ROMANES' MENTAL EVOLUTION, ETC. 51 



precise that it scarcely requires to be supplemented by 

 the subsequent experience of the individual." * 



Again : — 



" Instincts probably owe their origin and develop- 

 ment to one or other of two principles. 



"I. The iirst mode of origin consists in natural 

 selection or survival of the fittest, continuously pre- 

 serving actions, &c. &c. , . . 



" II. The second mode of origin is as follows : — By 

 the effects of habit in successive generations, actions 

 which were originally intelligent become as it were 

 stereotyped into permanent instincts. Just as in the 

 lifetime of the individual adjustive actions which were 

 originally intelligent may by frequent repetition become 

 automatic, so in the lifetime of species actions origi- 

 nally intelligent may by frequent repetition and heredity 

 so write their effects on the nervous system that the 

 latter is prepared, even before individual experience, to 

 perform adjustive actions mechanically which in pre- 

 vious generations were performed intelligently. This 

 mode of origin of instincts has been appropriately 

 called (by Lewes — see " Problems of Life and Mind " t) 

 the ' lapsing of intelligence.' " t 



I may say in passing that in spite of the great 

 stress laid by Mr. Eomanes both in his "Mental 

 Evolution in Animals " and in his letters to the 

 Athenceum in March 1884, on Natural Selection as 

 an originator and developer of instinct, he very soon 



* Mental Evolution in Animals, p. 131. Kegan Paul. Nov. 1883. 



+ Vol. I., 3d ed., 1874, p. 141, and Problem I. 21. 



t Mental Evolution in Animals, pp. 177, 178. Nov. 1883. 



