182 C. W. Soal 
mutationist view, at least in its crudest form, would postulate that 
a specific germinal variation or a succession of such variations hap¬ 
pened to give rise to the neural linkages requisite for the perfected 
instinct. The Lamarckian interpretation on the other hand, if applied 
to this case, would assume that the co-ordination was first perfected 
by trial and error during somatic life and the efficient combination 
then gradually stabilised in inheritance. This however would imply 
the pre-existence of a type of functional adaptation (intelligent 
behaviour) of which there is no evidence at this stage of evolution. 
The interpretation we adopt when expressed in ordinary biological 
terms is essentially a combination of the mutationist and Lamarckian 
theories. We postulate a selective synthesis from sporadic bodily 
movements which is neither germinal nor somatic, but organismal 
in character. The stable and efficient organic function in question 
has resulted from a series of steps which, while truly specific and 
appearing first as inherited variations, yet represent each a definite 
reaction on the part of the whole organism in relation to a particular 
set of environmental conditions. According to this view, if the suc¬ 
cession of generations in the phylogeny of any particular species of 
wasp could be telescoped in the manner of a cinematograph film, we 
should simply observe a progressive perfection of the mechanism of 
muscular co-ordination somewhat analogous to that observed in the 
acquisition of a complex habit. The particular bodily movements 
which have been selected and synthesised in this way constitute a 
new organic activity. In its earlier stages the new type of behaviour 
will vary sporadically, but as it becomes progressively integrated 
with the more focal activity-systems it will become more stable. On 
the other hand, those bodily movements which have not been co¬ 
ordinated into definite sequences may still take place, but they will 
remain fortuitous and indefinitely variable 1 . 
There are, however, in different species of wasp considerable 
modifications of this particular type of instinct relative to the kind 
of prey, the method of capture, and the manner in which it is dragged 
to the nest of the insect, which clearly represent divergent trends of 
racial evolution. But there are reasons, based upon a comparative 
study of different species and other grounds, for believing that these 
various specialised types of instinct were all preceded phylogenetically 
1 This example has been chosen for simplicity because the phenomena are 
largely external and therefore more capable of observation. The internal 
bodily characters of plants and animals we presume to be evolved in the same 
way, the only difference being that the sporadic reactions which become 
co-ordinated are of another kind. 
