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connecting principle, he afferts that we cannot investigate the ftimuli from this caufe;' and it is indeed true that the fubject is left by our author in the utmoft perplexity: but we may hope that future inquirers, especially fuch as poffefs a more accurate knowlege of animal chemistry, will be more fuccessful in their endeavours. The queftion is important to phyfiology; and those who attempt to folve it fhould have in view the late experiments on milk, a fluid which bears no fmall analogy to blood.

In the fubfequent part of this long chapter, Mr. H. makes ample amends for a mode of reafoning which, if admitted, would introduce univerfal confufion into science. In his idea that the coagulating lymph is the most effential part of the blood, .he coincides with fome preceding phyfiologifts of great celebrity. As a proof of the light which he is often unexpectedly throwing on the practice of medicine, we shall produce the following ingenious paffage :

Reft, or flow motion of the blood in the veffels, gives a difpofition towards the feparation of the red part, as well as when it is extravafated; fince the blood in the veins of an animal acquires a difpofition to feparate its red parts, more than in the arteries, efpecially if it be retarded in the veins; the nearer, therefore, to the heart in the veins the greater will the difpofition for feparation be; though it does not feem to retard coagulation. This is always obfervable in bleeding; for if we tie up an arm, and do not bleed it immediately, the first blood that flows from the orifice, or that which has ftagnated for fome time in the veins, will fooneft separate into its three conftituent parts: this circumftance expofes more of the coagulating lymph, at the top, which is fuppofed by the ignorant to indicate more inflammation, while the next quantity taken fufpends its red parts in the lymph, and gives the idea that the first small quantity had been of fuch fervice at the time of its flowing, as to have altered for the better the whole mafs of blood.'

The fections on the ferum and red globules of the blood contain a variety of facts which may be advantageoufly compared, 1. with the facts related by Mr. Hewfon, and 2. with the later writers on the effect of refpiration on the blood. Our author fupplies many obfervations from the beft of all poffible fourcesthe living human body, by which the late well-known doctrines may be corrected and extended. From p. 76 to 100, the celebrated theory of the living principle of the blood is unfolded. The facts flated in this fection are, we imagine, generally known to those who take an intereft in fuch inquiries, They are doubtlefs important additions to our flock of knowlege; and we are still inclined to think that Mr. H.'s adverfaries have often not been aware that they were raifing a difpute about words. If, according to their ideas, the term life can

not.

not be applied to a fluid, a previous explanation might have prevented the contraversy: but if the term be allowed to be fo applicable, it is not eafy to fhew in what refpect Mr. H.'s experiments are unfatisfactory:-no author, as far as we recollect, has demonftrated their deficiency.

Chapter II. is employed in a difquifition concerning the powers of the vascular fyftem. Mr. H. finds it neceffary to thew that there is in veffels a power of mufcular contraction, and that elafticity is, befides, neceffary to their function. In his preliminary remarks, we find much fubtlety, fome obfcurity, and perhaps a little confufion in arrangement, if not of ideas. The fecond circumftance depends on the enunciation of propofitions without the particular facts on which they reft.

Having clearly, as we think, detected the author in the abufe of general terms, we are apt to fufpect him of fubftituting words for ideas; and we may fufpect this where our own apprehenfion is in fault. Such opinions, however, as the following, through want of farther elucidation, will be in danger of paffing for crude or erroneous, whether they be really fo or not:

• Mufcular contraction has been generally fuppofed to arife from fome impreffion, which is commonly called, a ftimulus; I doubt, however, of an impreffion being always neceffary; and I believe that in many cafes the ceffation of an accustomed impulfe may become the caufe of contraction in a mufcle. The fphincter iridis of the eye contracts when there is too much light; but the radii contract when there is little or no light. I can even conceive that a ceffation of action requires its ftimulus to produce it, which may be called, the ftimulus of ceffation.'

Before the point, however, can be determined, it will be neceffary to take into account the transition of automatic into voluntary motions, and the power of habit. The dependency or independency of contraction on irritation, or impreffion, can only be clearly understood by tracing the motions of any mufcle ab origine.

