810 MEDICINE [HISTORY. the discovery of the circulation by Harvey (published in 1628), the mechanical philosophy of Descartes and the contemporary progress of physics, the teaching of Van Helrnont and the introduction of chemical explanations of morbid processes, and finally, combined of all these, and inspiring them, the rise of the spirit of inquiry and innova tion, which may be called the scientific movement. Before speaking in detail of these, we may note that by other influences, quite independent of theories, important addi tions were made to practical medicine. The method of clinical instruction in hospitals, commenced by the Italians, was introduced into Holland, where it was greatly developed, especially at Leyden, in the hands of the celebrated Sylvius. It is noteworthy that concurrently with the rise of clinical study the works of Hippocrates were more and more valued, while Galen began to sink into the background. At the same time the discovery of new diseases, unknown to the ancients, and the keener attention which the great epidemics of plague caused to be paid to those already known, led to more minute study of the natural history of disease. The most important disease hitherto undescribed was rickets, first made known by Arnold de Boot, a Frisian who practised in Ireland, in 1649, and afterwards more fully in the celebrated work of Glisson in 1651. The plague was carefully studied by Diemerbroek (De Peste, 1646) and others. Hodges, of London, in 1665 seems to have been the first who had the courage to make a post-mortem inspection of a plague patient. Bennet wrote an important work on consumption in 1654. During the same period many new remedies were introduced, the most important being cinchona bark, brought to Spain in the year 1640. The progress of pharmacy was shown by the publication of Dispensatories or Pharmacopoeias, such as that of the Royal College of Physicians of London in 1618. This, like the earlier German works of the same kind (on which it was partly founded), contains both the traditional (Galenical) and the modern or chemical remedies. Van Helmont. The medicine of the 17th century was especially distinguished by the rise of systems ; and we must first speak of an eccentric genius who endeavoured to construct a system for himself, as original and opposed to tradition as that of Paracelsus. Van Helmont (1578- 1644) was a man of noble family in Brussels, who, after mastering all other branches of learning as then under stood, devoted himself with enthusiasm to medicine and chemistry. By education and position a little out of the regular lines of the profession, he took up in medicine an independent attitude. Well acquainted with the doctrines of Galen, he rejected them as thoroughly as Paracelsus did, and borrowed from the latter some definite ideas as well as his revolutionary spirit. The archeus of Paracelsus appears again, but with still further complications, the whole body being controlled by the archeus influus, and the organ of the soul and its various parts by the archei insiti, which are subject to the central archeus. Many of the symptoms of diseases were caused by the passions and perturbations of the archeus, and medicines acted by modifying the ideas of the same archeus. These and other notions cannot be. here stated at sufficient length to be intelligible. It is enough to say that on this fantastic basis Helmont con structed a medical system which had some practical merits, that his therapeutical methods were mild and in many respects happy, and that he did service by applying newer chemical methods to the preparation of drugs. He thus had some share, though a share not generally recognized, in the foundation of the iatro-chemical school, now to be spoken of. But his avowed followers formed a small and discredited sect, which, in England at least, can be clearly traced in the latter part of the century. Discovery of the Circulation of the Ittood. The influence of Harvey s discovery began to be felt before the middle of the century. Its merits were recognized by Descartes, among the first, nine years after its publication. For the history of the discovery, and its consequences in anatomy and physiology, we must refer to the article HARVEY. In respect of practical medicine, much less effect was at fir.st noticeable. But this example, combined with the Cartesian principles, set many active and ingenious spirits to work to reconstruct the whole of medicine on a physiological or even a mechanical basis, to endeavour to form what we should now call physiological or scientific medicine. The result of this was not to eliminate dogma from medicine, though it weakened the authority of the old dogma. The movement led rather to the formation of schools or systems of thought, which under various names lasted on into the 18th century, while the belief in the utility or necessity of schools and systems lasted much longer. The most important of these were the so-called iatro-physical or mechanical and the iatro-chemical schools. latro- Physical School The iatro-physical school of medicine grew out of physiological theories. Its founder is held to have been Borelli of Naples (1608-79), whose treatise De motu animalium, published in 1680, is regarded as marking an epoch in physiology. The tendency of the school was to explain the actions and functions of the body on physical and especially en mechanical principles. The movements of bones and muscles were referred to the theory of levers ; the process of digestion was regarded as essentially a process of trituration ; nutrition and secretion were shown to be dependent upon the tension of the vessels, and so forth. The developments of this school belong rather to the history of physiology, where they appear, seen in the light of modern science, as excellent though premature endeavours in a scientific direction. But the influence of these theories on practical medicine was not great. The more judicious of the mechanical or physical school refrained, as a judicious modern physiologist does, from too immediate an application of their principles to daily practice. Mechanical theories were introduced into pathology, in explanation of the processes of fever and the like, but had little or no influence on therapeutics. The most important men in this school after Borelli were Steno (1638-86), Baglivi (1673-1707), and Bellini (1643-1704). An English physician, Cole (1660-1700), is also usually ranked with them. One of the most elaborate develop ments of the system was that of Pitcairn, a Scottish physician who became professor at Leyden (1652-1713), to be spoken of hereafter. latro-Chemical School. The so-called iatro-chemical school stood in a much closer relation to practical medicine than the iatro-physical. The principle which mainly distin guished it was not merely the use of chemical medicines in addition to the traditional, or, as they were called in dis tinction, "Galenical" remedies, but a theory of pathology or causation of disease entirely different from the prevailing "humoral" pathology. Its chief aim was to reconcile the new views in physiology and chemistry with practical medicine. In some theoretical views, and in the use of certain remedies, the school owed something to Van Helmont and Paracelsus, but took in the main an independ ent position. The founder of the iatro-chemical school was Francis de le Boe, called Sylvius (1614-72), belonging to a French family settled in Holland. Sylvius was for fourteen years professor of medicine at Leyden, where he attracted students from all quarters of Europe. He made a resolute attempt to reconstruct medicine on the two bases o r the doctrine of the circulation of the blood and the new views of chemistry. Fermentation, which was
supposed to take place in the stomach, played an important