228 BACTERIA. 



the occurrence of any induration of the milk gland, " indeed," 

 he adds, " I may say that no veterinary surgeon could, during 

 life, have diagnosed the existence of tubercular mastitis 

 (tubercular inflammation of the udder) without the aid of 

 a microscope." That tubercle bacilli make their way into 

 the milk, when there is tubercular ulceration in the milk- 

 ducts, can be readily understood, and has frequently been 

 shown ; but it has also been demonstrated by Professor 

 M'Fadyean that in cases of tuberculosis, bacilli may be 

 found lying free in what are otherwise apparently healthy 

 milk ducts. Fresh evidence is being accumulated every 

 day, but these facts alone, when considered along with 

 the occurrence of bacilli in milk, with the feeding experi- 

 ments already recorded by so many observers, and taken in 

 connection with the great prevalence of tubercle 'in certain 

 classes of animals, afford strong presumptive evidence that 

 milk is a source of tubercular infection, especially in children, 

 and in those in whom, on account of imperfect nutrition 

 and impaired digestion, the walls of the alimentary canal are 

 less able to resist the invasion of the organism known as 

 Koch's Bacillus Tuberculosis. 



The danger of contracting tuberculosis from taking meat 

 from cattle affected with the disease is perhaps not so great 

 as that associated with the drinking of tuberculous milk ; 

 it is nevertheless one with which the sanitary authorities 

 will have to deal, and one to guard against which it is 

 necessary to take very considerable precautions. There can 

 be little doubt that in those cases where the disease is 

 localized to any one of the viscera at the time of the 

 death of the animal, there is little danger to be anticipated 

 from eating the well-cooked flesh from other parts of that 

 animal ; and if we could be absolutely certain that the 

 localization was complete, all would be well. Even in cases 

 where the flesh is taken from animals in advanced stages of 

 tuberculous disease there would be a certain proportion of 

 cases in which no evil results would follow, and one observer 

 who made sixty-two experiments with such flesh boiled for 

 ten or fifteen minutes, found that only 35.5 per cent, of the 

 inoculated animals became tuberculous. Even in cases of 

 generalized tuberculosis Nocard failed in thirty-nine out of 

 forty cases to transmit the disease by means of raw muscle 

 juice injected into the peritoneal cavity of guinea pigs, but 



