XVIII PREVENTION OF TUBERCULOSIS 331 



County in which the dairy is situate, previous notice in 

 v^riting of his intention to enter such dairy for the purpose 

 of inspecting the cows kept therein. 



These special powers have been in force in Manchester 

 since 1900 and in other cities for considerable periods, so that 

 it is possible to obtain an estimate as to how far they have 

 succeeded in attaining the objects for which they were framed. 



These Milk Clauses require notification by dairymen of all 

 cases of udder tuberculosis among cows in cowsheds sending 

 milk into the city, and prohibit the sale of milk from such 

 cows within the city. They give powers for collecting milk 

 samples and additional powers of inspection for cowsheds 

 within the city. Their essential and characteristic feature is, 

 however, the power of inspection which they give of cowsheds 

 and cows supplying milk into the city, although themselves 

 outside, whenever the city authorities suspect milk from such 

 farms to be tuberculous. The inspection can be followed up 

 by prohibiting the infected milk from being supplied within 

 the city as long as it is dangerous. 



The effectiveness of these powers may be considered from 

 several points of view. 



(a) Their Influence upon the Prevalence of Tuhercle Bacilli 

 in the Milk supplied to the City enforcing them. — The following 

 table shows some of the results obtained. 



[Table 



