154 The Study of Animal Life PART n 



agreed as to the precise usage of the word ; thus when the 

 birds build their nests, or when the bees collect honey and 

 form their combs, their acts are with one accord said to be 

 instinctive ; but some would demur at using such a term to 

 describe the love of parents for their children, the courage 

 of brave men, or the artist's perception of beauty. But, 

 even supposing we agree to mean by instinct all those actions 

 which are neither simply reflex nor purely rational, there 

 will still remain great difference of opinion as to its origin. 

 Thus the love of parents will not be imagined as due to 

 practice, either in the individual or its ancestors, but rather 

 to take origin in some hidden necessity of nature ; while 

 the rapid closure of the eyes as protection from an expected 

 blow would seem in all likelihood to have begun in a rapid 

 exercise of intelligence, which, by being often repeated, 

 had ceased to be accompanied by conscious effort. 



It seems to us that there is still need of a vast amount 

 of observation and experiment before a theory of the origin 

 of instinct that will be at all satisfactory can be framed. As 

 already remarked, it is not easy to decide even in what 

 sense the term ought to be used. This being so, we shall 

 content ourselves with mapping the field of thought and 

 indicating the lines of inquiry that must be followed before 

 a just view of the subject will be possible. 



If we arrange examples of all the movements of animals 

 in the order in which they are performed in the lifetime of 

 the individuals, not limiting ourselves to those acts which 

 involve the whole organism, but considering also those which 

 a single organ or mass of tissue may execute, we shall see 

 at a glance all the possible varieties of activity with which 

 we can be concerned. It is, of course, only the move- 

 ments of comparatively large masses of tissue with which 

 we can deal at present. The molecular movements which 

 lie at the base of all the visible ones are as yet almost 

 unknown. 



Even before birth, visible movements of the parts of the 

 higher animals occur ; as, for instance, the beating of the 

 heart. Such movements may be either " automatic " or 

 reflex. At birth, in addition to such movements of its parts, 



