98 INSTINCTIVE BEHAVIOUR 
ways, as they grow accustomed to the ways of such a foster- 
parent as the writer of these pages. Still, though there is, 
apparently, no instinctive knowledge of the hen as their natural 
protector, and though I have seen no observable response to 
the clucking sound, this must not be taken as necessarily 
implying that there is no instinctive response to any of her 
modes of behaviour. ‘There is such a response tc her pecking 
on the ground ; there is probably such a response to her danger- 
note ; and there may be many other such instinctive modes of 
behaviour related to her actions. How far they extend can 
only be ascertained by patient observation ; and such responsive 
behaviour need not imply any instinctive knowledge begotten 
of inherited experience. 
We may now summarize some of the general conclusions 
which may be drawn from observations of instinctive behaviour 
in young birds. 
1. That which is inherited is essentially a motor response or 
train of such responses. Mr. Herbert Spencer’s description of 
instinct as compound reflex action is thus justified. 
2. These often show very accurate and nicely-adjusted 
hereditary co-ordinations. 
3. They are evoked by stimuli, the general type of which 
is fairly definite, and may in some cases be in response to 
particular objects. 
4. They are also generally shown under conditions which 
lead us to infer the presence of an internal factor, emotional 
or other. 
5. There does not seem to be any evidence of inherited 
knowledge or experience. 
TV.—THE Conscious ASPECT OF INSTINCTIVE BEHAVIOUR 
In our definition of instinctive behaviour all positive refer- 
ence to the presence of conscious states was omitted. By some 
writers, however, the fact that it is accompanied by conscious- 
ness is regarded as a distinguishing feature of instinct. Romanes 
