IV.] MINUTE MODIFICATIONS. 117 



yet that they show no inclination to become truly " rudi- 

 mentary structures." Accordingly he asserts 19 that such 

 rudimentary parts are formed " suddenly by arrest of de- 

 velopment " in domesticated animals, but in wild animals 

 slowly. The latter assertion, however, is a mere assertion ; 

 necessary, perhaps, for the theory of " Natural Selection," 

 but as yet unproved by facts. 



But why should not these changes take place suddenly 

 in a state of nature ? As Mr. Murphy says, 30 " It may be 

 true that we have no evidence of the origin of wild species 

 in this way. But this is not a case in which negative evi- 

 dence proves any thing. We have never witnessed the 

 origin of a wild species by any process whatever ; and if a 

 species were to come suddenly into being in the wild state, 

 as the Ancon Sheep did under domestication, how could you 

 ascertain the fact ? If the first of a newly-begotten species 

 were found, the fact of its discovery would tell nothing 

 about its origin. Naturalists would register it as a very 

 rare species, having been only once met with, but they 

 would have no means of knowing whether it were the first 

 or the last of its race." 



To this Mr. Wallace has replied (in his review of Mr. 

 Murphy's work in Nature^), by objecting that sudden 

 changes could very rarely be useful, because each kind of 

 animal is a nicely-balanced and adjusted whole, any one 

 sudden modification of which would in most cases be hurt- 

 ful unless accompanied by other simultaneous and harmoni- 

 ous modifications. If, however, it is not unlikely that there 

 is an innate tendency to deviate at certain times, and under 

 certain conditions, it is no more unlikely that that innate 

 tendency should be a harmonious one, calculated to simul- 

 taneously adjust the various parts of the organism to their 



19 " Animals and Plants under Domestication," vol. ii., p. 318. 



20 " Habit and Intelligence," vol. i., p. 344. 

 ' See December 2, 1869, vol. L, p. 132. 



