470 Bacteria in Relation to Country Life 



not to be wondered that a uniform product is so hard 

 to secure. Moreover, the manufacture of vinegar in 

 accordance with the old methods not only makes it 

 difficult to secure a uniform and high-grade product, 

 but is also very wasteful of alcohol. In many instances, 

 the liquid becomes infested with certain yeasts that burn 

 up the acetic acid, and also with vinegar eels which, 

 besides destroying large numbers of bacteria, also 

 detract from the appearance of the vinegar. 



Pure cultures in vinegar-making. — In order to make 

 vinegar manufacture more certain as to results, it has 

 been proposed that pure cultures be employed. Vinegar 

 eels and injurious yeasts and bacteria would be thus 

 eliminated, and the product would be uniform in char- 

 acter. The species that give the largest yields and pro- 

 duce the best-flavored vinegar could be selected, and the 

 vinegar industry thus placed on a more firm basis. 



Years ago an attempt was made to render vinegar- 

 making more certain in its results by the employment of 

 a method somewhat analogous to that of natural starters 

 used in cream-ripening. Quantities of wine were allowed 

 to sour in small vessels, and the skin formed on the sur- 

 face was carefully lifted off and placed on the surface 

 of larger quantities of wine which was t9 be soured. 

 Of course, care was taken to employ only such skin for 

 inoculation as was, to all appearances, healthy and free 

 from "vinegar eels." In practice, this method failed 

 to yield satisfactory results, for the simple reason that 

 the spontaneous skin formation in the small vessels 

 was, at times, due to one kind of organisms, and at 

 other times to entirely different organisms, 



