INTRODUCTION 



FOUR HUNDRED years ago, say in the year 1500, Biology, 

 the science of life, was represented chiefly by a slight 

 and inaccurate natural history of plants and animals. 

 Botany attracted more students than any other branch, 

 because it was recognised as a necessary aid to medical 

 practice. The zoology of the time, extracted from 

 ancient books, was most valued as a source from 

 which preachers and moralists might draw impressive 

 emblems. Anatomy and physiology were taught out of 

 Galen to the more learned of physicians and surgeons. 

 Some meagre notices of the plants and animals of 

 foreign countries, mingled with many childish fables, 

 eked out the scanty treatises of European natural 

 history. It was not yet generally admitted that fossil 

 bones, teeth, and shells were the remains of extinct 

 animals. 



It is the purpose of the following chapters to show 

 how this insignificant body of information expanded 

 into the biology of the twentieth century ; how it 

 became enriched by a multitude of new facts, strength- 

 ened by new methods and animated by new ideas. 



The Biology of the Ancients. 



Long before the year 1500 there had been a short- 

 lived science of biology, and it is necessary to explain 

 how it arose and how it became quenched. Ancient 

 books and the languages in which they are written 

 teach us that in very remote times men attended to the 



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