THE UNIQUE MAMMAL 5 



It will pay us to spend a little time over the first three of 

 these points. The fourth will be left for special treatment in a 

 later lecture to be devoted to that topic alone. 



While a number of other mammals for a part of the time 

 either sit, or stand, or even walk upright for short distances, 

 man alone habitually carries on the business of living in that 

 posture. All other higher mammals make locomotion the pri- 

 mary demand upon their fore-limbs. Even the gibbon, which 

 comes nearest to man in the proportion of the whole life span 

 spent in the upright position, still depends heavily upon his 

 fore-limbs as locomotor organs. And the degree or extent of 

 his assumption of the upright posture but fractionally approaches 

 man's, though it comes nearer to it than any other mammal's. 

 The effect of adopting habitually the upright posture and de- 

 pending solely upon hind legs for getting about was obviously 

 to free the arms for other activities and uses. With this freedom 

 came the development of the human hand; in which "we have 

 the consummation of all perfection as an instrument. This, we 

 perceive, consists in its power, which is a combination of strength 

 with variety and extent of motion; we see it in the forms, rela- 

 tions, and sensibility of the fingers and thumb; in the provisions 

 for holding, pulling, spinning, weaving, and constructing; 

 properties which may be found in other animals, but which are 

 combined to form this more perfect instrument." (Sir Charles 

 Bell's Fourth Bridgewater Treatise ^ 3d edit. p. 23 1, 1 834.) 



Anaxagoras, the intimate friend of Pericles, inspirer of 

 Euripides, and perhaps teacher of Socrates, was of the opinion 

 that the intellectual superiority of man over other animals 

 rested fundamentally on his possession of hands. This view had 

 a certain recrudescence in Benjamin Franklin's designation of 

 man as "the toolmaking animal", and finds today a certain de- 

 gree of real and substantial support in the underlying philosophy 

 of the behaviorist school of psychology. It was categorically 

 opposed by Aristotle, who almost uniformly spoke disparagingly 

 of Anaxagoras, perhaps because he did not understand him too 

 well. Aristotle turned the case end for end, saying that man had 



