The excretion of an unusual quantity of alkaline phosphate is not, as far as I have been able to ascertain, productive of any definite symptoms, nor does it, as far as I am aware, result in any derangement of the health. An extra amount simply filters through the organism and escapes partly in the urine, and is partly discharged from the intestinal surface. When one considers the large amount of alkaline phosphates in wheat, in meat, and in other kinds of food habitually consumed, one wonders at remarks being made about the deficiency of phosphorus in the organism, and suggestions that this deficiency can be made up if phosphorus or some compound be taken as medicine or with the food. That phosphoric acid is useful in some disturbances of the digestive system I have no doubt, and that some phosphatic salts are of use in the treatment of certain disturbances of the health, is likely, but that phosphatic salts act by furnishing phosphorus to the nervous system is most improbable. There are, no doubt, circumstances under which a proportion of the alkaline phosphates present becomes decomposed, the phosphoric acid combining with calcium or magnesium to form earthy phosphates which may be held in solution in the blood and intertextural fluid, or may be precipitated in an insoluble form in the tissues; or finding its way into the urine in a state of solution, may be precipitated from that fluid, either before or after it has left the organism. In the former case the earthy salt may be deposited on the epithelial surface of the pelvis of the kidney, ureters, or bladder, causing grave disease of the mucous membrane, and leading to the formation of stone, or the establishment of disease of the mucous membrane; in the latter it forins a deposit in the urine, partly amorphous, partly crystalline, well known to all who are familiar with the ordinary urinary deposits. It has often been suggested, in cases where an unusual quantity of phosphatic salts are being carried off by the urine, that phosphate should be prescribed, but it is hardly likely any advantage can result from the proceeding. There is no defect as regards the mere quantity of phosphate in the organism, but D* the increased excretion seems to be due to some derangement of the processes by which the phosphates are taken up by the tissues which should contain them, or to an unusual activity of the changes by which phosphates are removed and ultimately excreted from the body. We should endeavor, therefore, to put right any derangement of digestion or assimilation of the existence of which we could obtain some evidence or indication, rather than pour in at one part of the body salts of the same kind as those which are being rapidly carried off from another. The earthy phosphates-phosphate of ammonia and magnesia, or, ammonio-magnesian phosphate, and phosphate of lime, or calcium phosphate, are referred to on page 104. URINARY DEPOSITS. The subject of urinary deposits must always be of interest to the practitioner, and it is of considerable practical importance. In consequence of the expansion of other departments of medical inquiry, less attention has been given to urinary deposits of late years than formerly, but as no one can successfully treat many forms of urinary disease, unless he is familiar with the characters of urinary deposits and acquainted with the methods, chemical as well as microscopical, of identifying them and demonstrating their exact nature, the practitioner should take every opportunity of studying the character of the deposits commonly found in urine in various cases of derangement and of actual disease. Considerable practice in the wards of the hospital and some patience are necessary for any one who would become familiar with the multitudinous forms of the substances which constitute urinary deposits. Far too little attention is now given by the student to practical work in this department. Looking occasionally at a few deposits mounted in Canada balsam is of little real service. Nothing short of examining a number of specimens of urine obtained in the wards will enable the practitioner to gain that confidence in his power of identification which he desires. The presence of a deposit in the urine is of itself evidence that the secretion is not in its perfectly normal or healthy state, for healthy urine contains all its constituents dissolved, and the only thing that approaches deposit is a trace of mucus which forms a flocculent cloud, which subsides to the lower part of the fluid after the urine has been allowed to stand for a time. The presence of some deposits in the urine may be taken as an indication either that the oxidizing processes are not duly performed, or that the materials to be oxidized are in unusual amount, in consequence of the food taken being in excess of the amount the system requires. 67 Although, as a general rule, our treatment of a case is determined by various circumstances taken in conjunction with the results of a careful examination of the urine, there are a few urinary deposits, just as there are certain morbid constituents dissolved in the urine in certain cases, by which the nature of the disease may be conclusively determined. Care must be taken not to allow the judgment to be influenced only by the character of the urine or the urinary deposit, for serious mistakes are sometimes made if the practitioner ventures to found a diagnosis exclusively upon one fact or upon a series of facts, instead of allowing his conclusion to be based upon everything that can be ascertained in connection with the case. Moreover, by concentrating his attention too exclusively upon one symptom or one special feature of disease, the student runs the risk of neglecting to take into account broad general facts of far greater consequence, and of thus making serious mistakes of both diagnosis and treatment. The experienced practitioner tries to grasp all the broad general features of a case, and in grave maladies he is careful to have well before his mind the tendency to death, before he allows his attention to be concentrated upon any one or two special matters which, although of some consequence, are probably of considerably less importance as regards the welfare of the patient than a thorough grasp of his pathological condition at the time, and of the changes which take place in his symptoms from day to day. For these and many other reasons that might be urged, it is important that while the great value of the careful microscopical and chemical characters of urinary deposits is fully recognized, the investigation of a case should not be limited to these methods, but the diagnosis grounded upon all the clinical facts of the case. Urine Opalescent from Insoluble Matter being suspended in it.Urine often appears opalescent in consequence of insoluble or very imperfectly soluble matter, in a state of extremely minute division, being evenly distributed through it So very minute are the particles which cause the opalescence, that few of them, and sometimes none, subside after the urine has been allowed to stand even for a considerable time. Many sub stances may cause the appearance in question. Among the least common forms of opalescent urine, is that which depends upon an admixture of chyle, known as "chylous urine." The fluid is white and opaque, and looks like milk to which a considerable quantity of water had been added. Fatty matter in an extremely minute state of division is suspended uniformly through the fluid in these cases. It will neither rise to the surface nor subside to the bottom, if the urine be left to stand for many hours. Opalescence may also be caused by the presence of multitudes of bacteria, which increase enormously as decomposition proceeds. Earthy phosphate also may be diffused through the urine, and cause it to be opalescent. Mucus from the urinary passages, perhaps, holding in suspension very minute crystals of oxalate of lime, is another cause of an opalescent appearance; but deposit which most frequently gives rise to an opalescent appearance of the urine consists of urates, which gradually pass into an insoluble form in a varying time after the urine has left the bladder. This deposit is instantly dissolved if a little warm water be added to the urine, or if the latter be exposed to a gentle heat. The particles themselves are excessively minute, many of them so small as to be only just visible under the highest powers. There is no indication of crystalline forms in the largest of them. 66 CHYLOUS URINE. Chylous" urine will not be seen many times by any physician in this country, even though he be in large practice. Most of the cases observed, it will be found, originated in the tropics, where the condition is by no means uncommon. The urine, as I have already remarked, looks as if a little milk had been added to it. Indeed, such " Indeed, such "chylous urine" is sometimes prepared for the purpose of deceiving us. The fact can, however, be at once determined by careful microscopical examination with a quarter of an inch object-glass, when the fat-globules of the milk at once come into view. In true chylous urine the matter in suspension which gives to the urine its whiteness and its opacity is fatty matter in an extremely minute state of division ; in fact, it is the so-called "molecular base" of the chyle which |