452 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



ducing anything but themselves. The basis of mem- 

 ory is reasonably supposed to be a molecular (or 

 atomic) arrangement from which can issue only a 

 definite corresponding mode of motion. That such 

 an arrangement exists in the central nervous organism 

 is demonstrated by automatic and reflex movements. 

 It is also demonstrated by the fact that the memory 

 of the position and parts of amputated limbs is re- 

 tained by the sensory center, so that irritation of the 

 stump is referred to the lost limb. That the entire 

 record is not repeated in automatic and reflex acts, 

 but only that part of it which was last acquired, may 

 be regarded as due to the muscular and other systems 

 concerned in it having performed it most recently, and 

 having for a longer or shorter period omitted to per- 

 form the older movement, because the latest struc- 

 tures of the organs would render the performance of 

 the old movements impossible. In other words, the 

 physiological division of labor extends to memory at 

 the basis. In the case of the germ-plasma no other 

 specialization exists, so that the entire record may be 

 repeated stage after stage, thus producing the succes- 

 sion of type-structures which embryology has made 

 familiar to us. In the process of embryonic growth, 

 one mode of motion would generate its successor in 

 obedience to the molecular structural record first laid 

 down in the ovum and spermatozooi'd, and then com- 

 bined and recomposed on the union of the two in the 

 oospore, or fertilized ovum. 



If the doctrine of kinetogenesis be true, this energy 

 has been moulded by the interaction of the living be- 

 ing and its environment. It is the recorded expression 

 of the habitual movements of the organism which have 

 become impressed on, and recorded in, the rcproduc- 



