The use of the alkalies should be continued for some weeks, and, if any gouty symptoms exist, a grain of acetous extract of colchicum may be given at night.

Persons who suffer from this kind of indigestion should endeavour to promote the action of the lungs and the skin, and, with this object, should take active exercise, be much in open air, and sleep in an airy bed-room; and they should live on a simple and abstemious diet-not eating too largely of animal food, and carefully avoiding ill-fermented malt liquors, rich dishes, heavy pastry, and cheese. Where total abstinence is not feasible, the alcoholic drinks best suited to them are pale sherry, in small quantity, or brandy, largely diluted with water.

By such means the indigestion may often be stopped, the excessive acidity of the urine corrected, and the general health greatly improved; but the disorders have their origin in a peculiarity which is constitutional and abiding, and they are, therefore, very liable to recur.

Another faulty state of the general health attended with indigestion is now and then met with, in which the urine is apt to contain oxalic acid in considerable quantity, and to precipitate, on standing, the wellknown octohedral crystals of oxalate of lime.

Dr. Prout supposed that a more than common disposition to the formation of oxalic acid in the system is indicative of a peculiarity of constitution; and he expressed this supposed peculiarity by the term, oxalic diathesis.

Oxalic acid, which is composed of only carbon and oxygen, with the elements of water, and which exists in many plants, and may be readily formed by the oxidation of various animal and vegetable substances, may come to be present in the urine in several ways.

1st. It may be taken in the food; may escape conversion in the stomach, and after its absorption in the blood; and may thus pass off in the urine, in combination with lime.

Many vegetables contain oxalic acid in combination with alkalies or with lime. The stalks of rhubarb, which are largely eaten in this country in the spring in tarts, and sorrel, which is much used abroad as salad, contain it in considerable quantity in combination with alkalies. In some persons, the oxalic acid taken in these articles of food is changed in the process of digestion, or undergoes conversion in the blood by the influence of oxygen, and consequently, does not pass off, as oxalic acid, in the urine. In others, whose power of digestion is weaker, or in whom respiration is less active, the oxalic acid escapes conversion and passes off in the urine in combination with lime.

This may happen in persons who are in perfect health and who have no marked tendency in the formation of oxalic acid in the system. With this occasional, and, if we may so term it accidental presence of oxalic acid in the urine, we have nothing here to do. It may lead to the formation of a small calculus of oxalate of lime, and so have very serious results; but it does not denote any abiding disorder of digestion or nutrition.

2nd. Oxalic acid may be formed in the body, and, as Dr. Garrod has shown, its presence may be detected in the blood when none of it is taken in the food.

The oxalic acid which is formed in the body may, possibly, be derived immediately from the saccharine elements of the food, or from lithic acid and other substances that result from the waste of the tissues, or from both these sources at once.

We know, indeed, that out of the body, oxalic acid may be readily formed, under the influence of oxidising agents, from sugar, starch, and their chemical equivalents; and Liebig and Wohler have shown that it may also be readily formed from lithic acid.

Dr. Prout long ago inferred that oxalic acid might be derived from the waste of the tissues, from the fact that its habitual or frequent presence in considerable quantity in the urine is often associated with an unhealthy condition of the skin, and also from the fact, that, in rheumatic and in hectic fever, large quantities of another non-nitrogenous acid—lactic acid—which must, he imagined, have their source in waste of the tissues, are formed or set free in the body.

Oxalic acid is said to be constantly present in the urine of herbivorous animals, and, according to Lehmann, it often exists in the urine of men in perfect health, but in such minute quantity that it is not readily discovered. It may then, he says, be sometimes made apparent by freezing the urine. When urine is frozen, a great part of the water crystallises in a comparatively pure state, and, if this be removed, the concentrated urine that remains deposits crystals of oxalate of lime.

