pursued it. The sloping sand-dune caved and slid 

 beneath him. Forgetting the cactus, he leaped 

 along the crumbling sand and made a number of 

 lunges, each followed by a dive and an abrupt stop 

 on the sand. He ran in a circle round the crest of 

 the dune several times, occasionally coming to a 

 sudden stop. Then, sliding down the dune, sud- 

 denly stopped his play. 



He stood still at the foot of the dune for several 

 seconds and looked off into the distance. He was 

 debating what he should do next. Off he started 

 slowly toward the horizon. Into the edge of the 

 mysterious landscape of a mirage he walked and 

 vanished. I thought him lost and rose to move on, 

 when a purple shadowy landscape pushed up into 

 the sky and in this strange, dim scene a giant shad- 

 owy grizzly raced and played. 



Play is a common habit of animals. Darwin, 

 Wallace, and others have emphasized its impor- 

 tance as a progressive evolutionary factor in the 

 survival of the fittest. Play is rest and relaxation; 

 it gives power and proficiency; it stimulates the 

 brain to the highest pitch of keenness and arouses 

 all the faculties to be eager and at their best; it de- 

 velops the individual. Play not only is a profound 



