394 INFECTIVE DISEASES. 



of large tumours, mostly with central cretification. Tubercular deposit 

 in the intestines could be recognised from the outside, and on laying 

 them open the mucous membrane was found to be studded with tuber- 

 cular ulcers. These ulcers were most numerous in the large intestine, 

 and varied in size from a sixpence to a florin. Some were circular, others 

 slightly irregular in form, and others again distinctly oval. In the latter 

 case they were generally situated with their long diameter transversely. 

 The base of the ulcer involved the muscular coat, and was irregularly 

 radiated. The margin was broad, and elevated above the general surface, 

 producing a ring-like appearance. 



Mammary Gland. — The udder was infiltrated throughout with tuber- 

 cular new growth, but the invasion was most marked in the posterior 

 quarters. There was apparently very little tendency to caseation. 



Microscopical Examination of the Udder. — In order to study the histo- 

 logical characters of the gland, and the distribution of the bacilli, sections 

 were stained with logwood and rubin, and others again with fuchsine 

 and methylene- blue. The tubercular new growth consisted of the usual 

 histological elements, round cells, epithelioid cells, and giant cells. 

 Healthy lobules here and there were sharply marked off from those in 

 which the growth was compressing and obliterating the alveoli in its 

 progress. Bacilli were present in the giant cells, and also distributed in 

 vast numbers throughout the tubercular tissue generally. Bacilli were 

 found in epithelioid cells close to the alveolus, and also between the cells 

 lining the alveoli. In parts also the new growth had involved the milk 

 ducts, and therefore it was easy to account for the presence of the bacilli 

 in the milk. 



The bacilli were found in considerable numbers also in sections of the 

 intestinal ulcers. 



Experimental Infection of Rabbits. 



Ingestion. — A rabbit received the contents of a test-tuhe which 

 had been filled with milk from one of the posterior teats, mixed with 

 a small quantity of bran. In four weeks there was commencing 

 emaciation ; later, diarrhoea set in, and death occurred exactly fifty- 

 eight days after administration of the milk. At the post-mortem 

 examination the mesenteric glands were found to be much enlarged 

 and caseous. A cover-glass preparation from a crushed gland 

 revealed numerous tubercle bacilli. On opening the intestines there 

 was a patch of ulceration, showing the point of acce.ss of the bacilli. 

 The intestinal ulceration was a reproduction, to a certain extent, of 

 the condition in the cow which had been the source of the virus. 



Subcutaneous Injection. — A second rabbit was injected under the 

 skin of the back by means of a capillary pipette with about ten 

 drops of milk, including some of the deposit from the bottom of the 

 test-tube. The sample of milk had in this case also been taken from 



