﻿274 Macloskie : Heat of Imbibition by Seeds 



control bottle during the entire course of imbibition until germi- 



nation begins. The significant part of the process is that when 

 seeds are well protected from loss of heat, the imbibition-heat be- 

 comes cumulative, so as to reach a considerable amount and to be 

 effective in starting the radicle of the young plant. This may help 

 to elucidate the case cited by Uloth (i 87 1) of the germination of 

 seeds in ice. He found seeds of Acer platanoides and also of 

 wheat, between blocks of ice in an ice-house, having started to 

 grow and having pushed their roots several inches down into the 

 fissureless ice. His suggestion was that heat may have radiated 

 through the ice. It appears more probable that something like a 

 lighted taper or burning straw may have melted enough of the ice 

 to wet the seeds, that the heat of imbibition thus produced might 

 melt more of the ice, and this cumulatingly react upon the seed, 

 and so on acting and reacting, whilst the ice itself would present 

 an obstacle against the waste of heat by dissipation in other 

 directions. The fact of its not being an isolated case of a single 

 seed is evidence to prove that there must have been some general 

 cause at work. 



Princeton University, 



March 22, 1898. 



