118 



COMMON DISEASES. 



mistaken for tuberculosis. The lung symptoms, as seen on ex- 

 amination postmortem, vary so much that it is rather difficult to 

 describe them. Sometimes the lungs resemble those seen in ordi- 

 nary broncho-pneumonia. In other cases considerable areas of 

 the lung tissue is changed to a gray mass, soft to the touch. In 

 still other cases there are developed distinct abscesses. 



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I 



FIG. 45. ACTINOMYCOSIS— LUMPY JAW. (M. H. R.) 

 Note the enlarged jaw and the raw, granulating tissue exposed. 



This disease is usually of slow development. A small swell- 

 ing appears somewhere about the head, perhaps under the tongue ; 

 or the bones of the face near the teeth begin to bulge slightly out- 

 ward and the enlargements continue very slowly. The animal 

 may remain thrifty for a long time or indeed until the disease in- 

 volves the teeth, tongue or other organs and interferes directly 

 with nutrition. 



Prevention. — There is so little known concerning the life 

 history of the parasite and the methods of infection that a study 

 of prevention can be only partially satisfactory. It is generally 

 agreed that animals develop lumpy-jaw only after inoculation, i. e.. 

 the germs find entrance through some cut or scratch in the skin; 



