The appreciation of his work in physiology belongs to the history
of that science; we are only concerned here with its influence on
medicine. Haller’s definition of irritability as a property of muscular
tissue, and its distinction from sensibility as a property of nerves,
struck at the root of the prevailing hypothesis respecting animal
activity. It was no longer necessary to suppose that a half-conscious
“anima” was directing every movement. Moreover,
Haller’s views did not rest on a priori speculation, but on numerous
experiments. He was among the first to investigate the action of
medicines on healthy persons. Unfortunately the lesson which
his contemporaries learnt was not the importance of experiment,
but only the need of contriving other “systems” less open to objection;
and thus the influence of Haller led directly to the theoretical
subtleties of William Cullen and John Brown, and only indirectly
and later on to the general anatomy of M. F. X. Bichat. The great
name of Haller does not therefore occupy a very prominent place
in the history of practical medicine.
The work of Giovanni Battista Morgagni (1682–1771) had and still preserves a permanent importance beyond that of all the contemporary theorists. In a series of letters, De sedibus et causis morborum per anatomen indagatis, published when he was in his eightieth year, he describes the appearances met with at the post mortem examination as well as the symptoms during life in a number of cases of various diseases. It was not the first work of the kind. The Swiss physician, Théophile Bonet (1620–1689) had published his Sepulcretum in 1679; and observations of post mortem appearances had been made by Montanus, P. Tulp, Raymond Vieussens, A. M. Valsalva, G. M. Lancisi, Haller and others. But never before was so large a collection of cases brought together, described with such accuracy, or illustrated with equal anatomical and medical knowledge. Morgagni’s work at once made an epoch in the science. Morbid anatomy now became a recognized branch of medical research, and the movement was started which has lasted till our own day.
The contribution of Morgagni to medical science must be regarded as in some respects the counterpart of Sydenham’s. The latter had, in neglecting anatomy, neglected the most solid basis for studying the natural history of disease; though perhaps it was less from choice than because his practice, as he was not attached to a hospital, gave him no opportunities. But it is on the combination of the two methods—that of Sydenham and of Morgagni—that modern medicine rests; and it is through these that it has been able to make steady progress in its own field, independently of the advance of physiology or other sciences.
The method of Morgagni found many imitators, both in his own country and in others. In England the first important name in this field is at the same time that of the first writer of a systematic work in any language on morbid anatomy, Matthew Baillie (1761–1823), a nephew of John and William Hunter, who published his treatise in 1795.
Cullen and Brown.—It remains to speak of two systematic writers on medicine in the 18th century, whose great reputation prevents them from being passed over, though their real contribution to the progress of medicine was not great—Cullen and Brown.
William Cullen (1710–1790) was a most eminent and popular professor of medicine at Edinburgh. The same academical influences as surrounded the Dutch and German founders of systems were doubtless partly concerned in leading him to form the plan of a comprehensive system of medicine. Cullen’s system was largely based on the new physiological doctrine of irritability, but is especially noticeable for the importance attached to nervous action. Thus even gout was regarded as a “neurosis.” These pathological principles of Cullen are contained in his First Lines of the Practice of Physic, an extremely popular book, often reprinted and translated. More importance is to be attached to his Nosology or Classification of Diseases. The attempt to classify diseases on a natural-history plan was not new, having been commenced by Sauvages and others, and is perhaps not a task of the highest importance. Cullen drew out a classification of great and needless complexity, the chief part of which is now forgotten, but several of his main divisions are still preserved.
It is difficult to form a clear estimate of the importance of the last systematizer of medicine—John Brown (1735–1788)—for, though in England he has been but little regarded, the wide though short-lived popularity of his system on the Continent shows that it must have contained some elements of brilliancy, if not originality. His theory of medicine professed to explain the processes of life and disease, and the methods of cure, upon one simple principle—that of the property of “excitability,” in virtue of which the “exciting powers,” defined as being (1) external forces and (2) the functions of the system itself, call forth the vital phenomena “sense, motion, mental function and passion.” All exciting powers are stimulant, the apparent debilitating or sedative effect of some being due to a deficiency in the degree of stimulus; so that the final conclusion is that “the whole phenomena of life, health as well as disease, consist in stimulus and nothing else.” Brown recognized some diseases as sthenic, others as asthenic, the latter requiring stimulating treatment, the former the reverse; but his practical conclusion was that 97% of all diseases required a “stimulating” treatment. In this he claimed to have made the most salutary reform because all physicians from Hippocrates had treated diseases by depletion and debilitating measures with the object of curing by elimination. It would be unprofitable to attempt a complete analysis of the Brunonian system; and it is difficult now to understand why it attracted so much attention in its day. To us at the present time it seems merely a dialectical construction, having its beginning and end in definitions: the words power, stimulus, &c., being used in such a way as not to correspond to any precise physical conceptions, still less to definite material objects or forces. One recommendation of the system was that it favoured a milder system of treatment than was at that time in vogue; Brown may be said to have been the first advocate of the modern stimulant or feeding treatment of fevers. He advocated the use of “animal soups” or beef-tea. Further, he had the discernment to see that certain symptoms—such as convulsions and delirium, which were then commonly held always to indicate inflammation—were often really signs of weakness.
