THE DESCENT OF MAN. 371 



The keen eye that the human prototype inherited from his ape-like 

 precursors was also useful to him in other ways, for food-getting, path- 

 finding and perceptive purposes in general. In some respects, indeed, 

 sight may be regarded as the most serviceable of all the senses. Touch 

 and taste, upon which the lower orders of life rely, require actual con- 

 tact with the objects to be distinguished, and, consequently, only 

 afford a concept of the immediate environment. Hearing and smell 

 predominate among the vertebrates, have a broader range and are 

 especially useful in this, that they allow the mind to distinguish par- 

 ticular sounds and odors from surrounding conditions, and so afford a 

 perception of the local environment. The sense of sight offers still fur- 

 ther advantages in that it conveys a concept of the special as well as of 

 the universal environment and allows the mind not only to distinguish 

 particular objects, but also to compare them with each other and so 

 form a general conception of the outer world. Sight has this disad- 

 vantage, however: it only gives instantaneous information from one 

 quarter, and necessitates a turning of the head or body to take in sur- 

 rounding conditions, because light travels only along straight lines; 

 whereas hearing and smell accord instantaneous information from all 

 quarters, because sounds and odors disseminate in every direction from 

 the center of disturbance. Thus though primeval man might well 

 enough have relied upon his sense of sight exclusively for acquisitive 

 purposes, defense demanded that he develop a sentinel sense besides. 

 Heredity also determined this choice. Like the other anthropoids, man 

 continued to rely upon his hearing to warn him of danger approach- 

 ing from behind. Thus beside becoming adapted to walking and 

 weapon- wielding, we may imagine the human prototype developing 

 during the process of differentiation which fitted him for his mundane 

 career, the keen eye and acute ear that had been handed down to him 

 through heredity from his ape-like ancestors. 



Working upon the biological principle of variability and following 

 the interaction between heredity and environment, by a process .of re- 

 construction we have been able to form a tolerably complete conception 

 of the original condition of man. He was evidently a land-dwelling, 

 omnivorous, weapon-wielding animal. For this manner of life he was 

 psychically and physically fitted during the process of specific differen- 

 tiation. From his ape-like ancestors he inherited his prehensile hand, 

 his keen eye and his acute ear ; in adapting him to the earthly environ- 

 ment selection increased his cranial capacity, developed the convolu- 

 tions of his brain, set him upright on his feet and accorded him the 

 free use of his arms for acquisitive purposes. Thus endowed, primeval 

 man was evidently enabled to cope successfully with the carnivora, 

 and eventually make himself master of the forest. 



Taking the geological location of the remains of Pithecanthropus 



