THE PLANT AND THE ANIMAL 285 



background, because completely screened by other pre- 

 dominant processes. We have already seen 1 that 

 under the action of light the green parts of the plant 

 manifest a phenomenon exactly opposite to that of 

 oxidation, i.e. the decomposition of carbonic acid, 

 accompanied by the accumulation of carbon. This 

 process is almost twenty times as energetic as the 

 respiration of plants, so that, for instance, to one pound 

 of carbon burning down in a plant, twenty pounds of it 

 are formed : the plant uses for its requirements only 

 one-twentieth of all the carbon deposited in it, hence 

 the accumulation of matter, the enormous increase in 

 mass, that startles us in the phenomena of growth. 

 Whereas, in the case of animals at the stage of full 

 development, a certain balance becomes established 

 between gain and loss of matter ; in the case of plants, 

 growth, i.e. accumulation of matter, takes place almost 

 as long as they live. 2 However, this accumulation of 

 matter depends entirely upon the sun ; hence the utter 

 dependence of plants upon external conditions, and the 

 passivity which so sharply differentiates them from the 

 independent activity of animals. 



It follows that the difference between plants and 

 animals is not qualitative, but only quantitative. The 

 same processes take place in both kingdoms, but some 

 of them predominate in the one and some in the other. 

 If in the end we have oxidation, waste of matter and 

 manifestation of energy, we have before us the type 

 of an animal ; if, on the other hand, we have deoxidation, 

 accumulation of matter, absorption of energy, we have 

 the type of a plant. Plants and animals have divided 

 labour between them. Animals use up the matter and 



1 See chapter v. 



2 This comparison is, however, not quite accurate. It is more accurate 

 to consider as the individual in a plant a separate shoot which has a 

 limited growth, rather than the whole plant, which, like a tree for instance, 

 presents a complicated organism. It grows like a coral for an indefinite 

 length of time. 



