224 BACTERIA. 



larger proportion of cases, even amsngst the poorer classes, 

 partially, at any rate, composed of cows' milk. During this 

 first year of their life, children with tuberculosis of the 

 mesenteric glands, or of those glands connected with the 

 intestine, form a very small proportion of the cases of infantile 

 tuberculosis. Whilst the child is suckled by its mother there 

 is little tubercle, but after this first year there is a very rapid 

 rise in the mortality from tubercle. It is a somewhat singular 

 fact that although tuberculosis is frequently met with in 

 young married women, tubercular disease of the breast is 

 extremely rare, so rare, indeed, that one observer, Dr. Huber- 

 maas, who took great interest in this subject, was able to 

 collect the records of only some eight cases. In cattle, on 

 the other hand, where the mammary gland carries on its 

 functions when the animals are placed under conditions 

 which are far from healthy, or at any rate far from normal, 

 this tubercular disease of the milk gland is not by any means 

 of infrequent occurrence. 



Some of the earliest experiments from which actual proof 

 of the infective nature of tuberculous material was obtained 

 were those made by Gerlach and Chauveau, who used the milk 

 of tuberculous cows to feed young animals ; though tubercu- 

 losis was not produced in every case, the former was successful 

 in a sufficient number to justify his conclusion that there was 

 some specific virus in the milk of tuberculous cows which 

 could, when ingested, produce tuberculosis of the alimentary 

 tract, or of the glands associated with it. Numerous experi- 

 ments on young pigs, some of them accidental, others de- 

 signed, and others on calves and hens, have been recorded, 

 in which tuberculosis has evidently followed their being 

 fed with tuberculous milk. At the International Medical 

 Congress held in Copenhagen in 1884, Professor Bang, of the 

 Royal Veterinary School in that city, gave the results of a care- 

 ful examination of twenty-seven cases of tubercular disease 

 of the udder in cattle, in the milk of which he was able to 

 demonstrate the presence of tubercle bacilli, both directly 

 under the microscope and in the sediment obtained by means 

 of the use of a centrifugal separator. With this milk, or with 

 the separated sediment, he was able to produce tuberculosis 

 both by inoculation and by ingestion. Another observer, 

 Nocard, was able to demonstrate the presence of the specific 

 bacillus in milk in eleven cases, and Professor M'Fadyean and 



