Bacteriology of the Household. 731 



within the digestive tract of any one or more species of the micro- 

 organisms consumed. We must look to the effect upon the milk itself 

 for the cause of many but not all of these troubles. It is to prevent 

 these troubles that pasteurization is employed. 



Milk is sterilized or pasteurized for two purposes : to keep it sweet for 

 a longer time, and to kill any harmful bacteria it may contain. Sterilising 

 milk means boiling tJic milk for a certain length of time, or heating it 

 nearly to the boiling point, allowing it to stand for some hours and again 

 heating, repeating this several times. Boiled milk is very difficult for chil- 

 dren to digest. Paste nrization is done by bringing the milk to a tempera- 

 ture of from 60 to 65 degrees Centrigade (131 to 149 degrees Fahren- 

 heit) and holding it there for twenty minutes, after which it is cooled 

 quickly. It does not affect the taste, and such milk is more readily di- 

 gested than boiled milk. We should not need to depend upon sterilizing 

 or pasteurizing as a means for providing germ-free milk. The milk 

 should be produced in a clean manner, for clean raw milk is more whole- 

 some for children than cooked milk, no matter what the method of cook- 

 ing. Hot air and steam are valued germicidal agents ; hence their wise 

 use in the dairy. (See Bulletins 21, 22, Farmers' Reading Course.) 



The cow needs not only wholesome food, but to be kept clean. From 

 the time the milk leaves the udder there is danger of contamination. 



Look first on this picture. — A milkman dressed in clothes brushed 

 clean, his hands washed in soap and water, mot simply rinsed at the 

 trough, finger nails short and clean, the cow curried, the udder washed, 

 the pail covered until necessary to milk, the stable clear of dirt. And 

 then on this picture: — The cow lying in her own dirt over night, udder 

 soiled, milkman dressed as he has been while doing all sorts of work, 

 the cow's tail switching and the dirt flying, flies bothering the cow until 

 she kicks, — if not into the pail it is only by careful management that she 

 is prevented from doing so. Milk produced in this latter way is hardly 

 worth buying, while that of the first milkman we can afford to pay a 

 good price, — enough to encourage a man to keep clean and to have clean 

 stables and cows. Pay enough to allow the farmer to secure cement 

 floors, tight ceilings, good ventilating devices, and general cleanliness. 

 Then he will scrub his floors and hang up his milking suit to use only for 

 that purpose. 



" We always strain our milk, and the dirt and hairs are removed," say 

 some. Yes, but we do not like to eat bread that the mouse ran in, even 

 if the mouse has gone. A good part of the dirt is soluble and cannot be 

 strained out. A diseased cow ! We think it not profitable to throw 

 away milk, but consider the danger of infection to human beings ! It 



