VITALITY AND GERMINATION OF SEEDS. 217 



plantlets although their germination has commenced can 

 lie in a semi-dormant condition for as long a period as a 

 month without being killed and without any further 

 growth taking place. After a period of immersion of from 

 6 to 8 weeks, however, the vitality of all the seeds is lost. 



With all the other seeds, excepting Peas, though they 

 swell more or less, no actual germination or protrusion of 

 the radicle takes place. For this they apparently require 

 a greater quantity of oxygen than is contained in the 

 small amount of water in which they lie. It follows 

 therefore, that, with Peas and Hemp, since in such 

 experiments their incipient germination goes further than 

 it does with the other seeds, we should expect to find that 

 water exerts a more injurious effect upon them than the 

 known vitality of the seeds would lead us to infer. 

 Thus Peas which are possessed of considerable vitality are 

 but slightly more resistant than Haricots, and are less 

 resistant than Barley and Wheat, though the vitality of 

 all these seeds is, as is shown by later experiments much 

 less pronounced. 



In the case of Hemp, however, the factors mentioned 

 above interfere and protect the plantlet from injury, so 

 that of all the seeds experimented with Hemp offers the 

 greatest resistance to the action of water, and this in spite 

 of the fact that on such immersion the majority of the 

 seeds undergo incipient germination. 



Experiments were also made to find out the effect 

 of alternately soaking Peas in water and then drying 

 them. The Peas were left in water until thoroughly 

 soaked and were then spread out on sheets of blotting 

 paper and left to become slowly air dried. As soon as 

 they were quite dry a certain number were planted and 

 the remainder were again soaked and dried and then 

 planted, and so on. 



