The economy of the animal kingdom, considered anatomically, physically, and philosophically

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heari With spiritu us fluid and nervous juice, so that there is not a single potnt in the Whole machinery of the hostri, but is under the regimen Os Some peculiar fibre froin the cerebellum ;sor in a muscle, and consequently in the body, tho fibro With iis

fluid is ali in ali n. 370 ; such also is the cerebellum in thelieart. This is very evident DOm an experiment of Vietissens, Who says of the dog, that When the greater portion of the cerebrum is cui nWay, and the medulla betWeen the cerebrum and cerebellum entirely removed, Signs of life stili continuo intho motion of the blood and heari; and after the cerebrum is dividod Dom the cerebellum and medulla oblongata, the animal respires sor a considerable time, though not after the cerebrum is compressed by a violent percussion, nor does the hestri moveis tho cerebellum be Wounded, or cui in pieces, even Should the cerebrum be lest entire.' ' There is an experiment also by Someone, in Whicli a needlo Was thrust into the fourth ventriolo be- tWeen the sirst vertebra and the occipitat bono, When the dogmas immediately seiged with three or laur epileptio convulsioris, and in a stiori time expired; tho blood folloWing the with drasal of the noedio, to the amount of abolit tUO OUn ES.

See Alanget, Bibliotheca Anatomica' Wo fhould likeWiso bearin mitid, that the cerebellum in the incubated egg appearsio en large, and even to exist, simultaneoiasty With the heari, asmay be inferred Dom Malpighi's observations n. 242, 243 . But although tho cerebellum is ali in ali in the heari and largor vesself, yet it is only the remote cause of their pulsation, for it Only produces the notion of the blood, Whicli is itself tho proximate cause n. 514, 516). To the cerebellum it is oWing that nil things in the body exist, subsist, and are capable of motion; nos that they are put in motion by any aut of the cerebellum, but that When put in motion, they are by iis aut continued

560. In ordor that We may perceive ho the cerebellum actaupon iis biood, upon iis fibres, and henee iapon the muscie Oftho heari, it is my design to subjoin a completo description Oftho cerebellum; and this I Wili do the rather, as Without a linoWledge of it We cannot understand the modo of iis influx into the

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hears, Whicli is the main subjeci here. With respeet to the -- ternal sui face of the cerebellam, We may obsorve, that as thecerebrum is dividen by a membranous septum derived Dom thedura mater into tWo hemispheres, so uiso is the cerebellum, intowhicli the bosorementioned mater by a stight inflection mines iis entry, distinguishing the right portion froin the lest. Τhe Superior part of the cerebellum, Whicli lius immediately under

more acute shape. The dura mater is superinduced Over the Ce-

rebellum, beneath Whicli, in close proximity With tho brain, is thecellular membra ne and pia mater. Is We Jay bare tho cerebellum do Π to the pia mater, We then expose to vieW the Sursace aud. Order of the smuli circles, With Whicli the sursaco is ridged. In the superior plane of the hemispheres theso divisive ridges Or

formiy Observe parallel lines. But as ut the fides they run anteriori , SO On their Way to the bottom of the cranium theyapproach euch other, and ut the bottom inseri themselves intoother fissures, Which being as it Were the rOOts of the superior, and more closely connected and en solded, prevent the superior Dom being so divarica ted as to mine the interstices vider thanthey naturalty are. These roois as it Were Of the smali circles, after mahing Wonderfui inflexions and contorsiones, end round certain stightly elevated protuberances, by means of Whicli the

In these Jobes, protuberances Or subdivisions of the cerebellum, a disserent arrangement and Order of the furroWs prevallS; an Order running frequently in a contrary direction to that of thoselliat extend froin the generat furface of the viscus to iis margins . But stili in every protuberance so called, they appear to approX-imate to a certain kind of parallelism. There are the fame Lindos subdividod sursaces of the cerebellum oti euch fide round the medulla oblongata, the borders of Whicli thuy closely touch; of these there are severat, generalty three pnir. A larger On each haud, at the fide of the corpora pyramidalia and Olivaria, Where

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any conformity to the parallelism of the generat circles of the Superior Sursace, eXcept in the interior of the cerebellum isset Heuce it is that tho sursace of this subdivision is ploughed usinio ridges attached to the caudex of the medulla oblongata, Whicli the nearer they approach, the more they recede DOm thecircular Shape, and sollOW the longitudinat course of the above caudex. The felloW to this larger sursace oti the right fide is Sometimes subdivided in a manner differsent Dom that of tho fortiter. At iis farther limit it is marked With tortuous spires, and by means of intermediate articulations, so to speah, it is surroWed in a manner disserently Dom the other; such is the

Way in Whicli it seems connected With the common order undroot of the circles. The Other appendage of the surroWS ComeSinto VieW When a portion Of the cerebrum is removed With theliorigontal intervening septum near the annular protuberRUCO,

