194 
Journal of Agricultural Research 
Vol. II, No. 3 
In a preliminary investigation of the nonnitrogenous constituents of 
Cheddar cheese (unpublished data) the very pronounced differences that 
were expected in the quantity and variety of volatile acids, esters, and 
alcohols in good and poor types of cheese were not found. But since 
there were certain differences which could be only of biological origin, it 
was believed essential to this problem that the substances formed by 
the specific groups of organisms normally present in cheese be more 
carefully studied. For this reason it was decided to extend the investi¬ 
gation to an examination of the substances produced by representatives 
of the groups that had been found to be present in cheese in such num¬ 
bers that it was evident that they must be of importance in the ripening 
process. In this way it was hoped to find the groups of organisms to 
which might be assigned responsibility for the production of definite 
nonnitrogenous compounds that could be correlated with flavor produc¬ 
tion. The compounds particularly sought were the alcohols and esters 
and caproic and butyric acids. Formic, acetic, propionic, lactic, and 
succinic acids were also included in the list of substances to be isolated. 
To some extent the sources of these bodies were also studied. This 
paper is a progress report on this phase of our work. 
Ferdinand Cohn (1875) was the first to connect the cheese-ripening 
process with the activity of bacteria. Duclaux (1894, P* 265-267) 
considered that the volatile fatty acids found in cheese arose from the 
action of the bacteria on casein and from the hydrolysis of the fat. He 
believed also that butyric acid was a source of other volatile acids, the 
butyric acid arising partly from fat decomposition and partly from 
decomposition of casein. Baier (1895), Von Klecki (1896), and Weig- 
mann (1896, 1898) believed butyric-acid bacteria to be of importance 
in the ripening of cheese. Von Freudenreich (1897, 1902) attributed to 
the lactic-acid bacteria the principal r 61 e in the ripening process, especially 
in Emmenthaler cheese. Jensen (1904) in his work on Emmenthaler and 
other European cheeses has contributed much to the general subject of 
the chemistry and bacteriology of cheese ripening and in agreement 
with Von Freudenreich gives to the lactic-acid-producing organisms very 
great importance in the ripening process. Suzuki, Hastings, and Hart 
(1910) have investigated the source of the volatile acids and the forms 
of lactic acid found in American Cheddar cheese, studying in connection 
with these subjects the decomposition of lactose, lactates, fat, proteins, 
and glycerin. 
The constituents of a fresh cheese mass which can be sources of the 
nonnitrogenous bodies under consideration are paracasein, fat, lactose, 
lactates, and citrates. From paracasein there arises gradually during 
the ripening process a series of nitrogenous compounds which have been 
fairly well investigated (Winterstein; Steinegger; Benecke and Schulze; 
Van Slyke and Hart, Apr., 1903, and July, 1903; Dox). At least three 
of these—namely, cadaverin, putrescin, and ammonia—are slightly 
