ANOMALOUS FERMENTATIONS 199 



(5) A^wmalous_Jj^rin^ntatwns of Milk- There are a number of 

 changes, mostly due to fermentation, which occur in milk, and to 

 which reference must be made. These conditions have been termed 

 " diseases " of milk, but it is not altogether a satisfactory term. 



(a) TtjMwr_ Ferm.r.'n.f.a.t'i.nn, l Some bitter conditions of milk are due 

 to irregularity of diet in the cow. Similar changes occur in con- 

 junction with some of the acid fermentations and proteid decomposi- 

 tions. 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 J3itter_jpeptones. Such 

 bodies are produced by bacteria from the alFumrnoicTs of milk, 

 and hence the bitterness does not appear immediately after milk- 

 ing, but only after an incubation period. Some nine or ten different 

 micro-organisms have been credited with this power, and such 

 organisms may infect a farm, a byre, or a dairy, for months or even 

 years, contaminating the milk. In all probability, most outbreaks 

 of this bitter fermentation are due to Weigmann's bacillus of bitter 

 milk or Conn's micrococcus. There seems to be evidence for sup- 

 posing that some of the "bitter" bacilli produce very resistant 

 spores, which make them resistant against conditions in the milk 

 itself or externally. 



(b) Slimy fermentation. This graphic but inelegant term is 

 used to denote an increased viscosity in milk, and its tendency when 

 1 KM \\g 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. TcettemcelJc, 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 fermenta- 

 tion. In 1882, Schmidt-Muhlheim 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. M. Freudenreichii, one of the specific 

 micro-organisms of " ropiness " in milk, is a large, non-motile, lique- 

 fying 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 Hollandicus, and in hot 

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

 been detected by several observers, and classified as slime fermenta- 



