THE PLAY OF ANIMALS. 83 



mal psychology shall contain a chapter devoted to 

 play.* 



On account of this defect in the specific works on ani- 

 mal psychology I have been obliged to seek for most 

 of my material from other sources, and especially from 

 such books as contain descriptions of the habits of ani- 

 mals, though without aiming to meet the requirements 

 of psychology. Most of the observations described are 

 from Naumann, Bechstein, Rengger, Lenz, Ch. L. and 

 A. E. Brehm, K. and E. Miiller, Tschudi, Russ, Diezel, 

 Marshall, Darwin, Miss Romanes, Wallace, and Hudson. 

 A. E. Brehm's Thierlehen is the richest of these. It is 

 marred by the attempt to humanize the actions of ani- 

 mals, but this defect is not injurious to his descriptions 

 of plays. The examples without references in this and 

 the next chapter are from it. I have also made use of 

 such periodicals as Gartenlaube and Der Zoologisclien 

 Garten. I have examined many books of travel, but 

 usually with discouraging results. If they refer to the 

 play of animals at all, the most they say is that is was 

 " amusing," or " astonishing," or " droll," or " ex- 

 ceedingly funny," without any account of how or why. 

 Such a description as that of the young gorilla and 

 some other animals in the " Loango Expedition " forms 

 a notable exception. As far as personal observation 

 goes, I am familiar with the habits of dogs, as I 

 have always from my youth had various breeds of them 

 about me; and also I have collected enough material 

 in my frequent visits to the zoological gardens to fur- 

 nish cases of some kinds of play from my own obser- 

 vation. A complete review of all animal plays is not 



* Alix alone ^ives it a single paragraph, and that is, of course, 

 totally inadequate. 