In Mr. H.'s cafe of the ceffation of an accustomed impulfe, how did the motions take place, before the impulfe was habitual?

In the fubfequent part of this chapter, many of thofe queftions which occur in elementary treatifes of phyfiology concerning the capacity and power of the heart, and the ftructure and functions of the vascular fyftem, are very elaborately difcuffed; and, though all his inquiries hujus loci non funt, we are glad that the facts are come into the poffeflion of the public, even at the expence of order, brevity, and compactnefs, to the prefent

treatise.

Chap. I. of part II. enters on a practical bufinefs of furgery. Its fubject is union by the firft intention; by attending to which principle

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principle our author fo materially improved his art. The ob fervations, as in much of the remainder of the volume, are of fuch a nature as rarely to admit abridgment. The fubo:dinate heads of inquiry are, claffification of injuries and chirurgical difeafes-of injuries, in which there is no external communicationof injuries where the wound communicates externally—practical obfervations on union by the firft intention-of fcabbing-accidents attended with death in a fuperficial part. According to our apprenenfion, it happens to Mr. Hunter, here and on most other occafions, that his efforts at generalization tend rather to perplex than to elucidate the detail of particulars. His aphorifms are generally exceptionable in fenfe or expreffion. All alterations (he fays,) in the natural difpofitions of a body are the refult either of injury or difeafe.' In this propofition, a reader who is attentive to the import of terms muft object to the words natural and difpofitions:—to the first, as indefinite; to the fecond, as metaphorical. This fpecies of minute criticism, however, is fo irkfome, that we shall quit it altogether, after having adduced a fpecimen of metaphyfical pathology, which will remind the reader of the mode of philofophizing prevalent among the rudeft tribes of men: fuch tribes, it is well known, reafoning on all phænomena from the analogy of human intelligence.

There is a circumftance attending accidental injury which does not belong to difeafe, viz. that the injury done, has in all cafes a tendency to produce both the difpofition and the means of cure.

The operations of restoration arife naturally out of the accident itself; for when there is only a mechanical alteration in the structure, the ftimulus of imperfection taking place, immediately calls forth the action of restoration; but this is contrary to what happens in disease ; for difeafe is a difpofition producing a wrong action, and it must continue this wrong action till the difpofition is ftopped, or wears itself out; when this falutary effect, however, has once taken place, the ftate of the body becomes fimilar to that in a fimple accident, viz. a confcioufnefs of imperfection is excited, which produces the action of restoration.'

The many admirable practical remarks contained in the present volume are not indeed the worfe for their contiguity to paffages of a contrary nature: but the book is rendered tedious, and its utility is confequently circumscribed.

Chap. II. contains general remarks on inflammation, which fhew that the treatife before us is replete with paffages that may gratify inquifitive readers of all denominations. We have here, likewife, much nice and valuable difquifition, on fubje&s not commonly confidered as lying within the furgeon's province. It will well reward the effort which is neceflary to comprehend it thoroughly. Chap.

Chap. III. on the adhesive inflammation, is divided into fourteen fections; and it is indeed dives opum variarum. In Sect. I. we find a fatisfactory account of the dilatation of the vessels of inflamed parts; and the only remaining question is, whether the fyftole does not exceed the natural ftate as much as the diaftole; for, if this be fo, Mr. H.'s practical views will prove to be falfe. From Sect. II. we fhall introduce a paffage illuftrative of his remarkable accuracy of obfervation:

Many parts of the body in a natural ftate, give peculiar fenfations when impreffed; and when thofe parts are injured, they give, likewife, pain peculiar to themselves; it is this latter effect, which I am to confider. I may alfo obferve, that the fame mode of impreffion fhall give a peculiar fenfation to one part, while it shall give pain to another. Thus, what will produce fickness in the ftomach, will produce pain in the colon. When the fenfation of pain is in a vital part, it is fomewhat different from most of those pains that are common. Thus, when the pain arifes from an injury done to the head, the fenfation is a heavy ftupifying pain, rendering the perfon affected unfit to pay attention to other fenfations, and is often attended with ficknefs, from the ftomach fympathizing with it.

