Chap. VI.] SUMMARY. 167 



having adapted them during past periods of time : the adaptations 

 being aided in many cases by the increased use or disuse of parts, 

 being affected by the direct action of the external conditions of 

 life, and subjected in all cases to the several laws of growth and 

 variation. Hence, in fact, the law of the Conditions of Existence is 

 the higher law ; as it includes, through the inheritance of former 

 varin lions and adaptations, that of Unity of Type. 



