One observation arises on an examination of the effects of purgatives, viz. that the more active ones, which excite languor and nausea, are the most useful; apparently the relaxation thus produced, assists their purgative power, as a small proportion of emetic tartar greatly increases the action of the resinous purgatives in general. The diuretics also, which arc most useful, possess a similar effect; and the squills seldom succeed in increasing the discharge of urine to any degree, till raised to a nauseating dose. Another remark which we may suggest is, that, during the action of hydra-gogues, the secretion by the kidneys is scarcely in any instance increased; yet the patient recovers strength, appetite, and spirits: and indeed we have found, in the happiest recoveries, that the urinary discharge is not increased, till the load of water is in a great degree removed. A similar observation will recur when we speak of the operation of the paracentesis. Amidst these numerous advantages, it is with some surprise that we find a man of judgment and experience, Dr. Fordyce, so adverse to cathartics; and we suspect, that a little prejudice prevented him from using them with so much freedom as would show their utility. When We reflect also, that one of the most frequent causes of dropsy, obstructed liver, is greatly benefited by purgatives, our temptation to employ them will be increased.

As we pretend not to have enumerated all the purgatives employed at different times, but only to appreciate the value of the more useful ones, so, in the enumeration of diuretics, we shall follow a similar plan. Of these, the principal is the squill, with the rest of the onion tribe. It is, alone, a host: and could we render it a purgative as often as we find it injuriously so, viz. in pneumonia, we should perhaps want no other medicine for all curable dropsies. In every form, dry or fresh, in vinegar or tincture, it succeeds in the greater number of cases; but its nauseous taste renders pills the most convenient mode of exhibiting it; and the dry powder, which retains all its activity in a moderate bulk, best adapted for the purpose. With cream of tartar, and a small portion of jalap, it is highly useful, as combining a diuretic and purgative effect; and, with the resin of jalap and gutta gamba, in pills, its utility is almost unrivalled. Of the other vegetables of the onion tribe we use only the juice of leeks, which, though nauseous, is said to be often successful. The colchicum autumnale is apparently the next in power: we have sometimes thought superior, for it has succeeded where squills seem to have failed. The broom is a very useful diuretic; and the broom ashes, as combining the alkaline salt with the essential oil of the vegetable, have been highly commended. The alkaline salts themselves are useful in this way, though of weaker power. The broom seeds formed the secret remedy of Lemery; but these are acrid, and in general unmanageable.

The other diuretics are, the lactuca virosa, the juniper berries, the taraxacum, the nicotiana, and the fox glove. The first rests on the authority of Dr. Colin of Vienna, for the medicine has been rarely given in this country. The juniper berries are well known, and the diuretic effects of gin (from Giunipero in Italian) sufficiently understood. The taraxacum is still more powerful; and the tobacco, especially when its alkaline salt is employed, appears, from Dr. Fowler, to be a very active, useful medicine, meriting much more attention than it has received. The fox glove requires a longer discussion. It is arranged in a poisonous and suspicious order with the nicotiana, &c; and in many instances it seemingly shows a deleterious power. In dropsy, death often suddenly seizes the patient; but we have thought this sudden termination still more frequent when the fox glove has been taken. It is, however, a remedy of considerable power and utility. The weakness, the nausea, and the affection of the head, which often follows its exhibition, would point it out as chiefly useful to the strong and active. On the contrary, however, the weak, languid, worn out constitution is chiefly benefited by the fox glove; and the discharge of urine, which it occasionally produces, is astonishing. Every part of the plant is equally effectual; but the leaves are generally employed, and the dry powder is the most useful and certain preparation. We fear, however, that the injuries resulting from it have greatly overbalanced the benefits.

Diuretics from other sources have been numerous. From the animal kingdom we have received the can-tharides, which, with some physicians, have been a favourite remedy. We own, however, that in our hands they have not produced any diuretic effect, nor have we recognized their activity till they have reached the neck of the bladder. Some other species of the meloe have been supposed also diuretic, but experience has not decided on their virtues.

The chief remedy of the mineral kingdom is nitre, whose powers are not considerable; and chemistry has furnished us with the sweet spirit of nitre, an aethe-rial fluid, which in slight cases is often successful. The turpentine also, formerly mentioned, is a preparation frequently and generally useful as a diuretic.

Some other modes of relief remain. A powerful one is friction; and friction, with olive oil, has been employed since the time of Celsus, though the oil, by general consent, is considered as useful only to prevent excoriation. Perhaps the friction with camphorated oil has no very different effect; and when the external application of mercurial ointment has been found useful, friction may have had some share in the success. Mustard and horse radish have been ordered without any-determinate view, and have been attended with no very striking success. The mustard seed unbruised, often swallowed in dropsical and paralytic complaints, acts only as a gentle laxative.

Two important subjects remain: the first is the propriety of indulging diluted liquors, and the second the operation of the paracentesis. For nearly two hundred years it has been common to prohibit the use of fluids in dropsy; and the reason probably was, that as an excess of diluents sometimes brought it on, so they might continue or increase it. We recollect a case in the Medical and Physical Essays of Edinburgh, where a salt herring was ordered without any liquid: the thirst was burning and intolerable; but after a time it ceased, and a flow of urine came on. In such a violent agitation, nature might have exerted her powers to supply dilution; and the absorption, once commenced, might have continued. The experiment is, however, to