204 ON INSTINCT IN MAN AND ANIMALS. 
determine what we mean by the term instinct. It 
has been variously defined as—‘ disposition operating 
without the aid of instruction or experience,” “a 
mental power totally independent of organization,” or 
‘a power enabling an animal to do that which, in those 
things man can do, results from a chain of reasoning, 
and in things which man cannot do, is not to be ex- 
plained by any efforts of the intellectual faculties.” 
We find, too, that the word instinct is very frequently 
applied to acts which are evidently the result either 
of organization or of habit. The colt or calf is said 
to walk instinctively, almost as soon as it is born; 
but this is solely due to its organization, which ren- 
ders walking both possible and pleasurable to it. So 
we are said instinctively to hold out our hands to 
save ourselves from falling, but this is an acquired 
habit, which the infant does not possess. It appears 
to me that instinct should be defined as—‘ the per- 
formance by an animal of complex acts, absolutely 
without instruction or previously-acquired knowledge.” 
Thus, acts are said to be performed by birds in build- 
ing their nests, by bees in constructing their cells, 
and by many insects in providing for the future wants 
of themselves or their progeny, without ever having 
seen such acts performed by others, and without any 
knowledge of why they perform them themselves. 
This is expressed by the very common term “ blind 
instinct.” But we have here a number of assertions 
of matters of fact, which, strange to say, have never 
been proved to be facts at all. They are thought to 
