causâ" of the Roman dinner tables*, I may again mention sea-sickness, the sickness of pregnancy, the frequent vomiting of infants, and the habit some individuals have of rejecting constantly in this way a portion of all food taken, as evidence that little mischief comparatively can be derived from this source. And in the latter case of habitual or periodical vomiting, it may be remarked that the effort is usually attended with little nausea, though often with distension or other uneasiness preceding the act. These points must always be kept in view in judging of the effect of emetics in practice, and of the frequency and particular methods in which they may best be employed. * Celsus, lib. i. cap. 3. + I have known a patient, a young lady of delicate and irritable habit, who, during fourteen months, rejected invariably some portion of every meal; the quantity rejected, and the interval before vomiting occurred, depending much on the quality of the food. In this case (in which the malady depended not on organic disease of the stomach or pylorus, but seemingly on irritation translated from another part), the patient suffered chiefly from an uneasy distension preceding vomiting, little from nausea or the vomiting itself; and she even gained considerably in flesh while the disorder was going on. In another instance I have known the habit of vomiting continue for many years, after every meal of which animal food was the principal part; without any apparent injury to the constitution or increasing mischief to the stomach itself. 316 CHAP. XXI. ON THE USES OF DILUENTS. THOUGH there may seem little reason for considering these as a separate class of remedies, yet I doubt whether the principle of treatment implied in the name is sufficiently regarded in modern practice. On the Continent, indeed, the use of diluents is much more extensive than in England; and, under the form of mineral waters especially, makes up in some countries a considerable part of general practice. But putting aside all question as to mineral ingredients in water, the consideration more expressly occurs, to what extent and with what effects this great diluent, the only one which really concerns the animal economy, may be introduced into the system as a remedy? Looking at the definite proportion which in healthy state exists in all parts of the body between the aqueous, saline, and animal ingredients at the various organs destined directly or indirectly to regulate the proportion and at the morbid results occurring whenever it is materially altered - we must admit the question as one very important in the animal economy, and having various relation to the causes and treatment of disease. Keeping in mind then this reference to the use of water as an internal remedy, diluents may be viewed under three conditions of probable usefulness; — first, the mere mechanical effect of quantity of liquid in diluting and washing away matters, excrementitious or noxious, from the alimentary canal; secondly, their influence in modifying certain morbid conditions of the blood; and thirdly, their effect upon various functions of secretion and excretion, and especially upon those of the kidneys and skin. Other more specific effects there may be; but these are presumably the most important, and each may be made to contribute respectively to valuable ends in practice. The first is an obvious benefit in many cases, and not to be disdained from any notion of its vulgar simplicity. It is certain that there are many states of the alimentary canal, in which the free use of water at stated times produces good which cannot be attained by other or stronger remedies. I have often known the action of the bowels to be maintained with regularity for a long period, simply by a tumbler of water, warm or cold, on an empty stomach, in cases where medicine had almost lost its effect, or become a source only of distressing irritation. The advantage of such treatment is still more strongly attested, where the secretions taking place into the intestines, or the products formed there during digestion, become vitiated in kind. Here dilution lessens that irritation to the membranes, which we cannot so readily obviate by other means, and aids in removing the cause from the body with less distress than any other remedy. In some instances, where often and largely used, its effect goes farther in actually altering the state of the secreting surfaces, by direct application to them. But it is difficult for the most part to distinguish this result from the effect taking place through the circuit of the blood. I mention these circumstances upon experience, having often obtained much good from resorting to them in practice, when stronger medicines and ordinary methods had proved of little avail. Dilution thus used, for example, so as to act on the contents of the bowels, is beneficial in many dyspeptic cases, where it is especially an object to avoid needless irritation to the system. Half a pint or more of water taken when fasting, at the temperature most agreeable to the patient, will often be found to give singular relief to his morbid sensations; and, where such is the effect, may even become a valuable aid to the other treatment pursued. Or in cases where there is habitual excess of acid in the lower bowels (a source of frequent distress, though not so easily recognised as acid on the stomach), the solution of half a drachm or more of carbonate of soda in the quantity of water taken will add greatly to the good gained. It is often more beneficial in this way than given in smaller proportion of liquid; a point connected with the action of mineral waters, which clearly influence by quantity and dilution the medicinal effect of their contents, while having at the same time the mechanical operation due to water alone. In reference to the foregoing uses of diluents, it is to be kept in mind that the lining of the alimentary canal is to all intents a surface, as well as the skin; pretty nearly equal in extent; exercising some similar functions, with others more appropriate to itself; and capable in many respects of being acted upon in similar manner. Medical men themselves, and still more those with whom they have to deal, are prone to attach undue importance to the mere fact of a substance being taken into the stomach, as if this were equivalent to its being received into the system. As respects the subject before us, it is both expedient and correct in many cases to regard diluents as acting on this internal surface analogously to liquids on the skin. And I would apply this remark, not only to the mechanical effects of the remedy, but also to their use as the medium for conveying cold to internal parts; — a point of practice which either the simplicity of the means, or the false alarms besetting it, have hitherto prevented from being duly regarded. - The abstraction of heat from an inflamed or irritable membrane within, is often indeed quite as salutary as the cold directly applied to a hot and dry skin without. The extent of use is from obvious causes much more limited; but I have seen enough of the benefit from cold liquids freely given in the acute stage of gastric disorders, inflammatory and febrile, with express reference to this point of temperature, to justify the recommendation of more frequent recourse to it in practice. This is a point where the feelings and desire of the patient may fairly be taken in guidance, and we can rarely go wrong in following them. The test, in fact, is simple and immediate; depending on sensations which cannot readily be mistaken, and the changes in which not merely suggest the use of the remedy, but indicate the fit extent of its employ ment. The second condition under which diluents may be viewed, as altering certain morbid states of the blood, is one of more difficulty, and connected with questions in physiology and pathology still under active research. Independently of those recent observations of physiologists, which show the natural difference of proportion between the fibrin and serum of the blood in the two sexes, and under different ages and temperaments, we know as matter of fact that there are such morbid states, in which the proportion of water to the solid animal contents of the blood is below the healthy standard. Slight variations of this nature, as well as those of opposite kind, may be presumed to be perpetually occurring; delicate and beautiful though the adjustments of function are, through which the balance is maintained, and all inordinate deviations arrested in their progress. But passing over lesser instances, the singular facts observed as to the blood in the Asiatic Cholera, show the extent to which such change may take place under the influence of |