FERMENTATION 497 
The investigations carried out at the University of Wisconsin have 
given us much information on the use of spices as preservatives (Hoff- 
mann and Evans, 1911, Bachmann, 1916). Cinnamic aldehyde and 
eugenol were found to be especially important in preserving. Both of 
these are found in cinnamon and cloves and probably accounts for 
the preserving action of these condiments. In the later paper by Bach- 
mann a new method was used by which the plain and spice agar could 
be used in the same Petri dish. The results are quite similar to those 
presented in a former paper. Pepper and nutmeg were not able to 
retard growth of microorganisms. Cloves and allspice in large amounts 
were effective. In a later paper Bachmann (1918) reported that bac- 
teria, molds and yeasts show a marked sensitiveness to different brands 
of spice. The growth of microorganisms on a spiced medium may be 
taken as a criterion of the preservative value of the spice. 
Garlic was found to possess a prophylactic action by Minchin (1917) 
in diseases of diphtheria, typhus and typhoid. It would possibly 
possess the same action in food preservation. 
Fermentation. This process of preservation is limited to a certain 
few foods. The acids, principally lactic, are relied upon to suppress 
the growth of putrefactive bacteria. Brown (1916), in studying the 
brine pickle fermentation reports that many bacteria may enter the 
tank, but only those which can tolerate 12 to 20 per cent of salt are con- 
cerned in the normal fermentation. He found that the acidity of new 
brine is practically zero and gradually increases to 50 per cent N/10 or 
above. Lactic and acetic acids predominate with a ratio of about 2: 1. 
When the scum yeasts reduced the acid from the surface downward, the 
pickles were liable to decomposition. 
From the fact that lactic acid is so important in the keeping of 
pickles it may be wondered whether the salt is really necessary. Rahn 
(1913) has answered this: 
This question must doubtless be answered with yes. If no salt, or only 
little salt would be added the keeping quality of brine pickles would be like 
that of the dill pickles, or even less, since the spices of the dill pickles have a 
certain, though very small, disinfecting value. Salt retards all life activities 
of bacteria; it makes the fermentation go slower and it makes the acid destruc- 
tion by the scum yeast slower, too. The more salt the longer will the pickle 
keep. 
The fermentations involved in the preservation of sauerkraut are 
little different from those of pickles. According to Round (1916) 
bacteria are the important organisms concerned in the fermentation 
