COVERED PAIL TO EXCLUDE FILTH FROM MILK. 



117 



fresh milk and in the milk after standing for fifty hours at ordi- 

 nary temperature, the percentage of acid in the milk after fifty 

 hours, and the length of time until the milk curdled. The 

 results of a series of these tests are given in the following tables. 



THE REMOVAL OF DIRT BY STRAINING. 



The quantities of dirt in the milk before and after it was 

 strained are given in the following table. 



Table 62. 

 Quantities of dirt in milk before and after straining. 



Date of Test. 



November 23, 

 November 25, 

 November 26, 

 November 27, 

 November 30, 

 December 5, 

 December 6, 



Average, 



Wbight of Dirt per Liter 

 OF Milk. 



2 P- 



Gram. 



0.0245 

 0.0895 

 0.0555 

 0.0515 

 0.0725 

 0.0710 

 0.0505 



0.0593 



'5 p. 



Gram. 



O . 0020 

 0.0470 

 0.0495 

 0.0295 

 0.0360 

 0.0270 

 0.0310 



0.0317 



Gram. 



0.0225 

 0.0425 

 o . 0060 

 0.0220 

 0.0365 

 o . 0440 

 0.0195 



0.0276 



"(LI O 



91.8 



47-5 

 10.8 

 42.7 

 50.3 

 61. g 

 38.6 



46.6 



The smallest difference between the quantities of dirt in the 

 two samples was on November 26, when only about 11 per 

 cent, of the dirt was removed by the strainer; the largest dif- 

 ference was on November 23, when about 92 per cent, was 

 removed by straining. In the average of seven tests the amount 

 of dirt strained out of the milk was about 47 per cent, of that 

 in the milk not strained. 



The amount of dirt which could be removed by the strainer 

 depended largely upon the nature of the dirt. That in the 

 sample of November 23, in which the percentage strained out 

 was the largest, consisted mainly of hairs, skin scales from the 

 teats and udder, particles of hay, chaff and other materials of 

 a coarse, insoluble nature; there was but little manure or other 

 soluble material in this sample, while on the other hand in the 

 sample on November 26 where the percentage strained out was 



