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Lecture
introductory to the course of
INSTITUTES  OF  MEDICINE,
UNIVERSITY OF PENNSYLVANIA,
FOR THE SESSION OF 1835-6.
A
BY SAMUEL JACKSON, M. D.
Published by the members of the class.
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           PHILADELPHIA:
Printed by thomas b. town, 143 north second street.

               1835. 
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Philadelphia, November 9, 18S5.
DoCT. Saml. Jackson:

         Sir:

  At a meeting of the Medical Class of the University of Penn-
sylvania, it was unanimously resolved, that a copy of your eloquent
and instructive introductory address be requested for publication.
  The undersigned, a committee appointed for that purpose, tender
you  this request, hoping it will meet with your acquiescence, and
at the same time assure you of their individual esteem and respect.

                    Yours, &c.
                                 WILLIAM ELMER, JR.
                                 WM. B  CASEY,
                                 H.  S. PATTERSON,
                                 WM.  HOPE,
                                 ALEXR. VAN RENSSELAER,
                                 WILLIAM YOUNG.
                               Philadelphia, Nov. 11, 1835.
Gentlemen:—

  I have had the honour to receive through you the communication
of a resolution adopted by the Medical  Class of the University of
Pennsylvania, requesting the publication of my  introductory ad-
dress.
  This testimony, approbatory of my humble efforts in their ser-
vice, is too honorable to  be  declined—their request too flattering
to be denied—my lecture is placed at their disposal for publication.
  I beg you will make known to the gentlemen  of the  class, the
grateful  sentiments I feel towards them, and accept individually
the expression of my sincere esteem.
                    Your obdt.  servt.
                                      SAMUEL JACKSON.

  To
Messrs.WV. Elmer, jr. W. B. Casey,  H. S.. Patterson, Wm.J
         Hope,   Alexr. Van Rensselaer,  Wm. Young.       3 
 
INTRODUCTORY  LECTURE.
Gentlemen—
  By a new arrangement, the Institutes of Medicine, formerly
attached to the chair of the Practice of Medicine in this Uni-
versity, has been separated from that department, and created
into  a distinct chair.   The honor of this appointment has
been  conferred  on me.    Though appreciated as  such an
appointment  should be, it has not been .without some reluc-
tance and  hesitancy that  it has  been accepted.   The task
imposed on me in teaching the Institutes of Medicine, I feel to
be, with an  unaffected  diffidence, a labor to which I am not
equal.  Of all the departments of medical  science, none em-
brace so wide a range of investigation;  none  require for the
discussions they involve, as multifarious and profound knowl-
edge; none demand a higher order of intellectual exertion.  I
cannot  look  upon the position I occupy  without a distrust in
my capacity, to execute in a satisfactory manner,  the obli-
gations it imposes.  1 would have been much better  satisfied
with a less responsible station.
   Not only do I entertain  a distrust of my abilities to do  jus-
tice to the important questions constantly  arising for investiga-
tion and determination in  this  department of medicine, but I
feel,  that the occupations of a laborious practice, and a feeble
constitution,  do  not enable me to engage in the extensive
researches and experimental observations esssential  to their
elucidation.   The leisure  is also  wanted for  that calm  and
deliberate  observation and reflection on phenomena, so necesr. 
6
  sary to the establishment of great truths, and important doctri-
  nal principles.
    It is true that an extensive practice possesses advantages
  that are indispensable.  There can be  no greater  absurdity
  than the attempt to instruct in a science almost purely one  of
  observation, without the opportunity of observing the pheno-
  mena  that are the subject of  instruction.   Medical  science
  does not exist in books or in lectures.   It exists in nature:  it
  is nowhere else to  be met with.  Books may serve as guides
  in directing the inquirer in his  researches: but  they are too
  fallacious to be adopted as unerring oracles, uttering only the
  responses of truth.   A specious jargon of phrases and words,
 inconvertible  into the expression of any distinct phenomenon,
 is too often substituted for observations; and fictions-the dreamy
 imaginings, spun from the cobwebs of the fancy, are enunciated
 as the verified facts of the science, and its demonstrated princi-
 ples.    He who would aim at the possession of a true knowledge
 of medical seience, who would  achieve  for himself  the lofty
 reputation of  a Philosophical Physician, must devote himself
 to a study of the phenomena manifested in health and disease
 by actual observation, by experiment and research. It is in the
 laboratory, in the wards of hospitals, by  the bed-side of the
 sick,  in the  dissecting room, that  he must interrogate nature
 herself  for the revelation of her mysteries—that he may be
 enlightened by her  inspiration and imbued with  the  doctrine
 of living truth.
