CONTAGIOUS PNEUMONIA. 1 95 



tracts of less inflamed, less hyperaimic and still permeable parenchyma. 

 Sections through these hepatised areas present a dry appearance, 

 though elsewhere a considerable quantity of frothy or sanguinolent 

 serosity escapes from the mouths of the bronchioles and vessels. 

 Where hepatisation is stilly more advanced the section appears dotted 

 with yellow, gre}', or greenish points, and presents a marbled appear- 

 ance resulting from the blending of these colours, which indicate 

 pulmonary gangrene. Little necrotic areas undergoing delimitation, 

 or already separated from the adjacent tissues, and bathed in greyish 

 or blood-stained pus, may be seen. The bronchioles, and sometimes 

 the bronchi themselves, are inflamed. 



In the lobar form the lesions extend to the greater portion of one 

 or both lobes. The non-hepatised tissue is more or less hypera^mic 

 and Arm, but not friable, becomes red on contact with air, and gives 

 exit to an abundance of blood-stained serosity ; the inflamed portion is 

 firm, smooth, or slightly granular on the surface, and varies in colour. 

 In the neighbourhood of the congested parts, that is to say in the last 

 affected layer, sections are deep red with greyish points and lines ; 

 around the bronchi, towards the inferior margin and anterior extremity 

 of the lung where the inflammation has longest existed, sections are 

 less dariv in colour ; they exhibit an entire scale of colours, varying 

 between pale grey and brownish yellow ; little grey or yellcrvv spots are 

 seen scattered over a brownish ground, indicating necrotic fragments, 

 some still in continuity with neighbouring tissue, some in process of 

 delimitation and already infiltrated with pus. Whether or not suppura- 

 tion exist, these necrotic spots always exhale a foetid odour, which is 

 absent froin areas of simple hepatisation. Finally, cavernous spaces of 

 all sizes between that of a small nut and of a man's fist ma}^ be seen. 

 Destruction of pulmonary tissue is sometimes very extensive. At the 

 post-uwrteni of a horse which died on the tenth day I found a large 

 cavernous space filled with sanious material in the anterior portion of 

 the right lobe. The pleura was thickened, much injected, and out- 

 wardly adherent to the thoracic wall from the second to the seventh 

 rib ; inwardly to the anterior mediastinum. The organs within this 

 mediastinum were glued together by abundant exudate. Furthermore, 

 in other portions of the lungs — particularly in the lower parts — similar 

 cavernous spaces, multiple abscesses containing creamy pus, and 

 necrotic areas were found. These lesions all contained many var}'ing 

 species of microbes. Bacteriological examination showed the presence 

 among others of strepto- and staphylo-cocci. 



The specimen obtained from our last case of pneumonia exhibited 

 lesions indicating various stages of contagious lobar pneumonia. With 



