THE SEVENTEENTH CENTURY
William Harvey, an English physician of the 17th century, studied in Padua under Fabricius and later taught anatomy in London. He published De Motu Cordis (On the Motion of the Heart, 1628), which describes the circulation of blood throughout the body. As the first application of the idea of measurement to a biological phenomenon, the book exhibited true science in its solution of a medical problem. Its importance was quickly recognized by Harvey's contemporaries. The Galenic idea that the heart was a source of heat and that the lungs were cooling devices for the heart gave way before the elegant experiments of English scientists Richard Lower and John Mayow. Mayow passed venous blood through lungs and showed that the change from dark to bright red was associated with the uptake of some substance from the airÑan observation all the more remarkable in that the substance, oxygen, had not yet been discovered. Perhaps the greatest clinician of the century was Thomas Sydenham, who showed concern for the effects of environmental factors on health and had a humanistic approach to the treatment of patients. His written works on fevers and gout are classics of clinical detail and accuracy.
The century was also remarkable for the invention and development of the microscope. By using microscopes, a Dutch scientist, Antoni van Leeuwenhoek, discovered red blood cells, bacteria, and Protozoa as well as describing the microscopic appearance of muscle. The greatest microscopist of the century, Marcello Malpighi, described the embryology of the chick and was the first to observe capillaries, although it was Leeuwenhoek who realized that capillaries completed Harvey's postulated circulation of the blood.
Two philosophic schools of medicine arose in the century, both of which contributed to science but also slowed progress by their excessive rigidity. One, the iatrophysical school, regarded all physiological events as the rigid results of the laws of physics. The mathematician RenŽ Descartes subscribed to this school, but its greatest exponent was Italian scientist Giovanni Borelli.
Many of his studies were valid, but he also advanced such notions as that digestion was a purely mechanical process of grinding and crushing. The iatrochemical school, founded by Flemish chemist Johannes Baptista van Helmont, began as a jumble of ill-defined notions. The idea of the importance of chemistry in medicine, however, took on significance when propounded by English physicist Thomas Willis, who analyzed urine in detail and noted the presence of sugar in diabetic urine. Similarly, Dutch physician Regnier de Graaf collected pancreatic juice and recognized its importance in the digestion of food by chemical rather than mechanical means.
Along with the growth of medical science, an extraordinary amount of humbug was promulgated. Schools of therapeutics based on the "doctrines" of the Egyptian god Thoth and on Zoroastrian or Rosicrucian teachings were widely respected by royal courts. Because of the growing appreciation of the fact that correct medical therapy was based on reasons that could in time be found through research, it was easy for persons to develop false systems that had sufficient logic to give them a flavor of science and therefore of validity.
The great schools of medicine in the 17th century were those of Leyden, Paris, and Montpellier. During this period the Royal Society of London, the AcadŽmie des Sciences in Paris, and the Collegium Naturae Curiosorum in Germany were founded and dedicated to the advancement of science. By means of these societies ideas were exchanged and journals published, thus spreading information throughout much of Europe.