   But,  while experience is indispensable  to form a medical
 instructor, the incessant engagements of private practice, when
 extended, and the obligation it imposes for devotion and atten-
 tion to  the patient's welfare,  too often  interrupt  pursuits
 essential in the  higher departments of  the  science   The
 want  of this time  has of necessity interfered with a close study
 of many branches of knowledge,  that has a bearing on, and that
elucidate many of the phenomena of the animal economy   I can
only promise, thafthe deficiencies in the extent of my informa- 
7
tion, will be compensated, as far as lies in my power, by zeal for
your improvement, and by exertion to render available'^for your
advantage in your future professional life, the store of practi-
cal information, it has been my constant object to accumulate.
   I have not sought to exaggerate the importance of the Insti-
tutes of Medicine, in a  Medical Education.  The very name
implies their character—Institutae^—Laws—established princi-
ples—consecrated maxims.   Taken  in an enlarged sense, the
 Institutes of Medicines  embrace the laws of organized matter,
applicable to the understanding of the laws of the human organ-
 ism, governing its phenomena in health and in disease.  They
 become the bond of connexion, uniting the different branches
 of medicine into a single body of doctrines—they give a unity
 to the various departments and elevate them to the character
 of a  science.  Anatomy,  Physiology,  Materia Medica, and
 Practice, as they are treated of in the generality of works, and
 in  the lectures of the schools, are  each independent of the
 other—No necessary connexion exists between them.  What
 relation does  Special Anatomy, the forms, the positions, the
 structure of an organ, bear to the  Practice of Medicine, or the
 treatment  of  its  diseases?   it is so slight as scarcely to be dis-
 covered in a practical view.  In like manner,  what relation,
 in the works of  physiology,  is  seen to connect the function
  with the structure, or with the pathological condition of a tis-
  sue, or the therapeutic operation of a remedy, or the proceedings
  of practice? None. Materia Medica, also, confined to the des-
  cription of the physical characters and the properties of medi-
  cines, the effects they produce, and their prescriptive adminis-
  tration founded on authority, is dissevered entirely from Ana-
  tomy, Physiology,  Pathology, and  loosely hangs  upon the
  skirts of Practice.   The Practice itself directed to names, and
  groups of symptoms, as constituting diseases, stands in isolation
  from  its  collateral  branches.   The Institutes  of  Medicine
  remedy  these very obvious defects.  Embracing the whole
   animal organism in their researches, they investigate the nature 
8
of the organic elements, and develope the laws that give origin
to the organs.  They connect these with their animating forces,
the functions they execute, the modifications they suffer in di-
sease, or that are excited in them by medicinal agents. Every or-
ganic phenomenon is sought for,  and explained by  the laws of
the organization.  The whole are thus included in a consecutive
series, embracing all the departments of medicine, and render-
ing them  available, with a higher degree of certainty by the
physician, in the great end  of Medical Science—the preserva-
tion and restoration of health.
  The absence of the Institutes in courses of Medical Instruc-
tion, deprives  medicine of  the principles and character of a
science.   It degenerates into  a mere Empiricism, and those,
who under such  auspices  enter the profession  unacquainted
with medicine as  a science,  sink  into  routinists soon  de-
tected by the intelligent portion  of society, and often find
themselves rivalled in public confidence by empirical pretend.
ers, possessing like themselves, an established routine, in the
treatment of every disease.   That  the  Institutes have  the
bearing on the science I have asserted to belong to them, will,
I think, be apparent, from a general view of the  character and
objects of Medical Investigation.
  The Study  of Medicine is a Philosophical  research into
the nature, causes, general laws  and modes of modifying the
most numerous, complicated, and recondite, of  all those phe-
nomena, that, in various sciences, employ the intellect of man.
1 do not hesitate to assert that it is  the most elevated depart-
ment of Philosophy.   What is  medicine but the science of
organization, and of vitality?  And in what other science are
the facts or phenomena so  difficult  to seize on and appre-
ciate; to constitute into regular formula as connected with
each other; and influenced  and modified by so many  extrane-
ous circumstances, baffling calculation and perplexing research.
