CONDITIONS OF GROWTH AND NUTRITION. 427 



grape must it was employed to ferment, the other race, under the 

 same conditions, produced only 2.58 per cent, of alcohol and 

 311 mgrms. of glycerin. On the other hand, it formed a larger 

 quantity of volatile acids, namely, 127 mgrms. per 100 c.c. as 

 compared with 103 mgrms. in the other case. MULLER- 

 THURGAU (XXIV.) tested seven different races of Sacch. apicu- 

 latus, isolated by him, in grape juice, as well as in pear juice and 

 currant juice, and found that, in the first-named medium, the 

 production of alcohol varied between 2.5 and 3.8 per cent, by 

 weight. The same serial order was obtained, on the basis of the 

 rapidity of fermentation, in all three culture media ; and in every 

 instance a high proportion of volatile acids was obtained viz., 

 with race 8, for instance, in grape wine 93 mgrms. per 100 c.c., 

 and in perry 123 mgrms. (calculated as acetic acid), whereas the 

 elliptical yeast Steinberg i produced only 53 and 47 mgrms. 

 respectively in the same media. SCHANDER (II.), who afterwards 

 compared pure cultures of twenty -four Apiculatus yeasts, also 

 observed morphological differences in the cells. In some races the 

 cells are short, thick, and of the typical lemon shape, whereas in 

 others they are thin and elongated, the lemon shape being less 

 noticeable. Different races are also distinguishable by the cell 

 dimensions. Whilst old cultures of Apiculalus yeasts do not 

 generally produce a film on the surface of fruit juice or grape 

 juice, a growth of this kind, though slight, could be detected in 

 certain races. Racial differences were also exhibited in the form 

 of the streak cultures and giant colonies, though not to any very 

 decided extent. More pronounced differences became apparent 

 in the quantity and character of the sediment and in the per- 

 centage of the fermented wines, the alcohol content being 1.44 

 grms. per 100 c.c. in the case of the weakest race, and 4.53 

 mgrms. with the strongest. Another point of racial difference 

 consisted in the consumption of acid, and still others will be 

 referred to in the two following paragraphs. 



311. Conditions of Growth and Nutrition. 



In liquid media, such as beer wort and fruit juices, the repro- 

 duction of Apiculatus yeasts proceeds rapidly in the primary stage 

 of fermentation, in many instances more quickly than with the 

 ferments in technical use ; but this superiority soon disappears, 

 owing to the susceptibility of Apiculatus yeasts to alcohol. It is 

 most particularly noticeable on comparing the rapidity of repro- 

 duction of Apiculatus and Ellipsoideus races in very dilute must, 

 where the amount of alcohol formed is insumcent to retard growth, 

 or when only the initial reproduction up to the point when i per 

 cent, of alcohol has been formed is taken into consideration in 

 ordinary must. No precise observations of this kind, or with 

 regard to the amount of alcohol sufficing to stop growth under 



