493 
Doane-Buckley, and Trommsdorf methods, which show great dis- 
crepancies. When making a number of counts from the same speci- 
men of milk the Doane-Buckley technique gave the least variation 
and as compared with the others the highest counts. Russell and 
Hoffmann® in a similar comparison found the average variation 6 per 
cent using the volumetric, and 112 per cent using the smeared sedi- 
ment technique. Most recent writers agree that the latter method ^ 
should be abandoned as too inaccurate to be of service. 
Concerning the number of leucocytes which have been found in the 
milk of healthy cows kept under the best conditions and counted by 
the most accurate methods, a great variation has been noted. Sav- 
age found numbers ranging from 35,000 to 4,500,000 per cubic centi- 
meter, and more than three-fourths of the cows gave milk that aver- 
aged more than 100,000 per cubic centimeter. About the same fig- 
ures were found for mixed milk from entire herds; more than four- 
fifths of the herds gave averages above 100,000 per cubic centimeter. 
Doane found the number of leucocytes in the milk of a large number 
of cow^s to average more than 200,000 per cubic centimeter. 
Russell and Hoffmann made a large number of counts from the milk 
of cows in which there was not the slightest clinical evidence of udder 
disease, nor had there been any history of such, and obtained results 
as high as 1,800,000, while 33 per cent gave counts higher than 
500,000 per cubic centimeter; 83 per cent of those with slight udder 
disease or a history of garget gave counts of 500,000 per cubic centi- 
meter or over. 
Tests of milk from the same cow, taken from day to day, show 
great variations, although in general it may be said that a milk show- 
ing a high count one day will show a high count the next day, but not 
necessarily the next week or month; this, of course, when the health 
of the animal continues unchanged. The period of lactation seems to 
have no constant influence, except that the colostrum corpuscles are 
greatly increased after parturition. Bergey has shown that vddel}; 
different counts are often found in the milk from different quadrants 
of the udder. Buchholtz,^ Czerney,® and Michaelis^^ have pointed 
out certain facts relating to the secretion of milk that explain some of 
these discrepancies. They found that retention of milk in the gland 
ducts and alveoli for an unusual period causes a large increase in the 
number of leucocytes in the milk. When the milk is allowed to accu- 
mulate in the udder instead of being removed at regular and proper 
« Journal of Infectious Diseases, 1907, Supplement No. 3, p. 63. 
&Inaug. Diss., Gottingen, 1877. 
cPrag. med. Woch., 1890, Bd. 15, S. 401-416. 
(^Arcli. f. microsk. Anat., Bd. 51., S. 711. 
