PREDARWINIAN AND POSTDARWINIAN BIOLOGY 383 



always lagged behind the physical sciences. This is attributable in 

 large measure, of course, to the greater complexity of organic phe- 

 nomena, but I suspect that the fact that animals and plants admit of 

 an arrangement in generic and specific categories, which seem at first 

 sight to be in singular haiTQony with the spirit of ancient science and 

 philosophy, may be to a considerable extent responsible for the stolid 

 conservatism of systematic biology. At a time when the physical sci- 

 ences, through the labors of Kepler, Gallilei and Newton, had already 

 become modern sciences in the true sense of the word, biology was still 

 practically in the Greek stage. This is certainly true of zoology and 

 botany proper up to the middle of the last century, although zoology 

 had through medicine contracted some of the modern spirit, since by 

 that time anatomy and physiology had definitively abandoned Greek and 

 scholastic methods. 



At this juncture appeared Darwin's " Origin of Species." The 

 effect of this work was in the first instance destructive, for it tended to 

 dissolve and mobilize the rigid conceptual schematism that dominated, 

 not only the zoology and botany, but the whole cosmology of the time. 

 The conception of an evolution which melted all living beings, man 

 included, into a single vital stream, surging on into the future as it 

 has surged through the aeons of the past, continually creating new and 

 destroying old forms, could not fail to clash with the conception of a 

 world created once for all and since engaged very largely in marking 

 time. According to the old view, living objects are more or less vitiated 

 Platonic ideas or Aristotelian forms, according to the new they are 

 eddies or whirlpools in a living current that modify and regulate their 

 movements according to the obstacles, i. e., the " environment " which 

 they encounter. No wonder men like Cuvier declined to accept the 

 doctrine of evolution when it was first promulgated by Lamarck, and 

 that von Baer and Louis Agassiz regarded its rehabilitation by Darwin 

 as a heresy. All of these men believed in the existence of permanent 

 types of organic structure, which, after all, were merely Platonic ideas 

 parading under assumptions more or less theological, privileged moments 

 or aspects of animal and plant morphology interpreted as thoughts of 

 the Deity. It is quite unnecessary to mention the innumerable 

 scholastic and theological opponents of evolution. Their animosity 

 certainly had and still has other motives than a predilection for the 

 Mosaic account of creation. 



It is far pleasanter to contemplate the constructive aspects of Dar- 

 win's work. Since evolution, as conceived by him, admitted of a 

 mechanical explanation — for survival through natural selection is 

 mechanical and not teleological like survival through psychical effort 

 as postulated by Lamarck — it breathed the spirit of the physical sciences 

 and therefore allied itself with these rather than with psychology and 



