE.
resemble the German philosopher, who  had labored
sixteen  hours daily, for many years,  except on the
day of his marriage,  when he lost two hours ; but
who rose two hours earlier than usual the next morn-
ing, and thus regained the time he had lost.
  II.  The ways in which  we may directly aid  and
encourage  the  efforts  of  others,  to advance  our
science, are  numerous,  and  need not be  specified.

           The Hinderers of our  Science.

But there is always a class of men  in our profession,
who not  only  refuse to aid, but who  consistently
oppose,  every effort at improvement, as mere imper-
tinence, if made by a young man, or as mere folly or
intentional humbug, if by one more advanced in life.
Yet most discoveries have been  made  by men still
young.   Newton was but  twenty-three, Copernicus
thirty-three, Sir Charles Bell  thirty-three,  Fabricius
thirty-seven,  Kepler thirty-eight,  and  Harvey and
M. Hall forty-one, when their respective discoveries
were  made.  Never  making an observation nor a
deduction themselves, these persons seem to assume
that nobody else  has the right or the capacity to do
either, and receive what is suggested in good faith,
and after much labor and anxious thought,  with sus-
picion and unkindness.   I am bound to  say that the
number of such  in  our profession  is very  small ;
though their  opposition to all true progress (which
they call innovation) is sometimes so unscrupulous
and energetic as  to counterbalance, for a time, their
fewness in numbers,  and  much to  discourage the 
          THE HINDERERS  OF OUR SCIENCE.        97

actual  discoverer.   These gentlemen, it is, who in
their successive generations, have uniformly taken the
same position in respect to all  proposed discoveries
in our  science ; asserting  first, that it is no  discovery
at all;  secondly, that somebody made it long ago ;
and thirdly,  either that  it is of no account,  or  is
fraught with  only mischief to mankind.  They adopt
the policy of the dog in the manger; and like him
also, in respect to all scientific  improvement, starve
themselves.
   But, on the other hand, discoverers themselves do
not always remember that they must, from the very
nature  of their position as,discoverers, be in advance
of  their  age,  and  that,  therefore, some time  is
required to elevate their contemporaries to  their own
point of view.   Discoverers, therefore, sometimes
lose their temper,  or in their  enthusiasm perhaps
seem overbearing to others; who cannot possibly see
precisely and as  clearly  as they  do, because they
have not traversed the  same  ground with them.
A discoverer must expect, as  a matter of  course, to
meet for a time with comparative indifference, if not
actual  opposition, for  the reasons just mentioned;
and few, therefore, have lived to see  their discoveries
generally accepted, however important the latter may
have been.
   Thus in our scientific relations even,  there is need
of mutual forbearance ;  but the  true  scholar  wel-
comes every attempt at improvement, from whatever
source  ; remembering that by encouraging the spirit
of investigation and progress, he indirectly contri-
butes to that consummation which  is  the scholar's
                            7 
98
ANNIVERSARY DISCOURSE.
highest aspiration—that perfect state of our science
which  has been defined.   Nor is he discouraged by
failures; for with  Goodwin  he believes, that the
"human man can  conceive nothing which it cannot
finally execute."

 Fellows of the New York Academy of Medicine :

  To advance our science and art, is the main object
of this association  ; though  it would at the  same
time, also maintain the dignity and honor of our pro-
fession.  We have  here  no  superstitious rites,  or
cabalistic mysteries, for we have a  science now ; we
have  no plans  for self-aggrandizement ; we  only
labor to make  ourselves and our  profession wiser,
and  better qualified to relieve the  sufferings of our
fellow-beings.  But in the fulfillment of its objects, no
external influences, no   considerations  which  mix
themselves  up   with  the diverse  motives  and the
opposing interests  of  daily life, must  be allowed  to
obtrude themselves here ; and if it become necessary
to exert its disciplinary powers, it is better to err  on
the side of clemency than of undue severity.  Science
knows no party, clique, or  school;  but  then she is
dignified, liberal, charitable, magnanimous, and not
narrow-minded  and vindictive.  She cordially ex-
tends the hand of fellowship to all ranks and conditions
alike ; conducting  the poor  medical student,  pre-.
viously a laboring blacksmith, to  the  professorial
chair of the erudite Velpeau ; and out of four penni-
 less boys, the poorest of the poor, moulding a Galileo,
 a Kepler, a Davy, and a Farraday. 
CONCLUSION.
99
  But  when dissension enters, science takes  her
leave ;  and would that  every member of my pro-
fession realized the ennobling influence upon himself
of the spirit of kindness and courtesy towards his pro-
fessional brethren.  Like mercy—

      " Its quality is not strained,
      It falleth like the gentle rain from Heaven
      Upon the place below. It is twice bless'd—
      It blesses him that gives and him that takes."

  Let us then remember we are men—we are brothers.
Much has  this  Academy already done to  advance
our  science, much in  diffusing a spirit of kindness
and liberality among its fellows.   It now only waits
for  a local habitation,  for an edifice  commensurate
in beauty  and  capacity with  the  taste, the libera-
lity,  and the wealth of this great city,  to enable it to
extend  its benefits  to  our  profession  throughout
every part of our land. 
APPENDIX.
                 NOTE I.—Page 40.

