INFiaTIM-: CRANULOMATA. 357 



quently cljiained from vegetation, especially wild rve (llor- 

 dium niuriiuim) consumed l)v the animal. Infection occurs most 

 frequently in animals fed on dry feed as fodder, stover, straw or 

 hay. During January and February, VJ08 .S()% or 376 cattle of 

 41,400 slaughtered had actinomycosis of the tongue or submax- 

 illary hmph nodes, and of 12,484 cattle slaughtered in Julv, 1908, 

 44 or :M^/o were affected with actinomycosis. Some rather exten- 

 sive outbreaks ha^•e been investigated in which it seems highly 

 probable that infecti(.m has been direct from one animal to an- 

 other, or indirect b}- means oi the discharge of actinonnci itic ani- 

 mals that had been smeared on rubbing posts, feed racks and feed 

 troughs. {Oi 9S head of cattle, three of which \\'erc actim im\-cr.)tic 

 when placed in the feed lot in Nn\-eml)er, -l"i head were affected 

 with actinomycosis when inspected 'V 'j; months later.) 



Channel of Entrance. — The causati\c fungus mav gain en- 

 trance into the system by way of the digestive tract, the res]iira- 

 tory tract or through the skin. Abraded stu-faces appear to be 

 essential for infection, though it has not been proven that the 

 fungus cannot penetrate uninjured surfaces. The digestive tract 

 is the most frequent channel of entrance in cattle. The tongue, 

 especially the dorsal surface at the junction of the base and apex, 

 is subject to injury bv the rough, harsh food consumed bv cattle. 

 Tongue injuries mav also be inflicted b^• licking Itoards, posts. 

 etc., containing nails and splinters. Awns of wdieat, l)arle\- and 

 rye, chaff, splinters and hair accumulate in the erosions nr wnunds 

 of the tongue, producing the so-called "hair sores."' More than 

 12% of 48,000 cattle slaughtered during the winter months in one 

 of the Kansas Citv packing houses had "hair sores" upon their 

 tongues. The "hair sore" is intimately associated with lingual 

 actinomycosis: indeed it is rare to find actinomycosis of the 

 tongue or submaxillary Ivmph glands when there is no "hair 

 sore." Diseased teeth, especialh- if the gingival mucous mem- 

 brane is involved, also provide an entry for the ray fungus. The 

 possibilit}' of the infection passing through the intestinal or 

 gastric wall explains the ca.ses of peritoneal actinomycosis that 

 are occasionally observed 



Respiratory infection is not of common occurrence. This type 

 of infection probably occurs by inhalation of chaff' or awns con- 

 taminated with the Cladothrix actinomyces. 



The skin is probably the most frequent channel of entrance 

 in hogs. Actinomycotic scirrhus cords are quite common, the in- 

 fection taking place in the castration wound. Mammary acti- 

 nomycosis is sometimes observed in sows, especially those run- 

 nincr'in stubble fields, the infection taking place through abra- 