When the pain is in the heart or lungs, it is more acute, and is very much confined to the part diseased.

When in the ftomach and inteftines, efpecially the upper part of them, it is a heavy oppreffive fickly pain, but, more or lefs, attended with fickness, according to its preffure or proximity to the ftomach; for when fituated in the colon, it is more acute, and lefs attended with fick nefs.

We cannot give a better illuftration of this, than by taking notice of the effects of a purge. If we take fuch a purge as will produce both fickness and griping, we can easily trace the progrefs of the medicine in the canal; when in the ftomach it makes us fick, but we foon find the ficknefs becoming more faint, by which we can judge that it has proceeded to the duodenum, and then a kind of uneafinefs, approaching to pain, fucceeds; when this is the cafe, we may be certain that the medicine is paffing along the jejunum; it then begins to give a fickish griping pain, which I conceive belongs to the ilium; and when in the colon it is a fharp pain, foon after which a motion takes place.'

In Sect. III. we are fhewn, by a variety of conclufive experiments, that the heat of an inflamed part is increased much lefs than would be expected from curfory obfervation. A local inflammation never increases the local heat beyond the ftandard of temperature of the animal; and in a diftant part it does not reach fo high. We are rather furprized that the author miffed fo fine an opportunity of expatiating, as these facts afforded him. He himself feems to have unwarily adopted a conclufion very different from that to which they really lead: but the reflecting. reader will find evidence of a great production of heat; a great accumulation feems hardly poffible.

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Sect. IV., on the production of cold in inflammation, contains little to the purpose of this treatife, and indeed little to the purpose of pathological knowlege: it extends only to two pages. Proof is ftill wanting of that power to produce cold, with which fome phyfiologifts think the more perfect animals endowed.

Sect. V., on the period, &c. of adhesive inflammation, affords fome curious opinions, e. g.

I fufpect that a bliftering plafter only kills the parts, uniting the cutis and cuticle, by which means an irritation is produced in the cutis, and the extravafation is according to that irritation.'

Sect. VI., on the uniting medium in inflammations, contains original and excellent obfervations on the appearances exhibited by the coagulating lymph, when fecreted during inflammation. These facts will perhaps one day ferve to illuftrate the obfcure fubject of generation itself:

In a vast number of inftances, I have observed, that in the subftance of the extravafation, there were a great number of spots of red blood in it, fo that it looked mottled. The fame appearance was very obfervable on the furface of feparation, between the old fubftance and the new, a good deal like petechial fpots. How this red blood got here is the thing to be confidered, especially as a good deal was within the fubftance of the coagulum. Was it extravafated along with the coagulating lymph? In this cafe, I fhould have rather fuppofed it would have been more diffafed, and if not diffused, more attached to the intestine, and not in the centre of the coagulum; if it had been extravafation, one would have expected extravafation of injection, but we had none in any of thefe places; I have therefore fufpected, that parts have the power of making veffels and red blood independent of circulation. This appears to be evidently the cafe with the chick in the egg.'

Sect. VII., on the condition of the blood and of the pulse in inflammation, does not appear to us of fo much importance as

feveral of the others.

Sect. VIII. Inflammation produces different effects on the whole fyftem, according to the structure and fituation of the parts inflamed. Of the fpirit and tenour of this portion of our author's doctrine, the following paffage will give fome conception :

In common parts, as mufcle, cellular membrane, skin, &c. the fymptoms will be acute; the pulfe ftrong and full, and the more fo, if it be felt near to the heart; but perhaps not fo quick as when the part is far from it; fince there will be lefs irritability. The ftomach will fympathize lefs, and the blood will be pushed further into the fmaller veffels.

If the inflammation is in tendinous, ligamentous, or bony parts, the fymptoms will be lefs acute, the ftomach will fympathize more, the pulle will not be fo full, but perhaps quicker, because there will be more irritability, and the blood will not be fo much pushed into the fmaller veffels, and therefore forfake the skin more.'

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