  Of the different branches of medical science, ana-
tomy first took a systematized form.  Although the
Greeks transplanted the knowledge of Egypt to their
own soil, Homer  nowhere  distinguishes the muscles
from other parts, nor  does Hippocrates  even.  The
latter also  includes under  the  same term (vevpov or
ravoc), the  nerves, the tendons, and the ligaments,
and  also says these vevpa  contract  the  limbs.  He
did not discriminate between the veins and arteries,
calling them both <p\e{$ec.   Aristotle says, nearly one
hundred  and fifty years afterwards,  that the  vevpa
originate from the  heart, connect  the  bones,  and
surround the joints.  He therefore means the liga-
ments, and not the nerves, as some have supposed.
He also traced the veins to the heart.   Herophilus,
of Alexandria (b.c. 300), taught that the nerves are
the channels of perception  ; but he also included the
tendons under this term. There was now a stationary
period till  after the victories of Lucullus and Pom-
peius in  Greece  and  Asia Minor, and  the  rush  of
learned   men  from  these  countries  to  Rome,  to
exchange their art  and science for  Roman wealth.
                                           100 
APPENDIX.
101
Galen, who was born about 500 years after Aristotle,
speaks of the caste  of dissectors,  who began when
children, and who neither needed nor possessed any
books on anatomy, though books were needed in his
time.  The muscles and the structure of the bones had
ere now been recognized, but nothing  definite was
known of the nerves ; and Galen thought every muscle
consists of  a bundle of nerves  and sinews.  Yet  he
showed the necessity of the  nerves, and the  origin
of the voluntary motor apparatus from the  brain,
which is also the centre of the soul; against Gryppus,
who maintained that the heart is the seat of sensa-
tion and emotion.   Galen, however, still believed
that the heart is  the seat of courage and anger, and
the liver the seat of love.  He held that the veins
originate in the liver,  and the arteries in the heart;
and that there is an  opening through the  septum
between the right and the left ventricle, and which
was believed for 1340 years  afterwards.  He left a
treatise on the Anatomy of the Nerves ; but he dis-
sected only seven pairs of encephalic nerves, begin-
ning  with  the optic, which he called the first pair.
He spoke  of his anatomical work  "as a rehgious
hymn in honor of the Creator."
   Galen died in the  year 203, and the  dark ages,
so  called, now ensuing, no additions were made to
anatomy for the  long  space of one thousand years,
during which time the  authority in anatomy of Galen
was supreme.
   Mondini,  Professor  at  Bologna,  (see  page 42),
merely revived anatomy,  without essentially advanc-
ing it.   Like all  the rest, for the preceding thousand 
102
APPENDIX.
years, he also swore by Galen; and Galen's work, with
some  descriptions  of Mondini, was  the textbook  for
more than two hundred years.  Vesalius found Galen's
division of the encephalic nerves into seven pairs to
be incomplete.  He also accused Galen of other mis-
takes, and of having dissected the  lower animals only.
He should be regarded as the founder of modern human
anatomy.  The figures of his work, " De humanis Cor-
poris fabrica," were designed by Titian.   Eustachius,
and Fallopius, are  also grouped with him by Cuvier.
  Not till  about 1660 were nine encephalic nerves
recognized, by Willis, who added the  olfactory and
the spinal accessory to the seven pairs of Galen ; and
though  the  French nomenclature has long since ad-
mitted twelve pairs, all English writers still  persist,
on the  obsolete authority of  their countryman, in
including  the  twelve within the  limits assigned  by
Willis.  The latter also described the corpora pyrami-
dalia, Santorini having noticed their decussation, and
carefully examined the various ganglia.  The distinc-
tion,  however, between the  ganglionic system  of
nerves  and the cerebro-spinal, was  first made  by
Bichat about the year 1800.
  Inasmuch as  human dissections  were not legal-
ized among any of the ancient nations,  the internal
structure of the lower animals alone could be studied,
and that  of man  be inferred by analogy.  Indeed,
Herophilus is said to have been the first by whom
human  bodies were  dissected  (about B.C. 300); per-
mission having been  given him by Ptolemy to open
and inspect the bodies of living  criminals, for ana-
tomical and physiological purposes. 
APPENDIX.
103
  We  must, however,  by no means conclude that
human  bodies  were  not at all dissected,  because
human  dissections were  forbidden in ancient  times.
Medical men, doubtless,  sometimes  thought then as
did Abernethy, that "if the dead are not mangled,
the living will be ;" and qualified  themselves for surgi-
pal operations, independently of legal sanction, as was
not uncommon in this country thirty or forty years
ago.

           NOTE II.--PHYSIOLOGY (p. 65).

  Some notions of function  of the various parts and
organs of the body must have  been coeval with the
first observations of the organs themselves.   We may
therefore say of physiology, as of the art of medicine,
that  in the form  of proverbs, maxims, aphorisms, or
crude notions of more or less of the healthy functions,
it has always existed among all nations. No attempt
was however made to reduce physiology to a scien-
tific form till very recently.   Some suppose it a very
easy thing to ascertain  the  function of a  part, after
examining the  structure ; but, with few exceptions,
nothing is farther from the truth. Physiology, there-
fore, does not flow by mere  inference from anatomy ;
and therefore discoveries in  physiology have always
followed those in anatomy, " longo intervallo."   The
ancient anatomists knew  of the arteries  and the
veins ; but Hippocrates  did not know the function of
either,  and called  them both  by  the same  name.
Afterwards it  was held that the  arteries  hold  air
only,  and the  veins  blood.   Herophilus (300 B.C.) 
104
APPENDIX.
taught that the nerves are the channels of percep-
tion ; but then he included the  ligaments also under
the term nerve, and therefore could not  have known
their  structure.  Fabricius discovered the valves  of
the veins ; but Harvey discovered  their function  45
years afterwards.   The  anterior and the  posterior
roots  of the spinal nerves were known to Galen  ;
but their functions  were not ascertained  till about
fifty years ago (1807) by  Sir  Charles Bell.   The
structure of the various  parts of the brain has been
laboriously studied; but who yet knows the functions
of each of these particular portions ?
   And this follows from the very nature of physio-
logical science,  as compared with anatomy.   Descrip-
tive  anatomy is essentially a science of observation ;
physiology is a science of observation and deduction,
as has been shown (p. 66). 
 
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