The author propounds the theory that the Koch bacillus, by its metabolism, produces end-products that in pathogenic action and chemical characterization are closely related to ptomaines. The exaggerated oxidation produced by these compounds, it is said, is mainly responsible for the wasting away of the tissues of the tuberculous patient. For the discovery of the metabolic end-products of the tubercle bacillus in the urine the author has developed chemical tests that are described in detail. The positive outcome of these reactions makes possible the diagnosis of urotuberculosis. The author, however, makes the reservation that so far his general deductions are of an experimental character only.