the plentiful use of opium, hot and nourishing drinks, &c. was able to return to his duty! This inftance of bold and unprincipled proceeding, which is cited by the author with fo much triumph, may ferve to evince the great powers of nature, but can never form the criterion of rational practice or true profeffional skill. Similar confiderations would lead us to disapprove of Dr Jackson's treatment of patients in a convalefcent ftate. Imbued with all the prejudices of the humoral pathologifts, he roundly afferts that relapfe is the general confequence of repletion. Although we fhould be far from recommending the practice of gorging patients during recovery from difeafe, of forcing them to eat against their inclination, or allowing them, perhaps, to indulge fo much in the use of stimulating drinks as they are often inclined; yet nothing, furely, can be more injurious, than to stint convalefcents in their allowance of generous diet, which, when freely exhibited, fo manifeftly tends to aid and accelerate their progrefs towards recovery. So little do we imagine relapse to be the confequence of repletion, that we believe it proceeds, in many cafes, from a contrary caufe; as muft be well known to those whofe profeffional avocations have afforded them the means of knowing the health, and witneffing the mode of living, of the lower claffes of fociety, among whom, chill penury, and its confequent inconveniences, are generally reckoned among the moft common causes of the diforders to which they are fo frequently liable. The Appendix (to which we fhall now direct our attention) occupies about one half of the volume, and adds one to the numerous inftances we already poffefs of the futility of medical theories when founded on no juft or rational data, but when merely the offspring of erroneous deduction or difeafed imagination. A predilection for vague and frivolous hypothefis has long been deemed the opprobrium medicorum; and, indeed, if we examine the history of medicine from its firft origin down to the prefent time, we fhall behold little elfe than a fucceffion of fanciful fyftems, founded on a few fcattered obfervations, and erected, it would often appear, only to gratify the vanity of their projectors, and which have ferved little other purpofe than to perpetuate the folly and abfurdity of the times which gave them birth. The different fymptoms of difeafe have been confounded, and its different ftages blended together; the variety of the primary and fecondary action of remedies has been overlooked; and a few infulated facts have been grafped at, as fufficient to explain all the phenomena of animated nature. In this country, however, where phyfical science has, of late, made fuch rapid advances, phyficians now appear to have run into the oppofite ex M 4 treme; treme; and, from their anxiety to avoid thofe fatal errors of reafoning and practice, to which the fpeculations of too many medical theorists have given birth, have rejected with difdain, and without difcrimination, all attempts to generalize and improve the principies of medical fcience. Hence has arifen an opinion, that all theory in medicine was ufelefs, or, at least, of little moment in a practical point of view; and that experience was the only guide in which a prudent phyfician would confide. This opinion we hold to be equally ill-founded and dangerous; for, whatever difference may exist between the flow deductions of experience and the more prompt conclufions of a theorising mind, there cannot be a doubt, that all legitimate generalisation must rest on the firm bafis of obfervation and experiment. However much, then, we may reprobate the hafty affumption of thofe puerile hypothefes, to which we are fo often referred for proofs of the inutility of theories in medicine, and which, when applied to practice, may undoubtedly prove the fources of pernicious error, we muft, on the other hand, allow, that a fair and cautious induction of general principles may be of the highett utility in medical research, and, by facilitating the acquifition of neceflary knowledge, will give us a more ready and certain command over it when obtained, and enable us to accommodate our practical conduct to the different unforeseen occurrences that are conftantly obtruded upon us in the exercife of our profeffion. Till, however, the rules of the Inductive philofophy be more fully understood and practifed by phyficians; till the fcience of phyfiology be improved, and the fyftem of medical education reformed, we defpair of seeing any extenfive and fuccefsful adoption of general principles in medicine; for it cannot be expected, that mankind will ever be led to acknowledge their