Traité de l'Exiflence, de la Nature, et des Proprietes du Fluide, des Nerfs, et principalement de fon Action dans le mouvement Mufculaire. A Differtation on the Exiftence, Nature and Properties of the nervous Fluid, and particularly of its action in the Motion of the Mufcles. To which are added, Obfervations on the Senfibility of the Ligaments, Tendons and other Parts, the Infenfibility of the Brain, the Structure of the Nerves and the Hallerian Doctrine of Irritability. By M. Le Cat of Rouan. 8vo. Berlin. 1765. A BOUT ten or twelve years ago, the royal academy of fciences at Berlin, propofed, among its prize-questions, the following anatomical queries? Query 1. Whether the communication which is observed between the brain and the mufcles, by means of the nerves, is effected by a fluid which fwells the mufcle during its action. 2. What is the nature? and what are the properties of that fluid? 3. In what manner it can produce in the mufcles, that furprizing mode of action, in which motion and reft inftantaneoufly and reciprocally fucceed each other? The differtation before us was written in answer to these queftions, and had the honour of obtaining the prize. Its very ingenious Author, in order to proceed with regularity and precifion, hath divided it into four parts. In the first, he undertakes to demonftrate what the academy had fuppofed, viz. " that the motion of the mufcles and mufcular parts, depends principally on that connection which fubfifts between the brain and the mufcles, by means of the nerves." He obferves notwithstanding that this dependance is fubject to certain reftrictions and limitations it being notorious that the heart may be taken out of many kinds of animals, and of course all the nerves communicating thence to the brain be cut in two, and yet the heart will continue to beat fome minutes, nay in fome cafes, fome hours, after fuch feparation: although in the end it proves effectual in depriving the organs of all life and motion. Hence, fays M. Le Cat, we fee evidently the neceffity of a connection between the heart and the brain, in order to fupport life and motion in general; and at the fame time, that fuch connection is not effentially neceffary to every fingle motion of thofe organs; or in other words that its exertions are not fimultaneous and correfpondent to every one of thofe moments in which those motions are made. The nerves, we are told, are not the only canals whofe affiftance is neceffary to enable the mufcles to per form form their respective functions; nor doth the arterial blood contribute to their motion only, by fupplying the materials neceffary to their moving force. M. Le Cat confirms, by feveral inftruments, the affurances of Vieuffens and Stenen, concerning a mufcle's becoming paralytic on tying up the nerves that lead to it. He concludes, hence, therefore that the connection between the muscular parts and the brain, is the first and principal circumftance that is effentially neceffary to the motion of the primary organs; that the connection of the heart with the fame mufcles by means of the arteries, is the fecond; and that both one and the other is neceflary to their motion only as the mediate and general caufe, but not as the immediate and fimultaneous caufes of every fingle motion. Under the fecond head, our ingenious anatomist endeavours to prove that the communication between the brain and the mufcles, by means of the nerves, is effected by a fluid. This communication, fays he, can be effected only in two methods; either by means of the folid fubftance of the nerves, or by a fluid that is contained in their cavities. Several of the anatomifts have maintained that the nerves act only as claftic chords ; but our Author combats this opinion with great appearance of reafon; concluding that their action fhould be imputed to the fluid contained in thofe capillary tubes, of which each nerve is a congeries. To confirm his opinion in this refpect, he cites the experiment of Bellini in regard to the ligature of the diaphragmatic nerve. In the third part of this differtation, the Author admits, however, that, notwithstanding the existence of this nervous fluid is indubitable, its properties are but little known. It bears fo little refemblance, he thinks, to the other fluids of the human body, that we can form no just conception of it, by comparing it with any other fluid or material fubftance whatever. Hence, he defines it, as the inftrument both of motion and thought; a kind of middle fubftance between the foul and body; an amphibious fpecies of being, that is material from its impenetrability and impulfive force, though of the higher order or first clafs of material fubftances. At the fame time, he conceives it is nearly allied to immaterial Beings; by which it is capable of being affected in a manner totally different from thofe means which are dependant on mechanical principles. But M. le Cat is a much better anatomist than a metaphyfician, we fhall therefore pafs over the rest of his reveries on this fubject. In the fourth and laft part of his treatise, this Writer explains the mechanifm, or mode of action, in which he conceives this fluid is capable of effecting mufcular motion. This motion, he fuppofes, not to depend folely on the particular action of In of the fluid, but alfo on the ftructure of the mufcles. treating of