732 Reading-Course for Farmers' Wives. 



is safe to watch the cow in order not to use the milk of one that is 

 diseased. 



The milk was not looking quite right and the housekeeper interviewed 

 the milkman. Many hairs and much dirt in the milk was the complaint. 

 *' Oh well," he said, " I have to hire my milking done and you know how 

 it is, they won't always be careful ; I have told the man if the cow stepped 

 into the pail to throw the milk away, but he won't always do it unless 

 he is watched." 



Tests were made three years ago in the New York State College of 

 Agriculture by Commissioner R. A. Pearson and by Walter E. King of 

 the State Veterinary College to determine the importance of different 

 sources of milk contamination. Commissioner Pearson has given the 

 following as a result of these experiments : 



In most of these tests, a definite quantity of sterilized milk at 98° F. 

 was exposed to some one kind of contamination tliat we wished to test. 

 The milk was then examined and in that way we could get a fairly accu- 

 rate idea of what this particular kind of contamination amounted to. 

 Some of the experiments and their results are as follows: 



1. " Exposure to air in the stable. — Two liters (about two quarts) of 

 sterilized milk were placed in a sterile pail and exposed seven. minutes to 

 the stable air in a passageway behind the cows. This stable was doubt- 

 less cleaner that the average and the air contained less dust than is 

 often found in places where milk is being handled. Immediately after 

 this exposure, the milk was ' plated ' and found to contain 2,800 bacteria 

 per cubic centimeter (about fifteen drops) ; in other words, between 

 5,000,000 and 6,000,000 bacteria had fallen into the two liters of milk 

 in this short time. 



2. " Pouring milk. — When milk is poured from one vessel to another, 

 a very large surface is exposed to the air and great numbers of bacteria 

 are swallowed up. The following tests illustrate this point : About 

 five liters of milk were poured from one can to another eight times in the 

 stable air. It was found, after pouring, that this milk contained prac- 

 tically 100 bacteria per cubic centimeter more than it contained before 

 pouring; in other words, about 600,000 bacteria had got into the milk 

 because of this exposure. 



" In another similar experiment, when there was a little more dust in 

 the air, the contamination due to pouring eight times was two and one- 

 half times greater than in the preceding experiment. 



" The importance of pouring milk as little as possible from one vessel 

 to another has suggested to Dr. J. Roby, of the Rochester Health Depart- 

 ment, that milking pails should be made larger than those now used and 



