202 MICRO-ORGANISMS AND FERMENTATION. 



it contains invertase, and induces alcoholic fermentation in 

 solutions of saccharose, dextrose, and maltose. In ordinary 

 beer- wort it can produce about 2 '8 per cent, of alcohol (by 

 volume). 



SACCHAROMYCES AQUIFOLII (GROENLUND) 



was also found on the fruit of Ilex Aquifolium. It is a top- 

 fermentation yeast, and consists of large round cells. The 

 temperature limits for spore-formation are 8 and 31 C. ; the 

 spores contain vacuoles. In the films, spherical and egg- 

 shaped cells alone occur. Streak cultures in gelatine vary in 

 appearance, some being glossy and some floury. This species 

 imparts to wort a disagreeable, sweet taste, with a bitter after- 

 taste. It inverts saccharose and induces alcoholic fermentation in 

 solutions of saccharose, dextrose, and maltose. In ordinary beer- 

 wort it can produce about 3 '7 per cent, of alcohol (by volume). 



SACCHAROMYCES PYRIFORMIS (MARSHALL WARD) 

 (see Ginger-beer Plant, page 84). 



SACCHAROMYCES VORDERMANNI 



was discovered in Java by WENT and PRINSEN-GEERLIGS as an 

 essential agent in the manufacture of arrack. It is dis- 

 tinguished by its powerful action as an alcoholic ferment, 

 and yields a fine product, on account of which it is made use 

 of, in pure culture, in that manufacture. The cells are 

 ellipsoid, and form up to four spores. This species ferments 

 dextrose, maltose, and saccharose, and contains invertine. 



SACCHAROMYCES MARXIANUS (HANSEN). 



This species, which was discovered by MARX on grapes, and 

 described by HANSEN, develops in beer-wort in the form of 

 small oval cells, practically similar to those of Sacch. exiguus 

 and ellipsoideus. Elongated, sausage-shaped cells, often in 

 colonies, soon appear, however, and if the culture is set aside 



