84 



know that the presence of phosphate aids the fermentation. The 

 experiments cannot be arranged so as to enable the investigator to 

 study this influence irrespective of the volutin-production. Harden 

 and Young ^) liave even rendered it very probable tliat phosphates 

 are indispensable to fermentation. According to them the course of 

 the fermentation is represented by their well-known equation : 

 C,H,,0,4-2 PO,Na,H = C,H,„0,(P0,Na,),+2 CO,-f 2C,H30H+2 H^O. 

 CeH,oO,(FO,NaJ, + 2 H,0 = C,H„0, + 2P0,Na,H. 



In connection with this my experiments go to show that (if Harden 

 and Young are right) traces of phosphorus-compounds in a culture- 

 fluid, too small to cause the formation of volutin, bring about 

 tiiese chemical changes. That they are organic and not anorganic 

 phosphorus-compounds is of no consequence ; we need only think 

 of the nuclease-action, which, as described above, also belongs to 

 the volutin-free yeast-cells. 



Zymase-action therefore does not depend on the presence of 

 volutin, no more does the nuclease-action ; I have been able to prove 

 the same for katalase-action. Yeast-cells, entirely free from volutin, 

 suspended in 3 perc. H^O,, evolve immediately an abundance of 

 oxygen. No gas-formation takes place in H^O^ when the yeast-cells 

 have been previously destroyed by boiling. 



Hennebekg's totally different results with the zymase-action of 

 Saccharomyces cerevisiae may be attributed to the fact that such 

 problems can be solved only when, as was the case in my ex- 

 periments, the volutin-production can be absolutely precluded, for, as 

 Henneberg himself asserts on page 15, the volutin-contents of the 

 cells could in his experiments be replenished from the medium in 

 which they live. 



When Henneberg observes regeneration of the volutin in a solution 

 of sugar in water without the addition of salts, it is not the sugar that 

 constitutes the active substance, for in glycose pro analysi no fresh 

 production of volutin takes place, as I found over and over again. 

 When some months ago commercial glycose was sold in a some- 

 what impure condition, numerous volutin-containing cells appeared 

 in all my cultures without addition of phosphate. 



As for Henneberg's microscopic findings during the fermentation, 

 viz. a finer distribution of the volutin-granules in the initial phase 

 of the fermenting process, the question may be asked whether these 

 changes may perhaps be connected with other life-symptoms in the 



1) Proceedings of the Royal Society Vol. LXXXII p. 361. See also Euler and 

 Hammarsten Biocli. Zeitschr. Bd. LXXVI, 1916, p. 314. 