The quantity of oxalic acid is found to be increased, so that the urine, without any such concentration, deposits numerous crystals of oxalate of lime, under many circumstances;

1. It is increased, according to Lehmann, by emphysema of the lungs, by the diminished elasticity of the lungs that results from repeated attacks of catarrh, and by other conditions that impede respiration, and thus prevent perfect oxidation of the carbon, which passes off in the urine as oxalic acid, instead of escaping in the form of carbonic acid by the lungs.

It is also increased according to him, by drinks that contain much carbonic acid, and by the alkaline bicarbonates and vegetable salts; and he accounts for this increase by supposing that the superfluous carbonic acid which has entered the blood or been generated there from the salts of the vegetable acids, must obstruct the absorption of oxygen and impede the perfect oxidation of those substances in the blood which support respiration.

2. The quantity of oxalic acid in the urine is often increased, as Dr. Walshe has shown, during convalescence from typhus fever, rheumatic fever, and other acute diseases, in states of anemia, and in the course of many chronic diseases that interfere with nutrition.

3. A considerable deposit of oxalate of lime often exists in the urine of persons who have no appreciable disease of the lung or other organs, and who have had no positive illness, but who have disordered digestion and look and feel out of condition. As the general health improves, the oxalate of lime disappears from the urine; but under the influence of fatigue and many other conditions unfavourable to health, the indigestion and other ailments recur, and the oxalate of lime appears again.

Dr. Prout, observing an especial tendency to this kind of disorder in certain persons and certain families, and believing that diabetes, which he considered on chemical grounds to be a kindred malady, was constitutional, and to a certain extent hereditary, was led to suppose that the especial tendency to the formation of oxalic acid and the concomitant disorder of health had its origin in a peculiarity of constitution, and, as I have already mentioned, he designated this supposed peculiar constitution the oxalic diathesis. There is, however, no constant connexion between the disordered state of health and the presence of oxalate of lime in the urine.

A copious deposit of oxalate of lime may result from other conditions, and the ailments we are considering may exist without the oxalate. Very often, however, the ailments and the oxalate co-exist, and constitute and define a disorder which it is very important to recognise, because experience has shown that it can generally be controlled or much mitigated by a particular plan of treatment.

To the patient nothing seems amiss in the urine. He complains only of his indigestion and its accompanying ailments. It is the form of this indigestion that we have now to consider.

It presents no striking or distinctive characters. The appetite is often good, sometimes more craving than in health; digestion is not slower than it should be; there is no pain, no sense of oppression or weight at the stomach immediately after meals; there is seldom vomiting or heartburn. But much discomfort is caused by flatulent distension of the stomach especially two or three hours after a meal, when the stomach is getting empty, and sometimes there is pain in the stomach at that time. With this flatulent distension of the stomach there are often uneasy sensations in the belly which seem to result from flatulent distension of the duodenum or the colon.

The

This disorder of digestion is usually associated with other symptoms of constitutional disorder, and especially with nervous symptoms. patient in most cases grows somewhat thinner, is weak and readily fatigued, sleeps badly, is troubled with palpitation, is irritable in temper and depressed in spirits, and often hypochondriacal in a high degree, and has, or fancies he has, deficiency of sexual power. Frequently, too, he has a wearing pain, or a sensation of uneasiness across the loins, and empties his bladder more frequently than in health,—symptoms resulting probably from irritation of the urinary organs by the passage of the oxalic acid through them.

In some cases there is evidence of defective or faulty nutrition of the skin in a scaly eruption or a succession of boils.

These ailments vary greatly in degree in different cases. In some, they are very trifling; in others, the restlessness at night and the mental depression unfit the patient for his usual occupations, and render his life miserable. They are none of them peculiar to the disorder we are considering. Taken together, indeed, they often form a group that is tolerably significant; but the only sure evidence that oxalic acid is in excess is the presence of numerous crystals of oxalate of lime in the urine.

The urine then is always acid, generally more acid than in health; in most cases of an amber colour and transparent, and of moderate or rather high specific gravity. If allowed to stand in a conical glass vessel, a light cloud of mucus may form at the bottom, but there is often no other deposit.

