by straight lines; and thus a crystal very closely resembling that of an octahedron of oxalate of lime is produced. The urine which contains phosphatic deposits is generally neutral or alkaline, but crystals of triple phosphate are now and then found in acid urine.

If ammonia be added to fresh urine, or to a solution of phosphate of soda and sulphate of magnesia, ammoniaco-magnesian phosphate is precipitated in the form of beautiful stellate crystals ("100 Urinary Deposits," Pl. V, Fig. 58), and phosphate of lime is thrown down in the form of a fine granular amorphous precipitate. Ammoniaco-magnesian phosphate is slightly soluble in pure water, particularly if it contain carbonic acid. It is said to be insoluble in solutions of ammoniacal salts, but this statement is not, I think, accurate. Phosphate of lime occurs in urine in a crystalline form, as well as in amorphous granules. It is usually associated with the triple salt-always, if deposited from alkaline urine. In cases of disease of the bladder, in which the urea becomes very rapidly decomposed into carbonate of ammonia, much amorphous phosphate of lime and many crystals of triple phosphate are precipitated. Crystals of phosphate of lime are represented in "100 Urinary Deposits," Pl. V, Figs. 59, 60.

Phosphate of lime is soluble in albumên; indeed, it is by reason of its solubility in this substance that the phosphate of lime formed by the action of phosphoric acid on the egg-shell becomes applied to the formation of the osseous system of the embryo chick. Mucus also is a solvent of this salt, and from the mucus of the gall-bladder a considerable quantity is deposited as decomposition proceeds.

The conditions under which an excess of alkaline phosphates occurs, have already been considered on p. 64. The remarks made upon the question of "excess" of a constituent and its precipitation as a visible deposit, must be borne in mind. In the great majority of cases in which there is a deposit of earthy phosphates, there is no "excess" at all, and the deposition depends upon the urine being neutral or less acid than usual, or upon the decomposition of the urea, and consequently, the

F

formation of carbonate of ammonia after the urine has left the bladder. It is common enough to find triple phosphate in the urine in cases of dyspepsia, perhaps from the secretion of too large a quantity of highly acid gastric juice or from the formation of other acids.

A good deal has been said and written concerning the significance of a deposit of earthy phosphates in the urine, and I have even heard it suggested that the deposit showed not only that large quantities of the salts passed from the system, but that it was necessary to supply their place and thus compensate for the removal of phosphate from the organism. I remember a case in which phosphates were prescribed for the patient, who was suffering from typhoid, on the ground that large quantities were being excreted in the urine, and that, therefore, more should be given by the mouth, as if this excreting of phosphate was really a very important clinical fact in connection with fever. The physician was, in truth, troubling himself very needlessly about the phosphate, while he was neglecting to treat the low febrile state, which was of the utmost consequence. If we refine too much concerning the smaller and less important attendant phenomena of many forms of disease, we shall be apt to regard too lightly or to pass over the broad clinical facts of the case. While carefully directing our attention to the removal of comparatively unimportant symptoms, we may neglect to suggest remedial measures for the pathological changes which are jeopardizing, and may shortly destroy, the patient's life. The fact is, these earthy phosphates, consisting of phosphates of lime and magnesia and ammoniaco-magnesian phosphate, are always present in healthy urine in a state of solution, and if the fluid becomes alkaline, or if an alkali be added to the urine, the earthy phosphates are thrown down as an insoluble deposit, which is sometimes crystalline, but generally contains a certain quantity of amorphous phosphate of lime. In some cases, however, it has been shown that these earthy phosphates are actually excreted in more than the average quantity, when it may be advisable to give medicines containing these salts, or food in which they exist in considerable proportion. It must, however, be borne

in mind that bread and milk, and meat and fish of various kinds, contain considerable quantities of phosphates, and it is, I think, impossible to assent to the general proposition that the presence of these salts in excessive quantity is pathognomonic of any definite condition or morbid state, which can be relieved or even modified by giving them in quantity by the mouth. Their presence in excess is to be regarded as a fact which may accompany a number of conditions without having any causative relation to any one in particular.

