EVOLUTION OF THE COLORS OF BIRDS. 43 



originated, even if it has been instrumental in the de- 

 velopment of the aesthetic faculties. In speaking of the 

 culture of latent abilities he has yielded a most import- 

 ant point. There was obviously a time in the evolution 

 of organic life when piano playing, or, in more general 

 terms, appreciation of harmony, was not even a latent 

 faculty. It would be taxing our credulity to assume, for 

 example, that amoeba possessed it. Then it must, at 

 some time, have come into existence as a latent faculty, 

 and later on been developed by use, or culture, as Ball 

 calls it; and this developed faculty has been inherited. 



Spencer published in the Nineteenth Century for April 

 and May, 1886, two essays, which have since appeared 

 in a separate form, entitled "The Factors of Organic 

 Evolution. " " Among the most important criticisms of 

 this work is the one by Romanes in an article bearing* 

 the same title, which appeared in Mature August 25, 

 1887; and Ball's criticism in his pamphlet, "Are the 

 Effects of Use and Disuse Inherited?" Spencer gives 

 three forms of evidence in proof of the inheritance of 

 acquired characters (1) the crowding of teeth in dogs 

 and reduced size of the jaw in civilized man; (2) the 

 correlation of different parts of the organism, and (3) 

 the apparent direct influence of the environment in 

 altering the surface of an organism. 



Romanes and Ball agree that Spencer has failed to 

 prove his first point. Romanes says, in regard to this: 

 "Be it observed, I am not disputing that disuse may in 

 both these cases have co-operated with the cessation of 

 selection in bringing about the observed result. In- 

 deed, I am rather disposed to allow that the large amount 

 of reduction described in the case of the dogs as having 

 taken place in so comparatively short a time, is strongly 

 suggestive of disuse having co-operated with the cessa- 

 tion of selection. But at present I am merely pointing 



