THE PROGRESS OF SCIENCE 



57i 



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 con- 

 spicuous illustration of the fruitful 

 application of the experimental method 

 to a fundamental physiological prob- 

 lem, 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 ac- 

 cepted 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 cen- 

 turies. The Galenical physiology re- 

 mained, however, in complete authority 

 on all matters pertaining to the func- 

 tions of the body. It taught that the 

 liver is the source of the blood, one ! 

 kind of which flowed to the right ven- 1 

 tricle 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 gen- 

 eral system. It was supposed that the 

 blood flowed directly from the right 

 to the left ventricle through the per- 

 vious septum of the heart. The mus- 

 cular function of the heart in propel- 

 ling the blood was unknown. Such 



were the prevailing conceptions in 

 Harvey's time. While the lesser cir- 

 culation had been fully described, its 

 function was supposed to be the nutri- 

 tion of the lungs. It may be doubted 

 whether any one had even glimmerings 

 of the greater or systemic circulation. 

 The demonstration of this was Har- 

 vey'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 anato- 

 mist of the day, Harvey returned to 

 London as a general practitioner, and 

 in the course of time was appointed 

 Lumleian lecturer to the Royal Col- 

 ege of Physicians. It was before the 

 president, censors and fellows of the 

 college and an unusually large com- 

 pany of laymen that, on April 17, 1616, 

 he demonstrated the structure and ac- 

 tion of the heart and propounded his 

 new doctrine of the general circula- 

 tion. 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 au- 

 thority of Hippocrates, Galen and Co- 

 lumbus 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 exper- 

 imentation, to the fullness of the array 

 of evidence adduced, and to the bril- 

 liancy of the demonstration, its truth 

 could not long be denied. He himself 

 lived to see his discovery all but uni- 

 versally accepted, and Hobbes's oft- 

 quoted statement is well-nigh literally 

 true that Harvey, ' conquering envy, 



