The purpose of this paper is to call attention to some of the more important physiologic and pathologic factors and principles underlying infection of brain tissue and to detail a method of treatment which in my hands has proved satisfactory. In an effort to do this I shall not go into the problems of etiology and symptomatology but shall confine my remarks to a brief summary of the operative and postoperative course in four cases chosen to illustrate three types of disease of the brain-traumatic disease, acute abscess and chronic abscess. I shall quote from textbooks excerpts which I think have a bearing on the method of drainage of abscess of the brain with which this treatise is concerned.
Case 1.—W. F. S., a man about 35 years of age, was injured on May 4, 1925, by a piece of 1 by 1 inch (2.5 by 2.5 cm.) lumber driven