ORGANIC EVOLUTION — MENTAL 143 



anew in response to stimulation, only the ijower of ac- 

 quiring it being transmissible. As regards this power 

 also, just as regards instinct, there is not a vestige of 

 proof that it is increased by stimulation, by use. On 

 the contrary, it is a matter of common knowledge, that 

 as animals grow older their long stimulated powers of 

 acquiring mental traits become more feeble and tend to 

 cease. The conclusion we are forced to arrive at, then, 

 is this — that since whatever mental that is transmissible 

 (instincts and powers of acquiring reason) does not vary 

 under stimulation, therefore no acquired mental traits 

 can be transmitted, for no transmissible mental traits 

 can be acquired — an a priori conclusion capable, as will 

 be seen, of ample a posteriori confirmation. 



It may be objected that, since reflexes and instincts 

 appeared earlier in the phylogeny than reason, they 

 ought to appear earlier in the ontogeny, whereas some 

 reflexes and instincts, e. g. those pertaining in man to 

 the sexual functions, appear later in the ontogeny than 

 reason. The answer to this is threefold : (1) some 

 reflexes and instincts which appear late in the ontogeny, 

 without doubt have had the period of their appearance 

 in it shifted by the action of Natural Selection — have 

 been removed to a later date by the accumulation of 

 favourable variations ; (2) others again may exist in a 

 latent state from an early period, not becoming apparent 

 till stimulation is supplied, which stimulation is not 

 supplied till late in the ontogeny ; (3) others again may 

 not have been developed till late in the phylogeny, just 

 as some structures {e. g. horns and teeth), which do not 

 vary under stimulation, were not developed till late in 

 the phylogeny. 



In defining instinct as "the faculty which is con- 

 cerned in the conscious adaption of means to ends 

 by virtue of inborn inherited knowledge and ways of 



