108 EVOLUTION, OLD AND NEW. 



that we can descend by almost imperceptible degrees 

 from the most perfect creature to the most formless 

 matter from the most highly organized animal to the 

 most entirely inorganic substance. He will recognize 

 this gradation as the great work of Nature ; and he will 

 observe it not only as regards size and form, but also in 

 respect of movements, and in the successive generations 

 of every species.* 



" Hence," he continues, " arises the difficulty of ar- 

 riving at any perfect system or method in dealing 

 either with Nature as a whole or even with any single 

 one of her subdivisions. The gradations are so subtle 

 that we are often obliged to make arbitrary divisions. 

 Nature knows nothing about our classifications, and 

 does not choose to lend herself to them without reserve. 

 We therefore see a number of intermediate species 

 and objects which it is very hard to classify, and which 

 of necessity derange our system whatever it may be." 

 " The attempt to form perfect systems has led to such 

 disastrous results that it is now more easy to learn 

 botany than the terminology which has been adopted 

 as its language."! 



After saying that " la marche de la Nature " has been 

 misunderstood, and that her progress has ever been by 

 a succession of slow steps, he maintains that the only 

 proper course is to class together whatever objects 

 resemble one another, and to separate those which are 

 unlike. If individual specimens are absolutely alike, 

 or differ so little that the differences can hardly be 

 perceived, they must be classed as of the same species ; 



* ' Hist. Nat.,' torn. i. p. 13, 1749. t Ibid. 1 Ibid. p. 1G. 



