Thus he alludes to some researches of his own regarding the presence of urea in the fluid of dropsical effusions. Whenever the quantity of albumen present in the fluid was inconsiderable, the urea was often easily detected; but when it was greater, all traces of the salt were absent.

Although, therefore, no urea can be discovered in healthy blood, it is far from being improbable that it does actually exist, in small quantity, in it.

We shall now briefly allude to the circumstances under which urea has been found in the blood; and the first, that we shall make mention of, is when the kidneys have been extirpated in the lower animals.

The names of the experimenters-MM. Prevost, Dumas, Mitscherlich, Tiedemann, Gmelin, &c.—afford a sufficient guarantee for the correctness of the statement.

M. Marchand deemed it therefore quite unnecessary to repeat the experiment; but he varied the manner of performing it in the following manner, He passed a ligature round both kidneys in a healthy sheep, (dans un mouton sain, en une seule fois je fis la ligature des deux reins.)* When he deemed that the mortification was complete, the ligatures were removed, and the wounds were united by means of stitches: in a short time they healed. The animal, from the day of the operation, became exceedingly low and feeble; but it lived for nearly a fortnight. It was killed by opening the jugular vein, for the purpose of collecting as much of the blood as possible. Not more, however, than a pound could be obtained, before the animal expired.

M. Marchand took 400 grammes of this, and evaporated it to dryness in a sand-bath rather more than two grammes of urea were thus obtained. Traces also of urea were detected in the fluid, which had been rejected from the stomach by vomiting.

In human pathology we occasionally meet with cases, which exhibit somewhat analogous phenomena, as in ischuria renalis, Bright's disease of the kidneys, the Asiatic cholera, &c. &c. In all of these diseases the quantity secreted, as well as the quality, of the urine is greatly changed from a state of health. The urine voided during an attack of Asiatic cholera has been found to be quite destitute of any traces of urea.

In one or two cases of this disease, M. Marchand succeeded in detecting urea in the blood, which had been drawn during life. It is well known that several physicians have proved the presence of this animal salt in the blood, in some cases of Albuminuria, or Bright's disease of the kidneys.

We have already alluded to the remark of M. Marchand as to the occasional existence of urea in the fluid of dropsical effusion.

M. Nysten was, perhaps, the first to announce this curious pathological fact in 1811; but his memoir, although presented to the Royal Academy of Sciences in that year, was not published till a few years ago. He discovered urea not only in the dropsical fluids, but also in the fluids which were rejected from the stomach, when there was a complete ischuria renalis. Hitherto but few experiments have been made on this subject; but it certainly seems highly probable that the conclusions of M. Nysten are quite accurate, when we call to mind the results of the mortification of the kidneys, as induced in M. Marchand's experiments.

We may here allude to the circumstance of saccharine matter being occasionally discoverable in the blood of patients affected with Diabetes mellitus: the

The particulars of this operation are not given by the author, nor the manner in which it was performed. He alludes to the experiments of MM. Muller and Peipers (Archives für Physiologie, 1836,) as having suggested to him the mode of producing the mortification of the kidneys by means of a ligature.

saccharine matter seems to occupy the place of the urea, as it is well known that this latter principle is almost or altogether entirely deficient in the urinary secretion.-L'Experience.

ON THE ACTION OF DIURETIC MEDICINES.

The urinary secretion is liable to numerous changes, in respect both of its quantity and of its properties. In diabetes, the quantity is very greatly increased; whereas in almost all diseases, which are attended with copious perspiration or with diarrhoea, as well as in the various forms of dropsy, the urine is generally scanty. Again; as to the quality of the secretion we usually find that it is alkaline in chronic diseases of the brain and of the spinal marrow, highly charged with uric acid or with urate of ammonia in gout and rheumatism, albuminous in certain dropsies, in structural disease of the kidneys, &c. and saccharine in one form of diabetes.

Various medicines exert a powerful effect on the urine; operating either directly on the kidneys themselves; or indirectly and through the medium of other organs, as the skin or bowels; or lastly by acting on the blood itself and inducing certain changes in its composition. It is well known that many substances, such as various salts, turpentine, and several colouring matters, are discoverable in the urine, in a short time after they have been taken into the system.

But to confine our remarks to the question before us-viz. the action of diuretics, or those medicines which increase the flow of the urine-we may observe that diuresis may be produced either by the direct excitement of the kidneys themselves; or by the removal or counter-action of any existing circumstances, which may be impeding the secretion; or lastly by the use of a large quantity of fluid which thus passes through the system and is subsequently discharged partly by the skin and partly by the kidneys.

In considering the action of diuretic medicines, it may be well to divide them primarily into those which are so in health, and into those which increase the urine only in a state of disease.

The former class or section may be subdivided into

1. Acrid Diuretics.-These act directly on the kidneys, and, if used indiscreely, may cause inflammation of their tissue, hæmaturia, and strangury. Cantharides, squill, colchicum, mustard, mezereon, &c. belong to this class.

