ON THE

METHODS OF ACaUIPJNG KNOWLEDGE.
                 AN


     INTRODUCTORY LECTURE

             TO THE COURSE OF


THE INSTITUTES OF MEDICINE,

           FOR THE SESSION 1838-39)

               DELIVERED IN THB


    UNIVERSITY OF PENNSYLVANIA,

           NOVEMBER 6,  1838.
BY SAMUEL JACKSON, M.D.
     Philadelphia:
3. G. AUNER, 331 MARKET STREET.
PRINTED BY L. R. BAILEY, 26 NORTH FIFTH STREET.
             18 38. 
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St  «? 
-*—~1   ,    CORRESPONDENCE.,  u


                                                      >
         Hi               Philadelphia, November 21st, 1838.
 Professor  Samuel Jackson,
   Dear Sir.—We, the undersigned, a Committee appointed in be-
 half of the Medical Class of the University of Pennsylvania, to request
 of you for publication, a copy of your highly appropriate and eloquent
 Introductory Lecture, take great pleasure in the performance of this
 trust.
   Hoping that you will comply with our request, we are, with sen-
 timents of esteem,
                        Respectfully, your's,
                                        H.  RlDGELY,
                                        William A. Hill,
                                        Thomas Sappington,
                                        B.  Bardwell,
                                        A.  W. Read,
                                        Thomas J. P. Stokes,
                                        Lucas Gee.
                          Philadelphia, December 1st, 1838.
To Messrs. H. Ridgely, William A. Hill, Thomas Sappington,
  B. Bardwell, A. W. Read, Thomas J. P. Stokes, Lucas Gee:
   Gentlemen.—I have delayed an answer to  your polite  note of
the 21st, requesting, on the part of the Medical Class, my Introduc-
tory Lecture for publication, from an indisposition to part with the
present Lecture, but rather to retain it  as a standing Introductory,
to which the subject appears to me to be appropriate. It is difficult,
I find, to refuse the request of so respectable a body of gentlemen as
the present Class of the University. I have finally decided to place
it at their disposal.
  I beg you to convey to the  Class my most  respectful sentiments,
and accept  for yourselves the  esteem of
                                 Your's, <fcc,
                                    Samuel Jackson, M.  D. 
L 
INTRODUCTORY LECTURE.
Gentlemen—
  Uncertainty is a painful condition of the mind.  While it
prevails, there can be no decision in conduct, or perseverance
in action.  "Vacillation and doubt give a consciousness of weak-
ness and  inferiority.   The mind finds a refuge from this state
in fixed convictions,  however  acquired, or in the adoption of
positive ideas.  They are to the operations of the understanding,
what a firm footing is to the movements of the body.
  This painfulness of  mental  suspense  is  experienced  in  the
feverish anxiety and irritation felt, when, in journeying in an
unknown quarter, the road unexpectedly divides  into different
routes, without an indication as to the direction leading to the
place, where shelter and repose, are to be found.
  The confidence and energy inspired by unshaken convictions,
though they may be narrow and erroneous, are to be preferred
to the palsied feebleness resulting from vacuity of ideas, and in-
capacity to form settled opinions.   The mischiefs of  error do
not surpass those of indecision and delay;  while from force of
character  we  may anticipate the  perception and adoption of
truth, a circumstance it would be hopeless to look for from im-
becility.  A  single idea,  enthusiastically entertained  and con-
stantly acted on, has  made a hero, and governed mankind.  A
cyclopaedia of knowledge, stored  in  the irTemory, without the
temperament to enforce  convictions, has  not saved from the
stigma of folly.
   Every individual, with a species of mental instinct, is led to
the formation of positive determinations in the kind of know- 
                          (   «  )
ledge he does possess.   He endeavours to obtain a power and
fixedness of purpose in the transactions of life; he avoids  the
necessity of endless deliberation,  by acquiring  positive ideas
and absolute convictions, which, to him, will be invariable rules
and guides of conduct.
   The results of this  action of the mind, are as  various and
diversified  as  the  innate  differences  of individuals.  For  the
most part, the ideas and knowledge that compose our convic-
tions, are formed into circles of varying  dimensions, regulated
by our intellectual  and moral capabilities, and opportunities of
information.
   In the great mass of mankind, probably inseparable from
the present social condition, the circle is narrow  and confined.
Once formed, it is too often hermetically closed.   New ideas
cannot be admitted; no new fact can be recognised; no demon-
stration be listened to.   This  circle of ideas is  to them,  the
extent of God's universe.  Such  individuals possess firm convic-
tions ; they are harrassed by no doubts;  they are pertinacious
in their  opinions; fanatical, dogmatic, and contentious.   They
exhibit what Carlyle calls,  " the completeness of  limited men."
   Another class, with higher endowments and superior oppor-
tunities, possesses expanded circles, embracing extended and va-
ried knowledge, capable of enlarging for the admission  of new
ideas and truths, unfolded with the progress of science.  Such
men are liberal in their opinions; tolerant of opposition;  they
labour  to advance civilization^and social happiness; they are
the recipients  and  teachers of knowledge.
   To a chosen few of our race, is given the great privilege of
an intellectual range, confined by no artificial  limits.   Their
region  is the empyrean  of  truth.  With  struggles of deep
thought they penetrate to the truths hidden from  eternity in the
womb of time, waiting their birth-time.  They bring them forth,
and their influence is felt in the destinies of  mankind.  These
men are the pillars of fire, leading the march of science, and
progress of knowledge,  advancing  into the dark, unexplored
regions of the unknown.
   The  methods by which ideas are acquired, opinions and con- 
(  7  )
victions are formed, are various.  They differ  materially, and,
as they exercise a most controlling power over the justness of
our thoughts, and the genuineness of our knowledge, it will be
proper to examine these operations of the mind, as important in
regulating the numerous subjects of inquiry, that will occupy
us in the ensuing course of lectures.
   I. The first of these methods is authority, or the confidence
reposed in the truth of the convictions, opinions, or facts related
by another.  For a knowledge of the past, the absent, or what
we cannot ourselves perform, we must rely on authority.  The
influence of authority  is derived from that action of the mind
denominated faith, the expression of the innate sense of truth,
existing within ourselves.  We feel a consciousness, that with-
out some powerful motive of interest to corrupt and sway our
minds, it is impossible  we  should commit deliberate falsehood;
or, that from mere wantonness of purpose, we should invent or
father a lie, certain to  be detected and exposed, and have in-
famy stamped  on  our  name.   What we are conscious of in
ourselves,  we believe to exist in others.   When, then, we find
individuals publishing  and proclaiming as  the result of their
own  personal  knowledge, or  of their  investigations,  certain
facts, events, or opinions; if there be  nothing  contrary to our
own or universal experience; no gross violation of probability,
we adopt  their convictions,  and rely upon  them as  authority
for the truth of  what we have not the means, opportunity, or
inclination to observe or to investigate for ourselves.
