THE MEDIAEVAL ATTITUDE 



Jewish writers. In the second place, geology, unlike 

 physics, requires elaborate collections of rocks, min- 

 erals and fossils to be made and classified before any 

 systematic work can be attempted; such collections 

 were not in existence and little interest was shown in 

 establishing museums. 



The biological sciences, in addition to the disad- 

 vantages under which geology suffered, were further 

 restricted by the fact that no means of bridging the 

 gap between the physical forces and life could then 

 be imagined. No forces were known but those of a 

 mechanical and electrical nature, and no one saw how 

 these could be applied by the inductive method to 

 what they termed vital actions. Thus biology was 

 limited for two or three hundred years to the slow 

 accumulation of facts about living species of plants 

 and animals. Even the discovery of the microscope 

 did not accomplish more than to awaken some inter- 

 est in the composition of tissues and to extend our ac- 

 quaintance with a few minute organisms. On the 

 other hand, the progress in the knowledge of human 

 anatomy and physiology was much more rapid. 



Before closing this survey of the ideas which pre- 

 ceded our modern theory of evolution, a discovery 

 should be discussed because it had a profound influ- 

 ence in furthering the mechanistic, doctrine of life 

 which, if my ideas are correct, is the foundation for 

 any scientific theory of evolution. In 1628, Harvey 

 published his discovery of the circulation of the 



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