13S 



Very forcibly of those of horses suffering from tlie puhnonary form of 

 horse-sickness. 



These mostly circumscript affections of the lungs are usually covered 

 smoothly by the pleura. The parenchym is compact, extremely elastic, 

 and heavier than water. In some cases it is also very friable. The 

 changes in elasticity are so variable that in some cases the affected parts 

 are soft and phable, in other cases so tough and hard that a distinct grating 

 sound is emitted on incision. A variable quantity of sanguineus fluid, 

 or of yellowish-reddish, slowly coagulating, serum-like liquid runs from 

 the section. 



On the surface of the cut appears the well-known appearance of 

 interstitial pneumonia, specific in such dimension for pleuro-pneumonia. 

 Broad, whitish-grey bands of connective tissue surround interlobularly, 

 interalveolarly, and peribronchially the consequitive stages of croupous 

 pneumonia. Such an appearance is described in pathologic anatomy as 

 " marbled." The name "pleuro-pneumonia marbling " is generally applied 

 on account of the thickened lymphatic vessels traversing the hepatised 

 lung tissues like the veins in marble. Large and small dark and light 

 lobuh group themselves to an artistic mosaic, not without regularity, 

 although the point of departure of the infection is often hard enough to 

 locate. It must be considered of importance that in 80 per cent, of 

 the specimens, the stage of dark red friable, or haemorrhagic, hepatisation 

 has been found. Blackish-red lobuli are seen in the tough, atelectatic 

 tissue, only rarely penetrated by thick, thrombotised blood vessels. The 

 surface of the sections is usually coarsely granulated. Close by one 

 invariably finds lobuh in the stage of grey hepatisation. I cannot say 

 that it is difficult to find such places, as Sussdorf states. Such groups 

 of lobuli are often in dry necrosis. They are dark brownish-grey, and as 

 compared to the other lobuli conspicuously dry. I do not find that they 

 are always surrounded by dark lobules in my material. One frequently 

 finds patches (from 1 cm. to 20 cm. in diameter) showing oedematous 

 infiltration, and immediately alongside of them patches in advanced 

 necrosis. It is reserved for experiments to show the reason of such 

 difierences. The primary condition (stage of " engouement") of the lobuli 

 is always found ; it is conspicuous that it is always arranged so as to 

 surround the dark red patches. Healthy lobules, or such with a slight 

 crackling oedema, are frequently interspersed among the diseased ones. 

 We possess specimens of lungs in which single dark red hepatised lobuli 

 are scattered on otherwise absolutely healthy tissue, but the expression 

 " absolutely healthy " must not be taken literally, because the inter- 

 stities are always somewhat enlarged and infiltrated. The older the 

 stages, the more frequent is necrosis and sequestration. It has been 

 demonstrated specific for pleuro-pneumonia that several lobuli, or even 

 a whole lobe, necrotises and becomes separated in consequence of a 



