77 



regenerate this substance in volutin-free cells. It is not the calcium- 

 salts, but the amount of' phosphate in the tap-water that constitutes 

 the causative agent. When Henneberg ^) reports that in a culture of 

 beer-jeast, that has lost much of its volutin, a fresh volutin-formation 

 takes place a siiort time after an incubation in sugar, notably after 

 the addition of ammonium-carbonate, this is to be attributed, in my 

 opinion, only to some degree of impurity of the preparation used. 

 It is a fact that commercial glycose or cane-sugar, as I myself found 

 experimentally, will produce an increase or a recovery of the volutin. 

 In perfectly pure glycose (pro analysi), on the other hand, whether 

 or not after the addition of ammonium-carbonate (pro analysi), the 

 volutin is not recovered. 



There is, therefore, no longer any room for doubt that volutin 

 needs phosphorus for its formation. The question now ai-ises : are 

 there other methods by which its composition can be ascertained ? 

 When Torula monosa is treated for some time, say one liour, at 



n , 

 room-temperature with — NaOH, all the volutin is dissolved. By the 



same method nucleinic-acid may be prepared from yeast in the 



usual way. Does perhaps the volutin furnish the material for it? 



This hypothesis has been previously brought forward by Meyer 



also, as it seemed improbable to him that the comparatively slight 



portion of chromatin in the cell-nucleus — in connection with 



his reactions on volutin described above — could furnish all the 



nucleinic acid produced from yeast. Is there any foundation for this 



hypothesis, to which also other workers (among others Reiche- 



Now *) and Kohl *) ) inclined? In order to ascertain this the following 



experiments were made. 



Twenty-five malt-agar tubes were inoculated with Torula monosa; 



n 

 after 28 hours the strongly developed cultures were washed in — 



NaOH. The suspension, thus obtained, was well stirred ; one hour 

 later (when all cells were free from volutin) it was filtered b^^ 

 suction through paper-pulp, after which 1 cc. 5 perc. HjSO^ per 

 10 cc. filtrate was added. A precipitate was formed that was cen- 

 trifugalized and washed out again in distilled water. When it was 

 analysed this precipitate appeared to contain purin-bodies. It gave 

 after hydrolysis in the autoclave with dilute sulphuric acid a distinct 

 xanthin- and adenin-reaction and on further analysis a phosphate- 



') 1. c. page 74. 

 *J 1. c. page 71. 

 ^) 1. c. page 72. 



