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VITAL MAXIFESTATIOXS OF BACTERIA. 25

e. Diverse Fermentations.

Brieger-® examined a number of bacteria, especially patho-
genic, in regard to their products of decomposition. A coccus
which occurs in the human fseces alvs^ajs splits 3 per cent, cane-
or grape-sugar solutions in the same manner, producing ethyl-
alcohol within the short space of twenty-four hours. Traces of
acetic acid are also appreciable. A pathogenic bacillus, also found
in the faeces, forms in grape-sugar solutions propionic acid, accom-
panied by minute quantities of acetic acid. The coccus of pneu-
monia decomposes cane- and grape-sugar solutions into acetic
acid, and very minute quantities of formic acid, under evolution
of large quantities of carbonic acid. (The solutions had been
saturated with freshly precipitated carbonate of lime.)
Typhus bacilli split grape-sugar solutions, or starch, into
acetic and lactic acids, and ethyl alcohol. Staphylococcus pyo-
genes aureus, when cultivated in bouillon containing glycogen
(3 : 100) and a quantity of freshly precipitated carbonate of lime,
forms very small quantities of organic acids (principally oxalic
acid).
Fitz^ has also observed several carbohydrate fermentations;
among others, one in which ethyl alcohol appeared as chief pro-
duct. As products of milk-sugar fermentation, he found ethyl
alcohol and other substances not further determined. Cane-
sugar yielded butyl alcohol, butyric acid, and traces of lactic and
succinic acids. Starch yielded butyric and acetic acid: inuline,
which fermented as easily as starch, gave alcohol and volatile
acids.
Boutroux-* found gluconic acid as a product of the fermt-nta-
tion of milk-sugar.

B. Fermentation of Polijcalent AIcoJioIs.
In his communications concerning " schizomycetes fermenta-
tions," Fitz has described a number of different fermentations of
polyvalent alcohols: glycerine, erythrite, raannite, dulcite, and
quercite. Glycerine yielded normal butyl alcohol, with profuse
generation of carbonic acid and hydrogen, normal butyric acid,
and traces of a higher fatty acid (probably capronie).