BIOLOGICAL SCIENCE 53 



When the full stream of the recovery of the ancient 

 writings reached Europe in the years of the Renais- 

 sance, it was thought that science would show the 

 same marvellous development that literature and 

 philosophy had undergone. Hence at first medicine 

 sought to solve all its problems by the wisdom of the 

 ancients rather than to build up a sound system by 

 the painfully slow methods of observation and ex- 

 periment. Isolated revolts were led, especially by 

 Leonardo da Vinci and Paracelsus (1490-1541), 

 against the tyranny of Greek authority, but it was 

 not till 1543, when Vesalius taught anatomy from his 

 own observations, that the true method was generally 

 used. In 1628 William Harvey applied the methods 

 of the new anatomy to the problems of physiology, 

 and, as a first-fruits, revealed the mechanism of the 

 circulation of the blood. 



From that point growth was rapid, helped by the 

 new physical knowledge, by the application of the 

 microscope, by experiments on living animals, and 

 by the development of a less fantastic scheme of 

 chemical knowledge than that which had been 

 current among the earlier alchemists. 



The growth of medicine and the demand for new 

 drugs reacted both on chemistry and botany. In 

 the former science it led to the discovery of many 

 substances before unknown, while in the latter, 

 besides inducing the cultivation of useful herbs, it 

 caused more intimate research into the structure and 



