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threads ; fodder and other food particles ; parts of insects ; 

 down from birds ; skin scales, etc. 



As much as 8 to 15 milligrams of dry impurities have been 

 found in one litre of milk in some of the dairies in Germany. 

 As a rule most of the impurities get into the milk at the time 

 of milking. The fact that the dairy cows in Europe are kept 

 more hours per day in the stall than the cows of America will 

 account for this great quantity of impurities. When dairy 

 cows are kept in the stalls only a short time in the morning 

 and evening and spend the rest of their time on clean pastures 

 they can easily be kept clean ; yet they will not be hair-clean 

 and dust-clean without brushing and sometimes washing. 



But some one may say that the strainer and the separator 

 will remove all these filth particles from the milk. It is true 

 that many of these impurities are removed, provided they are 

 not soluble ; but these particles inoculate the milk with various 

 kinds of bacteria and introduce injurious soluble impurities 

 that cannot be removed by the strainer or the separator. 

 Milk is a good food for bacteria and many of them begin to 

 grow and multiply as soon as they get into it; then they 

 destroy some of the nutritive materials in the milk. Some- 

 times the dust particles may carry disease-producing bacteria 

 into the milk ; this is frequently the case if any of the cows in 

 the dairy have tuberculosis in a form in which the tubercle 

 bacilli are thrown off in the excretions ; it is also true if any 

 of the dairy servants have tuberculosis and expectorate indis- 

 criminately around the dairy. It is just as essential to have 

 healthy servants in a dairy as it is to have healthy cows. 



Grotenfelt gives the following primary principles to regu- 

 late the work in a dairy barn : 



1. The manure is to be cleaned out one and one-half hours 

 before milking time. 



2. The stable is to be aired every time it is cleaned out. 



3. The cows should be watered before every milking. 



4. The feeding should take place at least one and one-half 

 hours before milking. 



5. The cow should have a rest of one and one-balf hours 

 three times a day, during which time the stable is closed. 



