116 THE GENESIS OF SPECIES. [CHAP. 



"the most probable nature, or way of operation of the 

 secondary law, whereby species have been derived one 

 from the other." 1 



Now, considering the number of instances adduced of 

 sudden modifications in domestic animals, it is somewhat 

 startling to meet with Mr. Darwin's positive assertion that 

 it is " a false belief" that natural species have often origi- 

 nated in the same abrupt manner. The belief may be false, 

 but it is difficult to see how its falsehood can be positively 

 asserted. 



It is demonstrated by Mr. Darwin's careful weighings 

 and measurements, that, though little used parts in 

 domestic animals get reduced in weight and somewhat 

 in size, yet that they show no inclination to become truly 

 " rudimentary structures." Accordingly, he asserts, 2 that 

 such rudimentary parts are formed " suddenly, by arrest 

 of development " 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 : 3 "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 

 evidence proves anything. 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- 



1 "Anatomy of Vertebrates," vol. iii. p. 807. 



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



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



