1892.] Some Uses of Bacteria. 909 
have the Neufchatel cheese, we have the Limburger cheese 
and many other kinds. Of course we all know that these 
different cheeses have very different flavors. Now in the pro- 
duction of these different kinds of cheeses there are different 
methods used. For instance, in the manufacture of Edam 
cheese the cheese-maker puts a little slimy milk into the milk 
that he is going to make into his cheese. That slimy milk 
contains a certain species of bacteria, and that peculiar species 
connected with that slimy milk produces the peculiar flavor 
which we get in the Edam cheese. Sometimes cheese is 
allowed to ripen soft for a few days before it is pressed, and 
when thus ripened different kinds of bacteria grow in it and 
grow in it more rapidly and produce different odors. Exper- 
iments have just been begun along this direction which show 
that it is possible, artificially, to ripen cheese abnormally. 
You can take certain species of bacteria and grow them in 
cheese, and you get a very atrociously tasting cheese, and you 
can take others and get a very good cheese. Now in the use 
of yeasts we have learned to plant yeast in our bread; we 
have learned to plant yeasts in our material that we want to 
ferment, if we are going to make alcohol or if we are going to 
make beer. The brewer has learned that he must use an 
artificially prepared yeast. He has learned that if he simply 
allow the malt to ferment naturally through the agency of 
atmosphere yeasts he does not know what he will get. It will 
ferment, undoubtedly, but it will be likely to ferment in an 
abnormal manner. He, therefore, plants a. pure culture of the 
proper yeasts. But we have not yet learned to plant bacteria 
in the same way. The cheese-maker has not yet learned to 
cultivate bacteria as the brewer has learned to cultivate his 
y Some day, I think we may say in the not far distant 
future, after our Experiment Stations have had time to work 
upon this matter a little longer, the cheese-maker is going to 
be told of some way in which he can cultivate bacteria as the 
brewer does his yeast, and then he will know what kinds of 
bacteria will produce a badly-ripened cheese and what kinds 
will produce an exceedingly good cheese. The time is coming; 
it has not come yet, but when it does come we can see that 
