626 PSYCHOLOGY. 



itself, but with some different outer relation altogether. A 

 diagram will express the alternatives. B stands for our 

 human brain in the midst of the world. All the little o's 



Fig. 94. 



with arrows proceeding from them are natural objects (like 

 sunsets, etc.), which imj)ress it through the senses, and in 

 the strict sense of the word give it experience, teaching it by 

 habit and association what is the order of their ways. AU 

 the little x's inside the brain and all the little a?'s outside 

 of it are other natural objects and processes (in the ovum, 

 in the blood, etc.), which equally modify the brain, but 

 mould it to no cognition of themselves. The tinnitus aurium 

 discloses no properties of the quinine ; the musical endow- 

 ment teaches no embryology ; the morbid dread (of solitude, 

 perhaps) no brain-pathology ; but the way in which a dirty 

 sunset and a rainy morrow hang together in the mind copies 

 and teaches the sequences of sunsets and rainfall in the 

 outer world. 



In zoological evolution we have two modes in which an 

 animal race may grow to be a better match for its environ- 

 ment. 



First, the so-called way of * adaptation,' in which the 

 environment may itself modify its inhabitant by exercis- 

 ing, hardening, and habituating him to certain sequences^ 

 and these habits may, it is often maintained, become hered- 

 itary. 



Second, the way of * accidental variation,' as Mr. Darwin 

 termed it, in which certain young are born with peculiarities 

 that help them and their progeny to survive. That varia- 

 tions of this sort tend to become hereditary, no one doubts. 



