43 8 SACCHAROMYCES APTCULATUS. 



valley) and Winterthur ; and to the extent of 93 per cent, on 

 grapes from a vineyard at Brestenberg (Aargau) ; though in 

 other instances the proportions were more in favour of Sacch. 

 ellipsoideus. The above figures refer to single specimens of 

 grapes ; but of course the fungoid flora may vary on grapes from 

 adjoining stocks or even from the same vine, so that there is no 

 instance on record of wine must being imperfectly fermented 

 owing to the absence of any other yeasts than Sacch. apiculatus. 

 Such cases, however, have been known with currant wine ; though 

 why they should occur with this class of wine and not with grape 

 wine is unknown. Sacch. apiculatus is also frequently present 

 in abundance in the fermentation of cider and perry, at least at 

 the outset, to a greater extent than in grape must. 



The influence of Sacch. apiculatus in collaboration with Sacch. 

 ellipsoideus (mixed sowings) in the fermentation of wine has been 

 studied by MULLER-THURGAU (XXX. and XVI.). Various wine 

 yeasts were sown in flasks containing equal quantities of pre- 

 viously sterilised must, the yeasts being used alone in one 

 series, and conjointly with Sacch. apiculatus in another. The 

 number of yeast cells in each sowing was approximately the same, 

 so that the flasks with mixed sowings contained about twice as 

 many cells as those sown with wine yeast or Apiculatus yeast 

 exclusively. The amount of carbon dioxide liberated, and conse- 

 quently the progress of fermentation, was ascertained daily by 

 weighing the flasks. The results obtained in this way with two 

 of the yeasts during the early stages of fermentation have been 

 plotted in Fig. 202, the abscissae expressing the duration of fer- 

 mentation in days, and the ordinates the total amount of carbon 

 dioxide (in grms. per litre of the liquid under examination) 

 liberated as determined by the loss in weight up to the corre- 

 sponding days. The line marked by crosses shows the progress 

 of fermentation with Steinberg yeast No. i, a vigorous white wine 

 yeast from the Rheingau, whilst the dotted line represents the 

 work dore by a weak red wine yeast from Karthaus, near Ittin- 

 gen (Canton of Thurgau), and the unbroken line the progress of 

 fermentation in the sample inoculated with Sacch. apiculatus (3) 

 only. The small circles correspond to the carbon dioxide deter- 

 minations. Other particulars can be gathered from the chart 

 itself, especially the difference in the progress of fermentation with 

 the two yeasts, and the considerable extent to which their fer- 

 mentative activity was impaired by the Apiculatus yeast. Even 

 so vigorous a yeast as Steinberg No. i was greatly retarded by 

 the pointed yeast at the outset, so that, on the iQth day, for 

 instance, the total disengagement of carbon dioxide amounted to 

 38.1 grms. with Steinberg No. i, 6.8 grms. with Apiculatus, and 

 to only 1 1. 6 grms. in the sample with both yeasts, noth with- 

 standing the double sowing. In proportion, however, as the per- 

 centage of alcohol increases, the Apiculatus yeast is weakened, and 



