New York AGRICULTURAL EXPERIMENT STATION. 169 
mation of cheese flavors. These may or may not arise from 
common causes. The casein begins to undergo change at once, 
while the formation of flavors begins some time later, after 
which the two progress simultaneously. These two groups of 
phenomena cannot be measured by the same means or standards. 
Duclaux, Adametz, Weigmann and their disciples have 
directed their attention to the formation of flavors and have 
quite generally relied upon the odor and physical appearance of 
their material in judging of the rate and character of the 
ripening. In those cases in which they have gone more fully 
into the solubility of the casein, they have usually determined this 
point by its ability to pass through a porcelain filter, a method 
which von Freudenrich & Jensen* have shown to be extremely 
liable to error in practice. They have rarely attempted to show 
that the species of bacteria which they look. upon as the causal 
ones are present in cheese in any considerable quantities. They 
have, for the most part, confined themselves to showing that 
pure cultures of these species are able, by means of excreted 
enzymes, to digest the casein of milk and at the same time to 
form cheese-like odors. In some cases they have made cheese 
withthe additionof pure cultures or of solutions of their enzymes 
and have stated that the resulting product was better flavored 
than cheese made in the usual way. In establishing this point, 
however, they were handicapped by the lack of accurate 
standards for measuring such relations. 
Recently Adametz and Winkler! have placed a culture of one 
of these bacilli upon. the market under the trade name of 
“Tyrogene,” its use being expected to result in the production 
of a desirable Emmenthaler flavor in cheese. Some preliminary 
tests by von Freudenrich® have failed to indicate that it will 
accomplish this desired end. 
When the study of-the kinds of bacteria present in cheese 
was extended so as to include the numbers of each kind, it was 
found that the enzyme-forming bacteria previously mentioned 
8y. Freudenreich and Jensen. Landw. Jahrb. d. Schweiz., 14:169 (1899), 
‘Winkler. Molkerei Ztg., 14:817 (1900). 
Sy. Freudenreich. Ann. Agr. Suisse (1901). 
