besides, many other affections of the brain, arising from poison, for instance, or opiates, (the nature of whose operation we know very little about,) in relieving which, these famous cephalics would not be worth a straw; while a draught of warm water given in time is often of the greatest utility, if repeated vomiting is produced, (as Wepfer abundantly proves in his elaborate work on water hemlock,) although the warm water does not contain a grain of any aromatic, either of odour or flavour, which all our common cephalics abound in. I do not deny that the cephalics already mentioned, may often in the more simple cases, recruit the languid powers of the body; but a prudent practitioner will not draw an argument from the effects of medicines in simple and trivial cases, to more complicated and serious ones."

But to these epithets of medicaments just related, they add others of a different kind, which because they possess more manifest and certain effects, and are placed under more appropriate titles, you may say ought to be retained: such are calefacients, soporifics, dissolvents, incrassants, purgatives, diuretics, &c. since there are diseases in which calefacients are necessary, others where soporifics, dissolvents, purgatives, &c. are of great benefit. But although these are liable to fewer objections, yet there is no small degree of uncertainty attached to them, since it is obvious that medicines of very different powers are comprehended under the same title, and that some of them are better suited to particular states of disease than others; so that the right use of any of them must depend entirely on an accurate knowledge of the history of the disease."

Near the end of this dissertation, he makes some very proper observations on the absurdity of jumbling a great number of simple remedies together in the same prescription, and thinks, Quo simplicius eo melius. This ground, however, has been so often gone over before, that nothing new can be expected.

The discourse concludes with a panegyric on their noble patron the Duke of Chandos.

The second Dissertation is on the natural method of curing dis eases employed by the ancients before the discovery of the circulation of the blood by Harvey. Having in his first dissertation demonstrated, what he considers as the miserable state in which the materia medica was in his time; in this second, he proposes a plan for improving it. "I shall endeavour, says he, to demonstrate that great improvement may be made in the cure of diseases, if we begin with a correct knowledge of the use of remedies: but that this knowledge can only proceed from a correct and accurate know. ledge of the history of diseases; for from a complete history of a disease there naturally arise certain indications of cure, by means of which we are led to remedies suitable for that purpose." 6. I am, continues he, the more confident in this opinion, because I observe the great founder of our science to entertain the same seniments; a physician, he says, is sufficiently prepared to cure it

who knows the disease sufficiently: and Sydenham also, the great modern cultivator of simplicity in practice, says, I have often thought that if I had a clear knowledge of the history of any disease, I could always find a suitable remedy.' But not designing to accumulate great authorities only, I shall endeavour to give such an explanation of this simple plan of practice, that any one may be able to judge of it for himself." He then states the first steps which were taken to bring medicine into the form of a science, and these were merely observing and noting down the various symptoms that occurred in different stages of the same disease, and in persons of different ages or constitutions. This practice continued long before any attempt was made to adopt specific remedies, either to symptoms or diseases, unless, perhaps, cold water for thirst or febrile heat. He thinks this diligent and patient observation of symptoms, without interfering with Nature's operations, was the parent of those general conclusions respecting the event of certain signs and symptoms, called aphorisms. Before the discovery of Harvey, he thinks it would have been impossible to frame any rational theory for the practice of medicine, and that therefore the best rule was to rely on the simple palliatives or remedies which accident had discovered; that a knowledge of the history and obvious causes of any disease, together with the state of the functions at the time, were always sufficient to enable the physician to regulate the diet of the patient, which long continued to be the principal materia medica. Nature would very early point out several purgatives, astringents, sternutatories, and emetics, both in the vegetable and mineral kingdom; which, with baths, fomentations, and frictions, in conjunction with diet, would form no inconsiderable apparatus medicaminum.

Furnished with these instruments, and ever intent on the progress of symptoms in each disease, such aphorisms as the following would soon suggest themselves to a discerning practitioner.

1. An attack of sneezing cures the hiccup.

2. The dropsy is cured by a determination of the water to the bowels or kidnies, so is leucophlegmasia.

3. A troublesome diarrhea is cured by a spontaneous vomiting. Many such would be collected and treasured up to form a practical system of medicine; and such really was the system of the ancients, before anatomy or chemistry could have contributed much towards its perfection.

After this view of the simple system of the ancients, he proceeds to establish his second proposition, viz. "Diseases cannot be rationally cured by any medicines, or any auxiliary means which are not made subservient to certain indications, and directed to the fulfilment of them; any other attempt is only rash empiricism."

This proposition, which probably tew will be disposed to controvert, in his sense of it, he supports by arguments of his own, and the authorities of Celsus, Pitcairn, Boyle, and Sydenham. There are, however, some diseases in which the remedies already known

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are of no avail, such as hydrophobia; and surely no one would contend that we ought to remain satisfied, without attempting to discover others that are more efficacious; or else some more suc cessful manner of employing those we have; and this we think can only be done by trials, or empiricism directed by analogy. We cannot, therefore, agree with him in the opinion that medicine may, and ought always to be cultivated precisely in the same manner as astronomy, that is, by means of observations alone. He says that Sydenham always conformed to this rule, and by so doing, advanced far beyond all his predecessors and contemporaries.

He concludes, that all rational practice ought to arise from indications, presented by an attentive study of the history and symptoms of the disease, and never to be directed by any supposed theory concerning its nature or causes. That theory, usurping the place of observation, gave birth to those absurd classes of remedies, such as acids, alcalines, solvents, incrassants, &c.

The third Dissertation is entitled an inquiry into the importance of the humours of the body, in a medical view, and how far they may be deteriorated by cold.

