262 THEORETICAL CONSIDERATIONS 



We know, from other experiments, that the rays can affect living 

 protoplasm, and it therefore seems certain that their effects on photo- 

 synthesis are brought about, in part at least, in that way.* 



As to the effects of radium ra3'S on chemical analysis and syn- 

 thesis we know next to nothing. If, as now seems highly probable, 

 the conversion of carbon dioxide and water into formaldehyde and 

 hydrogen peroxide is the first step in photosynthesis, and if radium 

 rays can modify this reaction, then suitable tests for the formalde- 

 hyde and peroxide in exposed leaf tissues ought to reveal the fact. 

 Fenton^ has shown that the rays can decompose H2O2, and, there- 

 fore, a ^riori^ we might expect the evolution of oxygen in photo- 

 synthesis to be accelerated under their influence. 



In his presidential address before the Chemical Society of Lon- 

 don, Meldola^" urged the view that several organic substances besides 

 sugars may possibly result from the photosynthetic activity of the 

 green cell. If this shall be demonstrated, then failure to detect 

 starch or sugar in leaves exposed to radium rays will not necessarily 

 indicate that all photosynthetic activity has been inhibited. 



Fermentation : In studying the effect of radium rays on fer- 

 mentation by yeast we have to consider their effects, not only on the 

 living yeast-cells, but also upon the sugar solution, and upon the 

 enzymes secreted by the yeast and acting as the immediate cause of 

 the fermentation. The literature dealing with the discovery of en- 

 zymes in yeast and the proposal of the enzyme theory by Moritz 

 Traube,^*' ^^ in 1858, with the isolation of the alcohol-producing en- 

 zyme, zymase,! by Eduard Buchner,^^ and with other early discoveries 



hydrogen, according to the known formula, thus setting free formaldehyde and oxygen, 

 together with, in some cases, the transitory formation of HjOj. All these phenomena 

 he expresses by the following scheme : 



Light 



i 



chlorophyll 



i 

 — electricity + 



-%0 + CH,0 = ^J26, ^^ 



(CeHioOjV ^-^CH^O + H^CH. + O 



* The biogen molecule may also be a factor here. 



t Jost "^ suggests the desirability of employing the term zymase in a generic sense 

 for all substances produced by organisms and having the power of causing fermenta- 

 tive decompositions. To replace zymase he proposes the term alcoholase. This change 

 seems unnecessary as it merely involves the substitution of " zymase" for " enzyme," 

 which is now used generically. 



