MORBID ANATOMY 345 



may contain but little air. There may be areas of collapse or 

 those abnormally filled with air. The inflammatory foci of 

 the lungs are usually consolidated. In very young animals 

 there may be a fibrous exudate which is very soft and which 

 readily liquifies. The hepatization frequently involves an 

 entire lobe. The hepatized parts are frequently studded with 

 small suppurating foci, or are diffusely infiltrated with pus. 

 The plura over the affected parts is often inflamed. The 

 bronchial glands are swollen or infiltrated with a serous fluid 

 or with pus. 



In the digestive s}-stem, the mucous membrane of the 

 stomach and intestines, especially that of the small intestine, 

 is hyperemic and swollen. It may be covered with a tough 

 mucus and often sprinkled with hemorrhages. In other cases 

 it is very pale, swollen and easily torn. Frequently the con- 

 tents of the intestine are blood stained and the mesenteric 

 glands enlarged and cedematous. 



The brain is anaemic and often there is a serous effusion 

 into the lateral ventricles and subarachnoid spaces. In a few 

 cases there are signs of a purel}' venous, cerebral hyperemia as 

 for instance, great congestion of all the sinuses, venous plexuses 

 and vessels of the pia and the appearance on the cut surfaces 

 of the brain of numerous blood points which can easily be 

 wiped off. Kolesnikoff found microscopically the brain sub- 

 stance, especially the walls of the vessels, infiltrated with 

 leucocytes. Krajewski noticed dilation of the vessels, cellular 

 infiltration of their walls, filling of the perivascular spaces with 

 lymphoid cells and migration of lymphoid cells into the stroma 

 of the brain and into the protoplasm of the ganglionic cells. 

 The changes in the spinal cord, which are not well marked, 

 consist chiefly of anaemia and slight oedema especially in the 

 lumbar region. Mazulewitsch states that in acute paralysis 

 there are changes in the walls of vessels with an exudate along 

 the vessels and in the interstitial tissue of the gray matter of 

 the spinal cord. In chronic distemper, there is a localized 

 interstitial myelitis with partial atrophy of the cord. Hadden 

 found groups of emigrated blood corpuscles in it. In severe 

 cases, according to Trasbot, the spinal cord and its membranes 



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