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 Delbceuf’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.” 1 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. 