Not Astronomy: for there  the facts are  limited,  and  occur-
ing under a small number of physical laws well  known,  they1 
9
are determined by the principles of mathematical calculation,
with  absolute precision.  From this circumstance arises the
perfection this science has attained.  Not Jurisprudence and
Law: for in these the principles of equity are no longer the
subjects of investigation and contention, while the enactments
of statutes, and the rules of proceeding are accessible to mode-
rate research, and reduced to a fixed routine.   Not Physics
and Mathematics: for in these departments axioms  and theo-
rems never varying, are applied to the solution  of the problem
in question, and to which they  are always applicable.   Not
Chemistry: for in this science, also,  the general  principles
or  laws  are  few, and the facts of a  fixed character seldom
deviate from their ordinary occurrence, and can consequently
 be predicted with certainty.  Its difficulties exist in the exten-
sion of its phenomena, and their increasing complexity,  as it
rises from the  simple to the higher degrees of combinations.
But, in medicine, where are the positive elements of its calcu-
lations?  what  are the established axioms for the solution  of
its problems?  They do not exist.  Its principles are yet  to
be fixed; its almost endless facts, reported  from  age to age
by doubtful authorities, too often  loosely observed, and more
 imperfectly recorded, are uncertain, controverted, fluctuating,
 are yet  to be verified by a more  severe and  discriminating
observation, by enlarged and  careful experiment.   How im-
mense the range these phenomena occupy.   They commence
 with the first germ, a mere atom of shapeless, transparent, and
 semifluid albumen.   They follow the rudiments of the organs,
as  they appear and are developed, until  they attain their per-
fect condition,  passing through the ages of infancy,  youth,
 manhood, and old age; varying and peculiar  in each.   The
 elements of this compound structure, and most complicated
of mechanisms, are  each investigated in  all its varieties.  The
organs formed of these elements, as well as their functions, are
the subjects of rigid examination  in their natural  condition,
and as modified by disease.   But it  ends not here.   The
       B 
10
organic struture  arranged on Physical  and Chemical princi-
ples, is animated and vital: the animal economy exhibits a combi
nation of physical, chemical, and vital phenomena so blended,
that it is impossible clearly to discriminate and separate them.
Vitality probably,  may prove to be  the transcendentalism of
Physics and Chemistry. Medicine, for its completion,must ne-
cessarily wait the final perfection of those sciences, and espe-
cially in the investigation of the forces that give origin to its
phenomena, generated by its own actions, to the further de-
velopment of the Dynamicks of Physic and Chemistry,  un-
known in this  country,  but  appearing  in Europe, like a
crepusculous dawn on  the  horizon  of general science.  Vast
as is this collection  of phenomena, it constitutes  but a single
department of our science.  The forces of vitality governing
the living mechanism, are susceptible to the actions of exter-
nal influences to an unlimited extent, controlling, modifying,
disordering, destroying its mode of being, and the order of its
phenomena.  Man, the preservation of whose organization in
a natural state, is the end of our science, is so endowed that he
is operated on by the  influence  of the whole universe.   From
the planets circling in their vast orbs, and in their  remote-
ness almost inconceivable, to the mere atomic particles of this
earth, all possess the capacity to affect his  phenomena.  The
air, in its  sensible  and insensible properties, the waters, the
earth, the animate and inanimate things that cover its surface,
or lie concealed in  its bowels,  the imponderable agents of na-
ture,  caloric, electricity, magnetism, universal  in  their pre-
sence and power, though so many  of them are the means of
life, are acting to the  disturbance, disorder, and destruction of
our organism.
   What a multiplicity of phenomena is embraced in this view,
yet it does not comprehend all that enter into the domain of
our  science.  The instinctive propensities, the  moral  and
intellectual powers  of man, not only in their operations influ- 
11
ence the functions of his various organs, they are themselves
reacted on bv these same organs, become the subject of nume-
rous maladies, the most afflictive and dreadful in their conse-
quences, of all the host that desolate the human family.
   Am I not  right when I  assert that the  phenomena of me-
dicine constitute it, from  their  number, complexity, and di-
versified  character,  the  most difficult  of  sciences; that  the
investigation of the  causes of these phenomena, with a view
to their generalization, and reduction to principles, elevates it
to the highest ranks of philosophy.
   The immensity of the facts of medicine render their gene-
ralization necessary to their being  understood.   No memory
could be trusted to for  the retention and application of its
details.   The establishment  of Principles or Laws compose
science.  Until  this is established  it is an  empirical art—irre-
 gular, uncertain, not unfrequently  mischievous  in its proceed-
 ings.   Stability, certainty, safety,  can  alone be imparted by
 science.—Facts can be applied in Practice with precision only
 when they  can  be  reduced to positive  formula, in which
 the exact location, as regards its precursors and its sequences,
 is determined for each fact.  When this can be accomplished
 a science approaches  its  completion.   The beginning and the
 end have scarcely  a feature of  resemblance.   Who would
 recognise the present splendor of Chemistry, with its arranged
 formulas, the precision of  its facts, the accuracy of its calcula-
 tions, the certainty of its processes, in the crude notions and
 clumsy  operations of the alchemists.  How little similarity
 is to be traced of the magnificence of Astronomy, developed
 by Kepler, Newton,  La Place, and the Herschells, in the first
 observations of the  starry firmament made on the plains of
 Babylon by the watchers of the night, and the  Ptolemaic sys-
 tem to which they gave origin.
