GERMINATION OF THE SEED. 



267 



2. The Absorption of Oxygen during Germination. 



Concerning tliis, little is to be added as the result of recent 

 researches. That oxygen is absolutely necessary to the be- 

 ginning of germination has been long known. The amounts 

 of oxygen consumed during the early stages of the process 

 are given in the following table by J. Wiesner,^ in which the 

 percentages of carbon-dioxide evolved furnish data for an 

 easy calculation. 



100 grams of dried substance yielded of Co, — 



Nothing of importance has of late been added to the rela- 

 tion of depth of planting to access of atmospheric oxygen.^ 



3. The Temperature requisite for G-ermination. 



The approximate figures given by Professor Sachs' are 

 under three heads, — the minimum, the maximum, and the 

 optimum or best temperature ; for convenience of reference 

 they are here reduced to Fahi'euheit's scale. 



1 Quoted by Nobbe, Samenkunde, p. 172. 



2 Certain interestiug experiments in regard to the retarding effects of pure 

 oxygen upon germination cannot now be described in detail. It is sufficient 

 to state that the percentage of oxygen in admixture in the atmosphere is not 

 tar from that actually determined to bo the very best for germination. 



8 These experiments were reported in ISGl, the later series in 18G5. 



