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sparkling like diamonds, are also not unfrequently observed. Crystals of the triple phosphates (Fig. 4) are frequently met with, but not as often as those of uric acid and urate of ammonia. Pus globules (Fig. 7) are occasionally present, alone or along with the crystals above enumerated. Turbidity of the urine, and the subsequent deposit, may be owing entirely to pus, in which case pus globules alone occupy the field of the microscope. Blood corpuscles (Fig. 8) are also seen in urine containing blood.

The information which the microscope thus throws on the nature of urinary deposits, and on their pathological importance, is invaluable, and can be replaced by no other means of investigation. A microscope of ordinary power, one that magnifies about three hundred times, is all that is wanted, and a practical acquaintance with the principal salts and morbid products which it reveals may be acquired in a few hours.

The presence of these morbid salts in the urine, when it is only observed after digestion, and merely for a limited time, may be considered to principally denote the existence of imperfectly-elaborated chyle in the blood; although it may also be the result of deficient vital assimilating or nutritive power. The kidneys are then acting the part of emunctories, of

filters, purifying the blood of chyle which is unfit for assimilation. When the urate of ammonia deposit is found in the urine at all times and seasons, independently of the digestion of food, it is, as has been stated, that a still more advanced state of defective nutrition exists. Not only is assimilation defective, but organic molecular disintegration, or the normal destructive metamorphosis of tissue, is also defectively carried on.

It is probably from the same cause that we find an abundant deposit of urate of ammonia taking place during the latter stage and the convalescence of fevers, and of various inflammatory diseases. The functions of nutrition have been thoroughly impaired, and the digestion of food has been all but at a standstill. The patient has been disintegrating his nitrogenous tissues without repairing them, and absorbing and burning his fat and carbonaceous tissues to keep up the organic combustion, or animal heat. Thence the blood is loaded with waste materials, imperfectly transformed, which are eliminated by the kidneys in the shape of an abundant urate of ammonia deposit.

The epithelial scales (Fig. 5), which nearly always accompany the urate of ammonia deposit, are thrown off by the mucous membrane lining the urinary passages. When very abundant, their presence may be considered


to be the result of irritation of the mucous surface, produced mechanically by the urate of ammonia. Some persons may have turbid urine from the habitual formation of urate of ammonia, etc. for many years out irritation of the urinary mucous membrane taking place. With others it occurs as soon as the lithatic urine is secreted by the kidneys, and is productive of much suffering, of pain in the region of the kidneys, darting along the ureters, and of dull aching sensations over the pubis in the region of the bladder. These symptoms are often accompanied by a constant desire to pass water, which rouses the patient several times in the night, and is not even fully relieved by emptying the bladder. I have met with some patients so sensitive in this respect, that even in health, if the ingestion of food is followed by the formation of urate of ammonia, they become aware of its presence as soon as the urine reaches the bladder, owing to the sudden pain it occasions. I have attended many patients suffering from irritable bladder from this cause, who had been erroneously thought to labour under stone, stricture of the urethra, or inflammation of the neck of the bladder.

Fibrinous casts (Fig. 6) of greater or less length, formed in the tubules of the kidney, are not unfre

quently seen along with the epithelial scales and the morbid salts. They present, under the microscope, the appearance of hairs, and in them are sometimes entangled urate of ammonia, epithelial scales, pus or blood globules, and even crystals of oxalate of lime. Their presence is generally considered to indicate severe irritation or even disease of the kidney. I constantly find them, however, in simple cases of dyspepsia, in which the kidneys are evidently neither the seat of great irritation nor of actual disease.

When morbid deposits in the urine, the result of defective nutrition, are thus the cause of irritability of the urinary organs, it is in vain to hope for relief until the digestive functions have been restored to a more healthy state, and until the urine has ceased to be loaded with the lithatic salts. The latter keep up constant irritation in the bladder and urinary passages, in the same way as sand constantly thrown into the eye would keep up irritation or inflammation of the conjunctiva.

Uric acid crystals are found more or less abundantly under the same circumstances as the urate of ammonia, and in the same patients. I have in vain endeavoured to find a separate cause or reason for their presence in some cases, and their absence in others; as also for their appearance and disappearance in the

same person. I am, however, disposed to think that their constant existence indicates a more decidedly depraved state of the digestive functions, and a more debilitated, broken-down condition of the general health, than is shown by the presence of urate of ammonia alone.

I am disposed to think that the presence of uric acid and urate of ammonia in the urine, in such abnormal quantities as to constitute a deposit, is very much more frequently the result of defective digestion than of defective metamorphosis of tissue, at least in dyspeptic disease. That such is really the case appears to me evident, from the circumstance that I am able, in the majority of such cases, to trace them to the food ingested a few hours previously, and that they disappear from the urine secreted after a prolonged fast.

The oxalate of lime deposit has presented itself to me under the same circumstances as that of uric acid and urate of ammonia, and often in the same cases. The existence of oxalate of lime is supposed, by most writers, to be indicative of a peculiar diathesis, but my researches have failed to detect it in dyspeptic patients. Uric acid, urate of ammonia, and oxalate of lime, all appear to me, in them, to be indicative of the same organic states-viz., defective digestion, assimi


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