After an introduction of considerable length, in which he states the impossibility of explaining the secretions of the different fluids of the body, on the principles of chemistry, hydraulics, or hydrostatics; he lays it down as a medical fact, founded on observation, and which he denominates very properly, as we think, " res observatu dignissima.” "That no defective action ever takes place in the solids of the body, which is not attended with a corresponding deterioration of the circulating and secreted fluids; and that as soon as the due action of the solids is restored, the defects in the fluids begin to disappear."

Hence, he infers, we may understand why the healthy and vigorous action of the solids in the hardy rustic, produce from meagre cheese, salted and dried beef or bacon, better juices than the pampered Peer can from living milk and animal food, that has scarcely lost the vital principle. Having established this dependence of the sanity of the fluids on the due action of the solids, he proceeds to inquire into the effects of cold upon the condition of the humours of the body; respecting which, so many difficulties and disputes have so long agitated the professors of medicine.

Sanctorius appeared to have solved the problem by his important discovery and demonstration of the insensible perspiration, which being much impeded, or totally obstructed by cold, must deterio rate the humours, by retaining effete or pernicious portions of them within the body, which ought to be carried off by that outlet.

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This highly popular theory was first assailed by our countryman Dr. Keil, who contended on the other hand, "That some noxious principles were introduced into the system by the exposure to cold, which coagulated the fluids, and produced those aggravated symp toms which Sanctorius ascribed to the retention of excrementitious fluids.

Our author decidedly prefers the theory of Dr. Keil, which, he says, corresponds with the ancients, and blames Sanctorius for rejecting it. He, however, rejects both, and proposes the following one of his own. "Nature has established so just and nice a balance between the circulating powers of the heart and arteries, and that of the returning veins and secreting organs, that no impediment can take place in any of the latter, without great and ma nifest derangement in the former." For the demonstration of this fundamental proposition, he refers to Theophilus Benedictus, and the injections of Ruysch, which, he says, sufficiently prove," that any extraordinary power pressing upon, or urging the extremities of the circulating vessels, must necessarily produce great extravasations of fluids in every part of the body." Here we see that this enemy of theoretical speculations, is indulging in one as wild, and apparently as ill-founded, as any of those that he so severely coudemns.

Taking his theory for granted, and the well-known properties of cold in condensing all fluids, especially the animal fluids; he says, all the symptoms arising from cold, will admit of a very easy explanation. For the most remarkable effects of cold, are catarrhs and glandular tumours, in which the secreting vessels are impeded in their action by the debilitating powers of this pernicious agent, while the blood retiring from the surface, is thrown with greater force on the internal parts. The illustration and confirmation of this theory is as wild as the theory itself. The whole rests upon lentor, elasticity, and those applications of mechanics, hydraulics and hydrostatics, which became so fashionable for some time after the discovery of the circulation. Defluxions from the head and bronchiæ are made to depend much more on the moisture combined with the cold, than on the cold itself, and appeals to our feelings in confirmation of the opinion.

His plan of cure in diseases proceeding from cold, is precisely the same as that of all rational practitioners, whatever their theory may have been, or in whatever times they may have lived. He employs blood-letting, general or topical; laxatives, low and diluent diet; and the most effectual means of restoring a free circulation in the obstructed vessels on or near the surface, by warmth, friction, fomentations, blisters, &c. He does not omit, however, to guard us against the danger of pushing any of these so far as to induce inordinate debility in the patient.

After these means have been employed, if a rheumatism should assume the chronic character, he advises chalybeates and other tonics. In local inflammations proceeding from cold, he thinks lo cal remedies will be sufficient,

The fourth Dissertation, is a continuation of the preceding. In this the professor combats the humoral pathology, which makes diseases to depend upon, and arise from, a depraved state of the fluids, instead of the imperfect action of the solids.

The opinion of the professor is now. so 'universally received, that

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we do not think it necessary to do more than point out the foundations of his several arguments in support of the muscular and nerv. ous pathology, in opposition to the humoral. This subject, indeed, has been so ably discussed by Hoffman, Cullen, Brown, Beddoes, and Darwin, that we need only to refer to their works. He grounds his arguments, in the first place, on sympathy, which cannot be supposed to depend on the fluids. The instances of sympathy, which he principally lays a stress on, are those arising from an irregular or defective action of the uterus, in chlorosis, and emansio mensium; increased action of the uterus and its vessels in preg. nancy and menorrhagia, which are known to affect the functions of the stomach, the action of the heart, and the secreting glands of the whole body.

Hysteria is with reason much dwelt on, as this can have nothing to do with the humoral pathology, and must be referred to the mind or sympathy.

The stomach and heart are liable to be affected by passions of the mind so violently, as to have their actions suspended or inverted; and the former is often sympathetically affected by the diseases of the kidnies, ureters, bladder, or urethra. Spasmodic diseases, as may be expected, are not overlooked, of which no one suspects any derangement of the fluids to be the cause.

The liver and its secretion are laid much stress on by the supporters of the humoral pathology; Dr. Simpson, therefore, enters into this subject at considerable length, and explains the derangements supposed to depend on the vitiated state of the bile, to arise from its quantity, or the obstructions to its excretion; that diarrhæa, or the opposite state of the bowels, depends on `muscular and nervous action, not on the quality of the fluids; and concludes his dissertation, by referring the effects of emetics, purgatives, and poisons, to their stimulant action on the solids, not to any change they can possibly produce in the fluids in their primary operation. The Thesis on Croup, by Dr. James Simpson, printed in 1761, contains nothing interesting to practitioners at present; and the same may be said of the Thesis on the nature and use of purgatives.

Such are the contents of these Latin Essays, written long ago, which Dr. Duncan has judged it proper to re-publish in 1809. Whether they are re-published on account of the matter they contain, or as a model of style for the imitation of the students, for whose use it is now printed, we leave to those who may read them to determine,