86 



To ascertain whether volulin is indispensable to the fermenting 

 process we had to follow up another plan. It then appeared that 

 the zymase as well as the nuclease and the katalase do not depend 

 on the presence of this substance. The question might now be asked 

 whether — though the material that exhibits the colour-reactions, 

 demonstrated by AIeyer, is not the mother-substance of the 

 enzymes — it may be that the principal constituents of the volutin 

 still remain in the cell after tlie said reactions have disappeared. 

 To this question we can say that — as seen on page 80 — in ex- 

 tracting volutin-containing Torula monosa with dilute alkali we get 

 a nucleinic acid compound, not to be obtained by the same method 

 from an approximately equal amount of volutin-free Torula.- It 

 follows then that it is not only a colour-reaction, which gets lost 

 through unknown chemical changes in the cell, but undoubtedly a 

 nucleinic acid compound which the Torula loses in a phosphate-free 

 medium. We are, therefore, justified in assuming that this nucleinic- 

 acid compound is not indispensable for the enzymic action. Nor is 

 it indispensable to sustain the stock, for the Torula monosa maintains 

 the properties of the stock after a nine months' incubation in a 

 phosphate-free medium; also the multiplication continues to proceed 

 regularly, though at a somewhat slower rate. Such a culture trans- 

 planted after 9 months upon a phosphate-free medium is still capable 

 of fermenting (experiment page 85); in a phosphate-containiug 

 medium volutin is formed again directly in the usual way. This 

 substance, which appeared indeed to be a nucleinic-acid com- 

 pound, we can hardl} consider to be anything else but a reserve- 

 material, and most likely one of a peculiar nature. If namely we 

 bear in mind, that most probably phosphates must always be present 

 for the cells to draw from in the fermenting process, it will be an 

 advantage to the cell when it can draw this phosphate immediately 

 from that reservoir of nucleinic-acid in virtue of its nuclease; the 

 quantity of this phosphate may be ever so small, as after being set 

 free, it can be utilized again. It is obvious, therefore, that the 

 presence of volutin in hypho- and blastomycetes may be of great 

 significance for the fermenting process without however being indis- 

 pensable to the fermentation, as it has been proved that even the 

 merest traces of phosphorus, demonstrable only under the microscope, 

 in a volutin-free culture, suffice to render fermentation possible. 



S U M M A R Y. 

 The production of volutin-granules in moulds and in yeast-cells 

 depends on the presence of anorganic or organic phosphorus-com- 

 pounds in the culture-medium. In a phosphate-free medium Ustilago 



