vi DIFFICULTIES AND OBJECTIONS 141 



eliminated by disuse. But this is entirely begging the ques- 

 tion. Do meaningless peculiarities, which we admit often arise 

 as spontaneous variations, ever perpetuate themselves in all 

 the individuals constituting a variety or race, without selec- 

 tion either human or natural ? Such characters present them- 

 selves as unstable variations, and as such they remain, unless 

 preserved and accumulated by selection ; and they can there- 

 fore never become " specific " characters unless they are strictly 

 correlated with some useful and important peculiarities. 



As bearing upon this question we may refer to what is 

 termed Delboeuf's law, which has been thus briefly stated by 

 Mr. Murphy in his work on Habit and Intelligence, p. 

 241. 



" If, in any species, a number of individuals, bearing a 

 ratio not infinitely small to the entire number of births, are in 

 every generation born with a particular variation which is 

 neither beneficial nor injurious, and if it is not counteracted by 

 reversion, then the proportion of the new variety to the original 

 form will increase till it approaches indefinitely near to 

 equality." 



It is not impossible that some definite varieties, such as the 

 melanic form of the jaguar and the bridled variety of the guille- 

 mot are due to this cause ; but from their very nature such 

 varieties are unstable, and are continually reproduced in 

 varying proportions from the parent forms. They can, 

 therefore, never constitute species unless the variation in 

 question becomes beneficial, when it will be fixed by natural 

 selection. Darwin, it is true, says — " There can be little 

 doubt that the tendency to vary in the same manner has often 

 been so strong that all the individuals of the same species 

 have been similarly modified without the aid of any form of 

 selection." x But no proof whatever is offered of this state- 

 ment, and it is so entirely opposed to all we know of the facts 

 of variation as given by Darwin himself, that the important 

 word " all " is probably an oversight. 



On the whole, then, I submit, not only has it not been 



proved that an " enormous number of specific peculiarities " 



are useless, and that, as a logical result, natural selection is 



" not a theory of the origin of species," but only of the origin 



1 Origin of Species, p. 72. 



