172 MEXTAL EA^OLUTIOX IN ANIMALS. 



bears testimony to similar facts and also to the propensity 

 of Capons to sit. (See also ' Cottage Gardener,' 1860, 

 p. 379."*) 



In this connection I may also quote the following in- 

 stance, which I find recorded among Mr. Darwin's MS 

 notes : — 



"April, 1862. We had a kitten which sucked its mother, 



and, when a month old, taken to and sucked another 



cat ; then to and sucked two other cats, and then its 



instinct w^as confounded, and became mixed wdth reason or 

 experience : for it tried repeatedly to suck three or four other 

 kittens of its own age, which no one, as far as I am aware, 

 ever saw any other kitten do. Thus born instinct may be 

 modified by experience." 



In his " Naturgeschichte der Saugethiere von Paraguay," 

 p. 201, Dr. Eeugger gives the following curious instance of 

 interference with natural instincts brought about by changed 

 conditions of individual life. Speaking of a kind of Cat, 

 native in Paraguay, he says that there is no instance on 

 record of the animal breeding when in captivity, and that on 

 one occasion a female having been pregnant when captured 

 and kept in confinement by Herr Nozeda, brought forth her 

 young, but immediately afterwards devoured them. This, 

 which took place in her own country, shows that even so 

 well rooted an instinct as the maternal may be greatly 

 altered in the individual by even a few months of change in 

 the conditions of life. Similar facts in the case of the 

 domestic Sow, pet Mice, and other animals exposed to the 

 influence of domestication are, of course, very common. 



It is needless, I think, to give further instances to prove 

 the general principle that derangement of instinctive organi- 

 zation is apt to arise when an animal ceases to be in normal 

 converse with its environment. But I may here adduce a 

 curious instance of the derangement of the instinctive 

 organization in an animal which was apparently in all 

 respects in normal converse with its environment, and this to 

 such an extent that it may properly be regarded as a case of 

 insanity. But although perhaps pathological in nature, it is 

 none the less available as showing the imperfection of in- 

 stinct — the only difference between it and the cases previously 



* Ostronization, or the Caponizing of the Ostrich (S. Breutnall, Port 

 Elizabetli, 1883). 



