152 Bulletin of Laboratories of Denison University. [Voi. xi. 
no part in the curing process, but that this function must 
be ascribed to the non-peptonizing lactic-acid — producing germs. 
To this, however, he was loathe to subscribe, for how could 
the acid-producing germs which did not affect the casein in milk 
cultures, except to precipitate it, produce such profound 
changes in the cheese ? New media and methods were tried to 
develop bacteria which had perhaps been overlooked or lost 
entirely. In these attempts one or two anaerobes were found, 
but no important phenomena could be connected with them.^ 
Besides the above a number of other investigators had con- 
tributed data to our problem, but none which advanced materi- 
ally toward an explanation of the ripening process. Pammel^ 
had discovered an aromatic bacillus in cheese, while RusselP had 
isolated gas germs which caused “huffing” or swelling of 
cheese. Lloyd^ of England claimed to find B. acidi lactici in 
English Cheddar. 
This was essentially the situation when the writer, then a 
student under Dr. H. L. Russell of the Wisconsin University 
and Experiment Station, first took up the problem. Some of 
the observations had been made by means of a microscopical 
examination of cheese; others had been carried out before 
the time of solid media ; the most recent labors had been 
accomplished without uniform or established methods and while 
tending to overthrow proposed theories afforded no solution 
to the question.^ 
Our first attempt was to find a suitable method for isolat- 
ing the bacteria and at the same time to obtain reliable quanti- 
^ Von Freudenrich, Forschung auf den Gebiete des Kasereifungsprozesses. 
Cent, fur Bakt. II Abt. I 1895, 17, 19. 
2 Pammel, An Aromatic Bacillus of Cheese. Bui. No. 21, Iowa Exp. Sta- 
tion. Ripening of Cheese. Ibid. 
^ Russell, Gas-producing bacteria and the relation of the same to cheese. 
I2th An. Reports Wis. Exp. Station 1896, p. 139. 
* Lloyd, Observations on Cheddar Cheese-making. Bath and W. Eng. 
Soc. Reports for 1891, 2 and 3. 
^ Russell and Weinzirl, Cent. f. Bakt. II Abt. Bd. 3, pp. 456-467, 1897. 
