18 



BULLETIN 782, U. S. DEPAETMENT OF AGRICULTURE. 



concentration was considered a positive fermentation. Methyl alco- 

 hol was not fermented by any of the cultures, which may be due to 

 the poisonous character of this alcohol. As may be seen from Table 

 9, the majority of the cultures fermented propyl alcohol. Forty-eight 

 of the 68 cultures fermented both propyl and ethyl alcohol when 

 5 grams of alcohol per liter was used in the medium. It will be 

 noted that with the other quantities of alcohol more cultures fer- 

 mented the propyl than the ethyl alcohol. Amyl alcohol was not so 

 readily fermented. 



In ethyl alcohol the maximiun hydrogen-ion change was from P^ 

 7.1 (control) to Ph 5.7, in propyl alcohol from P^ 7.0 (control) to Ph 5.4, 

 and in amyl alcohol from P^ 6.9 (control) to Pg 6.6. While there was 

 not much difference between the fermentation when 10 grams and 

 5 grams of alcohol were used per liter, a larger number of cultures 

 fermented the alcohol in these cases than when only 3 grams was 

 used. In general, when a culture fermented ethyl it fermented propyl 

 alcohol, but this was not true in aU cases. Usually when amyl alcohol 

 was fermented ethyl and propyl were fermented also, but there were 

 several exceptions. Only one of the cultures which fermented man- 

 nite also fermented the monoatomic alcohols. Cultm-es 121, 133, 

 and 134, which fermented glycerin, were not able to ferment any of 

 the monoatomic alcohols. 



Table 9. — Fermentation of the alcohols. 



Culture No. 



Ethyl, grams per 

 liter. 



Propyl, grams per 

 liter. 



Amyl, grams per 



Man- 

 nite. 



Gly- 





10 



5 



3 



10 



5 



3 



10 



5 



3 



cerin. 



10 



+ 



4- 

 + 



+ 



+ 

 + 



+ 



+ 

 + 



+ 

 + 

 + 



+ 



+ 

 + 

 + 



+ 

 + 



+ 



+ 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



_ 



+ 

 + 



+ 



+ 

 + 



+ 



+ 



+ 

 + 

 + 

 + 



+ 

 + 



+ 



+ 



+ 



+ 

 + 



+ 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 



+ 



+ 



+ 



+ 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 

 + 

 + 



+ 



+ 

 + 



+ 

 + 



+ 



+ 



+ 



+ 

 + 



+ 

 + 



+ 

 + 



+ 



+ 



+ 



4- 

 + 



+ 

 + 



+ 



+ 

 + 



+ 



+ 

 + 

 + 



+ 

 + 



+ 

 + 



+ 





12 





31 





49 





59 



_ 



60 





61 





62 



_ 



66 





72 



_ 



73 





101 





102 







103 





104 



_ 



105 





106 



_ 



107 







108 





Ill 



_ 



112 





113 



_ 



114 



_ 



116 



_ 



117 



_ 



118 





119 



_ 



120 







121 



+ 



122 





