Ii Modern Medicine

The natural history of disease was a subject which Sydenham (q.v.) pursued with the greatest vigour and with life-long devotion. None before him had set himself to consider011 the actual cases of disease that lay before him as a subject of scientific description and analysis. This was the great achievement of the "English Hippocrates." He set well on its way the conception of infectious conditions as specific entities, a conception which has since been illuminated by the germ theory of disease.

To one infectious disease, syphilis, we must refer more particu larly. During the middle ages there had smouldered in various districts an obscure disease known most frequently as lepra.

Towards the end of the 15th century this disease broke out in epidemic form all over Europe, causing great destruction of life.

It received various titles, such as "the pox," "the French disease," "the Spanish disorder." Only tardily was it recognized that it was of venereal origin. In 153o, on the suggestion of Fracastoro, it received the cognomen syphilis. From the time of its recognition, syphilis has been pursued by a portentous mass of confused literature. Alarm, misunderstanding, religious feeling, false mod esty, wilful misrepresentation, and the change in type of the disease itself, have all contributed their quota of obscurantism and fable to a naturally difficult subject. Fracastoro did some thing to bring order out of the confusion.

The Rise of Physiology.

The later i6th and the earlier 17th centuries are marked by great activity in experimental physical science. The manner of working of physical phenomena was reduced to mathematical rules, based on measurement. This had a strong reaction on medicine. The first to apply these principles to medical matters was Sanctorius (1561-1636), a professor at Padua. He described a thermometer—though an extremely de fective one—for comparing the temperatures of different per sons and an apparatus for comparing pulse rates. He also sought to compare the weight of the body at different times and in dif ferent circumstances. In doing this he demonstrated that the body loses weight by mere exposure, a process which he ascribed to "insensible perspiration." He thus laid the foundations of the study of metabolism.

Another important professor was Jerome Fabricius of Aquapen dente, who taught at Padua for over so years, from 1565 till his death at 82 in 1619. He was the founder of modern embryology and the author of the first illustrated work on that subject. He investigated the valves of the veins and observed that their mouths are always directed towards the heart. He failed to draw any important conclusion from this fact and the real importance of Fabricius is not so much as an investigator, but as a teacher. He was the master of the discoverer of the circulation of the blood, William Harvey (1578-1657) (q.v.).

Harvey and Boyle.

Knowledge of the circulation of the blood has been the basis of the whole of modern physiology, and with it of the whole of modern rational medicine. The blood, it was seen, is a carrier always going round and round on the same beat. What it carries, and why, how and where it takes up its loads, and how, where and why it parts with them, are questions the answering of which has been the main task of physiology in the centuries that have followed. As each question has obtained a more rational answer, so medicine has made a step toward be coming a true science. Thus the work of Harvey lies at the back of every important medical advance.

In the second half of the 17th century there were two im portant scientific movements destined between them to develop yet further the conception of the workings of the body of which Harvey had made a beginning. These were the movement for the microscopical examination or analysis of the tissues (see BIOLOGY, HISTORY OF) and the movement from alchemy to chemistry. (See CHEMISTRY, HISTORY OF.) The revelations of the early microscopists showed at once an unexpected complexity of all the parts, and an unexpected re semblance of apparently diverse parts. Thus, the structure of the body came to be subjected to a process that we may call "microscopic analysis." After the first half of the 17th century, few improvements were made in the microscope until modern times, and the progress of microscopic analysis lay dormant. With the advance in the construction of the microscope in the I9th century, the method was taken up again with triumphant results.