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saccharose and in fifteen days at 25° C. generates 8.8 vol. per cent. of alcohol in a 15 per cent. dextrose solution.

Torula No. 7 (Figs. 116 and 117) was found in the soil under vines. It produces 1 vol. per cent, of alcohol in beer wort; on the contrary it excites no fermentation in solutions of saccharose, which it is unable to invert. In yeast water

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FIG. 114.-Torula No. 4. 1000.
(After Hansen.)

FIG. 115.-Torula No. 6. 1009.
(After Hansen.)

containing 15 per cent. of dextrose it formed 53 vol. per cent. of alcohol.

The last named species are perhaps active in wine manufacture, but hardly so in breweries and distilleries.

Rich. Meissner isolated eleven Torula species which all cause that disease called the ropiness (" Zähewerden ") of wines; he has shown by experiments that must as well as wine becomes slimy, oily and thick

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FIG. 116.-Torula No. 7. Sedimentary yeast.

1002. (After Hansen.) when seeded with these. Most of these forms do not produce films, but only a yeast ring; must is decolourised by all of them. In the few species which form a film the latter was in some cases white, and in a single instance olive green. Only two of the eleven species referred to bring about alcoholic fermentation. Common to all is the need of oxygen, without which they cannot grow. If the nutrient liquid contains more than 5 vol. per cent. of alcohol, growth as a rule ceases, but at the same time the organisms are not killed. These slime yeasts check the fer

mentation, not of the strong yeasts, but only of feebly fermenting yeasts in the first few days of fermentation. The ropiness of wine occurs chiefly in those wines which are poor in tannin; the disease can therefore

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FIG. 117.-Torula No. 7. Film growth on a wort culture ten months old. 1le.

(After Hansen.)

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FIG. 118.-Saccharomyces apiculatus, Reess. (a) A cell which has begun to develop a bud; a' and a" the same cell after the lapse of 1 and 3 hours; b another budding cell, b' after two hours, b" after three hours; c' is 4-hour older than e; d was observed at 24 P.M., d' at 31, d" at 33; e 103 o'clock, e 12, e" 12, e'" 1; ƒ 21, ƒ 31, ƒ"' 4, ƒ'""' 5, ƒ'"" 5 o'clock. About 250. (After Hansen.)

be prevented by the addition of tannin, which latter checks the growth of the slime yeasts. The addition of a pure wine yeast is an especially favourable means for suppressing the slime yeasts so completely that the disease does not appear.

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FIG 119. -Saccharomyces apiculatus, Reess. Most of the cells are in the act of
budding. The series 7 and m show abnormal cells. The two cells i each
contain a refractive ball; g was observed at 32 P м., g′ 5‡, g′′ 61; A 104, À°
14, h” 2} ; j 10ž, j′ 1‡ ; k 105, k′ 121, k'' 14, k'” 2‡ ; 1 7, 1′ 8, 1o 8 h. 5 m.,
81, 7" 94, 710; m 6}, m' 63, m′′ 7, m"" 74, m'"" 73. About 252. (After
Hansen.)

The cells (Figs. 118 and 119), which are generally 6 to 8 long and 2 to 3 μ wide, are in some cases pointed at both ends like lemons, in others oval. The fungus forms both kinds of buds. In order to change into lemon-shaped cells the oval buds must grow through one or more buddings The lemon form is produced more especially at the beginning of the budding and has then the preponderance; later the Oval cells predominate.

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It is a bottom yeast form which does not secrete invertase and in consequence cannot ferment cane sugar; it is also incapable of fermenting maltose. It therefore does not

form more than 1 vol. per cent. of alcohol in wort; on the other hand it forms 43 vol. per cent. of alcohol in yeast water containing 10 per cent. of dextrose.

Sacch. apiculatus, like many other fungi, undergoes a remarkable variation. Thus Hansen found that of two growths investigated by him, one gave 3 and the other 4:3 vol. per cent. of alcohol. Amthor investigated two varieties, of which one furnished 3.25 and the other 4:56 vol. per cent of alcohol, and Müller-Thurgau found that in seven cultivations in sterilised grape juice the alcohol production varied between 2.5 and 3.8 per cent. by weight. Will had two growths, one of which evolved a mouldy smell, the other an amyl ester-like bouquet. But whether such variations are permanent or not, or on what they depend, has not been investigated.

Its extraordinary power of multiplication is characteristic of Sacch, apiculatus. This and its competitive relations with Sacch. cerevisiae have been mentioned on p. 230.

Hansen's investigations on the circulation of Sacch, apiculatus in nature are described on p. 246. This fungus is generally distributed in nature on fruits and also in soil. Müller-Thurgau found it in the latter to a depth of 20 to 30 cm., and Berlese to a depth of 36 cm.

According to Will it is found commonly in bottom fermentation breweries, but only in small amount. It is generally present in those Belgian breweries where beer is prepared by spontaneous fermentation.

According to the investigations of Müller-Thurgau and Wortmann it is especially detrimental in the manufacture of wine, as it has a retarding influence on the fermentation, but not, however, if the liquid contains 3 vol. per cent. of alcohol. It is most effective during the first stages of fermentation. Sacch, apiculatus possesses in a higher degree than true wine

yeasts the power of decomposing and absorbing organic acids. MüllerThurgau's experiments show that this property also asserts itself when it works simultaneously with true wine yeasts, as is the case in the progress of ordinary wine fermentations. Finally, by the formation of volatile acids and other products it is injurious to the bouquet and flavour of the wine. According to investigations by W. Seifert it formed the largest amount of volatile acid (0-064 per cent.) and volatile ester of six pure yeasts in the same grape must. The amount of ester expressed in cubic centimetres of normal alkali on 100 c.c. of wine corresponded to 10-8, while with the other yeast species it varied between 1:32 and 44. When it ferments grape must a cider-like taste and smell are exhibited. Although the increase of Sacch. apiculatus occurring on fruit and grapes is not prevented by the addition of pure yeasts to the must, yet, as experimental results show, its detrimental influence can be very considerably restrained by the addition of a quick growing, vigorously-fermenting yeast (Müller-Thurgau). According to some French investigators Sacch, apiculatus yields a good cider with a strong bouquet; but, according to Müller-Thurgau, it has, on the contrary, a harmful influence on the cider fermentation.

Mycoderma Species.

These fungi are the so-called true film fungi which are distinguished by the rapid formation on nutrient liquids, particularly on beer and wine, of a covering film having air between the cells. The cells are usually short and sausage-shaped. They are strongly aerobic.

Mycoderma cerevisiæ, Desm. (Sacch. mycoderma). — Several species are included under this name. The species usually to be found in the Copenhagen breweries forms a dull, gray, wrinkled film on wort and beer. The cells contain from 1 to 3 refractive granules, which are of a fatty nature. This fungus does not induce fermentation, contains no invertase, and occurs in practically all lager beer, but does not succeed in growing so long as the bottles are well stoppered.

It is known with certainty that at least some of these forms do no harm in breweries under ordinary conditions; this holds good with regard to the species observed by Hansen, A. Petersen, Grönlund, Jörgensen and Prior. Bělohoubek and Kukla, on the contrary, mention a species which

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