THE EVOLUTION OF ORGANIC BEHAVIOUR 37 
How they arise cannot here be discussed. But they are, it is 
believed, subject to the influence of natural selection, which 
has guided them, throughout the ages of organic evolution, 
in the directions they have taken ; disadvantageous variations 
having been eliminated, and favourable variations surviving 
in the struggle for existence. Such modes of behaviour as are 
congenital and are due to hereditary transmission are therefore 
the outcome of variations which have been selected generation 
after generation. And the fit adjustment of this congenital 
behaviour to the needs of life is termed adaptation. It is here 
assumed that modifications of behaviour in one generation 
are not inherited, and therefore contribute nothing to the 
store of adaptive behaviour in the next generation. 
It must not, however, be supposed that the provisional accept- 
ance of this conclusion involves the denial of all connection 
of any sort between accommodation and adaptation. When we 
remember that plastic modification and germinal variation have 
been working together, in close association, all along the line of 
organic evolution to reach the common goal of adjustment to 
the circumstances of life, it is difficult to believe that they 
have been throughout the whole process altogether independent 
of each other. Granted that acquired modifications, as such, 
are not directly inherited, they may none the less afford the 
conditions under which coincident variations escape elimination. 
By coincident variations I mean those the direction of which 
coincides with that taken by modification. The survival of 
an animal depends on its adjustment to the circumstances 
of its life, no matter how this adjustment is secured. And 
this survival would in the long run be better secured, we may’ 
suppose, where the two methods of adjustment were coincident 
and not conflicting ;* just as a man who not only acquires by 
* Professor Mark Baldwin has applied the term “organic selection ” 
to the result of this interaction (American Naturalist for June and 
July, 1896). Cf. also H. F. Osborn (Sedence, Nov. 27, 1896); August 
Weismann (Romanes Lecture on “The Effects of External Influences 
on Development,” 1894), and “Germinal Selection,’ Monist, Jan., 
1896; and the author’s “ Habit and Instinct,” ch. xiv., 1896. 
