The Mammals 



they are able to travel at a high rate of speed when fright- 

 ened or pursued. They use their tails as a third leg, which 

 with their hind legs, forms a tripod for the support of the 

 body while standing in much the same manner as did some 

 of the dinosaurs. 



Nature has decreed that all life must have an urge — a 

 compulsion before It can leave Its low vaulted past and 

 ascend to a higher plane. This ascent is the result of mil- 

 lions of cooperating conditions, so admirably woven together 

 that they form the very essence of life Itself for every act of 

 living Is so related to the entire plan that It contains within It 

 the principles of progress. The great principles of progress 

 In all living things is work and without work, no progress can 

 be made. The whole economy of Nature produces a com- 

 pulsion that requires work which in turn creates progress. 



Throughout the vast periods of time since life first 

 squirmed in a single cell to the coming of the mammals, the 

 great compulsions of life were those of satisfying hunger, of 

 self-preservation, and of reproducing their kind. Up to this 

 limb in the tree of animal life all life was selfish as a matter 

 of necessity for all the lower forms knew neither home nor 

 care. The first dim dawn of the care of offspring probably 

 appears with some of the fishes. This dawn Is brighter with 

 the amphibians and brighter still with the coming of the 

 reptiles but this care for offspring had not ripened Into affec- 

 tion until the last great class — the mammals was reached. 

 There had been maternity but no motherhood for there Is a 

 vast difference between these terms. Maternity embraces 

 only the physical act of reproducing in kind while that of 

 motherhood embraces all of maternity and in addition 



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