460 Bacteria in Relation to Country Life 



found bacteria in ropy wine, to which they attributed 

 the disease, and showed that sound wine may be made 

 to become ropy by the addition of some diseased wine. 

 It is not ye't known whether this malady is caused by a 

 single organism, or whether there are several species 

 capable of producing the same result. 



Wine affected by this disease becomes turbid and gradu- 

 ally more viscid until, like ropy milk, it can be drawn 

 out into threads. The phenomenon is attributed to the 

 transformation of the sugar into mucilaginous substances 

 by the bacteria. Besides this bacterial mucilage or gum, 

 the ropy wine is found to contain a white, sweetish sub- 

 stance called mannite. Wines that contain more than 

 10 per cent of alcohol are not subject to this disease. 

 Beer wort and beer are similarly subject to ropiness. 



A number of organisms that may cause such ropi- 

 ness have been isolated; some of them capable of growing 

 only in unhopped wort, others developing in hopped 

 worts and in beers. Worts rich in nitrogenous matter 

 are most subject to this disease, while a high degree of 

 acidity is inimical to the bacteria. The same or similar 

 organisms cause ropiness in cider. 



Sarcina sickness. — There is still another malady of 

 beer, "sarcina sickness," caused by spherical bacteria. 

 Additions of hops to the beer, or additions of salicylic 

 acid in small quantities, may be employed for the sup- 

 pression of this disease. 



Loss of color in wine. — Among the common diseases 

 of wine, of bacterial origin, may be included that which 

 causes the loss of color. The color of red wine is changed 

 t;0 brown. The alcohol is changed into acetic acid, and 



