KEFIR. 159 



ling dirty gum arabic. That from New Jersey had been dry for more than two years but 

 revived when placed in a nutrient fluid and most of the studies were made with this New 

 Jersey form. 



The yeast in this kefir Mix states to agree with Saccharomyces kefir, and to differ from Saccharo- 

 myces cerevisiae. It agrees with Beyerinek's form in measurements, in being associated with a rod- 

 shaped schizomycete in a granular mass, in being able to ferment lactose, but not saccharose, and in 

 not producing spores. "Although I cultivated it in saccharose solutions of all strengths, it never 

 caused a trace of fermentation." It ferments milk. The cells of the yeast were of various sizes and 

 shapes, from spherical to elliptical, the spherical ones measuring 3.2^ to 6. 4m in diameter, the elliptical 

 ones varying from 3. 2m to 9.6m in the major axis by 3. 2m to 6. 4m in the minor axis. The bacteria are 

 described as short symmetrical rods, varying from 8. 5m to 4. 5m by o.8m, precisely agreeing with Kern's 

 measurements. 



"The cells increase by splitting perpendicularly to the long axis, the resulting cells being some- 

 times joined together, thus producing leptothrix-like threads of all lengths, even to 120m, and some- 

 times completely separated. Many of the isolated cells possess the power of motion, but after 

 repeated efforts I was unable to demonstrate the presence of cilia." 



He states it is not easy to induce these bacteria to produce spores, but that he was able to 

 observe spore formation by placing a clump of the yeast [Kefir grain] in a watch crystal with a little 

 water and covering the whole with another crystal. In 24 hours the threads began to form and 

 within 36 to 48 hours the spores appeared. 



" It will be remembered that Kern gives two distinct methods of spore formation one occurring 

 in isolated cells, the other in the leptothrix-like threads. * * * 



"My investigations on the North American form have led to results diametrically opposed to 

 those of Kern. First, I found but one method of spore formation; secondly, I found this method 

 occurring only in the leptothrix-like threads, although I sometimes found isolated threads bent or 

 curled in such a manner that spore formation was well simulated. Spore formation in the lepto- 

 thrix threads takes place as follows: At each end of each cell of the thread a small bright dot appears. 

 It becomes brighter, larger and much more highly refractive than the rest of the cell until finally it 

 assumes a well-defined spore wall and develops into the mature spore. Each cell has produced two 

 spores, one at each end, and each originating independently of the other. In no case did I see two 

 spores formed, as Kern states, by the division of a single agglomerated mass of protoplasm into two 

 portions." 



With this kefir-like substance Mix obtained alcoholic fermentation of milk with the formation 

 of carbon dioxide and lactic acid, and the production of a fermented milk closely resembling the 

 descriptions of kefir. 



"The milk does not sour in the ordinary sense, for it does not coagulate in large masses; still 

 it is acid, contains some carbonic acid gas and alcohol, and is by no means unpleasant to the taste." 



Mix further states that the North American form of kefir causes (1) alcoholic fermentation of 

 milk sugar; (2) the alcoholic fermentation of dextrose, and (3) that it does not cause the fermenta- 

 tion of cane-sugar. He thinks that the alcoholic fermentation of the milk takes place in the following 

 manner : 



"The Bacillus acidi lactis begins the process by forming some lactic acid, which in turn, assisted 

 by the bacillus itself, inverts the milk-sugar to galactose and dextrose. The galactose is further 

 acted upon by the Bacillus acidi lactis, and converted into lactic acid; the dextrose is acted upon by 

 the yeast, and converted into alcohol and carbonic acid gas. In the kefir drink, therefore, we should 

 find plenty of lactic acid, a little milk-sugar, not inverted, the amount depending upon the duration 

 of fermentation, some alcohol, and carbonic acid gas precisely what is found." 



In 1896, Ed. von Freudenreich published a paper on kefir, of which the following con- 

 densation includes the most important statements: 



From his own experiments which are in harmony with those of all previous observers he concludes 

 that Beyerinck did not have the kefir yeast because this yeast is unable by itself to ferment milk- 

 sugar. From Beyerinek's drawings and from the trouble he had in isolating the Bacillus, it seems 

 probable to von Freudenreich that Beyerinck had under observation the same bacterial organism that 

 von Feudenreich has studied and which he is inclined to consider Kern's Dispora caucasica, with, 

 however, a considerable number of reservations as to its morphology. He thinks that the motile 

 one-flagellate bacteria described by Kern probably had nothing to do with the Dispora. Other 

 observers he states have come to the same conclusion, for example, Adametz. The Bacillus subtilis 

 which frequently occurs in the kefir grains has nothing to do with the kefir fermentation according to 



