114 Milk and Its Products 
This germ is occasionally found in milk, and imparts 
to it a red color which is easily confounded with 
the red color due to the presence of blood from a 
wounded udder. A single germ rarely occasions 
more than a single fermentation. Often two or more 
are combined in the fermentation, and in many cases 
there are a large number of different germs that 
bring about the same fermentation. This is notably 
true of the lactic and putrefactive fermentations. 
The effect of the various fermentations is such as to 
_ destroy the value of the milk as such, if they are al- 
lowed to proceed to any great length; but the manu- 
facture of butter is greatly aided by many of these 
fermentations, and the presence of certain germs is 
absolutely indispensable to the manufacture of cheese. 
Relation of milk bacteria to the human system.—By 
far the greater number of germs ordinarily found in 
milk are absolutely harmless, and may be taken into 
the human system in large numbers with perfect 
impunity, the germs of specific disease excepted, and 
with these latter it is the products formed from their 
growth rather than the germs themselves from which 
danger comes. There are probably no germs normally 
found in milk that may be classed as harmful. This 
is also true of a considerable number of fermen- 
tation products resuliing from the growth of the 
germs in the milk. Many of these products give 
to the milk or its product an unpleasant taste or 
physical appearance, but are otherwise perfectly 
harmless. There are, however, certain germs which 
produce a fermentation which results in the forma- 
