22 THE STOllY OF THE PLANTS. 



own days at least spontaneous generation does 

 not take place — perhaps because all the available 

 material is otherwise employed, perhaps because 

 the conditions are no longer favourable. At any 

 rate, we have every reason to suppose that at the 

 present day every living being, whether plant or 

 animal, is the product of a previous living being, 

 its parent, or of two previous living beings, its 

 father and mother. 



Why should this be go ? Well, if you think 

 for a moment, you will see that it results almost 

 naturally from the other facts we have so far 

 considered. For the plant is a machine for 

 making living matter out of water and carbonic 

 acid, under the influence of sunlight. As long 

 as sunlight, direct or reflected, in sun or shade, 

 falls upon a green plant, the plant goes on 

 taking up carbonic acid from the air by means 

 of its leaves, and water from the earth by means 

 of its roots, and continues to manufacture from 

 them fresh living material. Thus it must be 

 always growing, as we say ; in other words, the 

 mass of living material must be constantly 

 increasing. Now, it results from this that the 

 plant would grow in time unwieldily large ; and 

 in simple types, when it grows very large, it 

 splits or divides into two portions. That is the 

 real origin of what we call eepeoduction. In 

 its simplest forms, reproduction means no more 

 than this — that a rather large body, which cannot 

 easily hold together, divides in two, and that 

 each part of it then continues to live and grow 

 exactly as the whole did. 



This seems odd and unfamiliar to you, because 



