Milk Fermentations. 71 



trouble, or whether it is restricted to one or more ani- 

 mals. For this purpose the fermentation or curd test in 

 some form or other is invaluable. Often the whole milk- 

 ing may be infected from the milk of a single animal, as 

 is frequently the case in udder inflammation. 



To prove whether the trouble is a general or incidental 

 one, can easily be done by separating the milk of the dif- 

 ferent cows, or if this is not feasible by massing that of 

 a few together, and so gradually narrowing down the 

 number. 



Where the trouble is a general one, and is not due to 

 the spreading of the infection from a local source, the 

 fault is usually to be traced to some error in handling 

 the whole mass of milk. Imperfectly cleaned cans that 

 are used in setting the milk often contaminate the entire 

 lot; then, too, noxious germs derived from the coat of 

 the animal often gain access to the milk. The herd, es- 

 pecially in the late summer, when the upland pastures 

 are dry and the grass is short, are generally pastured 

 on marsh or lowland fields. The stock seek the low places 

 frequently slime-covered mud-holes, and in passing 

 through these, their coats are fouled with the scum and 

 slime that is filled with putrefactive forms of bacteria. 



Sometimes the source of the filth may be in the barn 

 itself. Dirty stalls filled with moist and decaying mat- 

 ter may be the means by which the milk is often seeded, 

 or it may come from manure particles that contain putre- 

 factive organisms in abundance. Generally where the 

 source of contamination can be discovered, it will be an 

 easy matter to get rid of the obnoxious fermentation by 

 using physical means of disinfection such as steam or hot 

 water. In some cases pasteurizing the milk is of material 

 help. Chemical disinfection can sometimes be employed 

 advantageously, but the application of these agents should 



