The endothelium of the corneoscleral trabeculum is an important part of the filtration apparatus of the human eye.1-4 Minute details of structure and pathology are valuable, since they may eventually help to understand, prevent, and treat glaucoma. In this paper a new technique is introduced to demonstrate the trabecular meshwork with its endothelium and the supplying nerve fibers. The examination of the trabeculum of the normal eyes of a small child confirmed the findings of earlier authors. The studies of the trabeculum of eyes with two different types of angle closure following cataract surgery revealed extensive atrophy of the endothelium and changes of the trabeculae. The present paper represents my first report on the pathology of the chamber angle. More papers on this subject are intended. The reported findings are given with a short clinical description of the cases used for the demonstration. This is necessary, since this paper