ZOOLOGY EMERGES 51 



and a fifth in 1587, twenty-two years after his death. 

 In some editions it contains 4500 folio pages and 

 nearly 1000 illustrations. 



Through the renewal of observation the stream of 

 science, so long held in check by wrong methods, was 

 released, movement was started and the seventeenth 

 century was notable . for advance in independent 

 observation. The microscope was introduced as a 

 tool of investigation. The whole field of nature came 

 rapidly under examination. Structural studies were 

 applied to vegetables as well as to animals. Mal- 

 pighi (1628-1694), Swammerdam (1637-1680) and 

 Leeuwenhoek (1632-1723) investigated the structure 

 of insects and of other simple animals producing 

 valuable work on minute anatomy, on histology and 

 on embryology. To notice these really important 

 contributions in detail would unduly prolong the 

 story. Accordingly, we pass to Linnaeus (1707- 

 1778) with whom systematic zoology may be said to 

 have begun. 



