Page:Popular Science Monthly Volume 69.djvu/575

Rh hands none of its interest and is well worth the repetition.

By the terms of Harvey's bequest, founding the lectureship, the orator is among other things enjoined to exhort the fellows of the college 'to search out and study the secrets of nature by way of experiment.' The discovery of the circulation of the blood is itself a conspicuous illustration of the fruitful application of the experimental method to a fundamental physiological problem, as well as a type of the evolution of scientific truth through the various stages, from the accumulation of facts and observations to a universally accepted explanation. The discovery of the general circulation is one of the important landmarks in the history of science. It evidences, on the one hand, in a peculiarly striking manner, the overthrow of authority and the birth of the modern scientific spirit. On the other hand, in the discovery and more particularly in the methods by which it was attained are laid the foundations of experimental physiology and medicine, which have contributed so incalculably to human welfare.

The sixteenth century had witnessed! notable contributions to the knowledge of the structure of the human body. The work of Vesalius, Fallopius and Fabricius had brought about numerous corrections in the anatomy of Galen, which had been taught in the schools with but little change for fourteen centuries. The Galenical physiology remained, however, in complete authority on all matters pertaining to the functions of the body. It taught that the liver is the source of the blood, one! kind of which flowed to the right ventricle and thence by way of the veins to the lungs and the general system, the other by way of the arteries from the left ventricle to the lungs and general system. It was supposed that the blood flowed directly from the right to the left ventricle through the pervious septum of the heart. The muscular function of the heart in propelling the blood was unknown. Such were the prevailing conceptions in Harvey's time. While the lesser circulation had been fully described, its function was supposed to be the nutrition of the lungs. It may be doubted whether any one had even glimmerings of the greater or systemic circulation. The demonstration of this was Harvey's great work, all the more notable since the estimation of the significance of a scientific discovery is determined by the state of knowledge at the time when it is made.

After studying medicine at Padua under Fabricius, the foremost anatomist of the day, Harvey returned to London as a general practitioner, and in the course of time was appointed Lumleian lecturer to the Royal ColegeCollege [sic] of Physicians. It was before the president, censors and fellows of the college and an unusually large company of laymen that, on April 17, 1616, he demonstrated the structure and action of the heart and propounded his new doctrine of the general circulation. The formal announcement of the discovery in the De Motu Cordis et Sanguinis was, however, deferred for twelve years, furnishing an interesting instance of delay in the publication of a great discovery through fear of the prejudices of men. The motive which actuated Harvey is not far to seek. So complete was the dominance of the authority of Hippocrates, Galen and Columbus that few would have had the temerity to question doctrines which had the sanction of the ancients and were sealed by general acceptance.

The new theory was as usual given a tardy recognition, and in some parts, notably in France, was met with open hostility. Owing, however, to the care and accuracy in observation and experimentation, to the fullness of the array of evidence adduced, and to the brilliancy of the demonstration, its truth could not long be denied. He himself lived to see his discovery all but universally accepted, and Hobbes's oft-quoted statement is well-nigh literally true that Harvey, 'conquering envy,