Introduction
Progressive mental deterioration associated with increasingly severe neurologic deficit is a clinical picture which not infrequently confronts the pediatrician. After infection, brain tumor, or subdural hematoma have all been ruled out, the diagnosis of "Schilder's disease" or "diffuse sclerosis" is usually made in the belief that this represents a definite clinical and pathologic entity.The problem of separating the various diseases that are commonly included under these terms is an important one. First it must be recognized that diseases of totally different natures are grouped together simply on the basis of superficial clinical similarity without paying proper attention to distinct differences in the pathologic observations. Once this is done, eugenic counselling to parents of such unfortunate children can be made easier and more exact. There is evidently a need for classification of such diseases, which, in the absence of knowledge about exact etiologic agents, must be based upon neuropathologic