236 TKANSACTIONS LIVEBPOOL BIOLOGICAL SOCIETY. 



is not therefore until at least two hours after the seed 

 has been permeated with water that the evolution of C0 2 , 

 indicating the commencement of germination, begins. 

 The true latent period of germination is therefore in the 

 case of Peas at least two hours in duration and is probably 

 longer. During this period the protoplasm of the seed is 

 being built up and re-organised and the outward sign of 

 its complete re-organization is the commencement of 

 respiration. It will be noticed that in calculating the 

 latent period over half an hour has been allowed for the 

 time the C0 2 takes to diffuse outwardly through the 

 integuments of the seed and to escape and accumulate in 

 the air of the flask. 



The elongation and bursting through of the radicle, on 

 the other hand, takes even under favourable conditions 

 from 2 to 3 days and hence occurs considerably after the 

 actual commencement of germination. With Haricots it 

 is found that in five hours a few, and after 6 hours most, 

 of the seeds are soaked but a few of the seeds take as 

 much as 7 to 9 hours to be completely soaked. It should 

 be noticed however that the first seeds soaked will, ceteris 

 paribus, be the first to evolve C0 2 and hence the latent 

 period should be measured between the least time taken 

 to soak any number of the seeds and the earliest evolution 

 of carbonic acid gas. 



The first marked evolution of C0 2 takes place in 10 

 hours, though slight traces come off half an hour before 

 this. The latent period is therefore of from 3 to 4 hours 

 duration at least and is probably longer. 



The first emergence of the radicle on the other hand 

 does not take place until 3 to 4 days after the seeds were 

 soaked. 



It will be noticed that in the case of both Haricots and 

 Peas the time which elapses between the placing of the 



