xviii PREVENTION OF TUBERCULOSIS 335 



The actual figures for Manchester are given in the preced- 

 ing table, which was compiled by Dr. Niven. 



These tables show that the percentage of farmers sending 

 tuberculous milk to Manchester varied from 5-79 to 13-6, 

 the average being S'G. Except for 1908 there has been a 

 steady, though not very marked, decline since 1903. In 

 other words, there has probably been a moderate but steady 

 diminution in the number of farms with cows suffering from 

 open tuberculosis sending milk to Manchester. 



As regards udder tuberculosis the table shows no per- 

 centage diminution in either Manchester or Sheffield. In 

 Sheffield during 1909 the veterinary inspectors found as 

 many as 42 cows with tuberculosis of the udder out of about 

 3600 cows stalled in Sheffield city. 



Finding these cases of udder tuberculosis cannot be 

 considered as playing any effective part in the diminutidn of 

 iovine tuberculosis. The elimination of a certain number of 

 cases of open tuberculosis in cattle is no doubt some check 

 upon the spread of bovine tuberculosis, but the number of 

 cases eliminated is so small in proportion to the total bulk 

 of infectious matter in the country that the influence exerted 

 must be trifling. During nine years' work at Manchester 

 232 cows from country areas and 9 from city cowsheds, and 

 during eight years at Sheffield 74 country cows and 134 from 

 city cowsheds, suffering from udder tuberculosis, were found, 

 obviously a nearly negligible factor in the spread of the 

 disease in cattle. In addition any beneficial effects are 

 further reduced by the fact that not all these cows with udder 

 tuberculosis are slaughtered. The following table shows what 

 became of most of the Manchester and Sheffield cows found to 

 be suffering from udder tuberculosis or marked general tuber- 

 culosis : 



