SANITARY EXAMINATION OF MILK 125 



steam-heated jacketed container, and filtered through a 

 disk of absorbent cotton, said cotton to be free from sizing 

 or starch, which prevents satisfactory filtering of the milk. 

 Milk may be graded according to the degree of discolora- 

 tion of the cotton. 



Leucocytes in Milk. — In the milk of normal, healthy 

 cows may be found a number of leucocytes or white-blood 

 corpuscles. The mixed milk from a healthy herd seldom 

 contains more than 500,000 cells per cubic centimeter, 

 although this number is often exceeded in the milk of indi- 

 vidual cows. An inflamed or diseased condition of the 

 udder causes a great increase in the leucocyte content of 

 the milk, hence, at the present time, milk containing over 

 500,000 of these bodies per cubic centimeter is looked upon 

 as coming from a bruised or inflamed udder and is con- 

 sidered unfit for food. However, this number cannot be 

 adopted as a set standard, but it is well to class all milk as 

 suspicious when it does exceed this limit. A physical exami- 

 nation of the cows producing the milk should be made and 

 action taken according to the findings at this examination. 



Fibrin has been formd to accompany leucocytes; es- 

 pecially in acute cases. Professor Doane found that when 

 a cow's udder is badly inflamed these fine threads, or fibrin, 

 are found in the milk. The leucocytes in such milk also 

 tend to hang together in clusters. In some experiments 

 with m ilk from an inflamed udder, Doane found as many as 

 20,000,000 leucocytes per cubic centimeter of milk. Fibrin 

 was also found in this milk. As the cow's udder became 

 well, the nimaber of leucocytes dropped to 500,000 per cubic 

 centimeter. At this period, the fibrin disappeared. A 

 mmiber of counts were made from milk of different cows, 

 and it was found that fibrin accompanied a large number 

 of leucocytes. 



