518 Messrs. Twort and Ingram. Isolating and [Nov. 7, 



in animals which are less than a year old. It often appears in pregnant 

 cows, and becomes aggravated after calving. 



On post-mortem examination the lesions are found to he confined to the 

 bowels and the surrounding lymphatic glands. The mucous membrane of 

 the small intestine is seen to be very much thickened — in some cases it 

 may be three or four times the normal. It is thrown into characteristic 

 folds or corrugations, and may show areas of congestion. The large intestine 

 and caecum often present the same lesions. The affected glands are enlarged 

 and oedematous, but show no caseation. 



Scrapings taken from the thickened mucous membrane, and stained by 

 Ziehl-Nielsen's method, as a rule show enormous numbers of acid-fast 

 bacilli, though in some cases they are less numerous, and in others may be 

 very difficult to discover. 



In sections of an affected intestine the bacilli are found to be most 

 numerous near the surface, i.e. towards the lumen of the bowel, but they 

 are also found in the villi and in the deeper layers. The increase in 

 thickness is seen to be due to the formation of new connective tissue. " The 

 tissue is filled with large epithelioid cells, surrounded by small round 

 lymphatic cells, and in some cases with giant cells " (B. Bang). 



The presence of an acid-fast bacillus, not to be distinguished micro- 

 scopically from the tubercle bacillus, in the thickened mucosa of the bowels 

 of cattle suffering from chronic diarrhoea, was first shown in 1895 by Johne 

 and Frothingham (1), who considered the condition to be a form of tuber- 

 culosis, and with them Koch was in agreement. 



In 1881 J. Hansen and P. H. Nielsen, of Holland, pointed out the 

 thickening and corrugation of the mucous membranes of the intestines of 

 certain cattle dying from chronic diarrhoea, whilst Hurtrel d'Arboval, in 

 1826 (' Diet, de Med. et de Chirurg. V^t.'), under the head of chronic 

 enteritis in cattle, described conditions which might well have been due to 

 the micro-organism now known as Johne's bacillus. Bouley and Beynal do 

 not seem to have recognised it as a special form of enteritis (' Diet, de 

 Chirurg., M&l., et d'Hygien V&.,' 1860). 



The disease is prevalent in many countries. Van der Sluys(3) and 

 Markus(5) have described its occurrence in Holland, Lienaux and van 

 den Eeckhout(7) in Belgium, B. Bang (14) in Denmark, and Borgeaud (8) 

 in Lausanne. 



Johne described the first case in Dresden, and Bongert (12), Meissner (33), 

 and others have reported many further cases in Germany. Freger (13), 

 Matthis (15), and Lechlainche (18) in France, and Home (24) in Norway, 

 have also recognised and conducted experimental work on this disease. 