Whoro tho laurili and fifth puir of nervos issiae from their original fibres. It is in a similar manner that these circles attachthemselves to the margin of the abovementioned ring of the medulla oblongata, taking a course conformabie to iis figure,)into Whicli they obliquely 1low Dom the common sphere of the

circles. Intermediately and On each fide a Smniter Suaesaee prO-jecis, having lines observing the Samo Order and direction as theformer; namely, in the place Where the annular protuberanceceases, and the pyramidat fati Os the medulla oblongata receivesit. This appendix is smaller than the others, and is as it Were another Vermicular but transverse process, Whicli is articulated

into ali of them, having a more depressed solii surrounding it, Whicli imparis to it a poWer of solding and uti lding With theneigh bouring continuous Ones. But these particular subdivisions of the cerebellum, With severat Othors Whicli are formed by smali circles and surrounding corrugationS, are not equallyconspicuouS in eVery subjeci. MOreover after the cerebellum has been Spread Out, and has experieuced the essects of iis oWn gravity, the corrugations are Often unsoldest and their discriminations Obliterated, just iis Wheu a naphin tWisted luto Spiral

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folds is again vii lded, or us the forehead When contracted and Wrin kled is again sinoothed doW11 and wears an even Rud Serene aspect. The casu is disserent Willi rogard to the cerebrum; foreven When it lies dead, it has the appearance of stili surroWing

by Morgagni, Advers. Anat. Vi., tab. i., fig. 3 : and especiallyby Ruysch, Epist. Anat. xli., tab. xiii. xv.: and by DuVer-ney, Guvres Anatomique' pl. 1. The cerebellum, hoWeVer, although it seonis discriminuted oti the sursace into figures Seem- ingly So Various, as is traced by a compass, Stili has common Orgenerat circles knotted into a simple vermicular appendiX. ΤΟ the superior part of the cerebellum reach the circular sulci of the superior region; to the inferior part those of the posterior region. Hence it is that the appendix is double; there is, namely, a Superior, Whicli is larger, and an inferior, Whicli is Smaller. By means of a similar but very thin intermediate Stratum, eaeli appendix is bound ns it Were by a concatenated

srom Onch hemisphere in v Waving, Oblique, and laterat direction. But be re the common or generat circuition Of the fur-

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rOWs of the cerebellum passes into these appendices, it first insinuates itself into certain potes Whicli are 110t far distant Domthe fide of the appendix; sor When this generat orbiculatiori arrivus at the border of the appendiX, it traverses a certain centre, and by means os spirat circulis direcis iis coursu to apole, out of Whicli it passes by intervening appendices into the

Very Vermicular paris them selves, so that tho centro of the sphere of activi ty, Or the cynosure of each hemisphere, is notin the above processes, but at the tWO fides. This may be seen in Eustachius, Tabul. Anai., tab. vi., and in the plates of other anatomisis. With respect to the interior compages of the cere- bellum, Ne may Observe, that, ali the circles are surrounded by Some Common, elastie and cellular membrane, uniting together

the duplicatures of the subjacent pia mater; is this membranebo ruised Dom the subjacent one by the use of the bloW-pipe, there appear in great beauty and exact ordor the discriminations formed by the litile circles, and also litile arteries disposed in aregular Series, Whicli passing into the bes rementioned mater concent Within it their heads and capillary extremities, and

thrust themselves Out again into fhadoWy anfractuous litile cavortis, and transmit the blood, Whieli has undergone iis eXercitation, and is berest Os iis spirit, into someWhat larger canais, and Doui these, by creeping along in a tranSVerse, Oblique and parallel direction, into the severat channeis and generat sinuSes.

The pia mater itself, with the blood accompanying it, insinuatesitsulf toWards the interiors, in one place Only to a Shori diStanee, in another more deeply, and for the most part in a falciformmanner, Whicli is seen When the superior region is bisected doWnto the vermiform processes. The duplicatures insinuated in Oneplace unsold them solves and hecome even, in another Rre more intricate, so that their junctures are mutuatly dissimilar. Thelarmer, according as they are divided more Obliquely or trans VerSely, or more or leSS Vertically, appear in the plate in ShadoW, and are capable os being divaricaten in a larger Or smaller plane, and are divaricabie to a greater Or less eXtent. The lalter again,

in the interior sinus of the cerebellum, pass Oss lateralty and obliquety into sinalter solds, and terminate Only Where the eyebogilis to Iose the poWer of sarther tracing them, Or Where the uSeos optical instruments fatis. Τhus it is that the attenuation aud

