252 CREATIVE EVOLUTION [chap. 



in one point of the body reverberates, as it were, through- 

 out. The complication may therefore go on to infinity 

 in all directions; but it is the complication of the nervous 

 system which conditions the others in right, if not always 

 in fact. Now, in what does the progress of the nervous 

 system itself consist? In a simultaneous development 

 of automatic activity and of voluntary activity, the first 

 furnishing the second with an appropriate instrument. 

 Thus, in an organism such as ours, a considerable number 

 of motor mechanisms are set up in the medulla and in the 

 spinal cord, awaiting only a signal to release the correspond- 

 ing act : the will is employed, in some cases, in setting up 

 the mechanism itself, and in the others in choosing the 

 mechanisms to be released, the manner of combining them 

 and the moment of releasing them. The will of an animal 

 is the more effective and the more intense, the greater 

 the number of the mechanisms it can choose from, the 

 more complicated the switchboard on which all the motor 

 paths cross, or, in other words, the more developed its 

 brain. Thus, the progress of the nervous system assures 

 to the act increasing precision, increasing variety, in- 

 creasing efficiency and independence. The organism be- 

 haves more and more like a machine for action, which 

 reconstructs itself entirely for every new act, as if it were 

 made of india-rubber and could, at any moment, change 

 the shape of all its parts. But, prior to the nervous 

 system, prior even to the organism properly so called, 

 already in the undifferentiated mass of the amoeba, 

 this essential property of animal life is found. The amoeba 

 deforms itself in varying directions; its entire mass does 

 what the differentiation of parts will localize in a sensori- 

 motor system in the developed animal. Doing it only 

 in a rudimentary manner, it is dispensed from the com- 

 plexity of the higher organisms; there is no need here of 



