ii4 Habit and Instinct. 



from the mother after two hours, concentrated water-solu- 

 tions of tartaric acid, soda, and glycerine, introduced into 

 the mouth through glass tubes, were swallowed just as 

 eagerly as milk and water, with vigorous sucking. He 

 found, too, that the empty tube, placed on the end of the 

 tongue, occasioned just such sucking. And he believes 

 that, under the influence of hunger, touch, as a reflex 

 stimulus, overpowers any taste-stimuli acting at the same 

 time. It is certainly probable that the act of sucking is 

 a reflex started by the appropriate sense- stimuli, and, as 

 such, is of a purely congenital nature. But what leads the 

 infant to the nipple of the mother's breast, or the new- 

 born animal to the teats of its dam ? In the case of the 

 human infant, it finds its way very imperfectly and in- 

 adequately, being, under ordinary circumstances, guided in 

 its random efforts by the mother. Prof. Preyer believes 

 that, in the case of animals, they are at first guided to the 

 teats by the sense of smell. He states that puppies, 

 rendered incapable of smell by the severance of the 

 olfactory nerve, could no longer find the mother's teats 

 so long as they were blind. They crept about on her belly, 

 trying to suck everywhere. Blind puppies in the normal 

 state, on the other hand, find the teats at once. Pr. 

 Mills, however, expresses a different opinion as the result 

 of his observations. " I have not changed my opinion," 

 he says, " as expressed in my first paper on the dog, 

 that the puppy, and, I will now add, the kitten, find the 

 nipple of the mother by touch rather than smell, and 

 that they are drawn towards the belly of the mother by 

 the warmth of the part." This also is the opinion of 

 Mr. Mann Jones. " So far as my observations go," he 

 says in a letter from which he kindly allows me to 

 quote, " I am inclined to think that the heat of the 

 mother's belly determines the approach of the young to 



