WINE YEASTS. . 343 



and Kruis have undertaken elaborate investigations with 

 regard to the character of the distillate obtained by the use 

 of different species. 



In 1890 the Berlin Experimental Station sent out the first 

 yeast species cultivated from this group by P. Lindner. It 

 was described as Race 2. More recently another species, 

 Race 12, has been brought into practical use, and this appears 

 to be preferred, according to Lindner's communications, both 

 in potato distilleries and in pressed yeast factories. The 

 yeast is grown in ordinary large fermenting vats, and is supplied 

 in a pressed state in kilogramme lots. 



Henneberg has given a detailed description of both species, 

 from which it may be noted that the giant colonies differ 

 in appearance. In Race 2 they have an almost smooth 

 surface, scored by a few shallow, concentric and radial furrows ; 

 the outline is fairly straight. Race 12 has a very uneven 

 surface, scored by deep, irregularly radial furrows. The 

 ridges so formed constitute an extremely delicate concentric 

 pattern, and the outline is formed erratically by the termination 

 of the ridges at varying distances from the centre. The small 

 colonies in plate-cultures are similar. Race 2 has feebly- 

 developed budding colonies, whilst Race 12 forms large and 

 dense clusters. The cells of 2 are an elongated oval ; those of 

 12 are roundish and oval. 



(c) Wine Yeasts. 



When a number of pure growths are isolated from the 

 usual elliptical wine yeasts, it will be readily seen that they 

 vary greatly in morphological character, under similar con- 

 ditions of cultivation, especially if the general appearance is 

 taken into account. Species with both large and small cells 

 and every intermediate form are met with, from elongated 

 and elliptical, to oval and almost spherical cells. Pastorianus 

 forms of yeast also exist. Before 1890 a series of such types, 

 exhibiting stable morphological characters, and displaying 

 characteristic differences in spore-formation, had been isolated 

 in the author's institute. 



Hansen had published further information regarding the 

 individual species in his description of S. ellipsoideus I. (see 



