SUDDEN ADAPTATIONS 459 
intermediate sort, each element being always hereditary 
unless it gives place to a new element through mutation. 
While the parent form may continue to be inherited un- 
changed by certain descendants for innumerable generations 
the descendants of a mutation to which it has given rise may 
mutate again and again, until finally a form has arisen charac- 
terized by so many new elements that it is no longer capable 
of producing offspring like those of the original ancestral 
form. Then a new species has appeared; and by a similar 
differentiation through many successive mutations, there 
would arise genera, families, and groups of higher order. 
Whether the peculiarities of a mutation are beneficial or 
not is immaterial provided only they do not unfit the or- 
ganism for living under the conditions where it occurs. If 
it can gain a foothold either in the same environment as that 
of its parent or under some other set of conditions a new race 
or new species may be started. It has been commonly as- 
sumed by naturalists that every slightest peculiarity of an 
organism must have some important relation to its welfare 
whether apparent to us or not, since otherwise we could not 
understand its fitting into the environment under which it 
thrives. On this view we should have to suppose that all 
the peculiarities of the new forms of escaped primroses repre- 
sent sudden adaptations; but in that case it must be admitted 
that very diverse adaptations fit about equally well into the 
same environment. The assumption that every trait must 
be connected with some use, seems, however, to be quite 
gratuitous. This supposition is not at all necessary to the 
theory of mutations, although, as we have seen, it is a neces- 
sary incumbrance to the theory of natural selection. On 
the new view we may suppose that a mutation presents fea- 
tures which may be more or less beneficial, indifferent, or 
even more or less injurious; yet if it gets into an environ- 
ment which permits such a form to live, then the traits 
of each description may become characteristic of a sur- 
viving group. We all know that however useless or un- 
desirable defects or bad habits may be, they are not neces- 
sarily fatal, and are sometimes perpetuated. Thus we can 
account for the fact that many characters of the highest 