    How little can the navigation of the famed  Tyre or Sidon,
 coasting the shores of the Mediterranean in boats impelled by
 oars   be compared to the  boldness  of  modern navigation. 
12
Launching on  the  wide expanse of the ocean, the mariner
confiding in the principles of science, feels himself secure un-
der its  protecting care.   Fearlessly he braves appalling dan-
gers.  From a confidence in the resources and the power science
confers  on him, he  contends with the warring elements, and
triumphs over the storm and battling waves.  How wonderful,
(though familiarity  destroys the wonder) to  behold that little
bark—a speck, an atom in the immensity of ocean,  traversing
for months the trackless surface of the deep, and working its
way,  spite of adverse winds and opposing currents,  to its des-
tined  port, that a mere speck upon the earth.  What  a beauti-
ful illustration of the power of science.  How convincing a
demonstration that the perfection of an art is deriveable  from
the generalizations that establish  its principles, and elevate it
to a science.
   This  is to be accomplished for medicine, and until accom-
plished  it will  remain imperfect, its  reasoning fallacious,  its
observations  deceptive, its practice uncertain. It will  continue
in the degradation of a routine art, or an empirical profession.
Medicine, in the route of  its improvement, must follow the
track all others have pursued.
   The  commencement of every science is the  facts  accumu-
lated  by observation. While they are but partially developed,
small in number, and not correctly understood, the  relations
they bear to  each other are with difficulty  perceived, and are
often  misapprehended.  Their application to practical purposes,
must, for the most  part, be  empirical; for, while imperfectly
known, it is not possible to  connect them in the regular series
of their production, and thus to construct formulas of a positive
value, constituting  the principles of a sound theory—this last
can only  be accomplished  after  facts  or  phenomena  have
been  completely ascertained, and their accuracy verified  by
repeated observation and reiterated experiment. It is then only
they are fitted  to become the subjects of investigation by the
rational powers, that they are prepared to enter the domain of 
13
logic, and capable of the application of induction for useful ends.
Before the knowledge of phenomena is perfected, all attempts
for generalization  or the formation  of a  theory are  imma-
ture,  and prove abortive.  It is not a possible task; it is not in
 the grasp  of human intellect, however mighty  may be  the
force of its endowments, and the splendor  of  its genius, to
 establish from them principles  of an extended application,
 The form of a science, it is true, may  be imparted by the crea-
 tive energies of a  fertile imagination; but it is  as a  phantom
 shape called forth by the necromancer's wand—an unreal pre-
 sence, dissolving into thin air,  and vanishing before the  first
 gleam of light.
   Generalization, or more properly, causation, is an instinctive
 operation of the intellect.  Empirical proceedings are  painful
 to the intelligent mind.   It always  seeks the  connexion of
 cause and effect, the reason of events; for, possessed of these,
 it is  the master, not the slave of circumstances—it feels a con-
 sciousness of power—an innate sentiment of an elevated nature,
 destined for dominion—it controls, directs, and  renders nature
 itself subservient to its  designs.  Impelled  by this feeling it
 is not surprising,  that, in the earliest periods of  science, in the
 midst of the poverty and destitution of facts, the impulse of
 gifted genius, should have so often spurned and  overleaped the
 narrow bounds in which it was circumscribed.   The  true
 character of knowledge was unknown.   It was  little suspected
 to consist in the discovery of phenomena by  close attention
 and accurate  research—their verification  by experience  and
  experiment; and their co-ordination in the order of their occur-
  rence.   Knowledge was a product of the mind alone, and truth,
  the offspring of the intellect, was to  be discovered in the pro-
  found depths  of reflection,  or  drawn from  the rich stores of
  imagination.    Theories were then poetical creations.   Where
  facts were wanting suppositions were resorted to, and the  de-
  ficient links in the chain of consecutive phenomena were sup-
  plied by ideal  conjectures.   But, in the  progress  of science, 
14
facts accumulate, and are invested with a higher degree of accu-
racy.  Often a single discovery, or rectification of  an error,
is sufficient to sweep away the most elaborately arranged theo-
ry.   For theory deduced solely from the imagination, is but
as the filmy web, wove by the spider from its own entrails—
The fragile edifice fitted for entrapping the feeble, is instantly
broken down and destroyed by weightier cqntact, or the action
of a more vigorous force.
