122 Journal of Comparative Neurology. 



mals very early and always in ways more or less suggestive of in- 

 herited predisposition. Thus the young beaver when confined 

 away from others of its kind as well as out of sight of water nev- 

 ertheless goes through the motions of dam-building with what- 

 ever materials may be convenient. But such efforts as these grade 

 so easily into the serious work of life for which they are the 

 fit preparation that we soon pass beyond the limits of our sub- 

 ject. 



An interesting article in the Open Court for June 9th, 1892, 

 gives a description of the development of the play impulse in a 

 litter of Scotch Collie puppies and illustrates many of the points 

 above mentioned. Especially interesting is the application by 

 the mother of her acquired instinct for herding to her play with 

 the puppies. 



" When six weeks old the mother recognized that it was 

 time for frolics, and she would enter into the game with curious 

 delight, and evident effort to lead them. The Collie instinct 

 was strong to keep them herded, as she would herd sheep. If 

 one wandered she rounded him in. ■ Then jumping out of the 

 middle of the nine puppies she would drop down and tempt 

 them about her again. Soon the game, much like boys' game 

 of tag, became extremely lively — but all the time she never neg- 

 lected herding. Here were two instincts cooperating, or per- 

 haps conflicting, the one acquired from civilization and domes- 

 ticity ; the others much older. At about two months of age the 

 pups began to show marked individualities both in play and oth- 

 erwise. One or two sought human friendship much more mark- 

 edly than the others, running to me to be fondled rather than to 

 wrestle with their mates. Two from an early age manifested a 

 quicker sense of sport than the others ; and would challenge the 

 crowd, dashing about with tails wagging and with growls, and 

 dancing into any pup they met." 



The so called musical performances of animals may be re- 

 garded as expressions of the same category as play. 



The resort to some sort of vocal sounds as an expression of 

 pleasure in activity is almost universal. Even the mice and 

 shrews have their melodies. In general these sound.s may be 

 compared to those made by many men when settling themselves 

 to repose after great fatigue or the grunts of satisfaction emitted 



