266 EVOLUTION OF TO-DAY. 



actual retardation has taken place. It is evident 

 enough that acceleration must be the general rule. 

 The fact that embryology repeats past history, is a 

 sufficient proof of this, for such a repetition would 

 be impossible without such a law. 



Neo-Lamarckianism would, therefore, tell us that 

 one of the most important factors in the modifica- 

 tion of organisms is consciousness, which is the cause 

 of various activities. Cope regards consciousness as 

 one of the fundamental properties of protoplasm. 

 He thinks that all activities, even those now auto- 

 matic, such as the circulation of the blood, were 

 originally acquired by conscious effort. But at all 

 events it is plain that consciousness does regulate 

 the use or disuse of organs, and hence if this theory 

 is true, it is a very potent factor. Food becomes 

 scarce in any locality, and animals, driven by their 

 hunger, migrate into new regions, where they find 

 new conditions and new enemies to contend with. 

 In their endeavors to meet the new conditions they 

 acquire new activities, and these cause, by the prin- 

 ciple of use, variations to appear. All individuals 

 thus circumstanced will be affected in the same way, 

 and there thus arise simultaneous variations, which 

 may be preserved or rejected by natural selection. 



It is plain that this theory is more applicable to 

 animals than to plants. The motions of plants are 

 slight, and their consciousness is very questionable. 

 Use and effort would have little effect here. Still 

 to a certain extent it is believed to apply even here. 

 Plants do have a certain amount of motion of their 

 various parts, leaves, tendrils, etc. The sap is con- 



