ACTINOMYCOSIS. 441 



cavity, however, does not disappear, but is soon filled with fungus- 

 like growths, which force their way outward through the opening. 



When the tumors are situated within the cavity of the pharynx 

 they have broken through from some gland, perhaps beneath the 

 mucous membrane, where the disease first appeared, and hang or 

 project into the cavity of the pharynx, either as pendulous masses 

 with slender stems or as tumors with broad bases. Their position 

 may be such as to interfere with swallowing and with breathing. 

 In either case serious symptoms will soon appear. 



The invasion of the bones of the jaws by actinomycosis must be 

 regarded as one of the most serious forms of the disease. (Pis. 

 XXXIX, XL.) It may start in the marrow of the bone and by a 

 slow extension gradually undermine the entire thickness of the bone 

 itself. The growth may continue outward, and after working its 

 way through muscle and skin finally break through and appear ex- 

 ternally as stinking fungoid growths. The growth may at the same 

 time work its way inward and appear in the mouth. The disease 

 may also begin in the periosteum, or covering of the bone, and de- 

 stroy the bone from without inward. 



Actinomycosis of the lungs is occasionally observed, and it is not 

 improbable that at times it has been mistaken for tuberculosis. The 

 actinomyces grains are, however, easily observed if the diseased tissue 

 is carefully examined. The changes in the lungs as they appear to 

 the naked eye vary considerably from case to case. Thus in one 

 animal the lungs were affected as in ordinary bronchopneumonia as 

 to the location, extent, and appearance of the disease process. The 

 affected lobes had a dark-red flesh appearance, with yellowish areas 

 sprinkled in here and there. (See PL XLI, figs. 1, 2.) These latter 

 areas were the seat of multiplication of the actinomyces fungus. In 

 another case, of which only a small portion of the lungs was sent 

 to the laboratory, they were completely transformed into a uni- 

 formly grayish mass, very soft and pulpy to the touch, and appear- 

 ing like very soft and moist dough. (PI. XLI, fig. 3.) The ac- 

 tinomyces grains were exceedingly abundant in this tissue, and 

 appeared when the tissue was incised as minute sulphur-yellow grains, 

 densely sprinkled through the tissue, which readily came away and 

 adhered to the knife blade. In still another case a portion of the 

 lung tissue was converted into large, soft masses from 1 to 3 inches 

 in diameter, each partly inclosed in very dense connective tissue. 

 These soft, grayish-yellow masses likewise resembled moist dough in 

 their consistency, and the actinomyces grains, though neither very 

 distinct nor at all abundant, were easily fished out and indentified as 

 such. A portion of this growth, which was as large as a child's head, 

 was converted into an abscess filled with creamy semiliquid pus. 



