1921] The Age of Insects 27 



Apprenticeship has its part also in those manifestations of mem- 

 ory belonging to the species which play such an important part in the 

 behavior of arthropods. This kind of memory presents a character 

 of distinct superiority, inasmuch as it was made effective for the 

 race by the distant ancestors of the individual in the guise of a choice 

 between the various possible responses of differential susceptibility. 

 Choice, of a remarkably intellectual nature, is even more noticeable 

 in the instinctive manifestations of individual memory. The animal, 

 endowed with well-developed senses and nervous system, not only re- 

 acts to new necessities by new acts, but associates the stored impres- 

 sions of new sensations and thereby appropriately directs its further 

 activities. Thus, by an intelligent process, new habits are estabUshed 

 which by heredity become part of the patrimony of instinct modifying 

 the latter and constituting elements essential to its evolution. Of 

 these instincts acquired through an intelligent apprenticeship Forel 

 was led to say that they are reasoning made automatic and it is to 

 them particularly that we may apply the idea of certain biologists 

 that instincts are habits which have become hereditary and automatic. 

 Probably all superior instincts at first had this intellectual quality. 

 This certainly is true of all such as originated from more or less slowly 

 acquired habits; it seems to be the rule as well with instincts due to 

 mutations. It stands to reason that, whether they result from a sud- 

 den psychic change or from a sudden organic modification, these in- 

 stincts must always be preceded by some intelligent period of educa- 

 tion, during which they become perfected, in order to be handed on to 

 posterity and to assume the character of true instincts. 



Here, then, we are confronted with several classes of instinctive 

 acts, which differ not only in origin l)ut also in intellectual characteris- 

 tics. No doubt they are linked together by many intermediate mani- 

 festations, and in the animals with which we are now concerned they 

 often blend the one with the other or even with the reflexes, on ac- 

 count of the profound differentiation of nervous and sensorial centers. 

 It is, nevertheless, very difficult to consider them as manifestations of 

 a special faculty which we would fain place on the level of intelligence 

 by calling it instinct. The name instinct justly applies to certain 

 forms of activity which are innate and automatic, but these forms pro- 

 ceeded in diverse ways from the vital energy which is the source of all 

 organic activity, and the highest of them, which are at the same time 

 the most striking ones in the animals here studied, were originally acts 

 more or less requiring the exercise of true intelligence on the part of 