The fortunes of Brown’s system (called, from having been originally written in Latin, the Brunonian) form one of the strangest chapters in the history of medicine. In Scotland, Brown so far won the sympathy of the students that riotous conflicts took place between his partisans and opponents. In England his system took little root. In Italy, on the other hand, it received enthusiastic support, and, naturally, a corresponding degree of opposition. The most important adherent to Brown’s system was J. Rasori (1763–1837), who taught it as professor at Pavia, but afterwards substituted his own system of contra-stimulus. The theoretical differences between this and the “stimulus” theory need not be expounded. The practical difference in the corresponding treatment was very great, as Rasori advocated a copious use of bleeding and of depressing remedies, such as antimony. Joseph Frank (1774–1841), a German professor at Pavia, afterwards of Vienna, the author of an encyclopaedic work on medicine now forgotten, embraced the Brunonian system, though he afterwards introduced some modifications, and transplanted it to Vienna. Many names are quoted as partisans or opponents of the Brunonian system in Italy, but scarcely one of them has any other claim to be remembered. In Germany the new system called forth, a little later, no less enthusiasm and controversial heat. C. Girtanner (1760–1800) first began to spread the new ideas (though giving them out as his own), but Weikard was the first avowed advocate of the system. Röschlaub (1768–1835) modified Brown’s system into the theory of excitement (Erregungstheorie), which for a time was extremely popular in Germany. The enthusiasm of the younger Brunonians in Germany was as great as in Edinburgh or in Italy, and led to serious riots in the university of Göttingen. In America the system was enthusiastically adopted by a noted physician, Benjamin Rush (1745–1813), of Philadelphia, who was followed by a considerable school. France was not more influenced by the new school than England. In both countries the tendency towards positive science and progress by objective investigation was too marked for any theoretical system to have more than a passing influence. In France, however, the influence of Brown’s theories is very clearly seen in the writings of François J. V. Broussais, who, though not rightly classed with the system-makers, since his conclusions were partly based upon anatomical investigation, resembled them in his attempt to unite theory and practice in one comprehensive synthesis. The explanation of the meteoric splendour of the Brunonian system in other countries seems to be as follows. In Italy the period of intellectual decadence had set in, and no serious scientific ardour remained to withstand the novelties of abstract theory. In Germany the case was somewhat different. Intellectual activity was not wanting, but the great achievements of the 18th century in philosophy and the moral sciences had fostered a love of abstract speculation; and some sort of cosmical or general system was thought indispensable in every department of special science. Hence another generation had to pass away before Germany found herself on the level, in scientific investigation, of France and England.
Before the theoretic tendency of the 18th century was quite exhausted, it displayed itself in a system which, though in some respects isolated in the history of medicine, stands nearest to that of Brown—that, namely, of Hahnemann (see Homoeopathy). S. C. F. Hahnemann (1753–1844) was in conception as revolutionary a reformer of medicine as Paracelsus. He professed to base medicine entirely on a knowledge of symptoms, regarding all investigation of the causes of symptoms as useless. While thus rejecting all the lessons of morbid anatomy and pathology, he put forward views respecting the causes of disease which hardly bear to be seriously stated. All chronic maladies result either from three diseases—psora (the itch), syphilis or sycosis (a skin disease), or else are maladies produced by medicines. Seven-eighths of all chronic diseases are produced by itch driven inwards.[1] (It is fair to say that these views were published in one of his later works.) In treatment of disease Hahnemann rejected entirely the notion of a vis medicatrix naturae, and was guided by his well-known principle
- ↑ The itch (scabies) is really an affection produced by the presence in the skin of a species of mite (Acarus scabiei), and when this is destroyed or removed the disease is at an end.
