THE GROWTH AND SCOPE OF BIOLOGY 7 



directed the transformations of matter. This outside intelligence was 

 naturally not subject to inquiry, and it was this feature of the Aristotelian 

 doctrine which won to him the support of the conservatives of the Middle 

 Ages. The uprooting of this system of thought required time, and it was 

 not until the seventeenth century that other well-defined systems of 

 philosophy replaced it. In the meantime biology was struggling up 

 out of the inaction of the Middle Ages, through the period of the 

 Renaissance. 



The Revival. — In the early part of the period of renewed interest in 

 learning, several works on natural history appeared, which showed they 



Fig. 3. — Andreas Vesalius, 1514-1564. {From Garrison, "History of Medicine," W.B. 



Saunders Company.) 



were based in part upon observations made by their authors. The leader- 

 ship in the revival, as far as it concerned biology, was taken by Andreas 

 Vesalius (1514-1564) (Fig. 3), an anatomist. Born at Brussels, he went 

 to Paris at the age of eighteen to study medicine and there showed great 

 independence and force of will. After several years of practice he was 

 called to the University of Padua, in Italy, where everything was favor- 

 able to his work. In his teaching he first followed Galen but soon found 

 the latter incomplete and in places self-contradictory. He then realized 

 tha.t he must teach from his own observation and, to make this possible, 

 published two anatomical works which were masterpieces. His over- 

 throw of Galen infuriated conservative anatomists, including Vesalius's 



