DIFFERENT KINDS OF SO-CALLED MILK DISEASES. 101 



can be no doubt that the milk contains an extraordinary quantity 

 of luxuriantly-growing lactic bacilli. If milk during creaming be- 

 comes fermented, or during the manufacture of cheese yields puffy 

 cheese, all these indications point assuredly to the presence of a 

 large quantity of a certain kind of fission fungi, and possibly also 

 of budding fungi. 



The mystery which formerly surrounded certain changes in milk, 

 by which it was rendered slimy or ropy, has to a certain extent been 

 cleared up. It has now been proved that the viscous consistency of 

 such milk has been caused either through a slimy body produced by 

 the decomposition of the milk-sugar, or is due to the fact that the 

 milk contains masses of bacteria, chiefly cocci, in the form of zoogloa 

 bacteria, the cell membrane of which has experienced a peculiar 

 change, associated with a large amount of swelling. In the first 

 case, certain micrococci produce from the milk-sugar a slimy sub- 

 stance, about which very little is known, and also small amounts of 

 carbonic acid, and occasionally also mannite. In the second case it 

 would appear that no decomposition of the organic constituents of 

 the milk seems to take place by the action of the luxuriantly- 

 growing slimy masses of bacteria. Different kinds of bacteria 

 impart to milk an unpleasant, bitter, slightly rancid, and disagree- 

 able flavour, by either causing the production of butyric acid, and 

 perhaps also formic acid, or by separating peculiar bitter extractive 

 substances. 



Formerly it often occurred that on the surface of milk set for 

 cream, coloured patches, red, yellow, or especially blue, were after a 

 time developed; or that the entire mass of the milk assumed a similar 

 unusual colour. These phenomena are also caused by the action of 

 fission fungi, viz. colour-producing bacteria. At present only one 

 kind of bacteria is known which can colour milk blue and one 

 which can colour it yellow, viz. the bacillus cyanogenus and the 

 bacillus synxanthus, which are known in several varieties, and 

 which live in symbiosis, that is, live together with other kinds of 

 fission fungi. On the other hand, there are many kinds of bacteria, 

 chiefly belonging to the group of micrococci, which impart a red 

 colour to the surface of milk or cream. The most of these bacteria 

 do not exert a decomposing action on the organic constituents of 

 milk. The widely distributed micrococcus prodigiosus, which 

 under certain conditions produces blood-red patches on the surface 

 of milk, on the contrary effects, in the first instance, a decomposition 



