12 



NUTRITION FACTORS IN YEAST AND BACTERIA 



was repeated several times to remove most of the acid. The 

 last traces of acetic acid were neutralized by addition of nor- 

 mal sodium hydroxide solution. The neutralized solution was 

 made up to a volume equal to the original volume of the autolyzed 

 yeast, adjusted to the proper PH (7.4) and sterilized. One cc. 

 of this extract was used in each test. 



These acetic acid extracts from the charcoal gave very in- 

 teresting results. As shown in table IV, Nos. 5 (a) and 6 (a), 

 they are practically in accord with the results obtained from 

 the baryta extracts from the fullers earth after adsorption of 

 the vitamine-like substance. The first two extracts stimulate 

 both yeast and bacterial growth, while the extract from the 

 third shaking [7 (a) ] shows a very slight stimulating effect on 

 yeast growth and no effect on the growth of streptococci. 



TABLE IV. 



Effect of Shaking of Autolyzed Yeast with Fullers Earth 



and Norit. 



No. 



FULLERS EARTH 



1. Autolyzed yeast (5% solution) 



2. Autolyzed yeast shaken with 50 



grams per liter 



2 (a) Baryta extract of fullers earth 



(from 2) 



3. Autolyzed yeast (filtrate from 2) 



shaken with 100 grams per liter 



3 (a) Baryta extract of fullers earth 



(from 3) 



4. Autolyzed yeast (filtrate from 3) 



shaken with 100 grams per liter 



4 (a) Baryta extract of fullers earth 



(from 4) 



Net Yeast Growth* 

 in mm. obtained by 

 Funk and Our- 



Dubin selves 



14.5 12.5 



NOHIT 



5. 



Autolyzed yeast shaken with 50 

 grams per liter 



5 (a) Acetic acid extract of norit 



(from 5) 



6. Autolyzed yeast (filtrate from 5) 



shaken with 100 grams per liter 



6 (a) Acetic acid extract of norit 



(from 6) 



7. Autolyzed yeast (filtrate from 6) 



shaken with 100 grams per liter 



7 (a) Acetic acid extract of norit 



(from 7) 



12.0 

 4.0 

 6.0 

 3.5 

 0.5 

 0. 



13.5 

 3.0 

 3.0 

 3.0 

 0.5 

 0. 



9.5 



5.5 

 5.0 

 4.0 

 0.5 

 0. 



10.5 

 4.0 

 3.0 

 3.0 

 0. 

 0. 



Bac- 

 terial 

 growth 



44- 

 4-4- 

 4-4 



4-4- 



4- 

 4-4- 



4- 



* Slight variations between the results obtained by Funk and Dubin and by ourselves 

 are due to the use of different preparations of autolyzed yeast. 



