98 Lectures on Bacteria. [^ ix. 



this work while calling attention to the want of precise 

 investigation. 



But A. Levy, of Hagenau, has recently discovered that the 

 effervescing alcoholic kefir may be obtained without any 

 kefir-grains, but simply by shaking the milk with sufficient 

 violence while it is turning sour. A trial convinced me of the 

 correctness of this statement. The kefir obtained by shaking 

 was not perceptibly different in taste or other qualities from the 

 kefir of the grains, and the determination of the alcohol, kindly 

 made for me by Professor Schmiedeberg, gave i per cent, 

 in some specimens of the former kind and 0-4 per cent, in 

 one of the latter ; sour milk not shaken contained no trace of 

 alcohol or only a doubtful one. Our former explanation there- 

 fore must be abandoned, and there is no other ready at present 

 to take its place; but the case is full of instruction for our 

 warning. 



Turning now for a moment to the life-history of the kefir- 

 y ^ grains, we may briefly remark 



with respect to the Saccharo- 

 myces, that it grows in the 

 sprout-form observed in the 

 Saccharomyces of beer-yeast, 

 partly forming groups or nests 

 inside or on the surface of 

 the grains, partly separating 

 from them and entering the 

 S- 12- surrounding fluid. It is on 



an average smaller and narrower than Saccharomyces Cere- 

 visiae, but some idea of its form may be gathered from a figure 

 here reproduced of that Fungus which it very closely resembles 

 (Fig. 12). Of the Bacterium, of which the grains chiefly consist, 

 I beheve that we also know only the vegetative development. 



Fig. 12. Saccharomyces Cerevisiae. a cells before sprouting, b-d 

 sproutings in fermenting saccharine solution (sequence of development 

 according to the letters). Magn. 390 times. 



