It] ANIMAL LIFE 125 



energy to convert into locomotive movement. 1 It is 

 true that the more the nervous function is perfected, the 

 more must the functions required to maintain it develop, and 

 the more exacting, consequently, they become for them- 

 selves. As the nervous activity has emerged from the 

 protoplasmic mass in which it was almost drowned, it 

 has had to summon around itself activities of all kinds for 

 its support. These could only be developed on other 

 activities, which again implied others, and so on indefinitely. 

 Thus it is that the complexity of functioning of the higher 

 organisms goes on to infinity. The study of one of these 

 organisms therefore takes us round in a circle, as if every- 

 thing was a means to everything else. But the circle 

 has a centre, none the less, and that is the system of nervous 

 elements stretching between the sensory organs and the 

 motor apparatus. 



We will not dwell here on a point we have treated at 

 length in a former work. Let us merely recall that the 

 progress of the nervous system has been effected both 

 in the direction of a more precise adaptation of movements 

 and in that of a greater latitude left to the living being 

 to choose between them. These two tendencies may 

 appear antagonistic, and indeed they are so ; but a nervous 

 chain, even in its most rudimentary form, successfully 

 reconciles them. On the one hand, it marks a well-de- 



1 Cuvier said: "The nervous system is, at bottom, the whole animal; 

 the other systems are there only to serve it." ("Sur un nouveau 

 rapprochement a etablir entre les classes qui composent le regne ani- 

 mal," Arch, du Museum d'histoire naturelle, Paris, 1812, pp. 73-84.) 

 Of course, it would be necessary to apply a great many restrictions 

 to this formula — for example, to allow for the cases of degradation 

 and retrogression in which the nervous system passes into the back- 

 ground. And, moreover, with the nervous system must be included 

 the sensorial apparatus on the one hand and the motor on the other, 

 between which it acts as intermediary. Cf . Foster, art. ' ' Physiology," 

 in the Encyclopaedia Britannica, Edinburgh, 1885, p. 17. 