  Authority may be referred to for opinions or for facts.   In
all the moral sciences—metaphysics,  theology, law—opinions
are the most important  subjects settled by authority.  In  the
physical sciences, facts  are its  chief subjects.   The  physiolo-
gical  sciences place both facts  and opinions under its decision.
  From the necessity of the thing, most of our knowledge must
be based on authority.   The past, that cannot be re-enacted;
the distant that cannot be observed; the difficult, that our means
and capability of observation shut out from our power of direct
knowledge, must be known to us only from authority.  But, as
authority is nothing more than individual convictions, it is liable 
(  8  )
to all  the  fallacies that attend on  human judgments.  Too
much reliance is not to be placed on authority.  It is wholesome
to look on it with a jealous eye; to inquire into its pretensions;
to investigate its decisions; and ascertain the ground on which
they rest.
  Opinions are  arrived at  by a process of reasoning; and,
when authority has reference to opinions, the method of rea-
soning by  which they were formed should be communicated,
that we may judge of its soundness and strength.
  Experiment, observation, investigation establish facts;  and
when they  are to be received on authority, the processes  and
means by which they have  been determined, should be explain-
ed.  They can  then  be verified by repetition, or  their ade-
quacy to sustain the facts  can be appreciated.  A single au-
thority should  seldom be trusted to with unqualified faith.  In
impeaching authority, the question is not one of veracity, but
of capability.  It is not a suspicion of mendacity that  is enter-
tained, but, that the individual may not have  been sufficiently
guarded against  the numerous sources of  deception,  that sur-
round  and embarrass every  subject of investigation.  Very
honestly, may the appearance of truth be  mistaken for  truth
itself.
  When numerous, unconnected authorities, in distant periods
and in different  countries,  by observations and  investigations
original with themselves,  arrive at the  same  conclusions, we
have strong confirmative proof, that the authority is an enunci-
ation of a truth.  It may be received  as such.
  We must not  suffer ourselves to be imposed on  merely by
consonance of authorities, however numerous or respectable,
when they  merely repeat one another, or draw from some com-
mon authority, as an oracular source, which they merely reite-
rate.  That which is false in itself, though repeated by millions
of tongues,  and believed through ages, cannot become  true.
  The authority of Galen gave vogue to doctrines which were
commented on and reproduced in every variety of shape, for
more than a thousand  years, by an immense host of  authors.
Volumes on volumes were written, but they added nothing ori- 
(  9  )
 ginal. There was no exploring of phenomena as existing in na-
 ture; facts were not observed and examined to know them, as
 they are, but, as  they were represented and  explained by the
 oracle. Now, as these doctrines were mere brain-born hypotheses,
 so little force did they acquire  by this host of writers and com-
 mentators, that as soon as they were brought to  face natural
 phenomena and be  contrasted  with  them, though  by a gross
 empiric, they shrunk into insignificance, and vanished into mere
 nothingness. Such must be the end of the false.
  In proportion to the narrowness of ideas, and the limited range
 of knowledge, in  a community, is the reverence felt for autho-
 rity, and the submission to its dictates.  Authority has ruled, and,
 probably, always will continue to rule the world.  Creeds, formu-
 las, phrases, emanating from some authority, in religion, in gov-
 ernment, in politics, in party factions, in social relations, in medi-
 cal and in other sciences, have been the instruments of rule, as
 one mind must ever rule over many. They have been adopted as
 infallible truths, believed with so deep a conviction, as to become
 a part of existence.  Man sooner parts with life, than parts with
 what his mind has  lived  on as its daily food; with what his soul
 has clung to with the strong devotion of eternal truth. It is by
 these  instruments, that the intellectual power  of one mind, for
 good  or for ill, chains  up the intellect of the masses, or impels
 and guides it into action.   Make of it what we may, in every
 body  of  men  brought together, there must be one who is the
 master-spirit, and, he soon, for  the time, becomes the ruler over
 men.  Without the contrivances spoken of, the masses, with no
 other than physical or organic  instinctive motives to action,
 would languish in the deadness of inertia, or, incapable of com-
 mon principles of action, each striving for himself, society be-
 come a
                          " Universal hubbub wild
             Of stunning sounds, and voices all confused,
             Borne through the hollow dark
             With loudest vehemence."
Authority with all its defects, its  liability to  the  propagation
and perpetuity of error, must, then, be the principal source from
which we draw a large portion of our knowledge.
             B 
(  io  )
   The defects pertaining to authority may be counteracted by
extending the sphere of general knowledge, by a cultivation of
the positive sciences, and the disciplining of the mind by the rules
of a severe logic.  No mind, imbued with science based on prin-
ciples, and versed in the spirit of a just philosophy, will ever
regard as authority, any one, who does not explain the grounds
of his convictions; who does not  spread out the proofs of rea-
soning by which they were formed; who does not  sustain his
assertions, by the evidence of demonstration and facts.  Such a
mind can admit of no oracle, with self-intuition,  propounding
principles and facts for implicit belief. Yet, in our time, sects in
religion, politics, and in medicine, have  appeared, and continue
to arise, having  no other origin, than the unsustained and bold
assertions of one man.  The ignorant and the feeble, unable to
question, to canvass, and decide on such pretensions, quail be-
fore them; while it is to  be feared, the interested  and selfish,
sacrifice  truth and principle at the shrine of gain.
  II. The second source of our knowledge is testimony.  Tes-
timony  is  individual  evidence,  to  the  truth  of a fact,  de-
rived from observation or  experience.  Testimony  is not less
imperfect than authority. It is even more vitiated by the causes
productive of error and  untruth.  It is seldom  that  testimony,
though most conscientious, can be received  without the closest
scrutiny.   It is not that we distrust testimony from a suspicion
of intentional deception, but, few can guard against self-decep-
tion, by which testimony is rendered false.
  The sources of error in testimony belong  to  the individual
who gives  it, and to circumstances that are extraneous.  In the
individual,  the greater  or less  activity of the senses, and per-
ceptive faculties, will impart greater or less accuracy to obser-
vation and to the value  of testimony.  A man with dulness of
vision, or any other sense, will be  struck only by the grosser
features of an object.  All the nice, discriminating shades  and
outlines are lost to him.  His testimony, from  the natural defi-
ciencies of his senses, will give statements the  reverse of the
truth, and differ  totally from  the testimony of one  with  acute 
                         (   J1   )
senses, who detects all the characters of the  subject of obser-
vation.
  The differences in the acuteness of perception and the ac-
tivity of the knowing faculties, will produce entire dissimilitude
in the testimony of different persons, as to the  same thing or
occurrence.  There are some whose perceptions are so dull, that
they do not observe what is taking place around them, or note
the objects or scenes  they pass by.   They cannot recal any
circumstance, or any particular of what has  just come  under
their view.   There are others, again, whom nothing escapes.
Without apparently paying particular  attention, every thing,
even the  minutest, is observed and remembered.  Sir Walter
Scott was a striking  instance  of  this vivacity of perception.
