130 MILK AND THE PUBLIC HEALTH CHAP. 



The following figures from the Transactions of the British Congress 

 on Tuberculosis (1901), vol. iv., may be quoted in connection with 

 this estimate. Stockman examined 1312 cows and found 28 with 

 lesions of the udder. The cows were slightly selected, so this 

 percentage was probably too high. " However, I do not think it is 

 much below 2 per cent." Sir J. McFadyean concluded that probably 

 2 or 3 per cent of the cows in the country have tuberculosis of the 

 udder. Nocard remarked, " Tuberculous mammitis is a rare lesion, 

 and not seen in more than 2 per cent of tuberculous cows." Dewar 

 remarked, " Increased experience leads me to believe that the 

 number of tuberculous cows affected with tubercle of the udder is 

 greater than that usually estimated, i.e. about 3 per cent. Apart 

 from cows that are only recognised as tuberculous through the 

 action of tuberculin, I think the percentage would be from 5 to 7." 



On the other hand, Penberthy x thinks this estimate of 2 per 

 cent of tuberculous udders in cows is too high. He mentions that 

 in the county of London there are about 4000 cows kept, and about 

 12 cases of mammary tuberculosis are discovered annually (0'3 per 

 cent), while 3 per cent of the cases of tuberculosis in cows 

 slaughtered at Islington have tuberculous udders, and taking 25 

 per cent as representing the proportion of tuberculous to non- 

 tuberculous cows, this works out at 0*75 per cent. He quotes 

 other figures from Glasgow, Sheffield, Leeds, and Liverpool. It is, 

 however, probable that in large towns with rigid inspection cases 

 of udder tuberculosis would be promptly sold out of the town, and 

 this selective action would also in part operate as regards animals 

 sent in for slaughter. 



In Chapter XVIII. p. 333, the actual percentage of cows found 

 by the Manchester and Sheffield veterinary inspectors is given for 

 a, number of years. 



Dr. Hope 2 records that, during the years 1901-9 inclusive, 

 4919 cows in cowsheds outside the Liverpool city boundaries were 

 examined. Of these, 104 ( = 2'1 per cent) cows were suffering 

 from or suspected to be suffering from tuberculosis of the udder. 

 It is not explained, however, what exact proportion of these cows 

 were definitely proved cases of udder tuberculosis. 



Sir Shirley Murphy 3 gives the following figures : 



Last 6 months 1908. 1909. 



Outside London farms inspected * 190 439 



Number of cows examined . . . 4997 11,004 



Number of cows with tuberculous udders 147 219 

 Percentage of cows found to have clinical 



symptoms of tubercular disease of the 



udder 2'9 1-98 



1 Jonrn. Royal Institute of Public Health, 1907, vol. xv. p. 577. 



2 Annual Report, Liverpool, 1909, p. 184. 

 3 Annual Reports, London County Council, 1903 and 1909. 



