340 EVOLUTION, OLD AND NEW. 



few of which can be dimly seen"* " The results of the 

 unknown, or but dimly understood, laws of variation are 

 infinitely complex and diversified."! "We are pro- 

 foundly ignorant of the cause of each slight variation or 

 individual difference." { "We are far too ignorant to 

 speculate on the relative importance of the several 

 known and unknown causes of variation." He admits, 

 indeed, the effects of use and disuse to have been im- 

 portant, but how important we have no means of 

 knowing ; he also attributes considerable effect to the 

 action of changed conditions of life but how con- 

 siderable again we know not ; nevertheless, he sees no 

 great principle underlying the variations generally, 

 and tending to make them appear for a length of time 

 together in any definite direction advantageous to the 

 creature itself, but either expressly, as at times, or by 

 implication, as throughout his works, ascribes them to 

 accident or chance. 



In other words, he admits his ignorance concerning 

 them, and dwells only on the accumulation of variations 

 the appearance of which for any length of time in any 

 given direction he leaves unaccounted for. 



Lamarck, again, having established his principle that 

 sense of need is the main direct cause of variation, and 

 having also established that the variations thus en- 

 gendered are inherited, so that divergences accumu- 

 late and result in species and genera, is comparatively 

 indifferent to further details. His work is avowedly 

 an outline. Nevertheless, we have seen that he was 



* l Origin of Species/ p. 8. f Ibid. p. 9. 

 $ Ibid. p. 158. Ibid. p. 159. 