He invented less than he recollected. His descriptions of scenery
and of character, are realities; the one, drawn from nature, of
the places he had visited; the other,  portraitures, for the  most
part, of individuals v/hom he had met with.
  Excitement of the mind, of the imagination, or of the passions
and emotions, render objects confused to the perceptions  of in-
dividuals.  They become so distorted, when related, as to bear
no resemblance to the original.  Hence, in moments of strife and
contention;  in periods of violence and disorder; different wit-
nesses testify most discordantly to the same  facts and events.
History must ever contain much that is false, from this cause of
defect in  the  testimony on which it is founded.  History has
been justly defined, for the most part, "the epitomized synopsis
of rumour."
   The anecdote related of  Sir Walter Raleigh is well known.
 He witnessed a  transaction from a window of the Tower in
 which he was confined.  Several persons testified to the facts
 of the case,  all different from  each other, and each from his
 impressions.  He was so struck with this instance of the dis-
 crepancy  and  evident fallacy of testimony, that, losing all con-
 fidence in the testimony of history as  to the past, when that of
 the present is so uncertain and so  difficult to be known, he des-
 troyed the historical work in which he was engaged at the time.
   A source  by no means  unfrequent, of false testimony, are the 
(  »2  )
  prepossessions, pre-conceived opinions, the self-love and  inte-
  rests of individuals.  Under the bias of these feelings, the truth
  that wounds them, that would convict of long cherished error,
  that  threatens an  established interest, is offensive, is resisted
  pertinaciously, and whatever can tend to obscure it, to prevent
  its admission, to throw it back  from the  convictions of others
  as of ourselves, is eagerly sought for and insisted on.  It is too
  often a failing, not  to say a vice, even of great minds, to prefer
  and contend for the false, on which they have been committed,
  than  to acknowledge they could have been deceived.
    From these states of the mind, truth  in any department of
  science has always a birth-struggle for existence, in which it is
  well should it escape strangulation.   It is  slow in reaching its
  maturity, for its advance is  by successive  generations of men,
  never by the convictions and conversion of the age in which it
  comes to  light.  The generality of men,  having once formed
  their opinions, carry them  to their death; all  other testimony
  but that of their own convictions unheeded and disbelieved.
   III.  A third source of our knowledge, and established sys-
 tems of belief, are observation and examination.  By these ope-
 rations the mind receives its ideas direct through the action of
 the senses.   It would seem, on a first impression, that this me-
 thod must be certain, and free of fallacy and deception.  Nothing
 less so.  All the causes that corrupt  authority and testimony,
 are combined to deprave observation and examination.  The
 deficiencies in the activity of the  senses, the character of  the
 mind,  as rapid, hurried, confused, wanting in discrimination and
 judgments; the prejudices, the pre-conceived opinions that have
 been formed; are all opposed to correct observation and exami-
 nation.  Besides, it is not, as  appears to be a common belief,
 that, by observation, a phenomenon must be known.  So far is
 this from the truth, that phenomena actually present to the senses
 are not perceived, or, if noticed,  they are misunderstood.  To
 observe accurately an education or discipline, in the best methods
 of observation and examination, is necessary.  Extensive infor-

rsrner8 "*     eSS6miaI * C°nStitUtG *  dose and accurate 
(  13  )
  Few phenomena are single.  Most are  compound.  There
exists in them, properly speaking, elementary phenomena, and
as they exhibit several aspects, they are to be studied and ob-
served under each.  There may be  combined, in the subject of
observation, physical, chemical, electrical,  inorganic, organic,
vital phenomena.  Now, to  make a correct observation and
examination, there must be  knowledge  sufficient to recognise
each phenomenon separately; to place it in its proper category;
and to estimate the part it  performs, or its true value, in the
character or nature of the general phenomenon that is studied.
  Hasty, imperfect, and ignorant observation and experiment,
have been the most serious obstacles to the progress of science.
Medical science has especially suffered from their disastrous in-
fluence.  False observations, false facts, deceptive experiments,
have overloaded the science of  medicine, and retarded its ad-
vance.  A false  observation may occupy a short time for  its
promulgation.  But years are required to accumulate the proofs
necessary to establish conclusively its falsity.
  In the physiological sciences,  the phenomena to be observed
are more complex, than those of any other department of know-
ledge.  It is this circumstance that renders every thinking mind
so distrustful of medical observation; it is this circumstance, that
is the cause, in medicine, of the difficulty of avoiding error even
with the best intentions and  most guarded caution.
  From the numerous and diversified phenomena,  the  subject
of investigation, in  medical science, the most instructed  and
most careful observer, can with  difficulty, avoid the most seri-
ous mistakes, and falling into gross misconceptions.  The ani-
mal  economy,  in  its healthful condition, exhibits  a combina-
tion of physical, organic, chemical, and vital phenomena, so in-
timately blended, that they  cannot  exist separated from each
other.  In their  combination, they represent, apparently, but a
single  phenomenon; yet, regarded nearer, and with an instruct-
ed eye, this single phenomenon presents different aspects or
faces,  corresponding to its component elementary phenomena.
Its true character can be understood only by breaking it up into
its separate  parts.  But this  requires skill and knowledge. It is 
(  14  )
  not every observer who is competent to undertake it.  One who
  is not familiar with the phenomena in their separate existence,
  will never recognise them in their combination. His observations
  must be incorrect and his conclusions false.
    In the state of disease, not only are the preceding phenomena
  present, but they are  each modified; they exist in a state, dif-
  ferent from that which is natural, and a new series of pheno-
  mena enter into the combination.  Observation becomes, then,
  more complicated and difficult; the liability to error is increased
  in proportion; and a greater degree of caution, a more perfect
  discipline in  the  methods of observation, and  more extended
  information, are now  demanded on the part of the observer, to
  guarantee against deception, erroneous impressions, and false
 judgments.
   A perfectly accurate knowledge of phenomena, in medicine,
 must of necessity be very slowly, and gradually  attained.  Few
 individuals are so thoroughly instructed, as to be capable of
 resolving the  general and complicated phenomena of organiza-
 tion and life, in all their varying  conditions, into their  compo-
 nent phenomena; and then cataloguing them, in their  several
 series.   This  work, without which a complex  whole,  cannot
 be understood, must, in medical science, be executed by differ-
 ent  hands.  Observations, separately  made in  different views,
 or aspects of  the same thing, and by  different observers,  often
 appear to be in contradiction.   It is  only after a long  period
 and numberless detached empirical observations, that the ana-
 lysis is completed, and  what was at first supposed to be contra-
 dictory,  are recognised as merely different parts of  one  whole.
 When the analysis  has  been thus, tediously elaborated, the
 synthesis of the phenomenon can also  be  made, and the test
 thus be applied to the genuineness of the fact.
   While medical  science was hedged in by close and narrow
 views;  while  its facts were seen in a single aspect, it could
 make but little advance in the direct line of  a positive science.
