330 Life and Immortality. 



In animals possessed of a nervous system, contractions 

 only follow stimuli, which are carried to the contractile ele- 

 ments by nervous threads, the internal energy representing 

 the external stimulus being called nervous energy or neu- 

 rism. But where a nervous system does not exist, as is the 

 case in some low animals and in all plants, external stimuli 

 must be justly supposed to be converted into the same form 

 of energy, which in such organisms has a general circulation 

 throughout the contractile protoplasm. The attainment of 

 some position, favorable for the procurement of relief from 

 some unpleasant sensation, or the acquisition of some agree- 

 able one, or for both, is the important thing directly sub- 

 served by such movements in the generality of animals. 

 While we have the best of reasons for believing this to be 

 true in the vast majority of animals, because fundamentally 

 their structure is similar to our own, yet the inference that 

 the same is true of the lowest forms of life is justifiable until 

 it is proved to be mistaken. 



Whatever be the nature of any movement, whether the 

 projecting of portions of its own body-substance as pseudo- 

 podia in the primitive animal, the movement of flagella or 

 cilia in more specialized forms, or the turning of the radicle 

 of a plant-seedling in overcoming some obstacle, there is no 

 resisting the conclusion that the functions of these organs, 

 when once called into existence, are due to stimuli not unlike 

 those which affect the motions of the limbs of the higher 

 animals, and that the preliminary to all such movements, 

 which are not automatic, is an effort. And as no adaptive 

 movement is automatic the first time it is performed, effort, 

 therefore, may be regarded as the immediate source of all 

 movement. Now, effort is a conscious state, and implies a 

 sense of resistance to be overcome. But when an act is per- 

 formed without effort, resistance has been overcome, and the 

 mechanism requisite for its performance has been completed. 

 Automatism has now been reached. New movements, in 

 their incipiency, necessarily meet with resistance. How this 



