New YorkK AGRICULTURAL EXPERIMENT STATION. 59 
The first and most natural question, as to whether the milk- 
Ing machine will actually milk cows, is readily answered in 
the affirmative. Other questions relate to the effect of the 
continuous use of ‘the machine on the cow, to its effect upon 
the quality of the milk produced and to its economy. The cor- 
rect answers to these latter questions are not so easily ob- 
tained. : 
The question of the effect of the milking machine on the 
cow is an especially complicated one and although it has been 
studied already for more than three years, satisfactory data for 
its solution are not yet at hand. So far as the observations 
have gone it seems that when the vacuum with which the 
machine is operated is not excessive and the teat cups are so 
selected as to fit the teats properly the yield is probably as 
large as would be obtained by the ordinary hand milking. 
However, there is at present no basis, aside from experience, 
for determining what is the correct amount of vacuum. Again, 
‘in fitting the teat cups constant care is essential, as the size 
of the cup required by a given teat may vary at different 
periods of lactation. Recent mechanical changes in the ma- 
chine appear to have further increased its ability to milk cows 
successfully. The study of the question of the effect of the 
milking machine upon milk secretion is being continued and 
it is hoped that a more accurate measure of its effect may be 
later obtained. Whether one man can milk more cows with 
one or two ‘machines than he can by hand is also being ob- 
served. 
The effect of the machine on the quality of the milk can be 
measured by the germ content of the milk and, as might 
naturally be expected, the effect depends largely upon the way 
in which the machine is manipulated. This publication deals 
with the influence which variations in the construction of the 
machine and in the manner of its manipulation have upon the 
germ content of the milk. It is hoped that a knowledge of 
these relations may guide the users of milking machines in 
producing a more desirable quality of milk and in producing 
it at a lower cost. 
