BACTERIAL EVIDENCE 215 



the whole total of 9576 cows, the milk of which was tested for 

 tuberculosis, or among which cows with tuberculous udders were 

 detected by clinical examination, it was found that a total of 52 

 had tuberculous udders, which gives an average percentage of 054. 

 This percentage, if uniform throughout England, would yield on the 

 total number of cows and heifers in milk (approximately 2,000,000) 

 some 10,000 tuberculous udders.^ Professor McFadyean, in agree- 

 ment with many other authorities, is of opinion " that about 2 per 

 cent, of the cows in the milking herds in this country are thus 

 affected," ^ {i.e. have tuberculous udders). Not confining ourselves 

 to udder disease, it may be said about 25 to 30 per cent of all 

 milch cows in this country suffer from tuberculosis. So much for 

 the clinical examination of the cow.^ 



Bactepiologrical evidence. — If we now study the available 

 returns in relation to this subject as obtained by bacteriological 

 examination of milk as placed on the market, we arrive at much 

 the same conclusions, except, of course, that we find, owing to 

 obvious reasons, the percentages of diseased milk are much higher 

 than those of diseased cows. At the time of the first clinical 

 examination of cows in London cowsheds (1899), only one cow 

 was found in the district of Hackney to have a tuberculous udder. 

 In the same district yj samples of milk were taken, 17 of which 

 (or 22 per cent.) on bacteriological examination were found to con- 

 tain the tubercle bacillus.* Such a result might, of course, con- 

 ceivably be due to the milk of one infected udder being widely 

 distributed. But it was subsequently shown that 13 out of these 

 17 tuberculous samples of milk were derived from milk shops 

 supplied from country farms and not from Hackney cowsheds, 

 and even the other 4 samples were obtained at shops receiving 

 part of their supply from country sources. This discrepancy is 

 but an illustration of the marked difference which has been found 

 to exist between town and country milks. For example, in the 

 seven years 1896- 1902 in the city of Liverpool, 1 1 19 samples of town 

 milk were examined bacteriologically, and 23 samples contained 

 the tubercle bacillus, giving a percentage of 2-o. In the same period 



' Transactions of the British Congress on Tuberculosis, 1901, vol. ii., p. 294. 

 In 1901 there were 1,887,414 milch cows in England, 4,102,061 in the United 

 Kingdom, and 18,000,000 in the United States of America. 



2 Ibid., vol. i., p. 84. 



' For clinical methods, see Rep. Roy. Com. on Tuberculosis^ 1896, part iii., 

 pp. 1-8. 



* Report of MecUccd Officer to London County Council^ 1899, p. 52. 