 It continued to revolve in circles of hypotheses.  If it escaped
 from one, it merely glided into another.  The facts of medicine
have alternately been explained  by the principles of a fictitious 
(  15  )
humoralism, by those of a no less fictitious solidism; they have
been seen in the light of mechanical, chemical, galvanic pheno-
mena ; and been regarded as belonging to an exclusive vitalism,
spiritualism, or materialism.  This gyratory movement was a
necessary result of the knowledge of the age.  General  science
was too  little cultivated  and known, for enlarged and  general
views in any particular science, especially where the phenome-
na are so obscure and complicated as in medicine.   Notwith-
standing this awkward mode of progression, medicine continued
to advance.  From  each circle it carried with it what in  that
was true; for there was a body of truth obscurely hidden  in a
mist-cloud of the false, contained in each one.
  Exclusiveness is departing from medicine.  The active culti-
vation and diffusion of general science, have brought, within a
few years, a large mass of general knowledge  into the ranks
of the medical profession.  The complex character of the facts
of medical science,  is more  easily and  generally appreciated,
and  the necessity of investigating  them with minute attention,
and  under every aspect, is  recognised.  The aid of the  collate-
ral sciences, in developing the true character of the phenomena
of medicine,  is no longer repelled with disdain, as  superfluous
and  insufficient.  It is invoked as essential  to a complete know-
ledge of them.  The  recognition of the fact that the phenomena
of medicine are of  this compound  character; that none are
simple; that they are all to be examined in  the different  rela-
tions they bear to different  sciences, in order to  understand
them as they are in nature, and not  in our artificial systems,
has already produced its influence in improving medical obser-
vation.  It will probably enable  medicine to rely on observa-
tion, thus strictly conducted, as its most certain means of cor-
rect knowledge.  Observation will then prove to medicine what
it is to the physical sciences, a guide that  seldom leads astray.
   IV. Experience, another means of establishing  opinions, is
generally appealed to as an  infallible method for the  acquire-
ment of accurate knowledge. Its  claims to this character can-
not be admitted.  It has no advantages over other  methods, at
least, what is usually called experience. Experience, on which 
(  16  )
  so much stress is laid, is generally the impressions on the mind
  of an individual, flowing from his personal observation.   Now,
  we have just seen how  difficult  is  correct  observation, espe-
  cially in medicine. Few are qualified to form sound observers.
  The experience of an individual must, then, depend on  his ca-
  pacity for observation.  If he is not gifted with the requisites
  of an acute and well  instructed observer, his experience can
  have no value. It is a source of delusion.  Experience, further,
  must partake of  the  intellectual  character.   If that be hasty,
  loose,  and indefinite, experience possesses all of those defects,
  and is vitiated.
    I have watched, with some attention, persons who have been
  reputed  as  experienced, and  have  prided themselves on their
  experience.   Invariably  I  have found their experience,  as  it
  was termed, consisted in  a vague recollection of a limited num-
  ber of facts, often not more than one, two, or three, on a  parti-
 cular point.  These facts had  made a strong impression and
 were retained.  Numerous others, by which they were neutral-
 ized from a contrary result, were overlooked and forgotten. In
 consultations, I have remarked, that a single case has been quoted
 in successive years as justifying a practice, unsuccessful in every
 instance in which I saw it  applied.  Yet these hostile results were
 not permitted to have any weight.  The  same  has occurred
 with respect to remedies.  A particular medicine or prepara-
 tion has been extolled as adapted to certain symptoms.  Em-
 ployed  from this  experience, the result was disappointment;
 yet, subsequently, faith, I found, had  not been shaken by these
 sinister events, and experience was still appealed to in support
 of the reputed efficacy of the remedy.
  That experience, so called,  is  too frequently nothing more
 than a loose recollection of unrecorded facts, is strongly illus-
 trated by the following occurrence.
  A gentleman, formerly  at the head  of the profession, was in
 consultation with an intimate associate in a case of scarlet fever.
 In support of a  treatment he recommended, he stated, that he
had never lost a single patient with that disease.   His friend
who was well acquainted with the current  of  his practice, as- 
(  17  )
sured him he was mistaken;  and enumerated six or seven pa-
tients he had lost since the late epidemic had commenced.  His
surprise  was great.  The facts  had completely escaped his
memory.  Deception was out of the question.  This gentleman
was well known for his rigid regard for truth, and to be inca-
pable of deliberate misrepresentation.   Now, his supposed ex-
perience, on which he relied, in this instance, with so vague a
recollection of  cases, was evidently fallacious.   Yet the expe-
rience of most persons, is of this indefinite character.
  Another instance of erroneous experience, founded on vague
recollection, is furnished by Bouillaud. He asserts that the most
frequent alteration of the heart is dilatation, with  thinning of the
walls of  the ventricles.   He  repeats this assertion after Corvi-
sart; and yet, when an examination was made of cases on re-
cord, amounting to one  hundred and twenty-five, Bouillaud's
and others, but one was found of this character.
  Another illustration has lately been furnished,  by the statisti-
cal results of the mortality of amputations of the extremities.
The general  impression—that is, experience, on this subject-
was, that the mortality was very inconsiderable.  But it turns
out, when tested by figures, that this operation is attended with
the fearful mortality of  from twenty-three to twenty-seven per
cent.   What becomes  of the  boasted  certainty  of surgery!
Another erroneous impression, or false experience is corrected
by these  tables.  The English surgeons  were  accustomed to
boast how much more successful  they were, in amputations,
than the French surgeons;  and in this  country, it was the
general opinion,  that amputations  were  less frequently fatal,
than in Europe.  Now, if these tables are accurate, it appears,
that the advantage in  favour of  the English operators, is little
more than one per cent.;  while  from one to two per cent, is
against the surgery of the United States.  I may here remark,
however, that amputations are less  frequently resorted to in this
country, than in Europe, and only in cases in which  the opera-
tion is absolutely indispensable.   If the  mortality of  the opera-
tion be greater,  yet more limbs are saved in our hospitals, by
the perseverance of our surgeons in the treatment of the patients.
             c 
(  18  )
   It is obvious, from the foregoing  remarks, that the  value of
 experience, must depend on the manner in which that experience
 is gained: the opportunities,  the abilities, and the  methods of
 observation of the individual, whose experience  is proposed as
 authority.  But, in addition, experience to be relied on should
 be recorded;  all the facts accurately written down at the time
 when  observed.  These should  be arranged under the various
 heads to which they belong, and the memory of them be refresh-
 ed by a frequent reference to them.   And still further; where
 different  methods,  or  systems of proceeding are applicable,
 comparisons should be instituted, that the relative worth of
 each may be verified.
   Experience, the common  world experience, that every one
 in his own sphere  is relying on, and  which we every day  hear
 individuals boast of, is for the most part delusive.  It has no
 higher pretensions  to our confidence, as a source of knowledge,
 than any other of the methods by which knowledge is acquired.
