FERMENTATION 565 



what differences distinguish it from the typical 5. cervisice are very small 

 and by some systematists would not be considered specific. Peck and 

 Deerr 3 collected yeast from distilleries in Demerara, Trinidad, Cuba, Mauri- 

 tius, Java, Natal, and Peru. All of these except that from Peru were typical 

 budding yeasts, between which they could find no difference sufficient to 

 form a distinction. The Peruvian yeast was a fission yeast. 



In 1893, Greg 4 isolated from Jamaican distilleries a fission yeast, to which 

 he gave the name Schizosaccharomyces mellacei, and in the following year 

 Ei j kmann 5 found a fission yeast Sch. vordermanii in Java distilleries. Material 

 received by Peck and Deerr from a Peruvian distillery also proved to be a 

 fission yeast, the samples sent therefrom containing no budding forms. 

 All of these fission yeasts are very similar, if not identical with the original 

 fission yeast, Sch. Pombe, obtained by Lindner 6 from Kaffir millet beer. 



In Plates XXIX and XXX are shown the yeasts examined by Peck 

 and Deerr, distinguished as to country of origin by the initial letter, two 

 forms from Natal being shown. In Plate XXIX the specimens are drawn 

 from material obtained from fermenting beer-wort 36 hours old. The 

 sporulating yeasts in Plate XXX were obtained from gypsum blocks, except 

 the Peruvian type, which is from an old beer-wort agar culture. The 

 yeast marked NT is a non-sporing yeast from Natal, referred to else- 

 where in this chapter. Of other yeasts the most important are those to 

 which the fermentation of grape musts is due, and usually referred to as 

 S. ellipsoideus. A conjugating yeast, Zygosaccharomyces, was first observed 

 in the fermentation of apple juice by Barker 7 in England. Yeasts of the 

 type S. mali duclauxi, which do not invert cane sugar, have been pro- 

 posed for use in analysis by Pellet and Perrault 8 ; on the economic scale 

 the use of such ferments has been patented by McGlashan, 9 with the 

 object of removing the glucose in order to obtain a greater yield of sugar 

 on crystallization. Previously, however, Gayon, 10 in 1882, had suggested 

 the use of the pin mould, Mucor circinellioides, for the same purpose. 



Other Organisms of Special Interest. Moulds. The two orders, Peri- 

 sporiacecB and Mucoracece, are frequent inhabitants of distilleries. The 

 first order includes the genera Aspergillus and Penicillium, which have been 

 specially studied in connection with grain distilleries, where an unpleasant 

 taste is often ascribed to their presence. Aspergillus oryzce is of interest 

 as the organism to which the saccharification of rice is due in the preparation 

 of the Japanese spirit, saki. The Mucoracece are also an important family 

 unfavourably known in the distillery. Some can produce small quantities 

 of alcohol. Mucor oryzce, which is perhaps the same as Rhizopus oryzce 

 was isolated by Went and Geerligs 2 from raggi or Java yeast. Mucor 

 rouxii isolated from " Chinese " yeast has at one time enjoyed some notor- 

 iety as an alcohol producer. 



Lactic Acid Fermentation. The importance of the bacteria which produce 

 lactic acid in green malt in cereal distilleries is shown in a subsequent section ; 

 they occur chiefly in sour milk and in green malt ; through their agency 

 the production of lactic acid from beer wort has been proposed, and its pro- 

 duction from molasses does not seem prima facie impossible ; certain species 

 have been noted as causing disease in beer. 



Acetic Acid Fermentation. This fermentation is economically of import- 

 ance in the production of vinegar from alcohol ; it may take place under the 



