The most obvious and striking microscopic changes in the brain consisted of hemorrhages around the ves-sels of the olfactory bulb, brain-stem, medulla and cord. Infiltration of the perivascular sheaths and spaces due to mononuclear and polymorphonuclear cells was variablein intensity." Cuffing" of the veins and arteries was definite in the advanced cases of the disease. Scattered patches of infiltration in the gray and occasionally in the white matterwere common. The distribution of the inflammatory foci differs from that commonly seen in typical Borna disease. Nuclear inclusions of the character described as typical of Borna disease by Joest and Degen were absent. In-filtrations in the lumbar plexus, semilunar and other peripheral ganglia suggest a wide distribution of the virus.

Blood cultures prepared from 10 horses were sterile while the spinal fluid of 11 horses sacrificed or dead on account of encephalomyelitis gave cultures of haemolytic and non-haemolytic streptococei. Certain sections of the brain of a few horses (4 out of 10) contained the same organisms in small numbers. They were non-pathogenic for rabbits and horses on sub-dural and intravenous inoculation. They were con-sidered secondary invaders without etiologic signifi-