The importance of the study of urology has of late been more fully realized by Medical practitioners, and M. Demange in his thesis (_Thése de Paris_, 1878) has undertaken to give a full account of the progress of this branch of medical science, being also fortunate enough to be able to enrich it by several new or very little known observations on azoturia. The latter seem the most interesting part of his thesis; we give them here briefly. The normal quantity of urea which must be contained in the urine in the space of twenty-four hours is from nineteen to fourteen grammes. If more or less is excreted, this is caused either by some local or general affection. Some years ago, Bouchard, in studying the causes of loss of flesh in patients suffering from diabetes insipidus, discovered that a large number among them lost an enormous quantity of urea. Having thoroughly examined their symptoms he thought himself fully justified in describing azoturia as a special disease, having peculiar clinical symptoms. The affection begins with a sensation of ravenous hunger, polydipsia or profuse sweating. The thirst is excessive, and the urine passed is generally in proportion with the quantity of drink swallowed by the patient. Its density is from 1000 to 1002. In order to be able to calculate justly the amount of urea lost in twenty-four hours, all the urine passed in twenty-four hours, all the urine passed in this time must be kept and mixed. In some cases it has reached the amount of eighty-seven grammes, a most enormous quantity, which proves that nutrition is very much impaired. Senator Kien and M. Bouchard have shown that what is called extractive matter is eliminated, corresponding to urea in such cases, and that chlorates and phosphates are ejected in a similar proportion. We must, therefore, not be astonished if the patients present general symptoms which are analogous to those of diabetic patients, with the exception of the visual troubles of the latter. Both the crystalline lens and the retina remain intact, and the sight is only influenced by the anæmic state of the brain, which is caused by the dyscrasia, and which in certain cases produces a torpor of the intellect verging on imbecility. As in cases of diabetes mellitus and albuminuria, sometimes the quantity of urea decreases, and even falls below the normal amount. In order to be able to make an exact diagnosis, it is necessary to examine carefully, both the urea and the other excreta, for several days consecutively. As a rule, persons attacked by simple polyuria, or who are suffering from interstitial nephritis, beginning with polyuria, do not present the symptoms which we have enumerated.