66 CREATIVE EVOLUTION [chap. 



endure, capable of preserving and improving vision, has 

 survived. Still, this combination had to be produced. 

 And, supposing chance to have granted this favor once r 

 can we admit that it repeats the self-same favor in the 

 course of the history of a species, so as to give rise, every 

 time, all at once, to new complications marvelously regu- 

 lated with reference to each other, and so related to former 

 complications as to go further on in the same direction? 

 How, especially, can we suppose that by a series of mere 

 "accidents" these sudden variations occur, the same, 

 in the same order, — involving in each case a perfect har- 

 mony of elements more and more numerous and complex — 

 along two independent lines of evolution? 



The law of correlation will be invoked, of course; Dar- 

 win himself appealed to it. 1 It will be alleged that a 

 change is not localized in a single point of the organism, 

 but has its necessary recoil on other points. The ex- 

 amples cited by Darwin remain classic: white cats with 

 blue eyes are generally deaf; hairless dogs have imperfect 

 dentition, etc. — Granted; but let us not play now on the 

 word " correlation. " A collective whole of solidary changes 

 is one thing, a system of complementary changes — changes 

 so coordinated as to keep up and even improve the function- 

 ing of an organ under more complicated conditions — is 

 another. That an anomaly of the pilous system should 

 be accompanied by an anomaly of dentition is quite 

 conceivable without our having to call for a special princi- 

 ple of explanation; for hair and teeth are similar forma- 

 tions, 2 and the same chemical change of the germ that 

 hinders the formation of hair would probably obstruct 



1 Darwin, Origin of Species, chap. i. 



2 On this homology of hair and teeth, see Brandt, "tJber . . . eine 

 mutmassliche Homologie der Haare und Zahne"- (Biol. Centralblatt, 

 vol. xviii., 1898, especially pp. 262 ff .). 