importance, till they become acquainted with all the circumitances neceflary for their induction and application. One other caufe, which is, in fome measure, connected with the former, and which powerfully retards the advancement of medical knowledge, deferves to be fpecified, viz. the vague and undetermined ufe of language, and the improper application of terms, borrowed from other fciences, to explain the phenomena of the animal economy in the various ftates of health and difeafe. Thus, the language of chemistry, of mechanics, of morals, and of metaphyfics, has been fucceffively adopted in medicine, without much regard to the propriety of the innovation, and with still lefs concern for the honour of the profeffion, and the general welfare of mankind. The author of the prefent work, however, not content with retracing many of the errors of his predeceffors, has advanced a step beyond them, and, by a free and promifcupus ufe of thofe technical terms with which he was most fami liarly acquainted, has framed a phraseology to defcribe the actions of the living fyftem, which, in ridiculous abfurdity, far eclipses all former attempts of a fimilar defcription, and bids defiance, in extravagancy, to the rhapsodies of Paracelfus, or the reveries of the enthufiaft Van Helmont. Of this jumble of theories, this mixture of languages and confufion of tongues, it is difficult to give any regular and precife account; for, in it, arts and fciences. dance together in various circles of movement,' without any proper time, place, or meafure, fo as, at laft, to produce the molt confufed, chaotic mafs. A few extracts, perhaps, may ac-, complish what no analyfis is adequate to, and ferve to give our. readers fome diftant idea of this curious jargon, which we hope will long remain unique. When detailing the phenomena of febrile difeafes, Dr Jackson's. favourite expreffions feem to be borrowed from the language of profody, and through the whole of his Appendix our ears are tunned with an unceafing and unvarying ring upon the terms, rhythm of movement, rhythmical movement, rule of barmony,' &c. A certain rhythm of movement,' he fays, is a condition infeparable from a living animal body; as the integrity. of the order and force of that rhythm is the index of health.. But as movement is an expreffion of the prefence of life, andrhythmical movement an expreffion of health; fo, the mode of health is liable to be perverted, the motions of the machine to be even finally arrested or annulled.' (p. 188.) Sometimes he affumes the airs of a dancing-mafter; and informs us, that, in health, a variety of operations are carried on in various circles of movement, under different figures or forms of action,' (206.);) and that a change in the rhythm of movement is the first vi fible ftep of action, or even fuppofable ftep of action, arifing' from the operation of the caufes of fever,' (191). Then he plays the part of a teacher of mufic; and, comparing the human body to the inftruments of his profeflion, defcribes the scale of health,' the key of movement;' and fhews us, that the movement of health, though various, is in unifon in the parts and in the whole;' but that the modes in the fcale of perverted rhythm, or difeafed action, appear to be various, and the measure of the movement is different. In fome it is rapid, in others it is flow' (206.); and that means, which tune to harmony in one cafe, loofen the cords of life in another. Now he takes up the tools of the joiner, and frames debility into the primary hinge of action in febrile difeafes' (190.), and bleeding into the cardinal hinge of medical means' (231.); or he borrows the brush and pallet of the painter, to pourtray the various fhades," the variety of configuration,' and the outlines of general character,' of difeafe. Again, he reforts to the terms of mili tary tary art, obferving, that previous to reftoring the natural harmony of movement, it is often neceffary to arreft the irregular courfe of the exifting motions, in order to bring back, with greater facility and certainty, the form of the rhythm which has been loft; in the fame manner as it is often neceffary to cause a military column to halt, when moving incorrectly, fo that it may more eafily lay hold of the regular cadence of the ftep' (230). And, finally, to crown this climax of abfurdity, he calls to his aid the fcience of the bombardier, talks of the explofions' of the excitability of the fyftem, and affures us, that in vitiated atmofpheres febrile motions do not ordinarily explode with force,' (199.); and that there is evidently a point of explosive revolution in the animal machine, connected with time; but not connected