RopiNESS IN Milk and Cream. 403 



bacteria from the air rather than from the cans. There are two 

 reasons, for considering this improbable. 



First. If the bacteria had been present in the air, and were 

 in that manner contaminating the milk, all of the samples exposed 

 in the vessels, and incidentally to the air, should have become 

 viscid. 



Second. The bacterium which accidentally survived the cleans- 

 ing process in the utensils is the one more likely to occur under 

 the uncleanly conditions prevailing in the particular creamery 

 visited. 



Another establishment which had suffered to a similar extent 

 from the occurrence of ropiness was visited for the purpose of 

 obtaining additional information. The business was conducted 

 in a manner similar to the first except that several dairies instead 

 of one supplied the milk. At a time when the writer was not 

 present, the proprietor of the establishment set samples of the 

 milk of each patron noting those which became ropy. Upon 

 this evidence, he reported several dairies as furnishing ropy 

 milk. In one of those so reported, experiments were made of a 

 similar nature to those in the first case, as follows : Samples of 

 the milk of each of the twenty-eight cows were drawn into 

 sterile test tubes, with no precautions against the access of dust 

 from the udder. None of the samples became viscid, although 

 they were kept in a refrigerator for ten days. Agar plates were 

 exposed under ten of the cows, but no growth resembling that 

 of Bacillus lactis viscosus appeared. Samples of the mixed milk 

 were collected from the milk pails, before and after flowing 

 through the strainer pail and from that which had passed through 

 the strainer cloth, but none became ropy. 



In the creamery, the cans, etc., were rinsed with sterile milk 

 exactly as had been done at the first establishment. Two deep 

 setting cans, the strainer and several dippers were examined. 

 Four of the separate quantities of contaminated milk became 

 ropy. Two of them had been contaminated in the two deep set- 

 ting cans and two in forty quart cans used on the route in deliv- 

 ering the dip milk. Cultures of the organism in question were 

 obtained from all of the viscid samples except one, from a forty 

 quart can. The milk rinsed in the dippers and that poured 



