HISTORY OF ZOOLOGY. 9 



Aristotle has also noticed the relationship of the first 

 four groups, since he, without indeed actually carrying out 

 the division, has placed the animals with blood, evai^a 

 (animals proper, with red blood), over against the bloodless, 

 avai^a (animals proper, with colorless blood or with no 

 blood at all). 



DEVELOPMENT OF SYSTEMATIC ZOOLOGY 



Pliny. It is an extremely remarkable fact that suc- 

 ceeding the writings of Aristotle, in which systemization 

 is much subordinated and only serves to express the 

 anatomical conditions of relationship in animals, an exclu- 

 sively systematic direction should have been taken. This 

 is explainable only when we consider that the above-men- 

 tioned connection is merely a superficial one ; that in point 

 of fact the mental continuity of investigation was com- 

 pletely broken on the one hand by the decline and ulti- 

 mate complete collapse of ancient classic civilization, and 

 on the other hand by the triumphant advance of Chris- 

 tianity. The decay of zoological investigation, that had 

 only just begun to bloom, is announced by the writings of 

 Pliny. Although this Roman general and teacher was 

 long lauded as the foremost zoologist of antiquity, he is 

 now given the place of a not even fortunate compiler, who 

 collected from the writings of others the accurate and the 

 fabulous indiscriminately, and replaced the natural classifi- 

 cation of animals according to their structure by the un- 

 natural, purely arbitrary division according to their place 

 of abode (flying animals, land animals, water animals). 



Zoology of the Middle Ages. The rise of Christianity 

 resulted in the complete annihilation of natural science and 

 investigation. The world-shunning character, which or- 

 iginally was peculiar to the Christian conception, led 

 naturally to a disposition hostile to any mental occupation 

 with natural things. Then came a time when answers to 

 questions capable of solution by the simplest observations 

 were sought by painstaking learned rummaging of the 

 works of standard authors. How many teeth the horse 



