Leaves and their Work 173 



compounds, carbon compounds— has been made ready 

 for them in the light, by the dead vegetable matter 

 upon which they grow. Perhaps it is the fact of their 

 not having any work to do which enables them to grow 

 with such extraordinary rapidity, as they devote all 

 their energies to feeding and increasing in size. The 

 cells of the puff-ball, for instance, multiply at the rate 

 of three or four hundred million in an hour, and the 

 plant will attain the size of a large gourd in a few days. 

 The curious brown Bird's-nest orchis is another plant 

 which has no leaf-green, cannot provide its own food, 

 and lives upon dead vegetable matter. 



But there are other plants devoid of leaf-green, which 

 prey, not on the dead, but on the living ; sucking their 

 juices, and profiting by their labours in earth and air. 

 Among these may be mentioned the broom-rape, a 

 brown, uncanny-looking plant, which attaches itself to 

 the roots of living plants, clover and others, and draws 

 all its nourishment from them. 



In one way or another, then, all plants obtain car- 

 bon ; and when they have to do it by their own exer- 

 tions they must have leaf-green, and they cannot 

 usually have leaf-green without light, or, in any case, 

 without iron. 



But, it may be said, seeds, most of them, begin to 

 grow in darkness, underground, and so do bulbs ; and 

 they are usually p;,le yellow at first. If they have no 

 leaf-green, as they evidently have not, then, if cells 

 cannot be multiplied without carbon, and carbon they 

 cannSt get for want of this leaf-green, how do they 

 manage to grow ? 



In the same way that other plants do which are also 

 without leaf-green. They make use of the carbon stored 



