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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



face, with the corners of his mouth well depressed, 

 when his nurse pretended to cry. Jealousy was 

 plainly exhibited when I fondled a large doll, and 

 when I weighed his infant sister, he being then 

 fifteen and a half months old. Seeing how strong 

 a feeling jealousy is in dogs, it would probably be 

 exhibited by infants at an earlier age than that 

 just specified, if they were tried in a fitting manner. 



Association of Ideas, Reason, etc. — The first 

 action which exhibited, as far as I observed, a 

 kind of practical reasoning, has already been no- 

 ticed, namely, the slipping his hand down my 

 finger so as to get the end of it into his mouth ; 

 and this happened on the 114th day. When four 

 and a half months old, he repeatedly smiled at 

 my image and his own in a mirror, and no doubt 

 mistook them for real objects ; but he showed 

 sense in being evidently surprised at my voice 

 coming from behind him. Like all infants he 

 much enjoyed thus looking at himself, and in less 

 than two months perfectly understood that it was 

 an image ; for if I made quite silently any odd 

 grimace, he would suddenly turn round to look at 

 me. lie was, however, puzzled at the age of 

 seven months, when being out-of-doors he saw me 

 on the inside of a large plate-gkiss window, and 

 seemed in doubt whether or not it was an image. 

 Another of my infants, a little girl, when exactly 

 a year old, was not nearly so acute, and seemed 

 quite perplexed at the image of a person in a 

 mirror approaching her from behind. The higher 

 apes which I tried with a small looking-glass be- 

 haved differently ; they placed their hands behind 

 the glass, and in doing so showed their sense, 

 but, far from taking pleasure in looking at them- 

 selves, they got angry and would look no more. 



When five months old, associated ideas arising 

 independently of any instruction became fixed in 

 his mind : thus as soon as his hat and cloak were 

 put on, he was very cross if he was not immedi- 

 ately taken out-of-doors. When exactly seven 

 months old, he made the great step of associating 

 his nurse with her name, so that if I called it out 

 he would look round for her. Another infant 

 used to amuse himself by shaking his head later- 

 ally : we praised and imitated him, saying " Shake 

 your head ; " and when he was seven months old 

 he would sometimes do so on being told without 

 any other guide. During the next four months 

 the former infant associated many things and 

 actions with words ; thus when asked for a kiss 

 he would protrude his lips and keep still — would 

 shake his head and say in a scolding voice " Ah ! " 

 to the coal-box or a little spilt water, etc., which 

 he had been taught to consider as dirt}'. I may 



add that when a few days under nine months old 

 he associated his own name with his image in the 

 looking-glass, and when called by name would 

 turn toward the glass even when at some distance 

 from it. When a few days over nine months, he 

 learned spontaneously that a hand or other object 

 causing a shadow to fall on the wall in front of 

 him was to be looked for behind. While under 

 a year old, it was sufficient to repeat two or three 

 times at intervals any short sentence to fix firmly 

 in his mind some associated idea. In the infant 

 described by M. Taine (pp. 254-256) the age at 

 which ideas readily became associated seems to 

 have been considerably later, unless indeed the 

 earlier cases were overlooked. The facility with 

 which associated ideas due to instruction and oth- 

 ers spontaneously arising were acquired, seemed 

 to me by far the most strongly marked of all 

 the distinctions between the mind of an infant 

 and that of the cleverest full-grown dog that I 

 have ever known. What a contrast does the 

 mind of an infant present to that of the pike, 

 described by Prof. Miibius, 1 who during three 

 whole months dashed and stunned himself against 

 a glass partition which separated him from some 

 minnows ; and when, after at last learning that he 

 could not attack them with impunity, he was 

 placed in the aquarium with these same minnows, 

 then in a persistent and senseless manner he 

 would not attack them ! 



Curiosity, as M. Taine remarks, is displayed 

 at an early age by infants, and is highly impor- 

 tant in the development of their minds ; but I 

 made no special observation on this head. Imi- 

 tation likewise comes into play. When our in- 

 fant was only four months old I thought that he 

 tried to imitate sounds; but I may have deceived 

 myself, for I was not thoroughly convinced that 

 he did so until he was ten months old. At the 

 age of eleven and a half months he could readily 

 imitate all sorts of actions, such as shaking his 

 head and saying " Ah ! " to any dirty object, or 

 by carefully and slowly putting his forefinger in 

 the middle of the palm of his other hand, to the 

 childish rhyme of " Pat it and pat it, and mark it 

 with T." It was amusing to behold his pleased 

 expression after successfully performing any such 

 accomplishment. 



I do not know whether it is worth mention- 

 ing, as showing something about the strength of 

 memory in a young child, that this one, when 

 three years and twenty-three days old, on being 

 shown an engraving of his grandfather, whom he 

 had not seen for exactly six months, instantly 



1 '• Die Bewegungen der Thiere," etc., 1S73, p. 11. 