this structure, he fhews that the fibres of which the mufeles are compofed, are cylindrical tubes, filled with a kind of reticular, cellular or medullary fubftance, fomewhat resembling what is included in the hair or in quills. He conjectures the nerves and fanguinary veffels are joined to thefe cavities, and fupply them with their respective fluids. Now thefe fluids, fays he, dilating the above-mentioned fibres or their interftices, will neceffarily shorten them, and of courfe contract the mufcle. Thus, there is discharged from the nerves into the muscles a nervous, animated lymph, a kind of vital fluid, to which M. le Cat conceives that the foul itfelf is immediately united. In treating of the fenfibility of the ligaments, tendons and fome other parts of the body, M. le Cat, undertakes to proxe in contradiction to M. Haller, that the dura & pia mater, the membranes, ligaments and tendons are all fenfible, and that the fubftance of the brain is infenfible. The hofpital, to which our Author is principal furgeon, hath afforded him opportunities of making many of thofe experiments on human bodies, which M. Haller could only make on brute animals: fo that what is advanced by our experienced anatomift on this head, appears to be well worthy the attention of thofe, who wish to be acquainted with this curious fubject. Le Siege de Calais, Tragedie, dediée au Roi, par M. de Belky. The Siege of Calais, a Tragedy, dedicated to the King, by Mr. de Belloy; reprefented for the first Time, by his Majefty's Company of Comedians in ordinary, on the 13th of Feb. 1765. 8vo. Paris 1765. F OR the ftory on which this Tragedy is founded, the Reader may turn to Rapin, Smollet, or indeed almost any of our hiftories of England. The Author hath taken the liberty, indeed, to introduce an epifode, not immediately connected with the main fubject of the piece. This is very allowable, however, in poets, whom we do not expect to be ftrictly bound down to historical truth. Not that the events of this epifode are imaginary, altho' they did not happen exactly in the fame relations of time and place; the poet piquing himfelf on deducing all his facts from hiftory, in order that he might not be charged with imputing imaginary virtues and fictitious exploits to his countrymen, in a work undertaken with a view to the fupport of their national honour. The The fuccefs this Tragedy met with on the French stage, furpaffed every thing of the like nature that hath happened for fome years. The King bestowed the moft fignal marks of his approbation and beneficence on the Author; while the court and city crowded nightly to its representation on the theatre. The French, indeed, could not, both in gratitude and policy do lefs on this o cafion. The recent and repeated inftances of dishonour they had fuftained in the field and on the ocean, called for their utmost acknowledgments to the poet, who could make their faded glory blossom on the ftage, and effect that with a few ftrokes of his pen, which their generals and admi rals were unable to effect with their fwords. The piece is extremely well calculated for the end it was intended to ferve; it is alfo well written, but will appear very little affecting to those who are not interested in the national vanity of the French, with regard to their valour and loyalty. M. de Belloy feems to have had Mr. Addison's tragedy of Caro in his eye, particularly in the patriotic declamations of St. Pierre; many of whofe fentiments are noble and well expreffed. We fhall give our Readers an inftance or two: In Scene 4th of Act 4th this heroic magiftrate with his fon, Aurelia, Alienor, the Governor's daughter and fix citizens, are reprefented as prifoners in King Edward's camp. They are in doubt about their fate, as the King had intimated his defign of putting the family of St. Pierre, the mayor, to death, when Alienor acquaints them that he had prevailed on the Prince of Wales to release her father St. Vienne; who was gone to the King of France, in order to procure fome interceffion with Edward to fave their lives. Ali. Vous connaissez Valois, & le tendre retour St. P. Infpire mieux mon Maître, ô Puissance céleste ! Partez, oppofez vous à ce dangereux foin; Vous voyez cette guerre, en difgraces féconde, Digne de nos Aïeux & de ces tems fi chers Amb. Bien plus. Si du Deftin les nouvelles rigueurs Que la Gloire, à leurs yeux, offrira dans fon Temple, Ira chercher l'Honneur, éveiller les Vertus ; Et dans les Citoyens du rang même où nous fommes, Et qu'après un long cours de Siècles & d'années, Ce fa Patrie encore on fait les destinées. On these heroic declamations, which feem not a little to refemble the fine fpeeches of Cato's little fenate pent up in Utica, Alienor, like another Martia, exclaims, Ali. O courage! ô Vertu! dont l'heroïque ardeur, The fcene immediately fucceding is one of the moft pathetic, and beft written in the whole piece: But for the Reader's better understanding it, it may be neceflary to premise the following circumftance of the plot. The Count of Harcourt, who commanded the first line of the English army at the battle of Crefly, found, among the flain, his brother Lewis, or John of Harcourt, who fought against him on the fide of France. He was fo fhocked, it feems, at this difcovery, that he formed a refolution to refign his command under Edward, and repair to |