In some cases, however, together with oxalate of lime, the urine contains an excess of urea and is of higher specific gravity than in health; or it contains an excess of lithic acid, or of lithate of ammonia, and these substances are deposited at the bottom of the glass.

The crystals of oxalate of lime are not visible to the naked eye, except when many of them are entangled in a dense cloud of mucus at the bottom of the glass, in which case they can sometimes be seen as minute glistening points: but may, as Dr. Golding Bird, first showed us, in all cases, be readily discovered by the help of the microscope. The detection of them is important, because it throws light on the nature of the disorder and may determine the plan of treatment.

A disposition to such recurring derangements of the general health, and to the formation of oxalic acid in the system, may-like the disposition to gout, diabetes, and other kinds of faulty assimilationeither be inherited, or be induced, where no inherited tendency to it exists, by certain external conditions or habits of life.

The conditions which Dr. Prout assigned as most conducive to it, are-residence in a damp or malarious district, the too abundant consumption of sugar, the depressing emotions of anxiety and grief, exhausting bodily or mental labour, long courses of mercury, excessive smoking, and, indeed, all other circumstances that seriously depress the vital powers.

Among the inhabitants of this great city, there are, I believe, no circumstances that conduce to it so much as the foulness of the air we are always breathing, and the anxiety and exhausting labour of mind and body that are almost inseparable from the pursuit of wealth or distinction.

Now, all these conditions, by their action on the nervous system, enfeeble respiration; and it seems probable that, as Lehmann has suggested, the formation of oxalic acid may be immediately owing to defective oxidation of those materials in the blood by which respiration is supported: but in the cases we are considering, it is not the

less dependent on derangement of the general health, which is apt to reçur, and which constitutes a definite object of medical treatment. In some cases, it seems, from the high specific gravity of the urine and from the large quantity of urea that co-exists with the oxalate of lime, that there is a more rapid waste of the tissues than is natural, and that the respiration is not absolutely, but only relatively defective-insufficient, that is, for the complete oxidation of the large quantity of combustible materials on which the inspired oxygen acts. The indigestion, and the various other ailments that result from this general derangement of health, are much under control.

The remedy of most efficacy, where the urine is free from a red deposit, is the nitro-muriatic acid, which often prevents the formation of oxalic acid after a few days, lessens the flatulence and the palpitation, and makes the sleep quiet and the spirits more cheerful. From eight to twenty minims of each of the dilute acids may be given twice a-day in a glass of water, half an hour before breakfast and half an hour before dinner.

It was long ago known that nitric acid, or the nitric and muriatic acids, have occasionally great efficacy in indigestion; but it was Dr. Prout who rendered our knowledge on this point precise, and showed that it is in the particular form of indigestion we are considering, and in persons in whom there is a disposition to the formation of oxalate of lime in the urine, that they are especially of service.

The mineral acids have a tendency to cause a deposit of lithic acid, or of lithate of ammonia, in the urine, and when such a deposit exists, it is seldom advisable to give them longer. Dr. Prout tells us, that, when his patient lived at a distance in the country, he commonly advised him to take the acids for a month or until lithic acid or lithate of ammonia appeared in the urine.

All ailments that result from faulty assimilation and that depend primarily on peculiarity of frame or constitution, are very liable to recur. If, therefore, the mineral acids should prove of service, they may be had recourse to again and again on each recurrence of the same disorder.

If the tongue be clean, some of the light bitter tonics may be given with advantage in conjunction with the mineral acids.

When the urine from the first has a deposit of lithic acid or lithate of ammonia, the mineral acids should not be given, and the best substitute for them that I know of is the carbonate or the aromatic spirit of ammonia.

Where there is want of sleep, and great nervous irritability, and much flatulence and palpitation, the tincture of henbane, or the dilute hydrocyanic acid, or some other sedative, may be given with advantage in conjunction with either of the medicines I have just mentioned. So much for remedies which the Pharmacopoeia supplies.

The proper, regulation of the diet is equally important. Dr. Prout, considering the excessive use of sugar as one of the causes of this