.286 THE LESSON OF EVOLUTION 



life, although both are characterised by spontaneous 

 movements. From the biological point of view the 

 tissue life is the true life ; while from the same point 

 of view the somatic life is merely a co-ordination of 

 .the different organs, which in the higher animals is 

 brought about by the nervous system. What it is 

 more precisely is a question for the psychologist, 

 possibly for the theologian ; but that does not come 

 within the scope of the present paper. These two 

 different meanings of the word ' ' life ' ' have long 

 been recognised by physiologists, although it has not 

 been thought necessary to use different terms in 

 describing them; but, without this explanation, 

 these two distinct meanings, of the word " life " 

 might create confusion in the minds of some readers 

 who are not biologists. 



Although locomotion is characteristic of life, it is 

 not life itself. That name must be applied to the 

 cause of the movements, if it can be discovered. 

 Now, with reference to the voluntary movements of 

 our own bodies, we know them to be due to will, 

 which directs muscular contractions; and, in the 

 lower animals, down to unicellular forms, we see 

 movements take place without any stimulus, which 

 have every appearance of being voluntary also. 

 But w r e know that a very large number of our move- 

 ments are involuntary and uncontrollable by our 

 will ; and this is largely repeated all through ani- 

 mated nature. It is these that have given rise to 

 the idea that many vital movements are mechanical 

 and under the complete control of physical law ; 

 but this is a mistake. We have, is addition to 



