That there is still far from unanimity of opinion in regard to the degenerations and inflammations of the kidney is evident from a perusal of the literature. No classification is perfectly satisfactory, but Addis1 has given us to date one of the most workable of all the clinical classifications. Also the interpretation among writers of any complicated kidney disturbance is far from being uniform. This state of affairs is not recent. It was this uncertainty and fogginess of conception of the kidney diseases which led von Mueller2 in 1905 to separate the apparently degenerative from the evidently inflammatory lesions. His terminology, nephrosis and nephritis, has not passed into current medical terminology without criticism from many quarters, chiefly among his own German colleagues, Aschoff,3 Löhlein4 and others, but gradually it has gained in favor until, now popularized by Volhard and Fahr,5 Lichtwitz,6 Munk7 and others, it evidently has come to stay.