 The quality of that experience must regulate  its value.  Few
 only of the vast multitude,  who obtrude their self-termed expe-
 rience on the  world, are  endowed with truth-knowledge,  as a
 life-faculty, by which they continue to live among men as au-
 thority, undying for successive ages.  The rest flare like a lit-
 tle  taper, ending in a  curl of thin  smoke, lost  in the great
 whirlpool  of time, and are no more heard of.
  V. Among the most useful means of acquiring knowledge and
 forming our opinions is analysis.  Analysis is the art by which
 the multiple is reduced to the simple, the  compound separated
 into its elements. It has already been said, that nearly all pheno-
 mena, though apparently simple, are  in reality complex.  They
 cannot be properly known, their true character  and relations
 be understood, until they have been broken up and decomposed
into their  elementary constituents.   This  is accomplished  by
 analysis.
  The application of analysis, in the modern era, to the physical
 sciences by Bacon, has given to them the positive character they
 at present possess.   They no  longer  exhibit subjects involved
in refined and intricate hypotheses, or are attended with endless 
(  »■  )
arguments, ending in no conclusion.   Physics are now demon-
strated, not argued.  The same analytical method is applicable
to the intellectual sciences, and will confer on them, to a great
extent, the attributes of physics.
   Analysis is of two kinds.  The one, mental, or accomplished
by abstraction; the other, physical, or performed by experiment
and  demonstration.  The first  is applicable to the intellectual
sciences—to metaphysics, or investigations into man's mind, life
and destiny: to law,  or the principles best adapted to govern
man, in his individual movements, and social relations: to morals,
or the examination of the nature, sources, relations, and conse-
quences of human actions:  to politics, or the principles of gov-
ernment founded on  the social  and moral nature of man, and
intended to direct  the  movements of society in its masses, for
its protection, and, more especially, for the improved happiness
of the greatest possible number.
   The great questions embraced in those  subjects, which now
turn, when discussed, on vague  generalities, are capable of hav-
ing applied to them the  analytical method.  The truths that lie
in them, may be resolved by mental analysis and profound  ab-
straction.  It is, then, that our social  and political systems and
institutions, involving so deeply human interests and happiness,
and which prove  so inefficient to their  great  designs, can be
more thoroughly understood and perfected, on principles  better
calculated to accomplish their  intentions.
   The second, or  physical analysis, by experiment and demon-
stration, is chiefly applicable to  the physical sciences.   The high
state of perfection to which they have been  brought, and  the
triumphs daily accomplished, in the  arts, in  the conveniences,
and business of life, through them, are the results of the analy-
tical method of acquiring knowledge. No synthesis or combi-
nation can be effected, unless preceded by analysis, or separation:
and any synthesis will be perfect in  proportion  as the analysis
is complete.
   In the medical sciences, both methods of analysis  are to be
brought into application.
   Physical analysis, by dissection, has completed special ana- 
(  20  )
 tomy. Within  our own day, it has created general anatomy,
 and has very nearly rendered it complete.  At this moment, car-
 ried still further, analytical examination is directed to the minute,
 or molicular anatomy, and the development of the organs from
 their  first rudiments.  Muller has thrown a strong light on this
 interesting subject. Bae'r, Treviranus, Raspail, Erdman, Bres-
 chet and others, have contributed largely, or are still occupied
 in this research.   Genetic anatomy, or the evolution of the or-
 gans  and being, from the amorphous organic  matter  of the
 embryon, is another modern creation of physical analysis, applied
 to the physiological sciences; and is cultivated with zeal by
 Burdach, Carus,  Serres, Tiedman, Velpeau, Deschamps, and
 Breschet. The  completion of this branch,  will unfold the great
 law of organic formation; a law which must include within itself,
 the progression of the movements of life, as manifested in the
 order of formation. Much of pathological actions,  in their in-
 ception, most probably rests on this same law,  but cannot be
 seen or understood until the law itself is entirely made out.
  Pathological  anatomy, the diseased  modifications of tissues
 and organs, and the products of disease, have been, in our time,
 extensively explored by analysis through autopsial examinations.
 The materials of a science, are collecting; but  they have not
 yet been worked up into a science.   As yet, pathological ana-
 tomy  has been  occupied with the grosser  alterations—the last
 stage  of the destructive deterioration of the  organs.   It has
taught us the frequent  terminations of neglected o-r unchecked
disease, in structural alteration. It has  also settled the value of
 many symptoms of disease, formerly vaguely comprehended.
 It is true, by demonstrating their fatal  character, our attempts
 at cure are discouraged; but, at the  same  time, the patient is
 saved from harrassing, vain, and often mischievous efforts, to
accomplish what is no longer within the reach of human aid.
  But it is not from the last degenerated and disorganized con-
dition of  the organs, that we can derive a  knowledge that will
throw light on the nature of those alterations, the causes to which
they owe their origin; and  thus  enable us to cure them, while
curable, or to prevent their occurrence. For  these objects we 
(  21  )
must know the beginning, the first shades that announce  the
commencing change in the organized structure.  Pathological
anatomy is now employed like special anatomy, in that which
is gross and palpable to the senses.  It must follow in the steps
of general, molicular, and genetic  anatomy, penetrating to  the
intimate structure, where morbid  alterations and productions
take their start.   The opportunities of surprising nature in  this
secret work are, it is true, rare; for, as  in  this  state disease is
not fatal, this rudimentary condition can be observed only when
particular casualties bring it under notice.
  It is not intended to assert, by this observation, that a know-
ledge of the minute anatomy of the organs, either in their natu-
ral  or diseased state, can  reveal to us  the essential nature of
vital activity, natural or  morbid.   No  matter how close may
be  our  investigation, and to what extent we  may proceed in
a knowledge of the minute, still, as Burdach remarks, it is only
the  exterior side of life that  we can discover.  The interior
remains concealed.  The natural  solids  are, in fact, the pro-
ducts of the act of life: It terminates in them, and thus they
pass, as it were, out of the domains of life.  They must be re-
moved  and replaced by a new formation.
  The pathological alterations of  the organs, are, in like man-
ner, the products of modified vital actions or morbid  action,
alone, or  combined with deficiency or perversion of the con-
stituent elements of the organized structure in the fluids.  There
is this difference, however, between natural and morbid products.
When the morbid product is a new formation,  it is not suscep-
tible, for the most part, of removal as is the healthy structure. It
remains permanent.  If organized, it has the character of  a
new organic being, with an independent existence.   It lives at
the  expense of tiie surrounding tissues, which it finally contami-
nates and destroys.  If not organized, it  then acts as  a dead
foreign  body, a source of local irritation, and tends to perpetu-
ate the  action by which it was produced.
  In neither case  can be discerned  more than the results of
vital action.   The nature of this action can be penetrated
only by ideal analysis, commencing with the material; and, 
(  sa  )
the nearer we can approach to it in our physical investigation,
the more probability of avoiding error, and of  escaping wild
hypotheses. Now, the commencing formation or product of natu-
ral or morbid vital activity, in the natural or morbid structure,
brings us to the nearest possible point by which vital activity can
be approached. Minute, molicular anatomy, natural and patholo-
gical, is then the proper starting place for  that  investigation.

