248 The Trials of Milking Machines , 1913. 
This report therefore deals with the samples taken from the 
19th morning till the evening of the 23rd, when all the 
machines were at work except that machine N did not begin 
until the evening of the 19th. In order to make a comparison 
between machine drawn milk taken under the most favourable 
circumstances, such as existed at the trials ; hand drawn milk, 
and milk taken by a machine which was in constant use, three 
further sets of samples were taken. 
A. — On the afternoon of the 17th, when 48 cows were 
milked by hand and samples taken. These cows were, with 
few exceptions, those which were afterwards used in the trials, 
they had been groomed for several days in preparation for the 
trials and before they were milked their udders were washed ; 
the cans into which the milk was received had been steamed. 
The cows were divided into groups of four and the examination 
carried out on lines exactly similar to those observed during the 
trials. The conditions were clearly better than those found on 
an ordinary farm. 
B. & C . — Samples which were taken in the evening of the 
27th and the morning of the 28th. These were taken from 12 
cows in three sets of four, under the normal conditions existing 
at the farm. The machines used were those which had been in 
use for a considerable period. They had been steam sterilised 
on the 24th, and subsequently the tubes were washed each time 
after milking. The cans were steamed. This was in accor- 
dance with the custom at the farm to steam sterilise the tubes 
once a week. During the period of, the actual trials every 
opportunity was given to the competitors to wash and steam 
their tubes and cans twice daily. No other means of cleansing 
was allowed. After cleansing, the machines were locked up in 
a clean stone floored, white washed chamber ready for use next 
time. It is true some of the competitors did not make the best 
use of their opportunities but the conditions prevailing were 
undoubtedly better than are likely to be found on an average 
dairy farm. It may therefore be of interest to compare the 
bacteriological contents of the milks obtained with those found 
when the cows were milked by hand and those found when 
the cows were milked by an old machine under average 
ordinary conditions. In all cases the samples of milk were 
taken and examined on a similar plan. That is to say, as soon 
as each cow was milked a sample was obtained in a sterile glass 
stoppered bottle which was kept cool in ice. Proportional parts 
from each cow’s milking (there were four cows to each machine) 
were mixed together in a sterile flask, dilutions with normal 
saline were made and plates containing 10 whey gelatine were 
inoculated and incubated. A fresh sterile pipette was used for 
each stage of the procedure and the plates were completed 
