1893.] Bacteriology in its General Relations. 859 
early added to the cream in order to produce as a result of the 
fermentative changes the desired flavor. 
In this way uniformity of product is assured, and as many 
undesirable forms are choked out by the introduction and con- 
trol of pure cultures, the keeping qualities of the butter are 
much improved. 
The utility of bacteria in connection with milk and its pro- 
ducts may still be further extended, for the necessity of their 
presence in cheese making is even more imperative than in 
butter making. Here they are an indispensable requisite to 
the production of a palatable product. New cheese is flat and 
insipid, and it requires a certain period of time in which it 
undergoes a change that is called the ripening or maturing 
stage before it is fit for use. Duclaux and others have shown 
that the production of the delicate flavors are due to the trans- 
formation of the casein into soluble albuminoids by means of 
the ferments that are produced as a result of bacterial growth. 
This ripening process is then due to the action of specific 
germs. The various kinds of cheeses that possess such a vari- 
ety of flavors are, no doubt, due to the aetion of different forms 
of bacteria, but the threshold of this work is scarcely more than 
crossed, and, as one of the leading experts in this country has 
said, further advancein perfecting the processes of cheese man- 
ufacture is impossible, unless they include the aid of bacteri- 
ology. 
(1o be continued.) 
