DISEASES OF THE OX AND SHEEP. 271 



matory origin, and it increases as the fungus itself spreads 

 locally, and even in distant parts. 



The tumours themselves are generally roundish, smooth on 

 the surface, sometimes hardish, and sometimes soft in consistence. 

 They are generally of a greyish or yellowish white hue, but not 

 uncommonly assume a darker colour. On their surface one 

 often finds a number of small yellow nodules, and these, it may 

 be pointed out, not being found in other growths, are a reliable 

 sign as to the nature of the disease. 



Johne found in twenty out of twenty-one healthy pigs he 

 examined that the actinomyces was present in the little crypts of 

 the tonsils. Now, why does not the fungus cause actinomyces 

 here ? It is believed that the fungus is pretty widely distri- 

 'buted, but that unless its spores gain access actually into the 

 tissues, through a wounded or abraded surface, it does not set 

 up the disease. 



We have said that actinomycosis is especially common in the 

 mouth, and it seems indeed extremely probable that the spores 

 eaten with the food gain such access through slight injuries of 

 the lining membrane of the mouth, caused by the food, such as 

 straw, barley, and chaff. It has been noticed, too, in Lincoln- 

 shire, where the disease is very rife indeed, that the malady is 

 especially common in animals fed on straw, barley, and chaff. 

 But no doubt many other kinds of food oftentimes wound the 

 mouth. Why do they, therefore, not cause actinomycosis ? Our 

 Teaders are aware that straw is often very mouldy, and infected 

 with vegetable parasites of countless kinds ; and thus the same 

 straw which causes the abrasion, implants the spores of the 

 fungus which sets up the disease. 



It has been demonstrated that the disease can spread from one 

 animal to another ; indeed Johne showed this by actual experi- 

 mental demonstration. When an ox is so afiQicted in his tongue, 

 no doubt he conveys the disease to others feeding in the same 

 crew-yard on the fodder provided for all. There is related the 

 •<5ase of a woman who was attacked with actinomycosis. She 

 had been often among sick cattle, and had no doubt become thus 

 infected. Yet it is probable that the transmission of the disease 

 ^om one animal to another, or to man, is rather uncommon. 

 No doubt the animals derive, as a rule, their infection from one 

 •common source. 



