298 Jounial of Coinparafivc h^citrology and Psychology. 



HoBHOUSE. the latest author in the field of animal psychol- 

 ogy, has brought keen psychological analysis to bear upon the 

 results of a close experimental stud}-. A dog, a cat and a mon- 

 key furnished the best material, while other animals gave cor- 

 roborative data which, if not taken by Hobhouse himself, were 

 controlled and edited by him. 



Hobhouse is more generous in his estimation of his ani- 

 mals than is Thokndike, perhaps because the psychical mani- 

 festations for which he looks are clearly defined and character- 

 ized in his own mind. An advanced grade of intelligence is not 

 vaguely suggested by the term "free ideas," but is discussed in 

 concrete and comprehensive statements about "the practical 

 judgment, " and the "practical idea." By a practical ideals 

 meant "the function which directs action, not necessarily in ac- 

 cord with habit or instinct, to the production of a certain per- 

 ceptible result. It is further a necessary part of such an idea 

 that it rests on a perceptual basis, and is capable of being 

 brought into relation with another such idea, for example, as 

 means to end." . . . "The correlation of such an idea with a 

 remoter end, I call a practical judgment." ^ 



The possession of practical ideas and the ability to make 

 practical judgments Hobhouse attributes to dogs, elephants, 

 cats, otter, monkeys and chimpanzees, those being the animals 

 which he examined. 



The work of Klixe,- followed by that of Small, '^ has direct 

 bearing upon the problem of the present investigation. The 

 life habits of the white rat as described by S.\l\ll, present many 

 points of contrast with the habits of the guinea pig. Small 

 furnishes a diary of the young white rat, in which its immaturity 

 at birth and subsequent development are described, and later 

 its intellectual development as shown in ability to learn a laby- 

 rinth and to solve other simple problems. 



In the study of the psychical processes of the guinea pig I 

 have tried to determine : 



^ HuBHOUSE. Mind in Evolution, p. 207, 1901. 

 '^ Amer. Jour. PsvchoL, Vol. X, p. 276, 1S98. 

 •' Amer. Jour. Psychol., Vol. XI, p. So, 1S99. 



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