Anatuiuical Cliauges. 



639 



to be found. The centers are, as a rule, the size of a pea only 

 (Fig. 87), but exceptionally they may be as large as a hen's 

 egg (Friedberger). The larger ones are softer than the sur- 

 rounding tissue and sometimes pultaceous in consistency, and 

 their cut surface is, as a rule, somewhat gelatinous and translu- 

 cent in appearance. Very small lesions that are not hemor- 

 rhagic escape recognition with the naked eye, because they are 

 not different in color or consistency. In many cases there is a 

 pronounced tendency to hemorrhage so that the surface of the 

 brain, the walls of the ventricles, or the cut surface appear lie- 

 set with reddish-brown hemorrhagic spots varying in size from 

 mere points to areas of considerable size (acute hemorrhagic 

 encephalitis). These large hemorrhages are rarely of even 

 color throughout, but have a variegated appearance owing to 

 the presence of small hemorrhages round about them. In the 

 latter stages the centers become yellow in color owing to de- 

 struction "of the blood pigments. Should the animal survive, 

 a cvst forms owing to the absorption of the detritus, or there 



Fig. 87. Area of inflammatory softening of the most anterior portion of the right 



half of the medulla oblongata in a dog. The animal showed rolling movements to 



the right. In the diagram on the right a indicates the pons, b the trapezoid body, 



and c the position of the section. 



may be a scar formed. Should the area of inflammation be near 

 the ventricle of the brain, or involve the venous plexuses, a more 

 or less reddish turbid fluid collects in the ventricles (acute 

 hydrocephalus internus). Areas of inflammation near the sur- 

 face of the brain may lead to the production of extensive or 

 circumscribed patches of meningitis. 



The hemorrhagic form of the disease occurs more fre- 

 quently in the horse than in the other species. Encephalitis 

 due to distemper rarely causes hemorrhages and if present they 

 are unimportant. The hemorrhages found by Brusso & Galli- 

 Valerio were single. Marek has observed a single case of soft- 

 ening of the brain in distemper. 



Histological investigations were made by Dexler. Encephalitis in cases of 

 distemper has been investigated by Krawjesky, Brusso, Galli-Valerio, Lienaux, 

 and more recently by Marchand, Petit & Coquet, and Pecard. In the eases in 

 which there were no hemorrhages Dexler found perivascular and other cellular in- 