  The physical analysis of the organized structure, by anatomi-
cal research, being performed on the dead subject, partakes of the
simpler character of the  investigations in physics.  There is
no complexity of phenomena, arising from  activity of force and
movement, creating re-actions and confusing results.  But these
circumstances do  attend on physical analysis, when carried
into physiology.   It  loses its certainty.  The  subject to which
it is applied, cannot be isolated,  separated from all connexion,
and no other  phenomena than those attempted to be solved by
the experiment, be produced or observed.  On the contrary, in
the living being an universal consent or connexion of one organ
with another  prevails.  The  different  organs mutually act and
re-act on each other, producing an intercommunity of phenome-
na, rendering experiments in physiology difficult and uncer-
tain, and a hasty deduction from them hazardous.
  The experiments  in physiology are made by the mutilation
of some organ, or by vivisections.   It  is not to be questioned,
that many interesting facts have  been developed, and numerous
doubtful points in physiological  inquiries been settled  by these
means.   Yet,  often the experiments performed are extremely
cruel, the mutilation  extensive,  the organ  to be examined so
situated,  that  numerous others are involved.  The results to be
observed are  no longer simple. The phenomena are diversified.
There are profuse hemorrhage, excessive suffering, several im-
portant organic lesions perpetrated,  with a shock to the whole
system, prostrating its powers and destroying  its functions,  all
operating together, producing varied and complicated phenome-
na difficult to separate and distinguish from each other.  The
reports of experimenters, as it respects the  same experiment,
are often in direct collision, and  seldom correspond in all par- 
(  23  )
ticulars.   We can  admit only as facts those  phenomena that
are observed in all the experiments  performed; that are repro-
duced in each.  They alone can be received as fairly establish-
ed by the experiments.   All others  must be rejected as merely
accidents.
  In therapeutics, the direct actions of remedies on the organs
is very little understood.  Experiments, to a limited extent have
been made to illustrate this important  subject.  But the analy-
ses of the phenomena  are not less difficult, from the diversified
re-actions, and the incessant  fluctuation of the sensibilities and
forces of the organs, than in  the more violent experiments of
physiology.
  Therapeutic  experiments may be ranged under four heads.
First, the  exhibition of  remedies to  patients  labouring  under
disease.   This is the most common method pursued.  But, that
it is deficient in positive  conclusions,  is evident from the little
information yielded, by centuries of observation, on the physio-
logical actions of medicines administered in disease.   Even the
therapeutic effects  are still obscure, doubtful, and constantly
contested by different practitioners.
  In disease, there is always great complication of phenomena.
A new order of re-action, and of the  sympathetic  connexions
of the organs, totally different from that of health, take place.
The cases of different individuals in the  same disease, differ in
many material circumstances, owing to individual peculiarities.
We cannot  always determine from actions  excited in health,
that similar,  or even analogous actions and operations, can be
produced by the  same means in disease; neither,  can we be
confident, that what we have accomplished  in one  case, we
can, by the same proceedings, effect in another.
   The  economy itself is not idle in disease.  It has  processes
of its own, organic re-actions, transmission of  irritations, metas-
tases, crises  and critical evacuations  by hemorrhage, or by se-
cretion, from the bowels, skin, kidneys, lungs,  &c, all of which
are curative in their intention, and are directed by certain laws
of the economy.   Most, in fact, of the operations attempted by
practitioners, are but imitations, and I fear, it must be said, too 
(  24  )
 often very bunglingly executed, of the processes of nature for the
 cure of disease.   The more perfect this imitation is; the more
 closely the time and manner of exciting the various organic
 and functional operations, are copied from an  observation of
 nature, the greater  probability of success will  attend on the
 treatment pursued.
   Again, diseases have their regular laws, which they observe
 often with a strict fidelity.  They pass through stages  of limited
 duration.   All diseases of re-action must come to a termination
 within a  definite  period, varying from twenty-four  hours to
 several weeks, according to the particular nature of the disease.
 One stage of  the disease is the initiative of  the next that suc-
 ceeds it, and generally determines its intensity.   In a well or-
 ganized individual, with good  constitution, a disease, the first
 and second stages of which are regular in order, and the symp-
 toms of which are within its natural line, must terminate favour-
 ably.  The other stages, if not injudiciously interfered with,
 and sometimes even with this drawback, will pass  through
 their natural course in progression, and  the patient recover.
   How difficult, then, must it  be with  these complex circum-
 stances, to determine what is exclusively due to the natural recu-
 perative operations of the economy, and  what to  the artificially
 excited operations of the medicine.   Equal  difficulty is expe-
 rienced in determining with  certainty, whether  the favourable
 progress and  termination of a  case  is to be  attributed to the
 treatment,  or to the natural course of the disease, uninfluenced
 and unretarded by the remedies that have been exhibited.  The
 uninformed, the vulgar or ill-informed of medical practitioners,
 empirics of all kinds, draw no distinction between a recovery
 and a cure. There is a wide difference between  the two. But,
 whether  it be the half ounce dose of calomel, the drenching
 and incendiary stimulation  of the Thompsonian, the leeching
 and barley water of the Broussaians, the eternal purgative pill
 of the Morrisonian, or the nonentity of the Homoeopathic dose
that have been employed, when the disease takes a favourable
 course, each exclaims,  a cure accomplished by my remedy,
by my treatment!  Should the  reverse  occur, it is never the 
(  25  )
 intemperate proceedings, the extreme debilitation, the irrational
 one mode of acting for all  circumstances, the absolute ineffi-
 ciency of imaginary doses, abandoning the economy, when it
 requires the assistance of instructed skill and art from the fee-
 bleness of its powers, to sink in an unequal struggle; it is none
 of these that are, then, accused of the untoward event.  Nature
 or the disease, are  always saddled with  unfavourable results.
 The doctor and his remedy invariably claim all that is favour-
 able.  With observers of this character, can it ever be expected
 that truth will be elicited?  With this method of reasoning and
 observing, or rather absence of method, how is it possible ever
 to determine the  physiological  actions  of remedies,  or their
 therapeutic  value in the  treatment of disease!
  The following instance corroborates  strongly the  position,
 that the administration of remedies in  disease is an uncertain
 mode of determining their effects.  The late celebrated Doctor
 Fothergill, of London, declared, that after forty years' experi-
 ence, he had found no febrifuge equal to the diaphoretic antimony,
 administered in small doses.   Now, this  preparation  is a per-
 oxide of antimony, and is absolutely inert.   It may be taken in
 large quantities with no more effect, than any other inert matter.
 It has  been rejected by all the Colleges from their Pharmaco-
poeias.  Here is an instance of false experience, and an evidence
of the liability to be deceived, as respects the actions of reme-
 dies, administered in disease.   Numerous illustrations could be
 adduced, from the history of the materia medica and therapeu-
 tics, to sustain this view, but they would occupy more time than
 is at our disposal.
