HISTORICAL DEVELOPMENT OF ZOOLOGY 443 



Greek and Roman history and on down through the 

 Middle Ages zoology and most of the other sciences devel- 

 oped as mere appendages of the medical profession. 



Discovery of the Microscope. Interesting as they are, the 

 discoveries as late as those of the sixteenth and seventeenth 

 centuries merely paved the 

 way for the real development 

 of the various branches of 

 zoology. About the opening 

 of the seventeenth century 

 the microscope was invented. 

 A Dutch spectacle-maker, 

 named Zacharias Jensen, is 

 usually credited with its in- 

 vention. The development 

 of this instrument opened 

 an entirely new field of en- 

 trancing interest. Then for 

 the first time man became 

 aware of the teeming world 

 of minute life. So also was 

 the way opened for an un- 

 derstanding two centuries 

 later of the structure of the 

 animal body. 



Beginnings of Classification. All through the centuries there 

 had been no uniformity in the names used for the various 

 animals. As knowledge spread and interest in living things 

 grew this lack of uniformity in names became more and more 

 apparent. To the Swedish scientist Carl Linnaeus (1707-1778) 

 we are indebted for a system of exact naming. He is gener- 

 ally called the father of systematic zoology (Fig. 232). He 

 devised a system called binomial nomenclature wherein each 

 kind of animal is known by a name composed of two words, 



Fig. 231 



