68 PHYSIOLOGY OF YEASTS 



linized with sodium hydroxids. The distillate is received in dilute 

 sulfuric acid, and there results a liquid which, after neutralization, pos- 

 sesses toxic properties for the cells when introduced into them. Ex- 

 periments with B. coli and Staphylococcus pyogenes aureus indicate that 

 the yeast toxin is also poisonous to them. Like other toxins, it passes 

 through porcelain filters and is destroyed at 100. It is also vola- 

 tile. From some of its characteristics, it seems that this toxin ought 

 to belong to the amines. Fernbach 1 continued his study of toxic sub- 

 stances in yeasts by drying yeast cells at 37 C. and extracting them 

 with dilute hydrochloric acid. The filtered extract was toxic to 

 yeasts and bacteria. The toxic substance was destroyed at 10 C. 

 and was volatile. Haydruck 2 has been unable to confirm these 

 results of Fernbach. 3 



NUTRITION OF YEASTS 

 1. Mineral Elements 



Mayer 4 has studied the mineral elements which are necessary for 

 the yeasts. This author attempted to determine new media by the 

 introduction of new elements. The mineral mixture which yields the 

 bests results, is as follows: 



0.1 gram Monobasic potassium phosphate 

 0.1 " Magnesium sulfate 

 0.1 " Tribasic calcium phosphate 

 100.00 c.c Distilled water 

 15.00 grams Candied sugar. 



According to these investigations, potassium phosphate plays an 

 important role, after which is magnesium. It is interesting to note 

 that these mineral elements are the same, and almost in the same 

 proportion, as those which have been found by analysis of yeasts. 

 The synthetic method has then confirmed the results of the analytic 

 method. 



The investigations of Elion 5 and Stern 6 have confirmed the re- 

 sults of Mayer and shown that the phosphates, magnesium, potas- 

 sium and sulfur are indispensable elements in the life of yeasts. 



1 Fernbach, A. The poison elaborated from yeast. Comp. Rend. Acad. Sci. 

 149, 437-439. 



2 Haydruck, F. Yeast poison in yeast. Wochenschr. Brau. 26, 677. 



3 Fernbach, A. Toxic substance elaborated by yeast. Ann. Brasserie dis- 

 tillerie, 12, 361. Chem. Absts. 4 (1910), 948. 



4 Mayer, A. Lehrbuch der Garungschemie, 1902, 5th edition. 

 B Elion, H. Studien iiber Hefe. Cent. Bakt. 14, 1893. 



e Stern. Nutrition de la levure. Jour. Chem. Society, 1899 and 1901. 