  The exhibition of  medicine to persons in health,  is a second
 method that has, of late  years, been resorted to in order to as-
 certain the effects they produce, or their mode of action. Joerg
 and his associates, Andral and others, have made experiments
 of this kind.  This method is as yet too novel to have been very
 fruitful in the facts it has yielded.  This  line of investigation
is calculated to throw a strong light on this  obscure  subject,
and deserves to be further prosecuted.  Many remedies in their
therapeutic dose, produce positive symptoms that careful obser-
             D 
(  20  )
vation can determine. There are, however, many others whose
immediate influences are too obscure to be appreciated.  It is
perhaps impossible to determine  by this method the alterative
actions of remedies.
  A third method, is experiments on animals.  Useful facts may
be  obtained in this manner, but  the vitality and sensibility of           \
similar organs in animals  and man are not the same.   Hence
caution is necessary in the inferences to be drawn.
  A last method, consists in the facts derived from the effects
of poisoning doses of medicine.   Very little useful information,
it  appears to  me, is derived from this  source.  There is no
analogy between a poisoning, or destructive action, and a the-
rapeutic or curative action.  From the poisoning by arsenic,
we cannot understand the mode of action, by which, in thera-
peutic doses,  it  so  frequently accomplishes  cures  of diseases,
rebellious to all  other means.  From the saturation of the eco-
nomy by mercury, and its poisonous effects on the tissues, no
inferences can be drawn as to its therapeutic actions in altera-
tive doses, or in its minimum  doses, in calming the irritation
of the stomach in cholera infantum and other affections.   The
therapeutic action can seldom,  if ever, be demonstrated by the
poisoning action of a medicine.
   It is in the preceding subjects of investigation, that physical
 analysis  or experiments,  have  been  resorted to with more or
less success, for the demonstration of the facts of medical scn
 ence.  Mental analysis or abstraction, embraces a wider range
 and more elevated order of phenomena, connected with the phy-
 siological sciences. By this operation of the intellect, phenomena,
 incapable of physical examination, are traced up to their origin;
 they are combined in the order of their occurrence; their rela-
 tions and differences established; and, when possible, their na-
 ture determined.  Applied to  anatomical science, it has pro-
 duced general,  philosophical and transcendental anatomy.  In
 physiology, the nature and production of the functional, and of
 the organic actions; the laws that regulate them;  the mode of
 production, nature, and modifications of vital re-action,  whence
 result  the varied phenomena of vitality, are principally investi- 
(  27  )
            gated by mental analysis.   The higher questions of pathology,
            general and special; and of therapeutics, in  like manner, can
            for the most part,  be  investigated only by mental abstraction,
            observing always the  analytical method.
               The introduction of the  analytical method of research  into
 ,           medicine, is the work  of the present epoch.  It has banished,
            almost entirely, hypothetical discussions, formerly so prevalent,
            from the science,  and is  daily approaching it more nearly to
            the positive sciences.
               VI.  Argument, as it is in the power of most persons, is con-
            stantly resorted  to  for the purpose of producing conviction or
            establishing facts.   It is often mistaken and substituted for de-
            monstration.   An  argument is the train of thought or combi-
            nation of ideas, by which an opinion is supported or attempted
            to be proved.
               Demonstration is the evidence or proof, by investigation of
            the facts, obtained by  research, observation, or experiment; and
            which renders clear the truth of an opinion, principle, or ques-
            tion to be settled.   An  argument may be, but seldom is a de-
            monstration.   An ingenious mind can arrange an argument on
*           any subject,  and on  either side  of it.   Examples of this  are
            furnished daily in our  courts of law, legislative and other deba-
            ting bodies.   I believe it very probable that  an argument  sel-
            dom has produced a conviction on the mind,  or ever establish-
            ed a truth. During every session of Congress, and the different
            Legislatures, arguments of the highest order,  possessing  the
            weight of great intellectual powers, are continued for days and
            weeks  without influencing a single  individual in his vote.  Be-
            fore the question is brought up, and the argument commenced,
            the result is known; every vote can be counted on all leading
            questions.  This determination is never shaken  by an argu-
            ment.  A demonstration cannot be resisted with  this pertina-
            city of purpose.   There can be no more pregnant example of
            the futility of argument, as a  means of advancing knowledge,
            of investigating truth,  or enforcing honest principles.
               VII. Tabulation and enumeration. It is not sufficient that we
            acquire knowledge, and make observations  and experiments. 
<  28  )
The knowledge acquired, the facts and phenomena established,
should not be trusted to the treachery of memory, but, at once
be recorded, and arranged in a manner that will exhibit them
in their natural relations.   Tables, properly arranged, offer the
best means of accomplishing this  end.  In  the  formation of
these tables, all phenomena  of the same species, order, and           ^
class, should be placed under their respective heads. In all com-
plex subjects and questions, by breaking them down to their con-
stituent phenomena, and arranging each separate phenomenon
or  fact in its respective column, by summing up the table, we
find the phenomena or facts that are universal, and consequently
essential; and those  occasional  only, and of course acciden-
tal.  From the class,  to which the facts belong, we learn, also,
what phenomena are  the  most important of the  series, or of
the combination.
   In medical observations, this method  is the best calculated to
unravel the entanglement of the phenomena existing in disease,
and to present to the mind each  one in its single state, and its
just position and relation to others,  or the whole.   In any dis-
ease, for example, if the causes, and the symptoms as expressed
in the general functions; and the lesions, as detected in the tis-            ♦
sues and organs after  death, are each recorded under its pro-
per head in a table; when this has  been done for two or three
hundred cases, the numerical addition of each column, will give
the relative frequency  with which they  occur.  Those that are
rare, occurring in a limited number of cases, are  mere acci-
dents,  connected with some  peculiarity of the patient.  They
do not necessarily belong to the disease—are not part of it.
Those, on the other hand, that are  found in every case, or in
the great majority, are essential to the disease; those are the
phenomena that  are  to be taken into  consideration,  and that
should govern our conclusions.
   Similar tables, embracing all the  circumstances of the origin,
progress, treatment and termination of  cases, will  present the             ,
facts of disease in a positive  character,  and strip them of the
obscurity, confusion, and  uncertainty in which they now exist
jn most pathological and practical works. 
(  29  )
             The numerical method,  as this  plan has been named, was
           introduced a few years past, by M. Louis, of Paris.  Its merits
           have been  the subjects of considerable  discussion.  It has its
           advocates and  its enemies.  It  is extolled extravagantly  by
           some, unjustly depreciated by others.   It will not complete me-
;           dicine; it is not applicable to or  capable of solving all the sub-
           jects and inquiries embraced in the history of disease.   But
           this method will  render most complete and satisfactory the
           statistics  of disease;  and thus lay that  broad and solid founda-
           tion that has never  yet  been done, on which the structure of
           medical science can be durably erected.
