234 INSTINCT : 



mind when the ferrets were taken from her to be fed, that at one 

 time I thought she was going to desert them altogether. After 

 this, therefore, the ferrets were always fed in the nest, and with 

 this arrangement the hen was perfectly satisfied, apparently 

 because she thought that she then had some share in the feeding 

 process. At any rate, she used to cluck when she saw the milk 



coming, and surveyed the feeding with evident satisfaction 



Altogether, I consider this a very remarkable instance of the plas- 

 ticity of instinct. The hen, it should be said, was a young one, and 

 had never reared a brood of chickens. A few months before she 

 reared the young ferrets she had been attacked and nearly killed by 

 an old ferret, which had escaped from his hutch. The young ferrets 

 were taken from her several days before their eyes were open." 



This variability of instincts under varying conditions is a 

 matter of considerable importance in enabling us better 

 to understand the enormous variety of Animal Instincts 

 and the mode in which some of the most complex and 

 extraordinary of them may have originated. On this 

 subject Mr. Darwin says :* " Under domestication in- 

 stincts have been acquired, and natural instincts have 

 been lost, partly by habit, and partly by man selecting 

 and accumulating during successive generations peculiar 

 mental habits and actions, which at first appeared from 

 what we must in our ignorance call an accident. In some 

 cases compulsory habit alone was sufficient to produce in- 

 herited mental changes ; in other cases compulsory habit 

 has done nothing, and all has been the result of selection 

 pursued both methodically and unconsciously.'* Again, 

 among wild animals " changes of instinct may sometimes 

 be facilitated by the same species having different instincts 

 at different periods of life, or at different seasons of the 

 year, or when placed under different circumstances, &c. ; 

 in which case either the one or the other instinct might 

 be preserved by natural selection. And such instances of 

 diversity of instinct in the same species can be shown to 



* " Origin of Species," 6th edition, 1872, pp. 206, 207, 211, 233. 



