Iv ON INSTINCT IN MAN AND ANIMALS 93 
continued study in the same direction only render the 
erroneous conclusions more ingrained and more irremovable. 
Definition of Instinct 
Before going further into this subject we must determine 
what we mean by the term instinct. It has been variously 
defined as—“ disposition operating without the aid of instruc- 
tion or experience,” “a mental power totally independent of 
organisation,” 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 
explained 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 organisation 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 organisation, 
which renders 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 performance by an animal of 
complex acts, absolutely without instruction or previously 
acquired knowledge.” Thus, acts are said to be performed 
by birds in building 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 be so self-evident that they may be taken for granted. 
No one has ever yet obtained the eggs of some bird which 
builds an elaborate nest, hatched these eggs by steam or 
under a quite distinct parent, placed them afterwards in an 
extensive aviary or covered garden, where the situation and 
the materials of a nest similar to that of the parent birds may 
be found, and then seen what kind of nest these birds would 
build. If under these rigorous conditions they choose the 
same materials, the same situation, and construct the nest in 
