502 
Moreover, good milk of safe quality can not be had without a real- 
ization on the part of the farmer, the transportation agent, the dairy- 
man, and the housewife of the danger in utilizing old. warm, or dirty 
milk. Education is therefore an important factor in the improve- 
ment of the milk supply, which can not be accomplished through laws 
and regulations alone. In view of these facts, it is recommended that 
the subject be taught in the schools, that popular articles be fre- 
quently prepared for the press, that lectures and demonstrations be 
given in towns and townships, that pamphlets in plain language be 
prepared by the health officer for general distribution, and especially 
that rules and suggestions, with reasons therefor, be placed in the 
homes of dairymen and dairy attendants. 
DISEASES WHICH MAY RENDER MILK DANGEROUS. 
TUBERCULOSIS. 
This is probably the most important disease of cows from the stand- 
point of public health, and it is also the most prevalent. When Koch 
first discovered the cause of tuberculosis and combined the announce- 
ment of his discovery with the statement that he considered the 
affection identical in both man and cattle, this view was accepted by 
scientists as well as by the general public. His subsequent announce- 
ment in 1901, to the effect that this disease was different in man and 
in cattle, and that there was no practical need for preventing the use 
of the products of tuberculous animals for human food, was the cause 
of much rejoicing among those who were only too glad to grasp at any 
idea which would tend to separate the disease in man and in cattle, 
forgetting that bovine tuberculosis is also a dangerous disease to other 
cattle in the herd and should be stamped out for this reason aside 
from any danger to man. 
As a result of this radical statement of Koch’s, which was based 
upon incomplete and unsatisfactory evidence, several government 
commissions w r ere appointed in different countries, and many private 
and public scientists immediately took it upon themselves to solve the 
question raised by that investigator. The results of these experiments 
were so strikingly similar that it is now the generally accepted opinion 
among scientists that people, especially. children, may become infected 
with tuberculosis from cattle. It is not known to what extent such 
infection occurs, nor is it possible to obtain any definite percentage 
by the method formerly adopted of looking for the primary lesions in 
the intestinal canal, although much statistical evidence is recorded, 
showing that even by these figures primary intestinal tuberculosis of 
children has been observed in as high as 45.5 per cent of the tubercu- 
lous cases examined (Heller). Evidence which must be considered 
conclusive has been obtained by the Bureau of Animal Industry, as 
