New York AGRICULTURAL EXPERIMENT STATION. 61 
PREVIOUS STUDIES OF MILKING MACHINES 
The earliest available study of the effect of a milking machine 
upon the germ content of the milk is that by Harrison.t. In a 
dairy in which part of the cows were milked by hand and the 
others by the Thistle milking machine he repeatedly deter- 
mined the germ content of the milk obtained in each way. An 
average of 24 such examinations of the product of the milking 
machine gave 150,900 germs per cc. while 17 tests of the milk 
drawn by hand gave 11,000 germs per cc. Likewise the keep- 
ing quality of the machine-drawn product was markedly in- 
ferior to that of the milk drawn by hand. In this machine 
there were no air filters and the rubber parts were scrubbed 
daily and kept in cold water between milkings. 
Erf* traced the history. of the development of the milking 
machines and discussed the action of the Burrell-Lawrence- 
Kennedy machine which he had under observation for some 
months. 
Stocking,® in 1905, studied the Burrell-Lawrence-Kennedy 
machine as it was being used in two dairies. In both cases 
he contrasted the resulting germ content in the milk with that 
obtained when milk was drawn by hand. The unsatisfactory 
character of hand milking as a basis for comparison in such 
studies is shown by the fact that in one dairy the average © 
results obtained by hand milking in different experiments 
varied from 48,125 to 786,382 per cc. and the other dairy from 
997 to 11,712 per ce. 
The most important point brought out in this study was the 
favorable effect on the resulting germ content of the milk when 
the rubber parts were kept between milkings in a solution of 
‘Harrison, F. C. Machine-drawn milk versus hand-drawn milk. Cent. 
f- Bakt. II Abt. 5: 183-189. 1899. 
*Erf, O. Milking machines. Kan. Agr. Exp. Sta. Bul. 140. Oct. 1906. 
*Stocking, W. A., Jr. The milking machine as a factor in dairying. 
II Bacteriological studies of a milking machine. U. S. Dept. of Agr. 
Dae Le Bul, 92," Jan’ 1907. 
