The Brain and Nervous Energy 73 



have carried out a series of movements suc'h as 

 those referred to as a result of its own experi- 

 ence; the only kind of action which Mr. 

 Romanes believes can be accepted as an indica- 

 tion of intelligence. 1 



The burrows of the ordinary earth-worm are 

 carefully lined by leaves and earthy materials, 

 and terminate in a chamber in which one or more 

 worms pass the winter rolled up into a ball, kept 

 warm by the lining of the passage and the 

 effective plug they have constructed to exclude 

 external cold, and the danger of being flooded. 



It thus appears that with the development of 

 a brain or aggregation of nervous elements in 

 the head of a class of living beings, their 

 instinctive behaviour rises to a higher level 

 than that displayed by more lowly organised 

 animals. This state of things can be under- 

 stood, if we admit that the functions performed 

 by certain of the elements of nervous matter is 

 to transform energy acting on it into instinctive 

 processes. The evidence we have thus far 

 advanced supports this idea, and, still further, 

 points to the fact that the purposive movements 



1 The Formation of Vegetable Mould, bv Charles Darwin, p. go. 