  Theories, or generalizations  of facts,  must, and always will
exist.  They are important aids for the advance  of science.
They are necessary  to  knowledge.   They  precede and an-
nounce the approach of truth.  Some of you  have stood in
the gray of the dawn on an eminence,  looking  on  the plain
below, its varied objects dimly visible,  but nothing seen dis-
tinctly.  You have  beheld the clouds that fringe and canopy
the eastern horizon,  catching the first beams  of approaching
light,  refract the pure ray into a thousand gorgeous hues, and
painted with the richest dies, throw on the  objects they illu-
mine a false and uncertain coloring.   Forever changing, each
one glowing as it  rises  with a more brilliant and purer light
the gloom is scattered, and the forms of things stand  forth in
bold relief: the hill, the dale, the forest and the cultivated field,
the village and the distant town, the stream sparkling in the
 morning ray—all are distinctly figured in  the  scene.   And
 now,  heralded by these imposing splendors, appears the great
 luminary of the universe, in its eternal march, and all is light.
 Obscurity flies, every object  is individualised,  the minutest
 atom is  discovered; forms, properties, characters,  all are re-
 vealed in the broad  blaze of day.
   In  this scene is figured the advance of knowledge,  the pro-
 gress  of theories,  the approach of truth.  At first, from the pau-
 city and obscurity of facts, they are feeble, inconclusive,  falla-
 cious, but as facts are accumulated, are more perfectly embo-
 died,  and their relations more justly appreciated—new theo-
 ries supplant the old, for every discovery that changes the rela- 
15
tion of phenomena, necessitates a new theory for their expla-
nation, as they are then understood.   When subsequent inves-
tigations call into existence additional facts, new generalizations
are required.  Yet, with the progress of the knowledge of the
phenomena of a science, every change is an  advance on  that
which precedently prevailed.   Each successive theory is more
perfect,  consistent,  presents fewer anomalies and exceptions,
until the full and perfect completion of the facts of the science,
 the theory is the science itself, embodying and condensing its
 vast mass of phenomena into a few general principles or facts,
 rendering the whole frame of the science clear, perspicuous,
 easily understood, and distinct.
    While a science is in progress, and knowledge advancing,
 theory  must  be unstable and fluctuating.   This  objection
 does not in reality apply to the theory of the science, but rather
 to the defective facts of the science. It is, because the facts are
 changeable, that the theory is  mutable.  Without theory a sci-
 ence is a chaos of facts, of elements confusedly heaped together,
 difficult or  impossible  to comp'rehend.   Theory is nothing
 more than the arrangement of  phenomena in the order of occur-
 rence.   The error too often committed, is the belief,  that each
 successive discovery of facts, and the new theory to which
 of necessity it gives rise, are  the  completion of the science;
 that the limit of discovery has been reached; that all its phe-
 nomena are fully explored; and, consequently, that no source
 of change in the theory is to  be looked for.   This is the error
  that has proved fatal to so many theorists: imposed on by vanity
  and  self-love,  they have become  visionary enthusiasts, pro-
  claiming an epoch of perfection, a termination of laborious re-
  searches, a science accomplished.   But this exaggeration does
  not derogate from the theory  thus misunderstood, and put forth
  with fallacious pretensions.   It merely subjects the  vanity and
  ill-founded confidence of the author to ridicule.  Few of the
  sciences are so far advanced, that any of  their theories can
  be regarded as established.   We must look on all of them 
16
with distrust, and regard them as artificial aids to  assist our
knowledge as far  as  it is  unfolded, and  to  render it more
available to practical purposes.