             This method of M. Louis is further, a noble defence, protect-
           ing medical science against the inroads of  its worst enemy: a
           wild spirit of hypothesis, that has  heretofore spread a baneful
           influence  over its fair regions.  Writers, in  order to command
           attention, must now use  the language of strict observation, and
           all their theoretical inductions be the legitimate  results of well
           arranged facts, established in the clearest manner; or they will
           not be listened to.
             The numerical method is  incorporated  in medicine, as  " a
r           part and  parcel" of the  science.
             VIII. The last method of acquiring knowledge and of forming
           opinions, is by generalization. This is an intellectual operation, by
           which all the facts or phenomena of the same kind, or that form a
           series, are condensed, as  it were, into and is expressed and repre-
           sented by one general fact or phenomenon.  Thus, gravity  ex-
           presses the general fact or phenomenon, that all ponderable bodies
           tend to the centre of the  earth, regulated by  specific laws, and is
           the cause of the fall of bodies.  Now, this general fact is establish-
           ed by numerous separate and distinct facts.  Sir Isaac Newton
           first made the generalization, and, as the story goes, his mind was
           led to the train of investigation which resulted in its discovery,
           by the fall of an apple on his head.  All the world had seen
           bodies fall, but none before Newton had been able to generalize
           the facts observed, and establish the principles and laws govern-
           ing this common phenomenon.
             The same observations are applicable to affinity, attraction, 
(  30  )
 magnetism, caloric, electricity, all of which are generalizations
 of numerous particular phenomena, expressed by one compre-
 hensive phenomenon, in which they are included.
   Generalization is a most difficult operation of the mind, and
 much  exposed to error.   In the mathematical  and  physical
 sciences, where calculations and diagrams can be resorted to,          \
 generalization is a safe proceeding.  But in metaphysical, moral,
 and political science,  there is scarcely a single generalization
 that can be trusted.  They all contain a mass  of error.  In
 medical science, generalization is, equally, if not more hazardous.
 Few that have been, and that continue to be formed are worthy
 of confidence.   The  facts of medicine have  not as yet been
 proved with that severity of observation, and arranged in their
 appropriate order with that degree  of justness, which can alone
 enable a generalization to be made free of error. There are few
 of the generalizations of medicine, theoretical or practical, that
 should not be regarded with the greatest distrust.  There is not
 a practical precept, so absolutely established, as to  be concurred
 in by all the practitioners of the same country or  city, not to
 speak of those of different countries. No general theory of medi-
 cine has yet been proposed that has survived to the present time:          ♦
 and  most have  expired  in  the  period  that gave  them birth.
 Every generalization of the kind has assumed, that the animal
 economy was an unit, either as to its structure and its forces,
or as to both.   Now, the progress of our knowledge of the or-
ganization has shown, that it is in the highest  degree complex.
 To say nothing of the  fluids, no  two tissues or organs are simi-
 lar.  They differ in every particular; as to chemical composition,
 as to organic structure, as to organic forces, sensibility, irrita-
 bility, or mode of vitality: as to  functions, as to importance in
the economy, as to relations with each other and  with  exterior
agents. Each organ is a distinct, subordinate organization; a
 species of zoonite or inferior animal. They are made to depend
on each other, and to concur to their mutual existence  and ac-         )
 tions.  There is thus co-ordination,  confederation, union of dis-
 tinct special organizations with distinct special  powers and
offices, the whole regulated and controlled by general governing 
(  31  )
forces.  The animal organization represents unity  embracing
complexity: no general theory can embrace and explain the
endless diversity of phenomena thus arising, by a single princi-
ple.  In  medicine, instead  of looking  for a simple  and single
theory, we must expect and look for numerous theories: for the
organs, in their healthy and in their morbid states, are so differ-
ent from each  other, that  each requires a separate study and
rationale of its phenomena.  Theories, or the  development of
the laws observed in diseases that are independent of local lesions,
must be as distinct from each other as are the diseases them-
selves. When these generalizations cannot be made with a strictly
logical method, it is better to remain contented with a rational
empiricism, based on rigid  observation, furnished  and daily
corrected by clinical  instruction.  For this purpose, hospitals
placed at the command of the profession,  are  indispensable to
the improvement and perfection of medical science.  The want
pressing on our science, each day becoming  more  and more
imperative, is hospitals, devoted to clinical instruction and the
observation of disease. The public having the deepest stake—
their healths, and lives—in the advance of medicine, are bound,
and are loudly called on, to remedy this serious, I may say, dis-
creditable deficiency, in the scientific instruction of our country.
   I have now, gentlemen, laid before you the different methods,
with their respective  advantages and defects, by which know-
ledge is acquired and  rendered accurate; by which sound and
judicious opinions are formed; by which truth is to be sifted and
 separated from error.
   You must have perceived in the course of this examination,
 how difficult is the acquisition of knowledge; how obscured and
 deeply hidden from the view, is truth!  They are to be obtained
 only by severe application and labour.  In devoting yourselves
 to the study of medicine, you have commenced a life of unceas-
 ing toil.  The  questions it opens for investigation, place it within
 the domain of the highest philosophy.  Its practical application
 involves the deepest, often the most fearful responsibilities.  Be
 not discouraged at the prospect that lies before you.  There is
 brightness as well as  gloom. Let this consideration spur you on 
(  32  )
 to exertion.  In human affairs, nothing worth possessing is of
 easy attainment. The labour necessary to production or acquire-
 ment, is the cause of and imparts value.  There is no difficulty
 that will not yield to application. No obstacle that  perseverance
 will not remove.  No prize that industry may not gain.  Repu-
 tation never was and never can  be obtained  by accident.  A
 quack, in any profession, may have  a temporary fame with
 the vulgar, literate or illiterate;  but it soon sinks in disgrace, and
 disappears overwhelmed with dishonour. A man of science may,
 for a time, remain obscure and unknown, but his name and re-
 putation cannot continue in oblivion.  It is in the order of nature,
 that whatever is endowed with innate living force and fire, shall
 emerge into light; and that name, though it may for a time, be
 unknown, must arise from its obscurity, as the star from beneath
 the dark horizon, until it reaches its  appropriate sphere.
   There is no reputation more worthy of an honourable ambi-
 tion, than  that of a gifted, instructed, and conscientious physician.
 In the physical and barbarous  state  of society  which, though
 gilded by a more  refined  civilization, has not  yet terminated,
 medicine, with all the intellectual pursuits, was placed in the
 gradations of society beneath  its level.  The strong  arm for
 destruction and plunder, had  more honour  than the head and
 the heart devoted to the alleviation and succour of suffering hu-
 manity. As society advances to its loftier destinies, entering on
 its period  of intellectual  and moral ascendency,  the  medical
 profession, freed from the mass of quackery and imposition, that
 a blinded  community suffers to degrade it, will  rank  with the
 most elevated.  The first of poets, ages past, recognised and did
justice to  its  eminent science  and lofty character. Time serves
 to confirm its truth.
            u A good physician, skilled our wounds to heal,
             Is more than armies to the public weal."—Iliad. 
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