136 THE ASCENT OF MAN 



cerned, the main stimulus — fear of surprise by 

 enemies — has ceased to operate, and the muscles 

 for the erection of the ears have fallen into dis- 

 use. The ear itself in contrast with that of the 

 savage is slow and dull, while compared with the 

 quick sense of the lower animals, the organ is 

 almost deaf. The skin, from the continuous use 

 of clothes, has forfeited its protective power. 

 Owing to the use of viands cooked, the muscles 

 of the jaw are rapidly losing strength. The teeth, 

 partly for a similar reason, are undergoing marked 

 degeneration. The third molar, for instance, among 

 some nations is already showing symptoms of sup- 

 pression, and that this threatens ultimate extinction 

 may be reasoned from the fact that the anthropoid 

 apes have fewer teeth than the lower monkeys, 

 and these fewer than the preceding generation 

 of insectivorous mammals. 



In an age of vehicles and locomotives the lower 

 limbs find their occupation almost gone. For mere 

 muscle, that on which his whole life once de- 

 pended, Man has almost now no use. Agility, 

 nimbleness, strength, once a stern necessity, are 

 either a luxury or a pastime. Their outlet is the 

 cricket-field or the tennis-court. To keep them 

 up at all, artificial means — dumb-bells, parallel -bars, 

 clubs — have actually to be devised. Vigour of 