  What has been said of science  in general, is peculiarly ap-
plicable to medical  science.  More than any  other has it en-
countered difficulties, in its origin and progress.  The facts of
medicine, the  phenomena,  the objects of its research and ob-
servation, are, as has been shown, the most difficult, recondite,
and extensive in character, and varied in nature.  They can-
not be comprised in a single category, and studied in one point
of view.   In the human organism, the phenomena  of which.
in its natural or healthy, and its anormal or morbid conditions,
comprise the science of medicine, physical, chemical, and vital
phenomena and  laws  are concentrated in their most perfect
state, and highest degree of complexity.  The most important
of these phenomena, further pass in the interior of  the body,
or in the intimate  structure of the organs, concealed from the
view, and abstracted from direct investigation.   For the per-
fect understanding of a phenomenon, it must be regarded in all
its characters;  it must be examined in every light; it must be
viewed in its physical, chemical, and  vital attributes;  it must
be the  subject  of actual observation and experiment.   Is it,
therefore, surprising,  that  phenomena so complex, in their
nature, demanding  for their thorough and accurate  perqui-
sition,knowledge at onceprofound and varied, should, for so long
a period, have baffled  the efforts of the ablest intellects? It was
not in  the order of things that in the earlier epochs of our sci-
ence, they could have been  properly understood—they must
of necessity, from the imperfect state,  or entire absence of the
collateral sciences, have been viewed in lights altogether false,
and have led to conclusions  wholly erroneous.  It is less matter
of astonishment that so many mistakes should have been com-
mitted, than that so much  of truth, under difficulties so insu-
perable, should have been divined.  Let us not reproach the
early theories  of medicine.    What were called the facts of the 
17
science were still more absurd, and its theories must of conse-
quence have been frivilous, and even ridiculous.   The pheno-
mena attempted to be investigated could not be properly ap-
preciated.    The  methods  of observation pursued,  and the
means of research known, were wholly  inadequate to their
elucidation,  and developement of their nature.  But, as the
collateral sciences have advanced to a higher  state  of cultiva-
tion, and experimental  investigation, and careful,  patient ob-
 servation are more relied on as the sources of correct knowl-
 edge, the phenomena of organized beings are capable of, and
 have received a superior illustration.   The facts of medicine,
 studied and  developed after these methods, have attained a far
 more lofty rank, and may justly lay  claim to the character of
 positive phenomena.  With the advancing  improvement  of
 the facts of the  science, the greater degree of accuracy at-
 tending on medical  observation and  research,  the theories of
 the  science,  have  become  more   rational,  they  embrace
 a large mass of facts,  which they   render  advantageous by
 condensing them into a few general principles,  susceptible of
 an extended application, and capable of a practical bearing.
   Medicine, like every other science consists of two portions.
 Its facts and its theories.—The first are the phenomena, appre-
 ciable by the senses and faculties with which man is  endowed,
 determined  by  observation,  by research, and by experiment
 The last are the arrangement, the co-ordination of the  facts in
 the  order  of their  succession, and  the establishment of the
 relations one bears to another  in  the connexion of  cause and
 effect  This result is accomplished  by the  exercise of the ra-
  tional faculties forming inductions,  or the   relation of ante-
  cedents and events.  In this  view,  theory  is  not to  be,  and
  cannot be  confounded with hypothesis, or the conjectural
  relation of phenomena, by adopting  suppositious facts, where
 the positive are unknown.   A principal  difficulty to the pro-
 gress of medical science is  the number of the theories that
 Lmpose it. The structure of each organ, the function of each 
18
 organ and apparatus, the diseases of each  organ,  have their
 separate  theory:  and each of these subordinate  theories is
 more or less involved in, and forms an important part of the
 general theory of the science.
   In medical instruction, the theories or generalization of the
 facts of medical  science,  are  embraced in the Institutes of
 Medicine. It is the department in the arrangement of this school
 confided to my charge.  In surveying  this extensive range of
 the most  intricate,  embarrassing,  and  disputed questions of
 science, it is not with affected diffidence that I distrust my pow-
 ers  to  do them justice.  I can do no  more than promise to
 enter on  them  with zeal,  to investigate them diligently, to
 study carefully the  daily accumulating facts, the activity  and
 ardour of the profession in experimental and positive observa-
 tion, are developing; and to form conclusions  under the gui-
 dance of  a severe logical induction.  It is impossible, gentle-
 men, not to err in the decisions of so many, and complicated
 subjects, but,  in adopting this course of proceeding, and initia-
 ting you in this system of medical  inquiry, 1 enable you to
 correct for yourselves the errors of your instructors.    In
 abandoning mere authority as a supreme arbiter, and appealing
 solely  to  reason; in  looking to the remote and proximate con-
 nexion of facts for explaining  the  production of phenomena,
 every intelligent and instructed mind is made to judge of the
 validity of the argument, and the correctness of the observa-
 tions on which it is  founded.   You assemble in this hall less
 as scholars obedient to  a preceptor, and bound  to receive his
 dicta, than as  disciples assisting at the discussions of the diffi-
 cult questions of a high philosophy.   It is not  your memory
 that will be taxed  for  the  retention of  rules and precepts, a
learned nomenclature or formulas, and prescriptive directions,
too often found in practice futile and inapplicable.   I shall not
pretend to teach you positive truths,  and demand an implicit
belief.   The utmost that can  be  pretended to, in the actual
state of our science, is approximations and probabilities.   It is 
19
your convictions that are  to  be addressed, and to which we
can claim a right only when we can make the nearest possible
approach  to  demonstration,  the nature of the subject will ad-
mit.
