178 THE -DISEASES AND DISORDERS OF THE OX. 



pneumonia of long standing, and also in cases of sporadic pleuro- 

 pneumonia of oxen, but in neither of these instances is it so 

 well marked as in contagious pleuro-pneumonia of oxen. 



In animals which have only reached the first stage of the 

 disease, the tissue which binds together the lobules of the lungs 

 is seen to be chiefly involved. This tissue in the interior of the 

 lung is continuous with that which surrounds the organ under- 

 neath the covering called the pulmonary pleura; and it forms, 

 «o to speak, a supporting framework by which the lung is held 

 together, and divided into lobules. These partitions, or rather 

 walls, between the lobules are called " interlobular bands." Now 

 these bands, or rather walls, of the lobules (for it is only in sec- 

 tions that they look like bands) are impregnated with a yellow 

 :fluid called serum in different parts of the substance, generally 

 towards the centre, of one or both lungs. Now the *' marbled 

 appearance " results from the existence here and there in the 

 tissue of the lung of dark red or purple areas engorged with 

 blood-discs, fibrine, &c., separated by these "interlobular 

 bands." 



The latter are really walls of lobules, but on section they 

 naturally appear like hands. They vary in breadth from one- 

 twelfth to one-third of an inch, are greyish or yellowish, being 

 sometimes streaked with blood. These interlobular bands are 

 engorged with fibrin, which seems to have been deposited owing 

 to the distension of the lymph-vessels which are contained in 

 them. In accordance with the progress of the disease, these 

 bands become thicker and firmer, and sometimes they may be so 

 greatly stained with blood that several lobules may seem to be 

 united to form one patch of congestion. Here and there, too, 

 the lung-tissue may be but little affected by disease. Small 

 groups of lobules or single lobules may be invaded, and those 

 parts which are affected are not necessarily contiguous, this in- 

 flammation being in this respect like the pulmonary inflammation 

 brought on by glanders in the horse. 



In accordance with the degree to which the disease has pro- 

 gressed, the products of the abnormal processes may be absorbed, 

 ■or may form new tissue, the air-cells disappearing. The affected 

 lung-tissue, which was at first brownish-red in colour, gradually 

 becomes filled up with fibrine or coagulated lymph. Portions of 

 the lungs which have thus undergone fibrous degeneration are 



