Actiiioiitycosis. 323 



clumps of fungi are always surrounded by leucocytes in the fatty 

 and granular detritus, sometimes, too, with here and there a giant 

 cell. About this central, softened focus proliferating fibroplastic 

 tissue is formed, vascular and full of emigrated leucocytes, as a 

 zone of varying width. 



Actinomycosis is primarily a local affection, rutming a course of 

 months or years in duration. As the fungi penetrate the lymph 

 spaces and are carried to new positions fresh eru])tions in multiple 

 foci of infiammation along the lymph vessels and in the lymph glands 

 arise, with purulent softening and coincident production of new 

 tissue in the soft parts and in the bones. By hgemic convection 

 also the process may become a general one, a number of organs, 

 bones, etc., becoming synchronously or one after another involved. 

 [In cattle one of the most common and characteristic results of 

 actinomycotic infection is that seen in involvement of the jaw, 

 which may well illustrate many of the features of the disease. The 

 infection here is supposed to take place by the penetration of a 

 small spicule of grass or beard of grain into the gum along 

 the root of the tooth, such a foreign element having upon it 

 the actinomycotic fungus. In unknown way die fungus penetrates 

 along the root well into the alveolar process of the jaw, and there 

 produces the small nodules above described, each undergoing cen- 

 tral softening and disintegration, and being surrounded by a zone 

 of new tissue formation at its periphery. Gradually the process 

 loosens the teeth; and as they are elevated in their sockets by the 

 inflammatory tissue, and chewing becomes painful, the animal 

 stops eating. Sometimes the teeth are forced up so tliat the animal 

 is unable to close the mouth without pain, and the teeth may even 

 be lost. The process gradually spreads throughout the alveolar 

 bone and into and through the whole thickness of the jaw, the in- 

 flammatory change about each nodule at first causing absorbtion 

 of the calcareous matter, and thus giving the fungi a chance to 

 spread in this softened tissue. As each nodule grows older, the 

 formative tissue at its periphery produces new bone : and from the 

 coincident operation of the two factors of bone destruction and 

 bone formation the jaw becomes enormously enlarged ("big-jaw"), 

 riddled with the small points of softening representing the different 

 actinomycotic foci and with fistulous paths running all through the 

 mass, connecting these points of disintegration. The jaw may thus 

 have developed wdthin and upon it a tumor-like mass the size of a 

 double fist or much larger, composed of a coarse framework of 



