174 Report of the Department of Bacteriology of the 



The number of cells in the milk of each cow showed a decided 

 decrease at the first milking after the machine was used. The com- 

 parative averages of the cell content of the hand- and machine-drawn 

 milk likewise show fewer cells in the machine-drawn milk. If these 

 observations stood alone they would have little significance for it 

 is impossible to tell whether these differences were due to the change 

 in the method of milking or to the fact that they were fresh cows. 

 However, the data given on page 143 and in the following section 

 indicate that they are significant and that the smaller number of 

 cells was discharged because of the change in the method of milking. 



C. COMPARISON BETWEEN THE CELL CONTENT OF MACHINE-DRAWN 



AND HAND-DRAWN MILK. 



Table XVI gives the averages of the counts in Table II in such 

 a way as to show the differences between hand-milked and machine- 



Table XVI — Comparative Cell, Counts of Machine-drawn and Hand-drawn 



Milk: Station Herd. 



Number 

 of cells 

 per c.c 



Range of Counts. 



i 

 o 



SOO 

 o 



o o 

 10 - 



o . 

 © 9 



Count No. 1 — Average of 15 machine-drawn samples. 



Average of 8 hand-drawn samples. . . . 

 Count No. 2 — Average of 15 machine-drawn sample* 



Average of 8 hand-drawn samples. . . . 

 Count No. 3 — Average of 17 machine-drawn samples. 



Average of 8 hand-drawn samples .... 

 Count No. 4 — Average of 15 machine-drawn samples. 



Average of 8 hand-drawn samples. . . . 

 Count No. 5 — Average of 14 machine-drawn samples. 



Average of 7 hand-drawn samples .... 

 Count No. 6 — Average of 13 machine-drawn samples 



Average of 8 hand-drawn samples. . ... 

 Count No. 7 — Average of 12 machine-drawn samples. 



Average of 4 hand-drawn samples. . . . 

 Count No. 8 — Average of 12 machine-drawn samples. 



Average of 5 hand-drawn samples. . 



429,000 

 122,000 

 448,000 

 225,000 

 419,000 

 292,000 

 516,000 

 426,000 

 518,000 

 691,000 

 274,000 

 316,000 

 306,000 

 574,000 

 203,000 

 691,000 



Grand average of 113 machine-drawn samples 309,000 



Grand average of 56 hand-drawn samples 381 ,000 



12 

 7 



12 

 7 



13 

 7 

 8 

 5 

 8 

 3 



10 

 5 

 9 

 1 



10 

 3 



82 

 38 



17 

 14 



3 

 

 2 

 

 2 

 

 4 

 

 2 

 2 

 

 

 

 

 1 

 2 



14 



4 



