INFECTIOUS DISEASES OF CATTLE. 433~- 



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 pro- 

 ject into the 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- 

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

 XLIII, fig. 1.) 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 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, 

 inward. 



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 affected 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 PI. XLII, 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 were sent to 

 the laboratory, these were completely transformed into a uniformly 

 grayish mass, very soft and pulpy to the touch, and appearing like, 

 very soft and moist dough. (PI. XLII, 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 inelosed in very dense connective tissue. These soft,, 

 grayish-yellow masses likewise resembled moist dough in their consist- 

 ency, and the actinomyces grains, though neither very distinct nor at. 

 all abundant, were easily fished cut 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 creamy semiliquid pus. 



This case differed from the preceding in that all appearance of lung- 

 tissue had disappeared from the diseased mass. Only on the exterior 

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