TUBERCULOUS MILK 321 



Tuberculous milk also raises many important points. Probably 

 some 10-15 per cent, of all samples are infective to guinea-pigs, but 

 this does not necessarily indicate that this proportion would be 

 dangerous to man, for the material is introduced into the guinea- 

 pigs by inoculation after concentration by centrifuging (see also 

 section on " Milk "). Tubercle bacilli are present in milk not only 

 when the udder is tuberculous, but also when the cows are suffering 

 from tuberculosis elsewhere which is clinically recognisable. Thus, 

 when the lungs are affected, bacilli are disseminated from the air- 

 passages and also by the faeces. It is noteworthy that the incidence 

 of abdominal tuberculosis in young children occurs just when cow's 

 milk is the staple article of their diet. At the same time this 

 incidence does not seem to fall on those who consume most milk. 



Much might be done by the registration of all dairy premises, 

 the use of selected cows, the elimination of all tuberculous animals, 

 and by enforcing the inspection of dairy cattle by competent 

 inspectors at suitable intervals. The notification of all forms of 

 udder disease is now compulsory. In the absence of inspection 

 and the use of selected cows, treatment of milk intended for the 

 food of infants and young children by pasteurisation or sterilisation 

 has been recommended, but has disadvantages (see section on 

 " Milk "). The ideal method, and one which commends itself at 

 first sight as being the most satisfactory, is the elimination by 

 slaughter of all animals which are tuberculous. This was adopted 

 in the State of Massachusetts ; under an order of the Board of 

 Cattle Commissioners all beasts in the State were tested with 

 tuberculin, and every animal that reacted was slaughtered, and 

 strict quarantine combined with the tuberculin test imposed on all 

 imported cattle. Even in this small State such a plan was found 

 to be unworkable, the expense of compensation becoming formid- 

 able. A middle course seems to be the only practicable one, viz. 

 all manifestly tuberculous animals, especially where wasting or a 

 tuberculous udder is present, to be slaughtered ; other animals to 

 be tested with tuberculin, and those which react to be separated 

 from the healthy and to be disposed of (foi slaughter) as soon as 

 convenient, and in the meanwhile kept as much as possible in pasture. 



Avian tubercle bacilli have occasionally been met with in man. x 



Tuberculosis is diminishing among the white races ; it is, how- 

 ever, spreading among many coloured races. It is to be noted that 

 the decline began long before the germ origin had been demonstrated, 

 and, what is more, the rate of decline was almost as great before 

 any administrative measures were taken against it as since. Never - 



1 Lowenstein, Wien. Klin. Woch., May 15, 1913. 



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