KEPHIH. 135 



Beijerinck's genus, Granulobacter, includes a series of 

 bacteria producing butyl alcohol. We shall only attempt to 

 describe a process used by him for the preparation of such 

 species. He introduces coarsely ground meal of husked corn, 

 in successive portions, into boiling water until the mass has 

 the consistency of a thick paste. The last addition should 

 not be subjected to a temperature of 100 for more than a 

 few seconds. After rapid cooling, it is placed in an incubator 

 at 35-37 C. The pure cultivation may be carried out in 

 sweet- wort gelatine under anaerobic conditions. The pre- 

 dominant species form white non-liquefying colonies, with 

 Clostridium forms and oval spores. 



Duclaux describes a facultative anaerobe, Amylobacter 

 butylicus, obtained by infecting a potato mash with garden 

 soil. It exhibits the usual swollen sporogenous cells and the 

 granulose reaction. It ferments starch, and produces butyl 

 alcohol, butyric acid, and acetic acid. A large amount of 

 alcohol is readily produced when calcium carbonate is used 

 to neutralise the acid formed during the fermentation of 

 starch. The same alcohol is produced by fermentation of 

 saccharose (which is not inverted), maltose, lactose, glycerine, 

 mannite, and calcium carbonate. 



Bacteria also occur which produce amyl alcohol (fusel oil) ; 

 to these belong Perdrix's Bacille amylozyme, producing minute 

 quantities of this alcohol from potato starch. A similar 

 species was discovered by Pereire and Guignard, and H. 

 Pringsheim isolated another from potatoes. It is still an open 

 question how far the amyl alcohol produced during an 

 impure alcohol fermentation is due entirely to the action 

 of such bacteria. According to Ehrlich's experiments, fusel 

 oil may be obtained by the action of alcohol yeasts on 

 two of the decomposition products of albumen ; leucin and 

 isoleucin. 



6. Kephir, Koumiss, Mazun, Leben, Yoghourt, Ginger-beer. 



Kephir, on which the investigations of Kern have thrown 

 some light, is an effervescent, alcoholic sour milk, prepared 

 by the inhabitants of the Caucasus from cows', goats', or 

 sheep's milk. It is made by adding a peculiar ferment, 



