10 NUTRITION FACTORS IN YEAST AND BACTERIA 



SHAKING OF AUTOLYZED YEAST WITH FULLERS EARTH AND NORIT. 



Funk and Dubin 5 have shown that at least two different sub- 

 stances can be separated from autolyzed yeast by means of 

 shaking with fullers earth. By this method it is now possible to 

 separate the vitamine active for yeast growth, which has been 

 provisionally called "vitamine D," from the anti-beriberi or B 

 vitamine. 



Several preparations of autolyzed yeast were subjected to 

 shaking with various amounts of both fullers earth and norit, 

 as follows : The clear filtrate of autolyzed yeast, after removal 

 of the protein by heat coagulation, was first shaken for three 

 hours with 50 grams of fullers earth per liter, and filtered. 

 The filtrate showed very little loss of growth-stimulating effect 

 on yeast cells as compared with the original material, while 

 there was no observable loss of stimulation on bacterial growth. 

 This filtrate was again subjected to shaking with fullers earth, 

 this time with 100 grams per liter. The filtrate from this shak- 

 ing gave a yeast growth-increase about one half as great as that 

 given by the original 5% autolyzed yeast solution. This filtrate 

 gave as a rule no growth of streptococci, although in one or two 

 cases a slight growth was obtained. This second filtrate was 

 again shaken for three hours with 100 grams of fullers earth 

 per liter, the filtrate from this final shaking having almost no 

 stimulating effect on yeast growth and none on bacterial growth. 



We obtained practically similar results by subjecting auto- 

 lyzed yeast solutions to shaking with norit. The first filtrate 

 after shaking with 50 grams of norit per liter was still strongly 

 active on both organisms, while the second filtrate, obtained 

 after shaking the first with 100 grams per liter, showed a slight 

 effect on yeast growth, but was entirely negative on the growth 

 of streptococci, as was to be expected. The third filtrate, ob- 

 tained after again shaking the previous filtrate with 100 grams 

 of norit per liter, had lost all activity on the growth of both 

 organisms. 



A few experiments were also tried with Lloyd's reagent, the 

 results comparing favorably with those obtained with the other 

 two adsorbing reagents, although Lloyd's reagent is less ener- 

 getic an adsorber than fullers earth or norit. 



