EXPERIMENT STATION BULLETINS 247 



To positively establish the nature of the cause, milk which had been 

 sterilized and freed from bacteria was inoculated with a small drop of the 

 specimen. In twenty-four hours this milk which had been inoculated 

 developed ropiness and was used in turn to inoculate another lot of steri- 

 lized milk, and this in twenty-four hours was decidedly ropy. There was 

 no question about what we had to contend with and Mr. A was eager to 

 begin active measures, for on Wednesday so many of his patrons had left 

 him ; and, feeling that it was not right to sell milk of this kind, he had stopped 

 his milk wagon. This meant a pecuniary loss to him of one hundred and 

 fifty dollars a month. 



Three points of interest were now before us: The first was to eradicate 

 the trouble^ the second, isolate the micro-organism; and the third, to 

 locate it. 



Our attention was first directed to the cans. In order to render them 

 free from danger, each can was filled with boiling water and covered up; 

 from time to time it was emptied and refilled, until it had been virtually 

 subjected to boiling water for one-half hour. After the cans had under- 

 gone this treatment, they were exposed to the direct rays of the sun for 

 the rest of the day. The sawdust on the floor of the milk-house was cleaned 

 out and clean gravel substituted. The walls and ceilings were then washed 

 with a solution of corrosive sublimate made in the strength of one of sub- 

 limate to one thousand parts of water. Having done this, three or four 

 pounds of sulphur were burned in the milk-house. The cooling tank was 

 also washed with the corrosive sublimate solution. Nothing could be 

 done to the barn but to sprinkle it with the corrosive sublimate solution 

 and add a fresh supply of lime to the floor. Before milking, the cows 

 udders were washed with the corrosive sublimate solution made in the 

 strength of one to two thousand. The cows were however, finally removed 

 to another barn, before the trouble disappeared. 



In attempting to isolate the specific micro-organism, the tubes first inocu- 

 lated to demonstrate the microbial origin of the cause, had for their pur- 

 pose also, what appeared to be the most feasible method for isolation. By 

 the production of culture after culture from the cream, it was thought that 

 the "ropy" bacteria would increase in number to such an extent as to 

 reduce the other bacteria present to the least possible number. After 

 repeated cultivation in this manner for some time, plates were made and 

 after they had developed, this micro-organism which turned out to be the 

 specific cause, was very plentiful and there was no trouble in obtaining a 

 pure culture. 



Simultaneously with the eradication and isolation of the micro-organism, 

 we tried to locate the source of the bacteria During the removal of the 

 sawdust from the milk house, a bacteriologically clean dish containing 

 normal milk, which was gotten from a neighbor who had no trouble of this 

 kind, was exposed. At the same time, another dish of milk prepared as 

 the first, was exposed in the barn. Neither of these specimens produced 

 ropy cream. The udders of the cows and the hands of the milkers were 

 then thoroughly washed with the corrosive sublimate solution made in the 

 strength of one to two thousand. The milk from each cow was drawn 

 into an individual fruit jar and a number was placed upon it correspond- 

 ing to the cow from which the milk was drawn. In the preparation of the 

 cans used for this purpose, the boiling method of sterilization was employed 

 and the tops screwed on, with the usual rubber collar, immediately after 

 sterilization. They were not opened until the milker was ready to draw 



