6 EXPERIMENTS WITH PLANTS 



this is in most cases unnecessary. It is advisable to 

 wire the cork firmly in place, since a certain amount 

 of gas is given off by the seeds, which may force it 

 out of the bottle. 



For this, as well as for subsequent experiments on 

 seeds, it is well to select kinds which germinate quickly, 

 such as Horse-bean, Lima Bean (or other kinds of 

 beans), Sunflower, Pea, Lupine, Eadish, Squash, 

 Wheat and Corn. 



It will appear from this experiment that the seed 

 needs a sufficient amount of water, air and warmth, 

 in order to grow. Every need of the plant presents 

 a problem for the plant to solve. Some plants supply 

 their needs in what seems to be the best possible way, 

 while others adopt methods which appear much less 

 efficient. We may say that the plant solves its prob- 

 lem well or ill, though in so speaking we do not mean 

 to imply that the plant thinks or consciously adapts 

 means to ends, since we are convinced that this can- 

 not be the case. The problems which plants are called 

 upon to solve are very numerous, and the penalty of 

 solving them poorly is to die, or be crowded out by 

 more successful competitors. In studying the plant, 

 we should try first of all to discover its needs and then 

 try to think out for ourselves in each case the best 

 solution of the problem involved. 



Let us consider first the problem of water. How 

 much water does the embryo plant require, and how 