2. Exciting Diuretics.-These act as general stimulants of the system. They quicken the circulation, and thus cause a greater quantity of blood to pass through the kidneys than usual. But independently of this systemic effect, they act, even in small doses which do not affect the general circulation, on the kidneys-as is distinctly observed when these organs are at all inflamed or are otherwise very irritable. Alcohol, æther, the ethereal oils, resins and balsams, are the chief excitant diuretics. Turpentine may be considered as intermediate, and forming a link, between the former and the present division of this class of medicines.

3. Saline Alkaline Diuretics.-These act by first modifying the state of the blood, and by then stimulating directly the kidneys themselves. They cannot, perhaps, of themselves induce inflammation of these organs, although they may revive it, when it has recently existed. They increase the secretion, without accelerating the circulation; and hence they are rather antiphlogistic, than phlogistic medicines.

The various salts of the alkalis, more especially those in which they are combined with the vegetable acids, are diuretics of this class.

That these substances act directly on the kidneys themselves, after being taken into the torrent of the circulation, is proved by the following circumstances.

a. They are discoverable by chemical re-agents in the urine. The acid is often changed, but the basis or alkali remains unaffected. As far as we know, none of the other two classes of diuretic medicines can be recognised in the urine; for, be it remembered that the mere circumstance of the peculiar odour of turpentine, and of a few other substances, being present in the urine, shortly after they have been taken into the system, does not necessarily imply their actual presence in the fluid.

b. The degree of local action is not in any degree proportionate to the amount of diuresis induced. On the contrary, it rather seems that the less that the kidneys are irritated the greater is the diuretic effect produced.

c. A certain interval of time, from one to several hours, passes between their being taken and the manifestation of their effects. Phenomena, dependent upon sympathetic influence, on the other hand, display themselves very rapidly.

In cases of dropsical effusions the absorption of the fluid, and the cure of the malady coincide with the increase of the diuresis induced by means of the diuretics employed. The diseases too, which are attributed to an acrimony of the blood-as for example, various cutaneous eruptions-are frequently much benefited, and even cured, by the use of these medicines alone. Some physiologists have sought to explain the operation of diuretics in the cure of dropsies, by supposing that they have the power of directly fortifying the lymphatic vessels, and of favouring absorption in this way. But there are no good grounds for this conjecture; and we therefore deem it more wise to believe that they act only indirectly, and that it is by diminishing the serous part of the blood, that they stimulate the lymphatics to compensate for the loss.

We shall now allude briefly to the second division of diuretics-which comprehend those which have no immediate or direct effect on the kidneys, and act as provocatives of the urine only in a state of disease, by removing or counteracting any unfavorable existing circumstances.

Of these, bloodletting is one of the most important and efficacious in all plethoric or phlogistic states of the system. Low cooling diet has also a decidedly diuretic effect under such circumstances. Purgatives too, especially those which are saline and those which are hydragogue, are powerful promoters of ab. sorption.

On the other hand, when the system is much reduced, and the vital energies are impaired, the class of tonics, including the various vegetable bitters, steel, &c., is a most potent adjuvant in dropsica! cases. In short, very much depends on the cause of the effusion, and on the existing state of the constitution at the time that the physician is called. Of late years much attention has been paid to the pathology of dropsy; and there is perhaps not one subject in the whole range of medical literature more worthy of accurate investigation.

It is now established beyond all doubt that numerous cases of dropsy depend upon some disease of the heart. Auscultation has done much to reveal such cases, and has thus led to a more scientific and more successful mode of treatment. Where there is overaction of the heart, the repeated application of leeches over its seat, and the use of antimonials, digitalis, refrigerants, &c.*

* Perhaps the best formula is such a prescription as the following.

B. Sodæ carbonat.

Potass. nitrat.
Sacchari purific.

Aquæ distillat.

Vini colchici

Spir. æther. nitric...

3ss.
3xiss.
3ij.
3ij. M.

Three table-spoonfuls to be taken with lemon juice three times daily.

combined with extreme quietude of mind and body, constitute by far the most efficacious medication, not only in relieving the circulation, but also in dissipating any dropsical effusion, which may exist.

Another frequent cause of certain dropsies is a structural disease, more or less confirmed, of some of the abdominal viscera-especially of the liver and spleen. Perhaps no class of diuretics is so useful in such dropsies as that of hydragogue cathartics-such as gamboge, elaterium, &c. in union with the supertartrate of potass.

A third not unfrequent cause of dropsy-and this department of pathological enquiry has, until of late years, been very obscure-is structural change of the kidneys themselves. This variety of the disease is one of the most serious and least curable of all. All acrid and stimulating diuretics are necessarily injurious. The hydragogue cathartics, such as the compound powder of julep, &c., are to be preferred; and great attention should be paid at the same time to the maintaining of a free perspirable state of the skin.

The only other form of dropsy, to which we shall at present allude, is that which is apt to supervene on inflammation of a serous membrane. This is especially frequent in the chest after pleuritis. In the treatment of such cases, the use of mild mercurials, and of large doses of alkalis, such as the carbonate of potass, constitutes on the whole the best practice. The same remark is applicable to dropsy occurring after scarlatina, &c.—Archives d'Anatomie, &c. par Muller.

