284 Prof. Guthrie^ LL.B. — On the Subjective Causes oj [April 25, 



ing many botanists, and the mere fact that such varieties can be and 

 are classified and named, seems to prove that varieties are not all 

 round varieties due to chance (unknown law) but to definite laws, 

 which produce like results in places remote from each other. 



(4.) The theory of a law of variation in predetermined directions 

 :also renders more intelligible the development of organs so compli- 

 cated and specialized as the eye. 



Darwin admits that when he reflected at what an early geological 

 period eyes of apparently perfect organization were produced, he 

 hesitated long to come to the conclusion that mere casual variation 

 -and natural selection could have produced them. 



The hypothesis of natural tendency to vary in prescribed directions 

 would remove much of this difficulty. 



If we imagine that the early and lower forms of animal life were 

 sensitive to light over their entire surface, we can easily imagine 

 that the localization of this sensitiveness increased in degree, and its 

 suppression elsewhere might be an advantage to the animal. Such 

 a change being the first step toward the development of an eye if 

 occurring according to a law, a tendency to vary in a prescribed 

 direction might within a period, not inordinately prolonged, result in 

 the complete perfection of the organ. 



(5.) The migration theory supposes that man originated from a 

 single pair of ancestors belonging to some anthropomorphic species 

 now extinct, and that from this pair of ancestors, the Bushman and 

 the Caucasian have both descended. The theory of simultaneous 

 variation merely supposes that the Bushman and the Caucasian have 

 descended from the same ancestral anthropomorphic species but that 

 neither is the Bushman a degenerated Caucasian nor a Caucasian 

 an improved Bushman, nor that the Bushman and Caucasian descended 

 from common ancestors. 



It may be urged against the theory of variation by common innate 

 tendency that it only accounts for the existence of widely spread 

 species by supposing the previous existence of an equally widespread 

 parent species. 



This is true, but it is hardly a valid objection. 



Geology in no very distinct terms perhaps, but still conclusively 

 -enough, seems to tell us that the fauna and flora of the world 

 were formerly less diversified than at present : that species and 

 genera if not fewer in number were at least more cosmopolitan in 

 habit than at present : that for example the fauna and flora of 



