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most solid proofs of their good will. The reply of this small but vir tuous and unambitious state was such as to afford a lesson both of political and moral wisdom to all the nations of Christendom.--. We place, (said they) citizen ambassador, in the number of the most glorious epochas that have distinguished the annals of our freedom, the day of your mission to our republic. Your republic not only conquers its enemies by the force of its arms, but fills its friends with amazement at the generosity of its proceedings. The love of our liberty makes us feel the worth of the magnanimous exertions of a great people aspiring to recover their own. Those exertions have surpassed all expectation. Your nation, single against the rest of Europe, has afforded the world an astonishing example of what that energy can achieve which is produced by the sentiment of liberty. -Your army, marching in the steps of Hannibal, and surpassing by its deeds whatever is most wonderful in antiquity, led on by a hero who unites to every virtue the powers of the most distinguished genius, has cast a glance on a corner of the globe where a remnant of the sons of liberty fled for refuge, and where is found rather the plainness of Spartan manners than the elegance of Athens. You know, citizen ambassador, that the simplicity of our customs, the deep sentiment we cherish of liberty, are the only inheritance which has been transmitted to us by our fathers : this we have been able to preserve untouched amidst the political convulsions which have taken place in the succession of many revolving ages, and which neither ambition nor hatred has been able to destroy. Return then to the hero who has sent you : Carry back to him the free homage not only of that admiration which we share with the whole world, but also of our gratitude : Tell him that the republic of St. Marino, satisfied with its mediocrity, fears to accept of his generous offer of enlarging its territory, which might in the end prove injurious to its liberty."

• Here then is a striking and instructive instance of a community enjoying in grateful contentment their beloved and enviable freedom while a thousand years have rolled away, and who, satisfied with the peaceful possession of their native mountain, refuse to hearken to the most tempting offers of an enlargement of their dominion. What a contrast to the wieked and absurd policy of those Christian countries which, great in riches, in extent of territory and population, place their clief glory in subjecting to their tyrannical yoke the farthest ‘regions of the globe, whose weak and unoffending inhabitants could never have afforded the slightest pretext for inflicting upon them these atrocious injuries, and who have no knowledge of their con querors, but in the character and capacity of oppressors, plunderers, and assassins !' P. 360.

From these extracts our readers will form their opinion of a work which is evidently written on the spur of the oce casion : and we may rather' applaud the author for his dispatch in a concern of such magnitude, than blame him for not obtaining ends which require much time, long meditation, accurate investigation, and nervous and animated diction. The work is written with an easy flow: it brings together events nearly as they occurred in the order of time, and may be perused with pleasure by those who are hostile to the late minister. If some of the political reflexions, which might serve as food for essays, were expunged, the work would receive no injury : low expressions should be obliterated, and the correcting hand of the writer may be often advantageously employed. The reflexion, with which the history concludes, shall terminate our remarks ; and it is no bad specimen of the author's style, and his mode of winding up a period.

· Thus, by the profligate ambition and presumption of the French directory on the one part, and the pride, folly, and mischievous activity of the British administration on the other, was a war, which appeared well nigh terminated, re-commenced with additional fury; seeming but too likely to extend to a long succession of calamitous and mournful years, destined to be recorded in letters of blood. But the terrified imagination sees pourtrayed, on the veil which conceals futurity from mortal view, frightful forms and ominous characters, bearing little resemblance to the events actually pre-ordained, in the course of human affairs, to take place.' P.533.

Art. IV.-Philosophical Transactions of the Royal Society of London. For the Year 1801. Part I. 175.

