12 BACTERIA. 



the growth of the Bacillus prodigiosus), which has served the 

 purpose of the miracle-monger before to-day, sticky reddish- 

 brown patches have been described as occurring in unsound 

 bread, in which various bacilli, such as the ordinary potato 

 bacillus, Bacillus liodermos, Bacillus mesentericus vulgatus, 

 have been found, and on analysis of these patches dex- 

 trine, dextrose, starch, sugar, and even a small quantity of 

 peptone, have been separated ; moulds of other fungi are 

 also found in unsound bread. 



In 1882, Kern described the peculiar ferment known as 

 kephir grains, by means "of which the Caucasians set up a 

 double alcoholic and acid fermentation in milk. 



These kephir grains, says De Bary, in the fresh living state 

 are " white bodies, usually of irregular roundish form, equal 

 to or exceeding a walnut in size. They have their surface 

 roughened with blunted projections, and furrowed like a 

 cauliflower ; they are of a firm, tough, gelatinous consistence, 

 becoming gradually cartilaginous, and are of a yellow colour 

 when dried ; they are chiefly composed of a rod-shaped bacte- 

 rium," many of these being united to form long threads, 

 arranged in a kind of felt or network, the meshes of which 

 are filled with a tough gelatinous membran-e, which binds 

 the organisms together into a kind of zooglcea mass. This 

 rod-shaped organism is known as Dispora caucasica as at 

 the end of each rod is a rounded spore. 



Along with these may usually be found a small proportion 

 of a yeast-like fungus which, however, is merely entangled 

 in the gelatinous mass, although it certainly undergoes 

 development by sprouting. There is also present the 

 ordinary Bacterium lactis which, with a number of other 

 impurities, adheres to the kephir grains ; this also occurs in 

 the milk itself. To prepare the specially fermented milk, 

 one volume of these kephir grains is moistened and added 

 to about six or seven volumes of fresh milk, the whole is 

 protected from the dust, but is exposed to the air for about 

 twenty-four hours at the ordinary temperature of the room, 

 and is frequently shaken ; the milk is then poured off and a 

 fresh quantity added ; the milk that is poured off is mixed 

 with double its quantity of fresh milk, put into bottles, well 

 corked, and frequently shaken. This bottled sour milk 

 soon becomes sparkling and effervescent, and is ready for 

 use after it has been bottled for a day or two. It then con- 