   The Institutes of Medicines  comprise a vast field of most
interesting and important inquiry.  Its subjects are the gene-
ralization of the facts or phenomena of organization and laws
of vitality.   They sweep over the whole field of the science.
The elementary  composition,  the intimate  structure,  vital
forces and functional actions of the organs—the  modifying
powers of exterior agencies in the maintenance of the natural,
or developement of the pathological condition—the rationale
of the phenomena, or theories of the natural or anormal organi-
zation and vitality, constituting health and  disease, are the
inquiries at once profound and extensive, that will engage
your attention in this course of lectures.  It must be obvious,
however, that,  in the system of medical instruction, adopted
in this country, imperfect in its courses, and too limited in its
time, discussions so varied  and complicated  cannot be  em-
braced  in a single course or term of lectures.  Little more
can be accomplished in  so limited a period, than to prepare the
ground-work of this course,  and to arrange the basis on which
you may proceed to the completion of this department of your
scientific education, by future self-instruction.   The institutes
or principles of medicine,  by investigating the  production
of phenomena,  the ascertaining of their nature, their reference
to a fixed location, or as connected with an organ of the  eco.
nomy, give to  them a  positive value.  They banish all ambi-
guous phrases, and unmeaning terms from  the  science: and
medicine from  a conjectural  art,  takes a position  among the
positive sciences.
   A neglect of  the principles of medicine,  derived from an
analysis of the mechanism of the  animal economy,  entails a
most lamentable ignorance on the practitioner, disgraceful to
himself, and hazardous to his patient's welfare.  He may be a 
20
diplomated doctor—he may be a professor and learned teacher
—but he is not a physician—a medical philosopher—he cannot
avoid the most serious mistakes—he is exposed to the commis-
sion of gross blunders.   Let us adduce the proof.
  The symptoms of diseases are  the language addressed by
the suffering organs to  the senses.  But this language of the
organs, like our vocal language, is too poor to express, by a dis-
tinct sign, the varied condition of each organ.  The same symp-
tom is employed to announce disease in different  organs, and
diseases also of an entirely opposite nature.  Hence it happens
that physicians who attend to symptoms alone, will pronounce
very different opinions, give a different diagnosis in the same
case.   This circumstance, one of  daily occurrence, is a source
of great obloquy thrown on the profession, and justly destroys
confidence in its pretensions.  I have known a case, in which,
a different diagnosis has been formed by each  physician,  who
has seen it.  According to one, the disease was sub-pneumonia,
another pronounced it  disease of the heart, a third hepatic dis-
order, a fourth debility and dropsy; while the affection consist-
ed in disorders of the nervous functions,sympathetically excited
by a fixed local disease of the pelvic viscera.  Now,  how is
this?   Is medicine so devoid of principles, that it is incapable
of certain results, that men of eminence and experience are thus
liable to constant mistakes, from the  absence of science  in
medicine; or, are their errors imputable to the want of science
on their part?
  That symptoms are as equivocal as I have represented them,
can  be  illustrated  by  numerous  examples.  We  will select
a very common one:—cough.   Coughing is a  phenomenon
manifested  by  the  respiratory  apparatus.  It consists in the
rapid expulsion of the  air, through the air passages, from the
lungs.   Its object is to  disembarrass, or free them from various
irritating,  and  offending  causes,  and to prevent their com-
plete obstruction by the accumulation of  mucus, pus, or other
fluids.   It  is accomplished  by the sudden convulsive action
of the muscles of respiration, especially  the diaphragm, at the 
21
same time that the  air-tubes themselves are contracted, and
their calibre lessened by a spasmodic action of their muscular
fibres.   The resistance thus formed to the movement of the
air, gives to it greater impetus,  and the matter to be expelled
is with more certainty removed.  But these varied muscular
actions are"called into operation by nervous force,' or excite-
ment,  for which especial nervous organs exist—the respiratory
tract, forming the lateral columns  of  the  medulla oblongata,
and superior portion of the medulla spinalis.  Now, coughing
may be produced by irritations in any one portion of this com-
plicated apparatus.  It may proceed from the larynx, from the
trachea, from the bronchial tubes, from the vesicular structure,
 from depositions  in the cellular tissue of  the lungs, from  the
 pleura or exterior membrane of the lungs, or from the nervous
 respiratory organs: and these last may be the seat of  disease
 themselves, or merely sympathetically affected by disease loca-
 ted in very remote organs.   Of this  last  fact my practice at
 this time  presents to me  an  interesting  example.  A patient
 has been laboring under a violent cough  for several  months,
 which has resisted all  the treatment directed to allay it.  A
 close analysis of the  condition of the organs,  has led to the
  detection of cystic disease, the irritation of which, in a nervous
 temperament, has been productive of a nervous cough.
