MILK AS A FACTOR IN THE CAUSATION OF DISEASE. 
109 
so that really no milk from such cows as he experimented with 
should be on the market. 
In Dr. Ernst’s cases 36 cows were experimented with, and 
the bacillus was found in the milk of 12 of these 36. 
In the first series of experiments 88 guinea pigs were inocu¬ 
lated with milk from 16 of these tuberculous cows, and the milk 
from only six of these cows was found capable of producing the 
disease, and only 12 of these 88 guinea pigs became infected. 
2d series—90 rabbits were inoculated with milk from 19 
different tuberculous cows. The milk from only 4 of the cows 
produced the disease, and only 6 of the 90 rabbits became infected. 
3d series—48 rabbits were fed with milk from 5 tuberculous 
cows and only 2 became diseased, both being fed with milk from 
the same cow. 
Practically, then, when these well marked cases gave no 
greater results, it would seem that with the exclusion of these 
advanced cases, the milk would be harmless, unless the udder 
was affected. This seems to have been the opinion of the Royal 
Commission appointed by the British Government to consider 
the matter. It is also the opinion of such able authority as 
Prof. Theobold Smith, late of the Bureau of Animal Industry. 
In the Year Book of the U. S. Dept, of Agr. he says : 
“ We may, for convenience and clearness, typify those 
stages :— 
u 1 st. In the earlier stages of the disease, provided the udder 
is normal, the milk is free from tubercle bacilli. 
“ 2d. In the more advanced stages, provided the udder is nor¬ 
mal, the milk may or may not contain tubercle bacilli. If the 
disease has become generalized, the indications are that at some 
time or other, tubercle bacilli may pass into the milk. This 
passage is revealed at autopsy by disease of the glands of the 
udder. The indications are that this passage is largely tempo¬ 
rary, perhaps lasting only a day before the bacilli are caught up 
and filtered out into the lymphatic system. 
“ The indications are, furthermore, that comparatively few 
bacilli pass through the udder. The udder itself does not favor 
