Observations on Young Mammals. 117 



therefore of interest to ascertain how far the effects of 

 certain odours are congenitally definite. There is an oft- 

 quoted observation of Spalding's in this connection. " So 

 old," he says,* " is the feud between the cat and the dog, 

 that the kitten knows its enemy even before it is able to 

 see him, and when its fear can in no way serve it. One 

 day last month, after fondling my dog, I put my hand into 

 a basket containing four blind kittens, three days old. 

 The smell my hand carried with it set them puffing and 

 spitting in a most comical fashion." Experiments of my 

 own have led me to question whether the reaction is so 

 particularized — so specially a response to the smell of a 

 dog as such — as Spalding believed. A whiff from a 

 bottle of ammonia, and some straw from a pigsty, pro- 

 duced much the same effect. Dr. Mills, too, says that he 

 has been very much impressed by the fact, that at an early 

 age the kitten, when suddenly disturbed in any way, re- 

 acts much as if a dog had come upon it, though in a 

 less marked manner. " Nevertheless," he adds, balancing 

 the evidence, " the behaviour of a kitten, even a few days 

 after its birth, towards even the smell of a dog on the 

 hands, is very suggestive of an instinctive fear or dislike 

 of a dog. At the same time, I have seen a kitten act 

 much the same way when an irritant was placed near 

 its nose, or, after it could hear, when it was startled by 

 a noise." Even Dr. Mills himself, when he appeared 

 before his kitten, on its twenty-seventh day, in a 

 somewhat startling coat — " light in colour, with pro- 

 nounced vertical stripes " — caused the animal to open 

 its mouth, and, on his going nearer, to hiss. Mr. Mann 

 Jones tells me he has " often introduced young kittens to 

 dogs, and vice versa, and that there was no sign of re- 

 pugnance on the part of the younger animal, nor of the 



* Nature, toL xii. p. 507. 



