82 Revorr of tuk Bacrerioiocist of THE 
The trouble has been observed in nearly all sections of the State 
where white cheese is made. Cases of it have been reported to 
us from St. Lawrence, Jefferson, Lewis, Oneida, Oswego, Alle- 
gany and Cattaraugus counties. 
PREVIOUS SCIENTIFIC WORK. 
In 1896 W. T. Connell studied an, outbreak of rusty spot at a 
Canadian factory. From the infected. cheese he isolated an or- 
ganism which he named Bacillus rudensis: and when a starter of 
this organism was added to a vat of good milk the rust-colored 
spots were reproduced in the cheese. He concluded that the 
trouble was largely due to air-borne infection from the red growth 
along the factory drains. 
Beginning in 1899 we have repeated and extended these obser- 
vations as to the cause of the discolorations in the cheese. We 
have studied outbreaks in a number of factories in widely sepa- 
rated portions of this State and in all cases we have found 
Bacillus rudensis present in large numbers in the rust-colored 
spots in the cheese.2. We have many times repeated the experi- 
ment of adding a starter of this organism to a vat of good milk 
and have reproduced the rusty spots in the resulting cheese. 
NECESSITY FOR THE PRACTICAL APPLICATION OF THE ABOVE RESULTS. 
The work of Connell showed that Bacillus rudensis was at least 
one of the germs causing rusty spot in cheddar. Our own work 
has rendered it probable that it is the only germ directly con-— 
cerned with this trouble. 
Knowing only this fact we were not able to give specific advice 
in the practical problems which confront the dairymen in infected 
factories, but the fact was valuable because it gave a sound basis 
upon which to formulate methods of controlling the trouble. 
In planning methods we have kept in mind the fact that to be 
of most benefit the process must be neither so costly as to dis- 
courage the factoryman nor so vague in its directions as to con- 
fuse him and cause him to spend his time in fruitless effort. 
This publication is a record of our_attempt to apply our krowl- 
edge to actual conditions as they are found in infected factories. 

1Connell, W. T. Discoloration of Cheese. Canadian Dept. of Agr., Bul., 1897. 
2Harding, H. A., Rogers, L. A., and Smith, G. A. Notes on Some Dairy Troubles. N. Y. 
Agr. Exp. Sta. Bul. 183, Dec. 1900. 
