242 THE PHENOMENA OF PUTREFACTION 



fungus, capable of converting sugar into mannite (up to 50 grams per litre). 

 In nutrient solutions devoid of sugar this species fails to develop, a circumstance 

 sufficient to distinguish it from the bacteria (presumably) causing the loss of 

 colour of wine. Moreover, these latter as already observed by Mulder attack 

 cream of tartar first of all, whilst the bacteria of mannitic fermentation leave 

 this salt completely untouched. The fact, now firmly established, that a high 

 temperature (36 0. or over) favours the appearance of the last-named microbes, 

 explains the defective fermentation (familiar to Sicilian and Algerian wine- 

 growers) of wine must during the prevalence of the hot south -wine (sirocco or 

 simoom), the red wines, in particular, being greatly affected. According to G. 

 BASILE (I.), this wine disease is as frequent in Sicily as it is dreaded, and in some 

 years affects the greater part of the vintage. 



The bacteria here coming into action can be destroyed by heating up to 60 C., 

 a treatment impossible to apply hitherto on account of its fatal effect on yeast- 

 cells. However, by artificially inoculating (pitching) with strong, pure yeast, and 

 by cooling the mash down to 15 20 C., the liquid could be rapidly brought into a 

 state of alcoholic fermentation, which could be controlled by suitably regulating the 

 temperature. In this way the desired result would be ensured, and would amply 

 repay the increased outlay required. In this connection the experience gained by 

 M. RIETSCH and M. HERSELIN (I.) should also be borne in mind, viz., that the 

 iujurious influence of an excessively high temperature (36 0.) can be reduced by 

 aerating the fermenting liquid. 



In conclusion, it will be useful to remember that mannite is also formed 

 during the mucinous fermentation of sugar, and that this hexavalent alcohol is 

 also excreted as a metabolic product by certain E<umycetes, e.g. Penicillium 

 ylaucum. 



