INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 181 



a yellow tint to it. It may be considered as a specially modified 

 cellulose and be called Fungus-cellulose. It is rendered more opaque 

 and firm by boiling. 



This Mycoderma forms, like the common Nosfoc, with the same 

 material, masses of great cohesion. It has the property of absorbing 

 tannin in quantities ; the colour of the vinegar is thus perhaps due 

 to tannin derived from the wine in presence of some salt of iron. 



The fungus formed in wine in presence of a large amount of 

 air is Mycoderma vini or flower-of-wine, a thin pellicle of a greyish 

 colour and with delicate surface-folds. It belongs to the Saccharo- 

 mycetes. It is composed of cells 2 to 3 /i in diameter, which are 

 reproduced by budding, and under certain conditions by ascospores. 

 The alcoholic fermentation which it causes may be demonstrated on 

 samples of pure grape-juice kept in corked bottles at a moderate 

 temperature, when alcohol is produced, with development of SaccJia- 

 romyces ellijpsoideus and of a precipitate and surface-accumulation. 

 Exposed to the air and shaken, the liquid now produces a pellicle 

 formed of Saccharomyces mycoderma Eeess ; while it contains also S. 

 ellipsoideiis and all stages of transition between the two. Exposure to 

 light increases the films, and absence of light causes cessation of their 

 development. Ascospores are produced from any part of the pellicle 

 which becomes dry. Although the wine in this state contains bacteria, 

 yet the Saccharomyces appears to have the property of hindering their 

 acetic fermentation. 



The development of the alcoholic ferment, on the other hand, is 

 checked by a j^revious fermentation, or by the presence of borax. From 

 observations such as those already given, it is probable that the two 

 species of Saccharomyces are but difterent forms of one sjiecies ; they 

 have the same fermenting power in saccharine as in grape-juice 

 solutions. 



A third phenomenon exhibited by wine is that of "ropiness." In 

 this case, wine becomes thick and gelatinous, and, when examined 

 microscopically, shows the jiresence of immense numbers of bacteria 

 of 1 yu, or less diameter, in strings. It occurs in wliite wines, 

 especially when the grapes have not been strongly pressed — seldom 

 in red wines : this is probably due, as Fran(;ois and Pasteur have 

 observed, to the larger amount of tannin present in the red wines, 

 and hence the evil may be checked by addition of tannin to wines 

 thus attacked. A specimen of ropy wine contained a quantity of 

 Mucor racemosus in mycelium or isolated ; this fungus has the property 

 of producing alcoholic fermentation in a saccharine liquid. 



Cause of the Coloration of Pink Grains of Corn.* — M. Prillieux 

 has been investigating the cause of the singular pink colour which 

 grains of corn sometimes present. The conclusion at which he has 

 arrived is that it is due to the permeation of the grains by a 

 Micrococcus, which multij)lies within the tis-sues and destroys them, 

 attacking first of all the starch, then the proteinaceous substances, and 

 finally the cellulose of the cell-walls. The mode of destruction of the 



* 'Ann. Sri. Nat. (Rot.),' viii. (1879) p. 248. 



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