with it by a fixed and invariable law, as measured by the artificial hour' (331). One paffage more we fhall take the liberty of fubjoining, as affording a fpecimen of the author's happy talent for fine writing and elegant illuftration. If the apparent debility of fevers be a proper fpecific action, and not the expreffion of the effect of a preceding operation, viz. the perverted or difturbed rhythm of movement, the event is totally inexplicable. Without fupernatural aid, the machine must rest for ever; for debility ftands here like a cart before the horse. In this pofition arofe the vis medicatrix naturæ, like a fairy queen, to put the wheel in motion. The vis medicatrix nature is a loofe term; but it is fupposed to confift in a power given to the animal machine, not explicable by the common laws of its mechanifm, to raise efforts to combat the action of the causes of diseases, and to avert their destructive tendency. It is thus a fpecies of provifional power; and, as fuch, proceeding from wifdom which cannot err, it cannot be supposed to be otherwise than perfect. p. 204. 5. The varieties and caufes of fever naturally arreft our author's attention. With fingular infelicity of language, he terms epidemic difeafe, when it affumes a malignant form, a manufacture from Nature's storehoufe;' and conjectures, that when widely extended, it must be fuppofed to depend upon fome hidden derangement in the materials of the earth,-on a movement of parts into new contact, giving out a new or unufual product.' (221.) The ope ration of contagion he deems to be of a ftimulant nature, loofening, in an inexplicable manner, the hinges of organization." (p. 225.) And here we find another inftance of the want of fyftematic reafoning among phyficians, who argue not from facts, but from the chimeras of their own imaginations; and, without taking the pains to examine whether the phenomena in queftion accord with their defcription, refer them indifcriminate ly to a System, admirable, without doubt, for the fimplicity of its foundation, but deficient to an extreme in the erection and arrangement of the fuperftructure. Among the remedies which Dr Jackfon recommends for reftoring the natural rhythm of movement,' are venefection, bathing, and geftation. Reafoning from the well known confequences of bleeding in cafes of obftructed circulation, Dr Jackfon, with an unparalleled degree of temerity, has inferred, that thefe were the general effects of the remedy; and, because the pulfe was, in fome cafes, remarkably ftrengthened by evacuation, concluded, that its effects are ftimulative.' The idea, that abftraction is directly and unqualifiedly debilitating, and addition the contrary, could only have arifen at the table of the feast. From thence it has borrowed all its illuftrations.' (p. 235. 6.) And in fupport of his reafoning, he, with much fagacity remarks, The abftraction of blood, by its exprefs effect, diminishes the quantity of a body to be moved; and thereby increases the power of the mover: It thus facilitates motion. (p. 237.) But can the Doctor be fo ignorant of the laws of the animal economy, as not to know, that the ftimulus which excites the heart and blood veffels to proper action, is the very fubftance which he abstracts, in order to roufe their energy; and although its removal certainly facilitates the due performance of the functions of the vafcular fyftem, when it forms congeftions near to the centre of the circulation, yet this effect is to be explained in a much more fimple way? But this infatuated adherent to the fyftem of plethora, reafons where he hould have obferved; perverts the moft obvious facts, in order to fubject them to his own erroneous theory; and boldly recommends his rafh pernicious practice to general and almoft unlimited adoption. We know not in what circle the movements of Dr Jackfon's ideas are performed, but we truft that fome remedy exifts in Nature's ftorehouse' for the cure of fuch mistaken judgement, and for warding off the fatal effects that would enfue, were his opinions univerfally received, and his example univerfally followed. In his obfervations on the use of the cold and warm affufion in fever, Dr Jackson, with fentiments of envy, and a spirit of illiberality which we cannot fufficiently deprecate, endeavours to detract from the well-earned reputation of Dr Currie, and arrogates to himfelf the merit of having employed this efficacious remedy as early as the year 1774, although, he allows, the difcoverers are not of this age or country. Let Dr Jackfon, however, remember, that, according to his own ingenuous confeffion, he went out to Jamaica in 1774, at an early period of life, and |