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16
"natural way. In natural tuberculosis in the cow
"cases which show such obvious symptoms of the
"disease as emaciation and cough should be con"sidered
separately from the cases in which there are
"no such signs and in which the disease is to be
"recognised during life only by means of the injection
"of tuberculin."
"None of the cows investigated showed any sign
"of disease of the udder during life, and in all, after
"slaughtering, the udder was carefully examined for
"tuberculous lesions and tubercle bacilli. No tuber"culosis
was found except in one case in which one
"quarter of the udder showed four small nodules.
"These could not possibly have been detected during
"life. We found that the milk of the cows obviously
"suffering from tuberculosis contained tubercle bacilli
"whether the milk was obtained in the ordinary way
"or was withdrawn from the teat by means of a
"sterilized catheter. The presence of tubercle bacilli
"in the milk of cows clinically recognizable as tuber"culous
confirms the opinion we expressed in our
"second interim report that the milk of such cows
"must be considered dangerous for human beings."
"The experiments which we have carried out
"with regard to the infectivity of the faeces of tuber"culous
cows were dictated by knowledge of the fact
"that dirt of various kinds from cows and the cow"shed
is almost constantly present in milk as it
"reaches the consumer. Cows suffering from exten"sive
tuberculosis of the lungs must discharge con"siderable
numbers of bacilli from the air passages in
"the act of coughing and some of the bacilli thus
"expelled may find their way into the milk. But our
"experiments indicate that the excrement of cows
"obviously suffering from tuberculosis of the lungs or
"alimentary canal must be regarded as much more
"dangerous than the matter discharged from the
"mouth or nostrils. We have found that even in the
"case of cows with slight tuberculous lesions tubercle
"bacilli in small numbers are discharged in the
"faeces, while as regards cows clinically tuberculous
"our experiments show that the faeces contain large
"numbers of living and virulent tubercle bacilli."