THE PROBLEM OF UTir,ITY. 491 



The next alleged cause, Isolation, I do not admit to be a vera 

 causa at all, for reasons already given. It is, at most, an aid to 

 the dilFerentiation of new species by natural selection. 



The last alleged cause, the Laws of Grrowth, can never, of 

 itself, account for specific characters, but only for those struc- 

 tural and histological peculiarities of organisms which characterize 

 the higher groups such as classes and sometimes perhaps orders 

 and families ; and even these must always, when they first 

 originated, have had a utilitarian character, since it is almost 

 impossible to conceive that the details of structure of the various 

 tissues or organs produced under the action of these laws were 

 absolutely indifferent to the well-being of the organism. 



If, then, we admit, as I do admit, that certain growths, 

 appendages, or markings, which are of no use to the organism, 

 do occasionally appear, no agency has been adduced which could, 

 first, cause these useless characters to appear in every individual 

 of a species, and then totally cease to appear whenever any 

 portion of this species is selected and slightly modified so as to 

 occupy a new j)lace in nature or to save itself from extinction by 

 some new enemy. "Whenever useless characters are said to be 

 " specific," it seems to be forgotten that one species has always 

 passed continuously into another by a process of normal indi- 

 vidual variation and survival of the fittest. There is no chasm 

 in such a process, no sudden transition from one creature to 

 another of a different nature. The transition is by a purely 

 normal and almost imperceptible process of adaptation to new 

 conditions, and in itself furnishes no reason whatever why any 

 useless character, if it had constantly reappeared in the 

 countless millions of individuals during all the millions of 

 generations of the duration of the species, should at once 

 disappear, or be replaced by some new charact-,r equally uni- 

 versal, equally invariable, and equally useless. 



I strongly urge, therefore, that the general causes suggested 

 by Darwin as possibly leading to the production of useless 

 specific characters, as well as the more special causes enumerated 

 by Mr. Eomaues, do not apply to the actual facts of variation 

 and heredity so far as they are yet known to us ; and further, 

 that no attempt has been made to show, even hypothetically, 

 how, through the action of known causes, such characters, when 

 they do arise, can become first extended to every individual of a 

 species, and tlien be totally obliterated as regards any portion of 

 the species which may become modified so as to constitute a new 



