DIFFICULTIES OF THE THEORY 287 



organic and inorganic conditions of life; or by 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 sev- 

 eral 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 variations 

 and adaptations, that of Unity of Type. 



