266 



Nature-Study Agriculture 



U. S. D. A. 



FIG. 212. Section of a wire milk strainer, magnified, showing dirt from the 

 udders of ill-kept cows. 



Straining A black sediment of dirt is sometimes found at the 

 bottom of a pan after milk has stood in it for some hours 

 (Fig. 212). This shows that the conditions under which 

 the milking was done were not cleanly. If the cow is 

 not clean, it is impossible to keep dirt from her hair from 

 falling into the bucket, even if it is a milker's bucket with 

 a small opening at the top (Fig. 213). This fine dust 

 cannot be separated from the milk by straining; but 

 the milk should always be poured through four thick- 

 nesses of cheesecloth or some equally good strainer to 

 remove hairs and coarser particles. Cloth will serve 

 better than a wire strainer (Fig. 214). 



