It is a comparatively easy matter to omit substances from the diet that are injurious on account of the creatinin they contain. The mother substance of creatinin, namely, creatin, is present only in meat extracts, meat broths, etc.; in white of egg, in the yolk of egg, and in milk it is present only in traces; it is completely absent from vegetables. If all articles of diet containing creatin are eliminated from the bill of fare the urinary creatinin is reduced to a minimum in healthy subjects. The small quantity that continues to be excreted is probably derived from the creatin contained in the musculature of the patient. These small quantities amounting to a few centigrams a day can of course not be kept away from the kidneys.