Without laying too much stress on such results, it is worth while to say that, whereas most workers might be willing to surmise that metabolic or catabolic disorder must affect the sense of well-being, I must confess that the discovery of so much gross kidney disease in a group selected on other grounds filled me with a certain surprise. The literature is not without suggestions as to the possible correlation of renal and mental disorder. Ziehen,[8] for example, remarks that nephritis brings about mental disease in two ways,--through vascular changes which very frequently accompany chronic nephritis and other uremic changes in the blood. Inasmuch as we know that creatin, creatinin and potassium salts irritate the animal cortex, Ziehen notes that psychopathic phenomena may occur in man as a result of slight uremic changes. According to Ziehen, most of these nephritic psychoses run the course of what he calls hallucinatory paranoia (it may be remembered that Ziehen counts among paranoias a number of acute diseases and even so-called Meynert's amentia). Chronic nephritis, as well as acute diabetes and Addison's disease are thought by Ziehen to produce certain chronic forms of mental defect which he terms autotoxic dementia, but he regards most of these cases as really cases of arteriosclerotic dementia. It does not appear that Wernicke[9] has considered renal correlations systematically. Kraepelin[10] mentions the epileptiform convulsions of uremia as well as delirious and comatose conditions, especially those in advanced pregnancy. These uremic conditions may be both acute and chronic. But Kraepelin has not been able to convince himself of the existence of a clearly defined uremic insanity unless the delirious condition just mentioned may be regarded as such Binswanger[11] states that the mental disorders occurring in acute and chronic nephritis are either toxemic psychoses on uremic bases, or due to arteriosclerosis. In the latter cases, he states that the disease pictures are as a rule characterized by grave disturbances of emotions, chiefly of a depressive character. He adds that these are all too frequently the forerunners of arteriosclerotic brain degeneration.