It is not unlikely that irritation of the extremities of sensory nerves other than the pneumogastric may become the cause of reflex glycosuria. Even puncture of the floor of the fourth ventricle itself may be reflex in its operation, the roots of the pneumogastric being thus irritated. The effect of the irritation conveyed to the glycogenic centre is to inhibit the usual tonic influence of the vaso-motor nerve upon the vessel walls. Among the experimental irritations, in addition to puncture of the floor of the fourth ventricle, which produce glycosuria by reflex action, are injuries of the cerebral lobes and cerebellum, optic thalami, cerebral peduncles, pons varolii, middle cerebellar peduncles, and even of the sciatic nerve and brachial plexus; whence it may be inferred that pathological irritation in the same situations may result in a glycosuria, which is temporary or permanent according as the irritation is temporary or permanent. Finally, there is no reason why an inhibitory reflex action should not originate in the sympathetic itself. When we remember that this nerve is both sensory and motor in function, and that the inhibitory influence to which the heart's action is subject is accomplished through the sympathetic as a sensory nerve and the pneumogastric as a motor, there is no reason why similar results may not be brought about by the sympathetic alone. This being the case, we need not ascribe glycogenic phenomena to irritation in Eckhard's sense--that is, to a direct stimulant action of the irritant upon the vaso-motor nerves of the liver--but may suppose a sensory influence to ascend one set of sympathetic filaments and an inhibitory influence to descend through another. Dr. Pavy has recently put forward some chemical theories which explain the action of the hyperæmia in producing glycosuria, but they do not account for the hyperæmia itself. In healthy digestion the carbohydrates (starch and sugar) are converted, not into glucose, but into maltose, C_{12}H_{22}O_{11}, dextrin being intermediate in composition. Maltose is absorbed and assimilated, converted into glycogen. So, too, when glucose is ingested as such, it is converted by the glucose ferment into maltose in the stomach and intestines. For the proper production of maltose and its assimilation a good venous blood, producing a maltose-forming ferment, is necessary. In diabetes, in consequence of the dilatation of the arteries of the chylopoëtic viscera, the blood enters the liver too little deoxygenated, and a glucose-forming ferment is produced. The glucose thus formed is not assimilable, but passes off into the circulation and the urine.