18 
BULLETIN 782, U. S. DEPARTMENT 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 maximum hydrogen-ion change was from P H 
7.1 (control) to P H 5.7, in propyl alcohol from P H 7.0 (control) to P H 5.4, 
and in amyl alcohol from P H 6.9 (control) to P H 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 all 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 mono atomic alcohols. Cultures 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 
liter. 
Man- 
nite. 
Gly- 
10 
5 1 3 
10 
5 
3 
10 

5_ 
3 
cerin. 
10 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
4- 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
12 
31 
49 
59 
_ 
60 
61 
_ 
62 
_ 
66 
_ 
72 
_ 
73 
101 
102 
103 
IIM+ Mill +111+ II 
+M++ ++++I ++I++ +1 
104 
- 
105 
- 
106 
107 
_ 
108 
Ill 
_ 
112 
113 
_ 
114 
116 
117 
118 
119 
— 
120 
121 
+ 
122 
+ 1 
— 
