132 MICROSCOPIC TESTS OF MILK. 



tions, and the amount of sediment is noted. For this purpose 

 there is used a special centrifuge tube with the bottom drawn 

 out into a capillary tube, properly graduated. These tubes are 

 prepared by Franz Hugerslioff, I^eipzig. 



The mixed milk of cows with sound udders, as a rule, shows 

 sediment varying from traces to .5 cc. per liter, with 1 cc. 

 per liter as the maximum. On the basis of the examination 

 of hundreds of mixed milk samples, it is asserted that when 

 the test gives over 1 vol. per mille, it can be shown that one 

 or more quarters of the udders of the cows are giving milk 

 with an excessive number of cells. 



The test is recommended by Trommsdorff as an aid in the 

 diagnosis of chronic mammitis. He applied if to the individ- 

 ual cows in a dairy of good reputation producing milk for 

 infant feeding. On three different occasions within a period 

 of four months, he designated as diseased 20% on first test, 

 34.2% the second, and 27% on the third examination. The 

 number of cows tested on the three occasions varied from 35 

 to 38. In another dairy of 66, 12% were considered diseased; 

 in another of 75, 4%; and in another of 82 cows, 19.5%. 



The test is said to give identical results from duplicate de- 

 terminations. The criticism has been made that it is a meas- 

 ure not merely of leucocytes, but also of all substances that 

 might be centrifugalized down into a sediment. 



SigfnSficance of results. There has been a wide variation in 

 the amount of importance that has been attached to the results 

 of these tests. In some cases their tentative nature has been 

 very properly recognized and the results used as indication of ' 

 the desirability of an examination of the udders of the cows. 



But instances are not rare of cases where the milk of a dealer 

 has been publicly condemned on the ground of its containing 

 pus, staphylococci and streptococci. There are instances, too, 

 where the tests have been applied to the individual cows of 

 dairies. Excessive and unreasonable numbers of cows have 

 been condemned on the basis of the results where no symptoms 

 of mammitis have been present. The condemnation of the 

 majority of the cattle in a herd certainly focusses attention 

 upon the evidence warranting such a procedure. 



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