192 BACTERIA 



are due to irregularity of diet in the cow. Similar changes 

 occur in conjunction with some of the acid fermentations. 

 Weigmann and Conn have, however, shown that there is a 

 specific bitterness in milk due to bacteria which appear to 

 produce no other change. Hueppe suggests that it may- 

 be due in part to a proteid decomposition resulting in bitter 

 peptones. There seems to be some evidence for supposing 

 that the bitter bacteria produce very resistant spores, which 

 enable them to withstand treatment under which the lactic 

 acid succumbs. 



(5) Slimy Fermentation. This graphic but inelegant word 

 is used to denote an increased viscosity in milk, and its 

 tendency when being poured to become ropy and fall in 

 strings. Such a condition deprives the milk of its use in the 

 making of certain cheeses, whilst in other cases it favours 

 the process. In Holland, for example, in the manufacture 

 of Edam cheese, this " slimy *' fermentation is desired. 

 Tmttemcelk, a popular beverage in Norway, is made from 

 milk that has been infected with the leaves of the common 

 butter wort, Pinguicula vulgaris, from which Weigmann 

 separated a bacillus possessing the power of setting up slimy 

 fermentation. There are, perhaps, as many as a dozen 

 species of bacteria which have in a greater or less degree the 

 power of setting up this kind of fermentation. In 1882 

 Schmidt isolated the Micrococcus viscosus, which occurs in 

 chains and rosaries, affecting the milk-sugar. It grows at 

 blood-heat, and is not easily destroyed by cold. Its effect 

 on various sugars is the same. The M. Freudenreichiiy the 

 specific micro-organism of *' ropiness '' in milk, is a large, 

 non-motile, liquefying coccus, which can produce its result 

 in milk within five hours. On account of its resistance to 

 drying, it is difficult to eradicate when once it makes its 

 appearance in a dairy. The organism used in making Edam 

 cheese is the Streptococcus Holiandicus, and in hot milk it 

 can produce ropiness in one day. A number of bacilli have 