Part I. 175. sewed. 4to. Elmsly. THE first article in this interesting volume is · The Croonian Lecture, on the Irritability of Nerves, by Everard Home, Esq. F.R.S.' The case that suggested the author's inquiries and experiments was by no means a singular one. A person thirty-six years of age, of an irritable habit, was thrown from a horse with his whole weight on his thumb. The part swelled and became subject to spasms and paralytic affections, which in time extended to the head, and terminated in death. The injury, as is evident from concomitant circumstances, existed in the median nerve, which was divided as it passes from under the annular ligament, but without success. This injury miglit have been varied; the divided extremity might have adhered to the external wound, and been affected by its inflammation: it is at least certain that wounded and divided nerves do not heal easily, and it is equally certain that injuries at the divided extremities of nerves are referred to those extremities which existed previous to the division. The circumstances however show that irritation did continue at the extremity next the arm, and it is singular that no attention was paid to the irritated part. Mr. Home's views in the present article are directed to a very different quarter, viz. the contraction of the nerves themselves, independently of the muscular fibres. He divided, therefore, different nerves of animals, alive, and immediately after being killed. He found the contraction considcrable, and, cateris paCrit. Rev. Vol. 34. Jan. 1802.


ribus, uniform. We cannot enter into any controversy on the subject, because it would lead us too far; and shall only remark, that the language of experimental physiologists has been, unequivocally, that the nerves do not contract when divided; that our author's experiments are peculiarly doubtful, because he raised the nerve on a bistory, or divided it with a pair of scissors. Various physiologists would have told him that compressing the severed end of a nerve which leads to a muscle would have made it contract, and its elevation on a bistory, or its compression by the closing blades

of a pair of scissors, must certainly produce the same effect. The contraction of the muscle, as it shortens that organ, must of course excite a retraction of the separated nerve. In his experiments also he ought not to have included the coats of the nerve, which are certainly elastic, and not without suspicion of being muscular. He cannot hence, therefore, predicate irritability of nerves, which, if it were observable in his experiments, might be derivable from their tunics. On the whole, we think the present article, either in point of reasoning or observation, wholly inconclusive, and perhaps unworthy of a place in the present very respectable collection.

' II. The Bakerian Lecture. On the Mechanism of the Eye. By Thomas Young, M.D.F.R.S.'

This paper, in many views excellent, is designed chiefly to support our author's opinion, that the eye is adapted to vision, at different distances, chiefly, if not entirely, by the muscular fibres of the crystalline lens or its coat. We cannot give an adequate view of the whole, but shall follow Dr. Young so far as our circumstances will permit.

He begins with considering the refractive power of a variable medium, applying his observations to the structure of the crystalline lens. This part, from its mathematical form, is incapable of abridgement; but we must particularly mention with approbation his very simple and accurate instrument, the optometer, founded on the same principle, and for the same purposes, with that described by Dr. Porterfield in the fourth volume of the Medical Essays of Edinburgh. We ought perhaps to select our author's determination of the refractive power of the crystalline lens, and his remarks on the causes of the different conclusions on this point.

• For determining the refractive power of the crystalline lens by a direct experiment, I made use of a method suggested to me by Dr. Wollaston. I found the refractive power of the centre of the recent human crystalline to that of water, as 21 to 20. The difference of this ratio from the ratio of 14 to 13, ascertained from calculation, is probably owing to two circumstances. The first is, that the substance of the lens being in some degree soluble in water, a portion of the aqueous fluid within its capsule penetrates after death, so as somewhat to lessen the density. When dry, the refractive power is little inferior to that of crown glass. The second circumstance is, the unequal density of the lens. The ratio of 14 to 13 is founded on the supposition of an equable density: but, the central part being the most dense, the whole acts as a lens of smaller dimensions; and it may be found by Prop. VII. that if the central portion of a sphere be supposed of uniform density, refracting as 21 to 20, to the distance of one half of the radius, and the density of the external parts to decrease gradually, and at the surface to become equal to that of the surrounding medium, the sphere thus constituted will be equal in focal length to a uniform sphere of the same size, with a refraction of 16 to 15 nearly. And the effect will be nearly the same, if the eentral portion be supposed to be smaller than this, but the density to be somewhat greater at the surface than that of the surrounding medium, or to vary more rapidly externally than internally. On the whole, it is probable that the refractive power of the centre of the human crystalline, in its living state, is to that of water nearly as 18 to 17 ; that the water imbibed after death reduces it to the ratio of 21 to 20; but that, on account of the unequable density of the lens, its effect in the eye is equivalent to a refraction of 14 to 13 for its whole size. Dr. Wollaston has ascertained the refraction out of air, into the centre of the recent crystalline of oxen and sheep, to be nearly as 143 to 100; into the centre of the crystalline of fish, and into the dried crystalline of sheep, as 152 to 100. Hence, the refraction of the crystalline of oxen in water should be as 15 to 14: but the human crystalline, when recent, is decidedly less refractive.

