210 MICRO-ORGANISMS AND FERMENTATION. 



now is on a large scale in special factories, consists in first 

 boiling the starch (maize or rice starch) under pressure, then 

 liquefying the mass by the addition of a small quantity of 

 green malt, or hydrochloric acid, and sterilising the fluid at 

 a high temperature. By adding a culture of the fungus 

 grown from spores at 38 C. the change into sugar is soon 

 effected. 



In 1895 Went and Prinsen Geerligs published their re- 

 search on Rhizopus Oryzce (Chlamydomucor Oryzce), which 

 likewise converts starch into dextrose. 



Shortly afterwards Collette and Boidin announced the 

 discovery of two similar species, Rhizopus tonkinensis and 

 Eh. japonicus, which react more vigorously than M . Rouxii ; 

 other species have subsequently been discovered. 



A number of Mucor species produce small quantities of 

 acid in sugar solutions. A detailed investigation of this 

 subject has not yet been carried out. Wehmer, however, 

 has observed the formation of citric acid by M . pyriformis, 

 and several species have been shown to produce oxalic acid. 

 Most species liquefy gelatine, but quite slowly as a rule. 

 Albumen-splitting enzymes occur in the different species, and 

 some of these appear to play a part in the ripening of cheese. 



5. Monilia (Figs. 40 and 41). 



A number of different fungi of comparatively simple 

 structure are described under this name in works on mycology. 

 From a mycelium, the colour of which varies according to the 

 species, branches are thrown up which give rise to series of 

 oval or elliptical spores. The genus has an interest for us 

 on account of one of its species, named by Hansen Monilia 

 Candida from Bonorden's description, which possesses very 

 remarkable physiological properties. It occurs in nature in 

 the form of a white layer covering fresh cow-dung, and on 

 sweet, succulent fruits. When introduced into wort, it de- 

 velops a copious growth of yeast-like cells. At the same 

 time it excites a vigorous alcoholic fermentation, and whilst 

 this is progressing forms a mycoderma-like film on the liquid ; 

 the cells in this film extend further and further, and finally 



