446 CONTAGIOUS PLEURA-PNEUMONIA 



soon follows. Such animals may disseminate the virus for a 

 long time without being suspected and for that reason are the 

 most dangerous of all. 



A more severe type is commonly seen. The cough is fre- 

 quently more or less painful, the back somewhat arched and 

 the milk secretion diminished. These symptoms increase, the 

 appetite is affected, the animal loses flesh, the breathing 

 becomes more rapid, the cough more painful, pressure of the 

 fingers between the ribs produces evidence of tenderness, the 

 hair loses its gloss and stands erect, the skin becomes adher- 

 ent, the temperature rises to 103 to 105" F. Animals thus 

 affected may continue to grow worse and die in from three to 

 eight weeks or they may after a time begin to improve and 

 make an apparent recovery. The inflammation of the lung 

 does not, as a rule, subside and the organ does not return to 

 normal condition as in ordinary pneumonia, but with this dis- 

 ease the life of the affected portion of the lung is destroyed, the 

 tissue dies and a fibrous wall is formed around it to shut it 

 away from the living parts. The tissue, thus encysted, gradu- 

 ally softens, becomes disintegrated into a purulent-like sub- 

 stance. The recovery, therefore, is only partial. 



By those accustomed to examining the lungs of cattle, 

 other and extremely important symptoms may be detected 

 during the course of the disease. By auscultation an area of a 

 certain extent may be found where the natural breathing 

 sound is diminished or entirely lost. This represents the dis- 

 eased portion of the lung. In other cases a loud blowing 

 sound may be heard, quite different from any sound produced 

 when the lung is in a healthy condition. In some cases 

 crepitation is heard near the border line of the diseased area 

 and friction sounds produced by the roughened pleura may be 

 detected. By percussion an area of dullness may be discov- 

 ered corresponding to the portion where the respiratory mur- 

 mur has disappeared. This loss of respiration detected by 

 auscultation and the dullness brought out by percussion are 

 the most important evidences of an area of inflamed or con- 

 solidated lung. 



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