28o EVOLUTION, OLD AND NEW. 



satisfactory than Lamarck's, inasmuch as he immedi- 

 ately brings forward instances of various modifications 

 which have in each case been due to one of the three 

 main desires above specified, namely, reproduction, sub- 

 sistence, and self-defence. 



Lamarck concludes the chapter with some passages 

 which show that he was alive — as what Frenchman 

 could fail to be after Buffon had written ? — ^to the con- 

 sequences which must follow from the geometrical ratio 

 of increase, and to the struggle for existence, with 

 consequent survival of the fittest, which must always 

 be one of the conditions of any wild anipaal's existence. 

 The paragraphs, indeed, on this subject are taken with 

 very little alteration from Buffon's work. As Lamarck's 

 theory is based upon the fact that it is on the nature of 

 these conditions that the habits and consequently the 

 structure of any animal will depend, he must have seen 

 that the shape of many of its organs must vary 

 greatly in correlation to the conditions to which it was 

 subjected in the matter of self-protection. I do not see, 

 then, that there is any substantial difference between 

 the positions taken by Dr. Erasmus Darwin and by 

 Lamarck in this respect. 



" Let us conclude," he writes, " by showing the means 

 employed by nature to prevent the number of her 

 creatures from injuring the conservation of what has 

 been produced already, and of the general order which 

 should subsist.* 



" In consequence of the extremely rapid rate of in- 

 * 'PhU. Zool.,' torn. i. p. 111. 



