24 ARE THE EFFECTS OF USE INHERITED ? 



tion of a variety " unworkable " (p. 23). But this 

 seems hardly feasible, seeing that natural selection 

 must continually favour the most workable consti- 

 tutions, and will only preserve organisms in pro- 

 portion as they combine general workableness 

 with the special modification. On the other hand, 

 according to Mr. Spencer himself, use-inheritance 

 must often disturb the balance of the constitution. 



Thus it tends to make the jaws and teeth unwork- 



ji 

 able through the overcrowding and decay of the 



teeth there being, as his illustrations show, no 

 simultaneous or concomitant or proportional 

 variation in relation to altered degree of use 

 or disuse. 



ADVERSE CASE OF NEUTER INSECTS. 



Mr. Spencer also holds that most mental 

 phenomena, especially where complex or social 

 or moral, can only be explained as arising from 



