membrane suffering from the contact of a fluid only a little more acid than that destined to be continually touching it, should we not expect it to have been of such a character as to resist this action, like the mucous membrane of the stomach, instead of being excited to secrete a fluid which in excess might seriously damage it? It must be remembered that the mucous membrane of the bladder bears very well the contact of acid fluids which sometimes have to be injected; and it cannot be denied that patients may for years pass intensely acid urine, without there being any evidence of the secretion of the excess of alkaline fluid from the mucous membrane which is postulated.

When there is fermentation in the contents of the stomach, . with a setting free in large quantity of many organic acids, the urine is often only feebly acid or it may be decidedly alkaline in its reaction. Under these circumstances oxalate of lime will often be found in the deposit; but that the oxalate is not due in any way to the stomach changes, is proved by the fact that it is often found in large quantity in cases where the stomach performs its work perfectly well, while in many cases in which the action of the stomach is very seriously deranged no deposit of oxalate of lime takes place. Alkalies taken just before a meal sometimes act advantageously, partly because they stimulate the increased secretion of gastric juice more decidedly than an acid, and partly because by neutralizing organic acids set free by the decomposition of some of the ingredients of the food, the secretion of normal gastric juice is promoted.

The practitioner must not fail to bear in mind that great derangement of vesical action, and even actual and severe inflammation of the bladder, may result from carrying alkaline treatment too far, and it is very necessary to caution patients who have experienced benefit from alkalies and alkaline waters, on this head. I have seen many cases of most troublesome bladder disturbance caused by foolishly persisting in the use of alkalies. Patients generally know nothing of physiology, and having found what they call "a good thing" in the way of a remedy, are too apt to persist in its use even after its action is obviously detrimental. This effect being attributed to some other circumstance,

the pet remedy is continued until real illness is induced, and it becomes absolutely necsssary to call in the medical adviser, who would have given the patient such directions as would have saved him much suffering and trouble, and perhaps prevented a long and tedious illness, had he been consulted before the patient took upon himself the responsibility of his own medical management. The persistently alkaline condition of the urine occasionally met with is very difficult to successfully treat, and may continue in spite of large doses of acid persisted in for many weeks at a time. Indeed, no amount of acid that can be taken without risk will alter the reaction of the urine in some instances. The alkaline condition is usually associated with the deposition of earthy phosphates, and sometimes in very considerable quantity. In such cases, without very careful management, a distressing state of things may result. The earthy salts are often deposited upon the surface of the mucous membrane, not only of the bladder but upon that of the ureters and pelvis of the kidney. This process not unfrequently results in complete disorganization of the mucous tract, and generally leads to a serious state of things; not uncommonly portions of the deposit become detached, and receiving earthy phosphates upon their surface, layer after layer, concretions of a soft and very brittle character, but not unfrequently of considerable size, may be formed. The injection into the bladder, from time to time, of very dilute acid (one part of strong acid to one hundred of water), with frequent washings out of the viscus with tepid water, generally affords relief.

VARIATION IN QUANTITY AND IN THE RELATIVE PROPORTION OF THE SOLIDS OF THE URINE.

Among the commonest derangements of the urinary secretion within the healthy range is an increase of the solid matter in proportion to the liquid present. In a given quantity of urine the solids may be found to be double that of the ordinary amount, and other specimens within twenty-four hours may contain much less than the ordinary percentage of solid matter. In the case of a secretion like the urine, which is always changing,

at least as regards the quantity of its constituents, it is not possible to adduce a standard analysis which shall represent its normal composition. We may arrive at an average by making analyses of a portion of the mixed urines of the twenty-four hours, and instituting comparisons between the urines of a number of healthy individuals. In this way we are able to point to what we may call a healthy standard, but in nature variation is constant with reference to this, and in both directions. It is to the considerable and constant variation in the composition and quantity of the urinary constituents that what may be spoken of as the capacity of maintaining a steady, even state of health is to be attributed.

