EXPERIMENT STATION BULLETINS 249 



out to his patrons. The milk that he handled came from various sources, 

 for it was his practice to buy milk from the farmers in the vicinity of the 

 city. The milk that this single can contained was secured from a farmer 

 living three miles out o£ the city. A visit to his farm revealed the follow- 

 ing facts: The cows were pasturing in a large meadow adjacent to the 

 road and barnyard. Through the middle of this meadow ran a small 

 stream, but that portion of the pasture bordering upon this stream was 

 neither mar&hy nor very low. From the stream, the meadow had a gradual 

 but pronounced rise and it would not be considered a low pasture land. 

 There was no stagnant water about and the cows usually drank the water 

 provided at the well, yet sometimes refreshed themselves at this small 

 running stream. The milking was done in the open air and in cleanly 

 surroundings. There was no special means of cooling the milk and so far 

 as could be ascertained, it was not cooled at all. It was taken from the 

 cows, placed in a can and carted to the city by the milkman. The farmer 

 had no ropicess at any time so far as he knew, and had not noticed it on 

 this occasion in the milk he reserved. This can which turned out to be 

 ropy was taken to the home of the milkman and placed in his cellar, where 

 the top was removed and the contents exposed the same as several other 

 cans which he had at the same time, and in which ropiness did not develop. 



It was about one week after this had occurred that a sample of the cream 

 from the can in question was obtained. The milkman had preserved it. 

 Upon a bacteriological examination by means of plates, the micro-organism 

 producing the trouble was isolated and it proved to be identical with the 

 one which caused ropiness in the milk of Mr. A. Its biological history 

 corresponds precisely with that micro-organism which manifested itself on 

 Mr. A's farm four and one-half miles away. 



It was readily inferred that there must have been some means of com- 

 munication. Close questioning could establish no possible clue, for they 

 all claimed to have had no interchange of cans or milk within a month or two 

 of this time. Failing in this, I turned my attention to the water found in 

 the pastures of both farms, although the streams were not the same, both 

 however flowing into the Grand river. A close bacteriological examination 

 was made in each case but without any positive results. Another investi- 

 gation was made of the air of the milk-house, barnyard and stable and this 

 too failed to reveal the source of this micro-organism. Plates were exposed 

 under the udders of the cows while milking and these added nothing to our 

 knowledge. 



The infection had about disappeared when the last investigations were 

 made. Owing to their negative nature, we were forced to the conclusion 

 from our first work when the trouble was at its height, that the infection 

 came through the cows and that the bacteria were adherent to the udder. 

 This was demonstrated almost beyond a doabt by the can or pint jar ex- 

 periment and the flask experiment where the milk was drawn directly from 

 the udders. How these bacteria happened to locate there and whence they 

 came are still unsolved problems. What avenue of communication existed 

 between the two farms and what they have in common are yet unknown. 

 This class of bacteria may be found in the air, water or soil, but at pres- 

 ent it is not determined in which this one may live. 



CLIMATIC CONDITIONS. 



With the data now given, the climatic conditions may be profitably con- 

 sidered. In all of the cases in the northern states reviewed at the begin- 

 32 



