206 BACTERIA IN MILK AND MILK PRODUCTS 



varying percentage,* but, as a rule, the milk coming in to the 

 cities from the country has contained more tubercle bacilli than 

 the milk obtained from the town cows. This characteristic has 

 been found to occur in London, Manchester, Liverpool, and other 

 cities. 



It should also be added that there are a number of cases on record 

 where the tubercle bacillus has been found in butter. 



The Virulence of the Tubercle Bacillus in Milk. Martin and 

 Woodhead concluded as the result of their investigations for the 

 Koyal Commission on Tuberculosis that tuberculous milk possessed 

 a high degree of virulence for man. Sir Eichard Thome held that 

 tabes mesenterica (alimentary tuberculosis) of children had not 

 declined as phthisis (pulmonary tuberculosis) had done in recent 

 years on account of the conveyance of the virus of tubercle in milk.f 

 If the occurrence of primary lesion in the intestine is indication of 

 infection through the alimentary tract, then it is instructive to notice 

 that of all the tuberculosis in children in this country about 25 per 

 cent, is alimentary in origin, and in 60 to 70 per cent, of the cases 

 the mesenteric glands are affected. Both of these figures deal with 

 deaths only, but as Kaw has pointed out, no doubt a number of cases 

 of alimentary tuberculosis recover, the infection having been mild. 

 Amongst 269 tuberculous children under twelve years of age whom 

 Dr Still examined post mortem, he found it possible to determine 

 the channel of infection with some degree of certainty in 216 

 cases. In 138 (63*8 per cent.) infection entered through the lung ; 

 in 63 (29'1 per cent.) primary infection occurred, in all prob- 

 ability through the intestine. Of children up to two years of ago 

 he found 65 per cent, contracted infection through the lung, and 

 22 per cent, through the intestine. In infants under one year of 

 age apparently only 13 per cent, contracted tuberculosis through the 

 intestine. { 



It is recognised that, owing to the great tendency to generalisa- 

 tion of tuberculosis in children, it is a matter of extreme difficulty 

 to determine which was, in fact, the primary channel of infection, 

 and this must be taken into consideration in estimating the 

 significance of the frequency in the above figures. It should also 

 be remembered that the tubercle bacillus may, and probably 



* In 1898, 14 per cent, of the milks examined in Berlin by Petri contained the 

 tubercle bacillus. In 1899, in Islington, the percentage was 14 '4; in 1893, St 

 Petersburg, 5 percent. ; in 1901, in London, 7 per cent. (Klein) ; in 1901, at Croydon, 

 67 per cent., and Manchester, 9'5 per cent. ; in 1902, at Woolwich, 10 per cent. ; 

 in Camberwell, 11 per cent. ; in the City of London and in Finsbury, nil. These 

 percentages must not be accepted as anything but passing figures and illustrations 

 of what various investigators have found under varying conditions. 



f The Administrative Control of Tuberculosis (Harben Lectures), 1899, pp. 5-7 

 and 28-32. 



$ Practitioner, 1901 (July), p. 94. 



