124 
E. M. CAMPBELL-ON INSTINCT. 
across the room, he turned into one of intelligence, we should simply 
state that we observed the chair, and that we studied each step with 
a view of avoiding it. Nay, more, if we wished to adapt the 
illustration to the definition of an instinctive action, we should say 
that we had a distinct perception of the chair being in our way, 
but that we necessarily avoided it as the result of inherited or of 
acquired organisation. But to an observer our action in the three 
cases would he the same. If this be true of the human being, 
surely it is also true of the Echinodermata of which I have just 
spoken. Some indication of the nature of the action is offered by 
the absence of hesitation with which it is performed. Perception 
requires time, just as consideration implies deliberation, and all 
action is quicker if independent of consciousness. We start on the 
sudden occurrence of a noise, and our perception of it is too late for 
us to inhibit the reflex movement. But the test of promptitude 
when applied to animals requires great knowledge of their habits. 
Eurther, it would appear that the word Instinct is applied to very 
different degrees of inheritance. This is exemplified by the cuckoo 
and the web-spinning spiders. The cuckoo inherits an impulse to 
lay its egg in another bird’s nest, hut it rests with the individual 
cuckoo to find the nest it requires, and the circumstances under 
which it is found depend on the individual ability of the bird. On 
the other hand, the spider inherits the skill of execution as well as 
the impulse of web-construction. In the one case the inheritance 
of the instinct is related to a corresponding modification of the 
organism, in the other, viz. that of the cuckoo, there is no special 
modification of structure on which the instinct depends. We may 
regard it, if we please, as mere idleness. Domestic hens frequently 
lay in other hens’ nests, whether or not they have a nest of their 
own, either from carelessness or idleness. The same occurs among 
partridges. The yellow-billed cuckoo (Cueulus Americanus, Linn.), 
according to Audubon, constructs a nest for itself, but occasionally 
lays in the nest of another bird.* Even in these cases we must he 
cautious before we say there is no inherited modification of structure 
concomitant to the instinct, for we do not know that cuckoos moult 
the feathers on the abdomen, which would render them unfit for 
brooding, and it may be that some peculiarity in which the ova are 
developed determines the instinct. It is the old story ;—Which comes 
first, the structure or the function? Eurther, if the impulse of 
the cuckoo he considered instinctive, it is difficult to see why we 
should not apply the same term to the inherited aptitudes of 
humanity. The inheritance of special proclivities has been amply 
shown by E. Galton in ‘ Hereditary Genius,’ and if we accept 
Bomanes’ definition of Instinct as distinguishable from Beason, it 
seems impossible to draw the line between certain intelligent actions 
of man and the instinctive actions of other animals. It also appears 
that the application of the term Instinct requires some limitations in 
the case of actions which are performed by members of one species. 
Dogs admittedly belong all to one species, but the instincts of a 
* Morris, ‘ British Birds,’ vol. ii, p. 43. 
