RopiNESs IN Milk and Cream. 401 



an accumulation, although innocent in appearance, is neverthe- 

 less, teeming with bacteria which infect the milk which passes 

 through the strainer. None of the cultures made from the 

 accumulated filth revealed the presence of the bacteria causing 

 ropiness, nor did any of the milk samples become viscid. It was 

 noted, however, that the bacteria found in the filth of the aerator 

 were identical with those found growing in the milk which had 

 been poured over it ; also that those in cultures from the filthy- 

 strainer were the same as those found in the milk poured through 

 it. These facts are of interest as illustrating how directly filth 

 may influence the keeping qualities of milk by introducing bac- 

 teria. It should also be noted that the filth itself cannot cause 

 ropiness in milk, unless there are present in it the bacteria which 

 possess that power. 



A bit of the cloth strainer used over the top of milk cans was 

 placed in sterile milk. Samples of the mixed milk of the dairy 

 were collected from the milk pails, after passing through the 

 strainer pail, after passing through the aerator and through the 

 cloth strainer into the milk can. All of the samples were kept 

 cool, the various fermentations going on slowly, giving oppor- 

 tunity for the development of ropiness. None of the samples 

 became viscid. From this fact it was concluded that the milk 

 did not contain Bacillus lactis viscosus when drawn from the 

 udder, nor did it gain access to the milk during any of the pro- 

 cesses, to which the milk was subjected up to the time that it was 

 taken from the barn. 



It is important now to note the results obtained from a similar 

 treatment of the milk in the creamery. The evening's milk was 

 brought to the creamery and placed for the night in deep setting 

 cans surrounded by ice- water. That of the morning was aerated 

 and brought to the creamery where it was again strained before 

 delivering. A brass -wire strainer was used constantly because it 

 was of such size as to fit over the top of the cans, forming a con- 

 venient device for holding a cloth strainer in place. For this 

 reason all of the milk passed through the one strainer and 

 always into deep setting cans. The milk strained in the even- 

 ing remained in the cans over night. The meshes of the strainer 

 were seriously obstructed by an accumulation of filth, the result 