Urea is the most important of the solids of the urine. It is always present and in greater proportion than any other of the constituents of urine. The amount varies greatly within the physiological limit, and in slight departures from the healthy state it is not uncommon to find the urea amounting to double as much, or to not more than one-twentieth of what is stated to be its normal amount. The quantity of urea excreted by a healthy man during each period of twenty-four hours may be roughly stated to be 500 grains, and corresponds to about 32 grains per pound of the body weight. In many cases, however, it does not amount to nearly so much. Some organisms are exceptionally economical "machines," and do not consume even half as much food in the performance of the same amount of work as seems to be necessary in the case of the majority. Even in engines the greatest difference exists in this respect, and engineers are continually discovering new means of economizing fuel. As compared with an engine, however, the most extravagantly feeding man is a very economical machine.

A good deal of urea found in the urine is produced in the liver. In some diseases of this organ the quantity of urea formed in the twenty-four hours is lessened. It is probable that far too little consideration has been given to the action of the liver in the treatment of disturbances resulting in the formation and excretion of more than the normal amount of urea and uric acid. In some of these cases our attention should be mainly

directed to the action of the liver and intestinal canal, and we shall often find that as soon as the work performed by these organs is properly discharged, the urine will return to its normal condition.

The large proportion of urea excreted in fevers and inflammations has been supposed by some authorities to be proof of excessive oxidation, and to be necessarily connected with the high temperature of the body. In spite of the blood being stagnant in the vessels, and the air-cells of the lungs choked up, this illconsidered theory has been so forced upon us, that it will probably be some time before any view more in accordance with wellknown facts will be accepted. It need scarcely be said that a rise in temperature may be brought about in many ways, while it may be regarded as certain that the increased heat in fever and inflammation, and the increased quantity of urea formed, do not depend upon peroxidation; indeed, it will be found that there is usually a very large excretion of urea in diseases in which the activity of the processes concerned in oxidation is much reduced, instead of being in excess. The amount of urea excreted is often very great. Vogel mentions a case of pyæmia, in which 1235 grains of urea were removed in the course of twenty-four hours. Dr. Parkes obtained as much as 885 grains in a case of typhoid fever. These quantities are very large, if the patients did not exceed the average weight of adult men; but, unfortunately, their weight was not recorded.

Excess of Urea. This phrase is not restricted to those cases in which the total quantity excreted in the twenty-four hours is greater than in health; but a specimen of urine which yields crystals of nitrate of urea when an equal bulk of nitric acid is added to it in the cold, without having been previously concentrated, is said to contain "excess of urea." The quantity of urea dissolved in the fluid is so great, that nitrate of urea is formed, and crystallizes, just as if the urine had been concentrated by previous evaporation. This result may be brought about in several ways. In cases in which but a small quantity of fluid is taken in proportion to the urea to be removed; when an unusually large amount of water escapes by the skin and other emunctories;

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as well as in many cases in which an unusual amount of urea is formed in the organism, we shall frequently find excess of urea in a specimen of the urine.

"Excess of urea" is frequently found in the urine of persons suffering from acute febrile attacks. It is very common in cases of acute rheumatism, and is often met with in pneumonia and acute febrile conditions generally, in which cases there is also an actual increase in the quantity excreted in the twenty-four hours. In England, we meet with cases of "excess of urea” very frequently; but on the Continent they appear to be so rare that many authorities seem to doubt the truth of what English observers have stated on this point. Lehmann, I think, states that he had never seen a case in which crystals of nitrate of urea were thrown down upon the addition of nitric acid, without previous concentration.

Urine containing excess of urea is generally perfectly clear, of rather a dark yellow color, and of a strong urinous smell. Its specific gravity is about 1.030, and it contains 50 or 60 grains, or more, of solid matter per 1000. At ordinary temperatures, an aqueous solution which forms crystals of the nitrate upon the addition of nitric acid without previous evaporation will contain at least 60 grains of urea per 1000; 50 grains of urea per 1000 hardly gave the slightest precipitate after the lapse of a considerable time. But it would seem that the salts, extractive matters, etc., in urine, favor the crystallization of the nitrate when even a smaller quantity of urea than 5 per cent. is present. It should be mentioned that the above experiments were performed in the summer, in very hot weather. In one case, in which the urea readily crystallized on the addition of nitric acid, the urine had a specific gravity of 1.028, and contained—

Urine containing excess of urea is generally acid, but I received a specimen from Dr. Fergus, of Marlborough, which was