EVOLUTION OF INTELLIGENT BEHAVIOUR 165 
to separately acquire its experience, and well remembers what 
it has learnt,’”—a conclusion with which, as already stated, my 
own observations are entirely in accord. There is therefore a 
certain amount of destruction of even well-protected forms 
by young and inexperienced birds. If, then, two such forms 
resemble each other, the acquisition of experience is thereby 
facilitated and the amount of destruction reduced, on the 
assumption that the two fall within the same generic image. 
Upholders of natural selection are not, indeed, at one in accept- 
ing this explanation, and further observation is unquestionably 
needed. It is not improbable, however, that common protective 
coloration, such as the banding of yellow and black, seen in such 
different forms as the caterpillar of the cinnabar moth and the 
imago of the wasp, is of mutual utility. The following experi- 
ment was made with young chicks. Strips of orange and black 
paper were pasted beneath glass slips, and on them meal 
moistened with quinine was placed. On other plain slips 
meal moistened with water was provided. The young birds 
soon learnt to avoid the bitter meal, and then would not touch 
plain meal if it were offered on the banded slip. And these 
birds, save in two instances, refused to touch cinnabar cater- 
pillars, which were new to their experience. They did not, 
like other birds, have to learn by particular trials that these 
caterpillars are unpleasant. Their experience had already been 
gained through the banded glass slips; orsoitseemed. I have 
also found that young birds who had learnt to avoid cinnabar 
caterpillars left wasps untouched. Such observations must be 
repeated and extended. But they seem to show that one aspect 
of the Miillerian theory is not without some facts in support of 
it; and, so far as they go, they afford evidence that black and 
orange banding, irrespective of particular form, may constitute 
a guiding generic feature in the conscious situation. 
It may be said that the generic condensation of experience 
here indicated implies the formation of general and abstract 
ideas, and that we cannot in face of the evidence accept 
Locke’s dictum that abstraction is ‘an excellency which the 
faculties of brutes do by no means attain to.” Romanes 
