ii4 CREATIVE EVOLUTION CHAP. 



draw directly from the air and earth and water. 

 But now we come to another difference, deeper than 

 this, though not unconnected with it. 



The animal, being unable to fix directly the carbon 

 and nitrogen which are everywhere to be found, has to 

 seek for its nourishment vegetables which have already 

 fixed these elements, or animals which have taken them 

 from the vegetable kingdom. So the animal must be 

 able to move. From the amoeba, which thrusts out 

 its pseudopodia at random to seize the organic matter 

 scattered in a drop of water, up to the higher animals 

 which have sense-organs with which to recognise their 

 prey, locomotor organs to go and seize it, and a 

 nervous system to coordinate their movements with 

 their sensations, animal life is characterized, in its 

 general direction, by mobility in space. In its most 

 rudimentary form, the animal is a tiny mass of 

 protoplasm enveloped at most in a thin albuminous 

 pellicle which allows full freedom for change of shape 

 and movement. The vegetable cell, on the contrary, is 

 surrounded by a membrane of cellulose, which con 

 demns it to immobility. And, from the bottom to the 

 top of the vegetable kingdom, there are the same habits 

 growing more and more sedentary, the plant having no 

 need to move, and finding around it, in the air and 

 water and soil in which it is placed, the mineral elements 

 it can appropriate directly. It is true that phenomena 

 of movement are seen in plants. Darwin has written 

 a well-known work on the movements of climbing 

 plants. He studied also the contrivances of certain in 

 sectivorous plants, such as the Drosera and the Dionaea, 

 to seize their prey. The leaf-movements of the acacia, 

 the sensitive plant, etc., are well known. Moreover, 

 the circulation of the vegetable protoplasm within its 