EFFICACY OF MERCURY AS AN ANTIPHLOGISTIC REMEDY.

M. Delhaye, the author of the following observations, very justly remarks,— "The wish to explain everything in diseases is one of the greatest errors in every exclusive system of medicine, whether this be the humoral doctrine, the physiological, or the doctrine of solidism.

There are certain occurrences or facts, which every practical man will admit to be true, and which are yet as mysterious and inexplicable to us in the present day, as they were two centuries ago—thus shewing how little progress has been made in the physiology of disease.

In spite of all the ingenuity and earnestness of a very able sect of physicians, who have striven to reduce the various forms of morbid action to a few general and primary elements, we suppose that few, if any, of their disciples will be inclined to deny the existence of certain specific diseases and of certain specific remedies.

Take, for the example, syphilis and its (almost) unquestioned antidote, mercury. Can we give any explanation, in the slightest degree satisfactory, of the essential nature either of the disease itself, or of the modus operandi of the drug ? Certainly not.

Again; is not ague an essential and specific form of febrile action? and is not Peruvian bark its antidote, par excellence?

All attempts to explain the intrinsic and real nature of these diseases have entirely failed. In short, we believe that there is nothing exclusive in medicine; and for this reason we do not hesitate at once to express our adoption of a rational eclectism, in preference to all the much vaunted doctrines and systems which have been proclaimed for the last 150 years. It seems to us to be a great error, that of supposing that the science of medicine can ever attain to that exactitude and precision, which appertain to those sciences, which have to do with inanimate matter. A chemical result is invariable and uniform-provided the experiments are entirely alike—at all times and in all places. The same is the case with the facts of mechanics and of the other branches of natural philosophy. But this does not hold good in medicine. No two cases even of the

same disease are entirely alike; there is always some trait or mark of difference in the vehemence, duration, or succession of the symptoms; and the art of the wise physician is to detect the physiognomy, so to speak, of each case, and to deal with it accordingly. Then, too, the influence of the mind and of the feelings on the course of a disease will never be overlooked by the practical man in directing his treatment.

But to proceed to the immediate object of this paper, we shall first mention a few cases, to illustrate the efficacy of mercury in certain forms of ophthalmia.

Case 1. Chronic Scrofulous (?) Ophthalmia.-A young girl, of a nervous irritable constitution, had for some months been suffering from sharp darting pains through both eyes, intolerance of light—so great that she always kept her head bent upon her chest, and the tarsi were quite contracted inwards, &c. and these symptoms were attended by loss of appetite and general feverishness. It was a matter of difficulty to ascertain the state of the eyes, in consequence of the spasmodically closed state of the lids. The cornea of the left eye had partially lost its transparency, and presented a deep ulcer on its lower half. The right eye seemed to be only sympathetically affected.

Dr. Delhaye says that, when this case was first submitted to him, he was a most believing proselyte to the doctrines of the physiological school, and that he therefore advised bleeding, leeches, blisters, low diet, &c. The disease however was not at all mitigated by this treatment.

M. Stievenart of Mons, a distinguished oculist, was called into consultation. Agreeing with Dr. Delhaye as to the nature of the disease, he suggested the omission of all depletory and lowering measures, and the use of small doses of calomel and belladonna-a pill, consisting of a fourth of a grain of calomel and a sixth of a grain of powdered belladonna leaves, to be taken every four hoursof an opiate collyrium, and of frictions upon the eyelids with the extract of hyosciamus, thrice daily.

On the third day after the adoption of this treatment, the patient could look at objects without much uneasiness, and by the end of the week both eyes were well, with the exception of the ulcer on the left one.

It is to be observed that a nourishing and somewhat generous diet was administered at the same time, malgré les symptomes de gastrite, adds Dr. Delhaye.

Case 2. A child, who from her infancy had been subject to repeated attacks of ophthalmia, was seized in her seventh year with scarlatina, which was accompanied with severe thoracic symptoms. Purulent effusion into the right cavity of the chest took place, and required the operation of paracentesis thoracis. While recovering from this dangerous affection, the eyes, more especially the right one, became the seat of a most distressing ophthalmia. There were frequently recurring sharp pains through the orbits, great intolerance of light, &c. Antiphlogistic measures were used for some time, but without any advantage.

Dr. Delhaye, remembering the happy result of the former case, now adopted a similar treatment, although he was in some degree afraid of a mercurial action in a system so debilitated. The calomel and belladonna were given in small doses, the eyes were bathed with a mildly anodyne wash, and a nutritious_regimen allowed. The cure was complete by the twelfth day; and it is worthy of remark that the fistula in the side-for this was still open-had nearly cicatrised by the same time.

Case 3. A girl, 18 years old, and of a lymphatic habit, had been subject from her childhood to attacks of ophthalmia, which had caused slight opacity of both cornea. The present attack was a very protracted one, and was attended with much constitutional disturbance. Leeching, blistering, &c. had been tried without effect.