INFECTIOUS DISEASES OF CATTLE. 411 



the manner described, may become transformed into an abscess which 

 finally bursts to discharge creamy pus. The abscess 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 api>eared, and hang or project into 

 tin- cavity of the pharynx, either as pendulous masses with a slender 

 stem or as tumors with a broad base. 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 re- 

 garded as one of the most serious forms of the disease. (Plates xxxix, 

 Fig. 1, XLI.) It may start in the marrow of the bone and by a slow ex- 

 tension 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 externally as stink- 

 ing 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 destroy the bone from without 

 into. 



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

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

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

 be 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 aft'ected as in ordinary broncho-pneumonia 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 Plate XL, 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, 

 the-e were completely transformed into a uniformly grayish mass, very 

 soft and pulpy to the touch, and appearing like very soft and moist 

 dough. (Plate XL, Fig. 3.) The actinomyces 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 like- 

 wi.M resembled moist dough in their consistency, and the actinomyces 

 grains, though neither very distinct nor at all abundant, were easily 

 fished out and identified as such. A portion of this growth, which was 

 as large as a child's head, was converted into an abscess filled with 

 my semi-liquid pus. 



