226 Veterinary Medicine. 



pneumonia shows a circumscribed area of inflammation and indu- 

 ration with the Hquid pus in the centre immediately surrounded 

 by a vascular (limiting) membrane. Abscess may be single or 

 multiple though in the latter case it is commonly a symptom of 

 pyaemia. 



In gangrene of the lung the part may be in the dried condition 

 of an eschar ; it may indicate gangrene only by its altered color, 

 its flaccidity, its fetid smell and the altered appearance of all its 

 microscopic elements ; it may be denoted by a putrid softening, 

 the tissue easily breaking down into a stinking pulp of mixed fi- 

 brous and granular materials ; or lastly there may be merely a 

 cavity with traces of putrid contents, the dead mass having been 

 detached, disintegrated and expectorated. 



Modifications of the Blood aiid Distant Organs. 



A marked feature of pneumonia is the destruction of red blood 

 globules. This is early indicated in the staining of the visible 

 mucosae by the liberated haemaglobin and by actual count they may 

 be reduced in the horse from 7,500,000 to 6,000,000 per cubic 

 millimeter (Trashot). There is an increase of white globules, an 

 absolute increase, not only in ratio to the red. The haematoblasts 

 are enormously increased especially during defervescence. The 

 fibrine (fibrine formers) is materially increased ; in the horse from 

 3.5 to 6.7 or 7.5 per 1,000 (Grehaut). Albumen is diminished. 

 Soda salts are increased. The bronchial lymphatic glands are al- 

 ways congested, swollen and reddened with some serous effusion. 

 They may become the seat of inflammatory cell growth (embry- 

 onic tissue) or even of suppuration. The abscess may open into 

 the bronchia or pleura. These are especially to be dreaded from 

 their tendency to implicate the inferior laryngeal nerve and induce 

 roaring. 



Pleurisy is inevitable when the inflammation reaches the sur- 

 face of the lung, hence hydrothorax is often present. Pericardi- 

 tis and hydropericardium are similarly met with. Endocarditis is 

 occasionally present and may be traced to strain of the valves of 

 the laboring heart, or to direct infection with the pneumonia mi- 

 crobe. Dilatation of the right ventricle is common as a result of 

 the obstructed pulmonary circulation. 



