230 Experimental Zoology 
dary place, for adaptive mutations, like all others, are given; 
not made by selection. 
If it were possible to change each character of a species, so that 
first in one respect, then in another, the organism would become 
better suited to new conditions, — molded to them, as it were, — 
we could imagine that the evolution of organisms has taken 
place in this way. The process of adapting would be the same 
as the process of evolving. This view assumes not only that 
each character may, in turn, be changed without the rest of the 
organism becoming seriously affected, but also that new species 
may be created in this way. Itis this process that the Darwinian 
school has assumed to take place, and hence, for them, evolution 
and adaptation are closely similar processes. 
On the other hand, the mutation theory assumes that new 
species appear without regard to whether the change will be an 
adaptive one or not. If the new form should be one suited 
to the old, or to some new locality, it has a chance of surviving, 
i.e. it is sufficiently adapted to exist. From this point of view the 
problem of evolution is a different one from that of adaptation. 
Moreover, it will be seen that while the process of evolution is one 
that can be studied by scientific methods, the adaptation of an 
organism is not a causal problem at all. If anew form is adapted, 
that is the end of the matter; if it is not, it perishes. The scien- 
tific problem deals with the origin of mutations and their causes. 
Their adaptation is an independent question, and depends on 
whether the proper external conditions exist at the time when 
the mutation appears. Inasmuch as only those mutations sur- 
vive that can survive, we find that organisms are always adapted 
to the environment in which they exist, and this condition of 
living things gives the appearance of a fundamental problem 
where in reality no such problem exists. The causal prob- 
lem is the problem of the origin of new forms; the question 
of their survival is only an historical question for all living 
species. 
Under certain conditions, and ‘in certain cases, the two prob- 
lems appear, at first sight, to merge into each other. For if, 
