MEASURES AGAINST INFECTION 389 



would prove a safeguard. All badly affected carcases would 

 then be condemned, and those slightly affected could be separately 

 dealt with and special precautions taken to eliminate tuberculous 

 pieces, etc. 



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 may gain access to 

 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 dis- 

 seminated 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 always 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 sterilisa- 

 tion has been recommended, but has disadvantages (see section 

 on "Milk"). The ideal method would be the elimination by 

 slaughter of all animals which are tuberculous. This was tried 

 in the State of Massachusetts ; 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. These measures were found to be un- 

 workable, the expense of compensation becoming formidable, 

 even in so small an area. A middle course seems to be the only 

 practicable one, viz. all manifestly tuberculous animals, especi- 

 ally 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 arid to be dis- 

 posed of (for slaughter) as soon as convenient, and in the mean- 

 while kept as much as possible in pasture. 





