ALCOHOLIC FERMENTS. 201 



In old cultures of films there are colonies of long and short 

 sausage-shaped cells, often with verticillated branches. 



Kelated to this are two ellipsoid species, described by WILL, 

 which are also disease-yeasts. One of these, a bottom-fermenta- 

 tion yeast, gives colonies in wort-gelatine, which, when young, 

 form whether on the surface or embedded in the gelatine a 

 network with large meshes ; afterwards they grow denser in 

 the middle, with irregularly-fringed edges ; sometimes, how- 

 ever, compact colonies with regular outline are formed under 

 the same conditions. The maximum temperature for spore- 

 formation is 39C. ; at the optimum temperature (34 C.), the 

 first indications of spores are seen after eleven hours. The 

 lower limit for spore-formation is 4 to 5 C. The vegetative 

 cells are killed when heated in sterilised wort for half an hour 

 at 70C. The temperature limits for film-formation are 41 

 and 4 C. In old films, more especially, numerously-branched 

 clusters are found, consisting of much elongated cells. This 

 species imparts a rough bitter after-taste to beer and also causes 

 turbidity. 



The second ellipsoid species which was obtained from a beer 

 showing yeast-turbidity, gives colonies in wort-gelatine, some 

 of which are sharply defined, whilst in others the outline is 

 indistinct. The temperature limits for spore-formation are 

 32 and 0'5 C., the optimum temperature being 24 C. The 

 temperature limit for the vitality of the vegetative cells in wort 

 is 70C. In old films very numerously-branched clusters 

 occur. Besides causing yeast-turbidity, this species also imparts 

 a sweetish, disagreeable, aromatic taste to beer, and a bitter 

 astringent after-taste. The yeast sediment always has a dark 

 colour. 



SACCHAROMYCES ILICIS (GROENLUND), 



which was found on the fruit of Ilex Aquifolium, is a bottom- 

 fermentation yeast, consisting mainly of spherical cells. The 

 temperature limits for spore-formation are 8 and 38 C. The 

 spores have no vacuoles. In the films, slightly-elongated cells 

 are found. Streak cultures on gelatine have a floury, but 

 otherwise a variable, appearance. This species, grown in wort, 

 imparts a disagreeable, bitter taste. According to SCHJERNING, 



