New YorK AGRICULTURAL EXPERIMENT STATION. 69 
could be held long enough for the lactic acid colonies to de- 
velop. On account of the great fluctuation in germ content 
four dilutions were made from each sample drawn by hand 
and by the Globe machine. Only three dilutions, plated in 
duplicate, were made from the product of the Burrell-Lawrence- 
Kennedy machine. All of the plates were held for 5 days at 
23° C. and counted under a lens magnifying four diameters. 
In the work with the Globe machine duplicate plates were 
prepared on standard lactose gelatin but the making of these 
plates was not continued since the development of liquefying 
colonies prevented an incubation sufficiently long to allow for 
a’ growth of all the acid forms. 
PROBLEMS STUDIED 
While it is true that each step in the handling of a milking 
machine has an important bearing upon the quality of the milk 
produced, there are certain steps which are of maximum im- 
portance. In the years during which the milking machine has 
been under observation the aim has been to find the critical 
points where attention to details would bring the maximum re- 
turns for the minimum amount of effort on the part of the 
dairymen. The fact had been constantly kept in mind that it 
is the aim of the progressive dairyman to produce clean milk 
and to produce it with a minimum expenditure of labor. 
There is no question but that the point where the average 
user of a milking machine can make the maximum improvement 
at the minimum cost is by a careful attention to the keeping 
of the rubber parts in a solution of salt or some similar 
substance. 
Conditions where brine is not used.— The determining factor 
which has hindered the progress of the earlier types of milking 
machines was the inability to secure milk of a proper keeping 
quality. Harrison’ in his study of the Thistle milking machine 
found that the keeping quality of the machine-drawn milk was 
much inferior to that of milk drawn by hand. He also found 
that the germ content of the machine-drawn milk was about 
2See footnote ]. 
