630 THE POPULAR SCIENCE MONTHLY. 



of one or two days, especially in relation to temperature. The earliest 

 sensations of temperature are, however, of less immediate psychoge- 

 netic significance than those of touch. The hands of the child are 

 the feelers of his soul. Through the excitation of the tactual cor- 

 puscles, at the points of the fingers and in the lips, the infant receives 

 the first knowledge of things without him ; and through the difference 

 in the sensations arising from the touch of his own skin and that of 

 foreign objects is the foundation laid for self-consciousness on one side 

 and for making experiments on the other. His fingers are, in fact, the 

 instruments with which he endeavors to explore everything that comes 

 within his reach. 



Professor Kussmaul has described some important experiments on 

 the sense of taste in infants, in which he found that all new-born chil- 

 dren could distinguish strong tastes, and that a very different reaction 

 took place when the tongue was wet with a solution of sugar, from 

 that which followed the application of quinine, vinegar, or salt. Si-ns 

 of distaste were excited by the three latter substances, and of satisfac- 

 tion by the sugar, which showed beyond doubt that the power to dis- 

 criminate tastes begins at birth. The opinion that infants will take 

 alike whatever is offered them holds good if at all, only of substances 

 whose taste is weak. If the child seems displeased at the taste of a 

 strong solution of sugar, as sometimes happens, that is only the effect 

 of the surprise which all new intense sensations occasion. After the 

 first trial, it will want more sugar, and show its satisfaction at getting 

 it. The same is the case with the young of animals, which readily 

 distinguish tastes and seem astonished at new ones ; and the newly 

 hatched chicken will at once select the food, where it is given a choice, 

 which is most agreeable to it. Taste is, then, the first sense which 

 affords clear perceptions, and is the first which gives occasion for the 

 exercise of the faculties of memory and judgment. 



The sensations of smell can hardly be separated from those of taste. 

 Infants appear able to distinguish odors very early, but to what ex- 

 tent has not been ascertained. They are able to tell one kind of food 

 from another by this means, and have been known to decline the ac- 

 quaintance of a new nurse whose presence was disagreeable to them. 

 It is known that animals that are born blind are guided to their food 

 the mother's milk by this sense. Some odors, as that of tobacco- 

 smoke, have been found to be disagreeable to young animals ; others, 

 as that of camphor, pleasant. 



All infants are deaf at birth, because the outer ear is as yet closed, 

 and there is no air in the middle ear. A response to a strong sound is 

 observed, at the earliest, in six hours, often not for a day, sometimes 

 not for two or three days. The awakening of the sense may be recog- 

 nized by means of the drawing up of the arms and the whole body, and 

 the rapid blinking which a loud noise provokes ; and it is a sign of 

 deafness if the child, after its ears have had time to come into a suit- 



