Changes in the brain resulting from an abscess necessarily vary with the type of the infection, its virulence and duration. The changes consist not only of a localized suppuration that has replaced some of the tissue of the brain, but also of reactive phenomena around the abscess. The contiguous areas either may remain intact or may exhibit more or less severe changes, depending on the intensity of the reactive phenomena. This is shown mainly as a capsule formation which checks or walls off the pus. As the reactive phenomena in young abscesses are less advanced, their membranes are also less complex and more favorable for histologic studies. The opportunity to carry on such studies presented itself in the two following cases, one cerebellar and the other cerebral
REPORT OF CASES
Case 1.—Clinical History (Dr. Bassoe).
—A white woman, aged 52, admitted to the Presbyterian Hospital on Nov. 9, 1924, had