    Examples  not less  pregnant,  might be adduced as regards
  other  symptoms—such  as  dyspnoea—irregular  or  difficult
  breathing—palpitations of the heart,  vomiting, purging, head-
  ache, delirium, and other symptoms of  various  kinds, all of
  which are produced  by affections  the  most  diversified, by
  causes the very opposite of each other, by conditions of organs
  wholly  dissimilar.
    If  the symptoms of disease possess this doubtful character,
  how  are we to be guarded against the serious mistakes  into
  which they may lead us?  There is  but one method—by cul-
  tivating medicine  as a science—by the investigation of all its
  phenomena,  in a spirit of strict observation-by the establish- 
22
  ment of principles reducing the multiplicity of facts to certain
  formulas, or well arranged  categories. Medicine then becomes
  a high  philosophy, and  its. practice, the application of fixed
  principles, for the solution of doubtful questions, and the ob-
  taining of positive results in all its proceedings.
   The Institutes of Medicine have  for their objecfthe attain-
  ment of this end.  Every phenomenon is fixed at its true value:
  it is attached to an organ, and has a specific intention—it  ex-
 presses  a condition of the  organ.  Diseased  phenomena  are
 consequently  on  the line of functional phenomena—disease
 is a morbid or  pathological  function:  the  same law presides
 over both; they proceed from and express an organic condition,
 and mode of vitality.   In order, however, to be able to com-
 prehend this fact,  and to  accomplish  these objects, the animal
 economy, that  most complicated piece of mechanism, must be
 decomposed, be resolved into  its component elements.   Each
 apparatus is to  be separated  into its  constituent organs,  each
 organ into its  tissues, each  tissue into its organic elements.
 The nature of  each of these, its mode and expression of vital
 activity, and influence on  the composition of the whole econo-
 my are then to  be ascertained.   The  simple phenomena of the
 organism, the elementary principles  of the organs,  and their
 elementary  vital  phenomena  being thus determined,  the
 observer is prepared to advance to the study of the compound
 structures, and combined organs.   It is only when  having
 established his  axioms, that he can proceed with confidence to
 the  calculations of the  problems  he is  called on to resolve.
 This is the only basis on  which to  erect a scheme of sound
 observation. It is the only safeguard against the deceptive signs
 that  so often lead the medical practitioner astray.
  In the course of lectures,  I shall have the honor to deliver
to you in this school, it will  form my principal object to give
this direction to your studies, and to  imbue you with this spi-
rit of analytical and positive philosophy.  No more lasting
benefit could be conferred  on society, could a broad scheme of 
23
medical education, placed on a level with the higher range our
science has taken, be introduced into the medical instruction
of our pupils.   It would be a cause of gratified pride and am-
bition, to know, that the pupils of this University, should be
imbued with this spirit, and be  distinguished from those of
all other schools, by the philosophical manner in which they
investigate the nature of disease, and proceed in its treatment.
   Endowed with this  knowledge you will possess  confidence
in yourselves; you will win the confidence of the public.  Sel-
dom will you  find yourselves at a loss  to comprehend, and to
explain  the phenomena you witness.   You will understand
what you observe—you will know  when to do,  what to do;
and what is not less important to know, when and what you
are not to do.  You will be placed in the most estimable posi-
tion in  society, honored,  respected, esteemed,  and  beloved
by the grateful hearts of those whom you have served in the
most essential of all human interests.   How often will you
then find applied to you the expression of Hierophilus—Manus
Dei—the hand of God; for you will be enabled to understand,to
correct and rectify the defects of that nice and delicate mechan-
ism—the master-work of the Great Creator—the wonderfully,
and fearfully formed organism of man. Most truly and fervently
do I hope,  that thus accomplished in the elevated philosophy
of medical science, you will verify in your professional life, the
language of the sacred  preacher—" The  knowledge of the
physician lifteth up his head, and in the sight of great men he
shall be in admiration." 
 
 

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