406 



ACTINOMYCOSIS 



FIG. 161 



tumors. It is claimed that the ray fungus itself never leads to suppu- 

 ration and that pus appears only after the inflammatory tissue has 

 secondarily become invaded by pyogenic microorganisms. In cattle 

 the disease generally begins at the head, and the lower jaw is the part 

 which is apparently first affected, but actually it is the posterior part 

 of the tongue, the region of the papillae circumvallatse, which is 

 primarily affected. This region has generally been found infected 

 in every case of actinomycosis of the head, and even when lumpy 

 jaw had not yet developed, careful microscopic examination has 

 frequently shown invasion of the tongue. 



The most common tongue affection in cattle is in the form of 

 ulcerations on the back of the tongue; the loss of substance is either 

 round, oval, or band-like in shape. The margins of the ulcers are 



elevated, irregular, and ragged. 

 These ulcers are frequently 

 covered by hairs and vegetable 

 fragments. If a section is made 

 through the ulcerated surface, 

 grayish-white nodules are seen 

 extending into the muscular 

 portion of the organ. These 

 actinomycotic foci contain a 

 greenish-yellow, tenacious, sticky 

 material in which may be seen 

 grayish, yellowish, or brownish 

 granules, presenting masses of 

 the fungi. Sometimes the tongue 

 contains fistulous tracts. In 

 other cases the surface and the 

 muscular substance of the tongue 

 shows a smaller or larger num- 

 ber of nodules, of peanut to hazel- 

 nut size. These have sometimes broken through the surface and then 

 exhibit sharply defined openings. When such actinomycotic nodules 

 have existed for a long time the connective tissue of the tongue is 

 much increased and the organ much enlarged and very tough and 

 hard in consistency, often as hard as a board. This is the so-called 

 wooden tongue of actinomycosis. 



In the maxillary bones the disease arises from the alveoli of the 

 teeth or from the periosteum. When the alveoli are the starting 

 point of the infection the normal bone gradually becomes replaced 

 by a soft, sarcoma-like mass, and while bone substance becomes 

 necrotic and is more or less removed new bone is simultaneously 

 formed by the periosteum in consequence of an osteoplastic (bone- 

 forming) inflammatory process. The new-formed bone may again 

 be broken through by the granulomatous masses and these may 

 protrude externally through the skin, or internally into the cavity of 



Actinomycosis. Section of granulation tissue 

 of jaw of cattle. Carmin stain, Gram gentian 

 violet. X 400. (Author's preparation.) 



