36 THE GENESIS OF SPECIES. [Chap. 



mentioning* the frequent sudden appearances of domestic 

 varieties, he speaks of " the false belief as to the similarity 

 of natural species in this respect." ^ In his work on the 

 "Origin of Species," he also observes, "Natural Selection 

 acts only by the preservation and accumulation of small 

 inherited modifications." ' And " Natural Selection, if it 

 be a true princij)le, will banish the belief ... of any great 

 and sudden modification in their structure." * Finally, he 

 adds, " If it could be demonstrated that any complex oi-gan 

 existed, which could not possibly have been formed by nu- 

 merous, successive, slight modifications, my theory would 

 absolutely break down." ' 



Now the conservation of minute variations in many 

 instances is, of course, plain and intelligible enough ; such 

 e. g., as those which tend to promote the destructive facul- 

 ties of beasts of prey on the one hand, or to facilitate the 

 llight or concealment of the animals pui-sued on the other ; 

 provided always that these minute beginnings are of such 

 a kind as really to have a certain efliciency, however small, 

 in favor of the conservation of the individual possessing 

 them; and also provided that no unfavorable peculiarity 

 in any other direction accompanies and neutralizes, in the 

 sti-uggle for life, the minute favorable variation. 



But some of the cases which have been brouirht for- 

 ward, and which have met with very general acceptance, 

 seem less satisfactory when carefully analyzed than they at 

 first appear to be. Among these we m.ay mention " the 

 neck of the giraffe." 



At first sight it would seem as though a better exam- 

 ple in support of " Natural Selection " could hardly have 

 been chosen. Let the fact of the occurrence of occasional 

 severe droughts in the country which that animal has in- 



* "Animals and Plants under Domestication," vol. ii., p. 114. 



3 "Origin of Species," 5th edit., 18G9, p. 110. 



*Ibid., p. 111. Mh'id., p. 227. 



