The Trials of Milking Machines , 1913. 
249 
within three hours of the milking. The plates were counted 
until no fresh colonies appeared, or until liquefaction took 
place. In no case were they counted fewer than three times. 
It should be remembered that the samples from the hand 
milked cows were only taken on one occasion and that in the 
afternoon. They should therefore be compared with after- 
noon machine milkings and the figures obtained should not be 
too literally accepted. The milks, however, are sufficiently 
interesting to be included in the report. 
Hand milked ; one 
Machine Trials. 
occasion, 12 groups of 
Average of 5 days after- 
4 cows each. 
noon specimens. 
No. of organisms per c.c. 
No. of organisms 
2,000 
per c.c. 
1,000 
410 
1,500 
718 
1,500 
732 
1,000 
1,044 
4,000 
1,408 
1,500 
2,266 
2,000 
3,338 
1,000 
3,706 
6,500 
4,242 
4,000 
7,188 
6,000 
48,938 
Total 32,000 
Total 73,990 
Average 2,666 
Average 6,727 
It is seen that six of the machines averaged less than the 
hand drawn milk and five of them averaged higher than the 
hand drawn milk. 
There is no doubt that the average of the machine drawn 
milk is greatly increased by the presence of one machine which 
was bacteriologically consistently bad throughout the trials and 
finally gave an average of 48,938 organisms per 1 c.c. It is 
doubtful whether it is fair to exclude this machine, but even if 
it be done, the general average still stands at 2,500 organisms 
per 1 c.c., which is very little better than the hand drawn, or if 
the worst hand drawn milk be excluded to compensate for the 
exclusion of the worst machine drawn milk, the averages 
work out at hand drawn 2,318, machine drawn 2,500, the 
hand drawn being thus 182 organisms per 1 c.c. better than the 
machine drawn. 
One further point remains for consideration before the 
keeping qualities of the samples and the report upon the 
individual machines are considered and that is the fact that 
except in the case of one machine all the machines gave a 
better bacteriological content at the afternoon milkings than 
they did in the mornings. 
