The century opened auspiciously, and those who were awake saw signs of
the dawn. The spirit of Science was brooding on the waters. In England
the influence of John Hunter stimulated the younger men to the study
of the problems of anatomy and pathology. On the Continent the great
Boorhaave—the Batavian Hippocrates—had taught correct ways in the
study of the clinical aspects of disease, and the work of Haller had
given a great impetus to physiology. The researches of Morgagni had,
as Virchow had remarked, introduced anatomical thinking into medicine.
But theories still controlled practice. Under the teaching of Cullen,
the old idea that humors were the seat of disease had given place to a
neuro-pathology which recognized the paramount influence of the nervous
system in disease. His colleague at Edinburgh, Brown, brought forward
the attractive theory that all diseases could be divided into two
groups, the one caused by excess of excitement—the sthenic—the other
by a deficiency—the asthenic—each having its appropriate treatment,
the one by depletion, the other by stimulation. In a certain measure
Hahnemann’s theory of homœopathy was a reaction against the prevalent
theories of the day, and has survived through the century, though in a
much modified form. Some of his views were as follows:
“The only vocation of the physician is to heal; theoretical knowledge
is of no use. In a case of sickness he should only know what is curable
and the remedies. Of the diseases he cannot know anything except the
symptoms. There are internal changes, but it is impossible to learn
what they are; symptoms alone are accessible; with their removal by
remedies the disease is removed. Their effects can be studied in the
healthy only. They act on the sick by causing a disease similar to that
which is to be combated, and which dissolves itself into this similar
affection. The full doses required to cause symptoms in the well are
too large to be employed as remedies for the sick. The healing power
of a drug grows in an inverse proportion to its substance. He says,
literally: ‘Only potencies are homœopathic medicines.’ ‘I recognize
nobody as my follower but him who gives medicine in so small doses
as to preclude the perception of anything medicinal in them by means
either of the senses or of chemistry.’ ‘The pellets may be held near
the young infant when asleep.’ ‘Gliding the hand over the patient
will cure him, provided the manipulation is done with firm intention
to render as much good with it as possible, for its power is in
the benevolent will of the manipulator.’ Such is the homœopathy of
Hahnemann, which is no longer recognized in what they call homœopathy
to-day.”—(A. JACOBI.)
The awakening came in France. In 1801 Bichat, a young man, published
a work on general anatomy, in which he placed the seat of disease,
not in the organs, but in the tissues or fabrics of which they were
composed, which gave an extraordinary impetus to the investigation
of pathological changes. Meanwhile, the study of the appearances of
organs and bodies when diseased (morbid anatomy), which had been
prosecuted with vigor by Morgagni in the eighteenth century, had been
carried on actively in Great Britain and on the Continent, and the
work of Broussais stimulated a more accurate investigation of local
disorders. The discovery by Laennec of the art of auscultation, by
which, through changes in the normal sounds within the chest, various
diseases of the heart and lungs could be recognized, gave an immense
impetus to clinical research. The art of percussion, discovered by
Avenbrugger in the eighteenth century, and reintroduced by Corvisart,
contributed not a little to the same. Laennec’s contributions to the
study of diseases of the lungs, of the heart, and of the abdominal
organs really laid the foundation of modern clinical medicine. A little
later Bright published his researches on diseases of the kidneys, from
which we date our knowledge of this important subject. One of the most
complicated problems of the first half of the century related to the
differentiation of the fevers. The eruptive fevers, measles, scarlet
fever, and small-pox, were easily recognized, and the great group of
malarial fevers was well known; but there remained the large class of
continued fevers, which had been a source of worry and dispute for
many generations. Louis clearly differentiated typhoid fever, and by
the work of his American pupils, W. W. Gerhard and Alfred Stillé, of
Philadelphia, and George B. Shattuck, of Boston, typhus and typhoid
fevers were defined as separate and independent affections. Relapsing
fever, yellow fever, dengue, etc., were also distinguished. The work of
Graves and Stokes, of Dublin, of Jenner and Budd, in England, of Drake,
Dickson, and Flint, in America, supplemented the labors of the French
physicians, and by the year 1860 the profession had reached a sure and
safe position on the question of the clinical aspects of fevers.
The most distinguishing feature of the scientific medicine of
the century has been the phenomenal results which have followed
_experimental investigations_. While this method of research is not
new, since it was introduced by Galen, perfected by Harvey, and
carried on by Hunter, it was not until well into the middle of the
century that, by the growth of research laboratories, the method
exercised a deep influence on progress. The lines of experimental
research have sought to determine the functions of the organs in
health, the conditions under which perversion of these functions occur
in diseases, and the possibility of exercising protective and curative
influences on the processes of disease.
The researches of the physiological laboratories have enlarged in every
direction our knowledge of the great functions of life—digestion,
assimilation, circulation, respiration, and excretion. Perhaps in no
department have the results been more surprising than in the growth
of our knowledge of the functions of the brain and nerves. Not only
has experimental science given us clear and accurate data upon the
localization of certain functions of the brain and of the paths of
sensatory and of motor impulses, but it has opened an entirely new
field in the diagnosis and treatment of the diseases of these organs,
in certain directions of a most practical nature, enabling us to resort
to measures of relief undreamed of even thirty years ago.
The study of physiology and pathology within the past half-century
has done more to emancipate medicine from routine and the thraldom of
authority than all the work of all the physicians from the days of
Hippocrates to Jenner, and we are as yet but on the threshold.