TRANSMISSION OF MODIFICATIONS 389 



was quite generally taken by the older naturalists. As Romanes 

 puts it, 1 " Instinctive actions are actions which, owing to their 

 frequent repetition, become so habitual in the course of genera- 

 tions that all the individuals of the same species automatically 

 perform the same actions under the stimulus applied by the 

 same appropriate circumstances." He adds : " Rationaf actions, 

 on the other hand, are actions which are required to meet cir- 

 cumstances of comparatively rare occurrence in the life history 

 of the species, and which, therefore, can be performed only by 

 an intentional effort of adaptation." 



If, now, instinct be inherited habit, and reason only modified 

 instinct, then we have an unbroken chain, from the -simplest 

 adaptive act up to the highest mental generalization, all the 

 product of inherited experience. This is inheritance of indi- 

 vidual modifications (acquired characters) of the most pronounced 

 type, and if true, it affords the most important evidence upon the 

 question now under consideration. 



A critical analysis of the matter makes clear the fact that this 

 conclusion involves the following extreme assumptions, whose 

 correctness must be carefully considered and not accepted with- 

 out question, as is too often done : 2 



1. That instinctive acts are performed perfectly at the first 

 attempt, the traditional " unerring instinct." 



2. That they are carried out substantially in the same way by 

 all individuals of the race and by the same individual in succes- 

 sive performances. 3 



3. That instinctive acts are always adaptive, thus showing 

 their ultimate origin in purposeful acts. 4 



4. That habit precedes instinct, and that instinct finds its 

 directive force in inherited experience. 5 



It is well to consider these points somewhat carefully. 



Instinct not unerring. The earliest instinct of the young 

 mammal is to suck. Moreover, it is an instinct connected with 

 the preservation of life ; yet the calf will be entirely satisfied 



1 Romanes, Animal Intelligence, pp. 16-17. 



2 Read, in this general connection, Habit and Instinct, by Lloyd Morgan, 

 especially pp. 29-127. 



3 Romanes, Animal Intelligence, p. 17. 4 Ibid, p, 15. 6 Ibid. pp. 16-17. 



