MILKING MACHINES Le] 
very small, as in experiments Nos. 533, 540, and 586. In many 
of the tests the difference in germ content of the hand and 
machine drawn milks is very marked. The average for the 
whole series shows that the machine samples contained about 
one-third the number of bacteria that was found in the hand 
drawn milk. It is quite evident from these experiments 
that the air drawn into the machines carried in a great many 
bacteria and was doubtless the cause of the high numbers in 
the previous experiments where the machines were sterile. 
| In order to be sure that the cotton filters were the cause of 
the greatly decreased germ content, another series of tests 
was made where the conditions were the same, except that 
the cotton filters were omitted. The results are given in 
Table 34. It was found that in most cases when the filters were 
not used, the germ content of the machine milk was decidedly 
higher than that of the hand drawn milk in the majority of 
previous experiments which have been given. In these ex- 
periments, the machines were found to be completely sterilized 
by the formalin treatment, so that the larger germ content 
was not due to the condition of the machines. It seems evident 
from these results that the large germ content was due to the 
bacteria drawn into the milk from the stable atmosphere. 
ERE VAST TREATMENT. OF THE MACHINES. 
Lime water is supposed to be a good antiseptic and in some 
degree at least a germicide. One series of experiments was 
made where the rubber tubes and teat: cups were treated with 
a lime water solution, the other part of the treatment of the 
‘machines being the same as in the other tests. 
The experiments given in Table 35 will indicate the results 
obtained by this treatment. It was found by testing the tubes 
that considerable numbers of bacteria remained in them from 
one milking to the next in spite of the careful washing. Some- 
times several thousand bacteria were found per cubic centi- 
meter in the water with which the tubes were rinsed. 
It will be seen that the machine drawn milk normally con- 
tained many more bacteria than the milk drawn by hand, the 
difference being much greater in the experiments in this table 
than in those where the tubes were treated with formalin, all 
other conditions being similiar. While the lime solution would 
not be objectionable so far as its effect upon the wholesome-’ 
ness of the milk is concerned, it is evident that it is not at 
all satisfactory as a means of sterilizing the tubes. So far 
