282 



FOOT-NOTES TO EVOLUTION. 



organism " must break down sooner or later, man not 

 less than others. Senility brings even to the best some 



form of nerve decay. The wisest man 



Degeneration of„, , jl-uuj o-i 



*,. must come to second childhood. Senil- 



senihty. . , , , 



ity may come prematurely as a result of 



influences adverse to mental and 



physical activity. These influences 



are manifold and the enumeration 



Fig. 25. — Sacculina attached 

 to the crab. 



Fig. 26. — Sacculina with 

 limbs absorbed. 



of causes and results of the weakness of old age need 

 not be attempted here. 



Race degeneration, or continuous decline from gen- 

 eration to generation, may be distinguished from the 

 wearing out of the individual. The for- 

 mer results from the continuous preser- 

 vation of the unfit. As the destruction 

 of the unadapted is the chief element of race progress, 

 so is their survival the chief element in race decay. De- 

 generation occurs when weakness mates with weakness; 



Race 

 degeneration 