The principal objection to be urged against the frequent presence of these deposits, is their tendency to form soft concretions in the urine, or to collect upon the surface of the mucous membrane. This depends upon the urine becoming alkaline, as explained on p. 28. In many cases, there is no doubt that by attention to diet and by giving mineral acids frequently during the day, in moderate doses, the deposition may be reduced or entirely prevented. Tincture of iron with free acid, and a grain or two of quinine three or four times daily, often has a beneficial effect; but a purgative treatment is also requisite in most cases. The obstinate persistence of phosphatic deposit should be attended to, the practitioner directing his mind to the consideration of the state of digestion and to the general condition of the patient, instead of concentrating his attention on the fact of the phosphate deposit only, and endeavoring to counteract the discharge or to make up for the loss.

In various cases of disease arising from more or less complete paralysis of the nerves, owing to changes occurring in the nervous centre itself, or at the distribution of the nerves in the mucous membrane, the action of the bladder may become impaired, and it may fail to expel its contents completely. The urine thus retained sometimes undergoes change, and the mucous membrane suffers in consequence. It has been supposed that the formation and excretion of large quantities of earthy phosphate was somehow due to degenerative changes in nerve matter, but this is probably not the source of the phosphates in these cases. In general there is not really an excess, but the urine being alkaline the earthy phosphate it contains is thrown down in an

insoluble form. Earthy phosphate is precipitated, and the condition thus induced gradually increases, unless proper preventive measures be adopted. There are cases in which phosphates are deposited upon every part of the urinary mucous membrane -bladder, ureters, and the pelvis of the kidneys-apparently depending upon changes which result originally from some affection of the nerves. Although the formation of epithelium and all the essential phenomena of nutrition and secretion may take place independently of nervous action, it is quite certain that the regularity of these changes, the even flow of nutrient pabulum, and the regulation of the proper proportion distributed, are determined by the nerves. Hence, it follows that if the nerves distributed to a structure be destroyed, or their action impaired, directly or indirectly, the tissue soon suffers, its structure becomes altered, and its function is imperfectly performed or suspended. Such changes in the epithelium precede and favor the deposition of the phosphates upon the surface.

Some of the cases of disease of the bladder with phosphatic deposit, perhaps the great majority, are due to local change. The condition known as chronic inflammation, affecting one part of the mucous membrane, is very prone to spread. It may extend from urethra to bladder, and even into the ureters and pelvis. A rough, almost ulcerated state of the mucous membrane may also spread in the opposite direction; beginning in the kidneys, it may pass downward to the bladder. In all cases, the urine in contact with any portion of such altered surface would be decomposed, and its earthy phosphates precipitated. These, with the epithelium and mucus of the part, would form irregular projections with intervening depressions, in which more urine would be decomposed; and so the process might proceed, unless the nutritive changes taking place below the surface return to their normal condition, when the matter deposited would soon be thrown off, the even growth of new, healthy epithelium would proceed below, and the surface would again assume its smooth, healthy character. For this reason, in such cases, it is of the first importance to pay attention to the general health, for it is obvious that if the blood be in an

unhealthy condition, the action and nutrition of the nervecentres will suffer. Until this is corrected, the normal state of the mucous membrane cannot be restored.

Disease of the mucous membrane, and impaired action of its muscular coat, may also result from lesions of the central part of the nervous system, and some of these cases are among the most distressing which the physician is called upon to treat. The affection may begin in the nerve cells of the posterior roots and those of the cord itself. These gradually undergo change, and may cease to act, or the nerves arising from them may be pressed upon or degenerate in structure at some distance from their point of origin. Over such chronic structural changes, when firmly established, we can exert little influence by remedial agents.

On the other hand, I have seen cases in which earthy phosphates have been constantly present in every specimen of urine passed during several years-without any disorganization of mucous membrane of the bladder, ureters or pelvis, and without the formation of stones or any form of concretion. In these cases the reaction of the urine was decidedly, but not very strongly, alkaline. The phosphates were in an amorphous state, but after standing for several hours crystals of phosphate of lime were deposited (“ 100 Urinary Deposits," 1884, Pl. V, Fig. 60). In the case of some of these patients the formation of phosphatic calculi undoubtedly occurs, but in others it is quite certain the condition is due to functional disturbance of the digestive process only-the patient being, for the most part, weak and thin, and in what may be called a low state of health; various plans of treatment have been devised and tried, but occasionally the condition persists in spite of every attempt to alleviate it by ordinary remedies. In these cases, living in the open air in a good climate must be recommended, with complete change for a time in the usual routine of life. A sea-voyage usually does good; the appetite improves, and the patient may gain many pounds in weight. But return to sedentary work in a town is too often followed by a return of the low state of health and the feebly alkaline phosphatic urine. Very likely the patient