These considerations will explain the inconsistency of different observations on the refractive power of the crystalline; and, in particular, how the refraction which I formerly calculated, from measuring the focal length of the lens, is so much greater than that which is determined by other means. But, for direct experiments, Dr. Wola taston's method is exceedingly accurate.' P. 41.

The whole extent of the retina is not equally sensible, nor is its vision equally perfect: the imperfection, Dr. Young remarks, begins within a degree or two of the visual axis, and at the extent of five or six degrees becomes nearly stationary; but, at a still greater distance, is principally, if not wholly extinguished. The imperfection is owing to the unavoidable aberration of the oblique rays, but chiefly to the insensibility of the retina, throughout its whole extent; the sensible portion of which probably coincides with the painted choroïd of quadrupeds. In general, the retina is of such a form as to receive the most perfect image on every part of its furface that the state of each refratted pencil will admit; and the varying density of the crystalline ren«lers that state capable of delineating such a picture to the greatest advantage. This contrivance is truly a beautiful one, and it is here admirably developed; but, with all the advantage it affords, the eye is seldom perfectly achromatic. Our author next considers more particularly the faculty of the eye of accommodating itself to the different distances of an object, and inquires whether it may arise from the diminution of the radius of the cornea, the increased distance of the lens from the retin:1, or a change in the figure of the lens itself. We need scarcely observe that Dr. Young decides in favour of the latter cause, in support of which his arguments and experiments are highly judicious and well contrived. We dare not say that the proposition is demonstrated: but, in Dr. Young's hands, it has attained an elucidation and degree of evidence which we scarcely ever expected to have found. He admits, that the action formerly attributed to the external coats cannot afford a solution of the phænomenon. The change must be in the lens itself. He thinks he can trace nerves not wholly into the lens, but very nearly approaching it; and, on the whole, is of opinion that it must be considered as a muscular organ.

• I consider myself as being partly repaid for the labour lost in search of the nerves of the lens, by having acquired a more accurate conception of the nature and situation of the ciliary substance. It had already been observed, that in the hare and in the wolf, the ci. liary processes are not attached to the capsule of the lens ; and if by the ciliary processes we understand those filaments which are seen detached after tearing away the capsule, and consist of ramifying vessels, the observation is equally true of the common quadrupeds, and, I will venture to say, of the human eye. Perhaps this remark has been made by others, but the circumstance is not generally understood. It is so difficult to obtain a distinct view of these bodies undisturbed, that I am partly indebted to accident for having been undeceived respecting them: but having once made the observation, I have learnt to show it in an unquestionable manner. I remove the posterior hemisphere of the sclerotica, or somewhat more, and also as much as possible of the vitreous humour, introduce the point of a pair of sciszars into the capsule, turn out the lens, and cut off the greater part of the posterior portion of the capsule and of the rest of the vitreous humour. I next dissect the choroid and uvea from the sclerotica; and, dividing the anterior part of the capsule into seginents from its centre, I turn them back upon the ciliary zone. The ciliary processes then appear, covered with their pigment, and perfectly distinct both from the capsule and from the uvea; and the surface of the capsule is seen shining, and evidently natural, close to the base of these substances. I do not deny that the separation between the uvea and the processes extends somewhat further back than the separation between the processes and the capsule ; but the difference is inconsiderable, and in the calf does not annount to above half the length of the detached part. The appearance of the processes is wholly irreconcileable with muscularity; and their being considered as muscles attached to the capsule is therefore doubly inadmissible. Their lateral union with the capsule commences at the base of their posterior smooth surface, and is continued nearly to the point where they are more intimately united with the termia nation of the uvea ; so that, however this portion of the base of the

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