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Whereuer tho reticulatest texture of the vesself, and the SaΠ-guineOUS membrane, penetrate into recesses otther visibie Orimpervious to vieW, there also they are accompanted by the perpetuatly mobile, cortical Or cineritious Substance, Whieli is more-over attached to them; so that sueti as are the implication, representation and influx of the foliated mater aud reticularly complicaten vesset, such or similar are those of the abovementioned substance; DOm this, as iis parent, a White medullarySubstance is again everyWhere educed, Whicli procreated homilie former occupies the interiors of the brain. I therelare,

the compages of the brain be cut through tho middie down to the Durth ventricte, the form os a smali tree-the arbor vitae-muhes iis appearance. Anii is the brain bo fliced obliquety in the direction of the sume vermiform hinges, it displays similarboughs or branches; in this casu the medulla, Whicli lies more deeply inWards, is laid more Open to vieW, hecause the trutilisinosculate With the branches sarther in; Whetice sueti as is thechange in the obliquity or direction of the dissecting lini se, Suchalso is the change in the aspect of the arboreal formation. Τhere appear to be three large medullary stems that inosculate immediately vitii the trunk just as it passes into the peduncte. Τhe hictost With iis branchos is single. The middie One is formed of tWo siems, to Whicli bolong branches Whicli inosculate With it obliquoty. In like manner the loWest groWS Out Of tWO

branches. So that there are as many principat trutilis to this tree RS there are medullary processes, besides in uumerable Sm alter trutilis Whicli aro impla ted in the largor in regularorder. Is a horigontal section be mane, the arboreal appearanceis deStroyed, and that os a variegated inurbio is assumed. 'Vesee also litile diverticula for the blood, scattered like Stars, aud

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rod in liuo. Is tho liniso bo passed farther into the substance, thon after removing the litile cortical and meningeni vatilis, thospaelous medulla is expOSed to VieW Without any interspersed undstrinted cineritious substanee. The medullary Stem, placedi, oblud the medulla oblongata, buries itself as it Were in iis oWn Soli, and by means of a flexure of the arcii commonly Over themiddie ventricte, leaves a liOlloW; for Where the Stem grOWSinto the medulla oblongata, it unites in ono the medullae of tho

stitoliod into it on eaoli sido by processes. But the ulmost si illis requisite on the part of the anatomist, to find tho direction in Whieli the roois pass, and the circuitous course by Whicli thoy dipiuto those that extend Dom the cerebrum to the spine. Is the medullary trutili of the cerebellum be opened in sueti a mannorthat the branches are thrown to the margins, the medullaryspace is bi ought tu vies, With rhomboidal nuis passing throughit, and whicli space Vietissens calis the medullary centre of the hemispheres of the cerebellum; also the lesser tract Whicli sur- rounus the laurili ventricte, and Whicli is called the semicircular

centro.

56I. From these considerations it appears that the cere- bellum is a unique and grand torus Of cineritious Substance, and acts in a manner peculiar to itself upon ali iis nerves, undby means of these upon iis muScies. MoreOver QVery Sinuous constriction of this great mass tali es a direction inWards onlyinto the common peduncio, and heiace into the processes intowhicli it dividos itself; sor overy oye of iis troe has relation totis bough, every bough to iis branch, and every branch to iis tWig; conSequently every particle os cineritious substance has a relation to iis oWn proper fibre, stud every one of the fibros tothe stum sormed of the fibros collectively, Whicli the cerebellum draWs toWard it duritig every constriction, possessing aS it doeS

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the faculty of adduction nour the laurili ventricie, Where iis large peduncte passes; sor the ventricle gives Way On eneli Side. From this, Whicli is the largest nervous torus, We may See themode of expansion aud constriction Os every smulier cortical torus of the brain, and which Wheu cui represenis in like manner the appearance of a treo, and in a smaller type maintains a resemblance to the largor one n. 164, 505). But as the actualdeterminations of the tori of the brain are voluntary, and the things determined, or tho actions in the bOdy, are COm-pound, the tori for this reason retain the voluntary form, and have that Lind of connection Vith the proximate paris OfWhich We have spolien, und send out a variety os peduncles, inorder that the cerebrum may be able to aut hom iis tori uponevery individual peduncte separalely; thus UpOn Some Os One and

Some of another torus, as also Simultaneou8ly upon ait; so that om this simulta eous Or successive action Of severat tori indisserent places upou their peduncles, the corresponding action

since the cerebellum, With uninterrupted constancy, perform8 iis animatory motion in the one Only manner proper to itself, and nevertheless transmits iis fibre into ali the viscera, euch of Whichis moved in a manner disserent DOm the other, as lar inStance, into the auricles and ventricies of the heari, it is consequently necessary that the proximate causes of their action Ahould pro-

the viscus into Which it enters, as SOon as the cerebellum censesto animate, Or as SOOu as it is compressed, deprived of iis biood, cui in pieces, or otherWise injured n. 559). 562. The medulla oblongata and medulla spinalis, since theytransmit the blood into both venae cavoe, und through the a stos particular , into the superior vena cava. HOW the spinat mar-roW, Whicli is the continuation Of the medulla Oblongata, concurs with the bratiis to continue the motion of the heari, and what is the concatenation Os causes Dom sirst to last, We cannot learn and demonstrate Dom any viscus beller than Dom the Spinal marroW, Whicli is the distributor and mover of iis oWnblood, and transmits it more particularly into the agygos, thetice

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into the superior cava, and in part also into the inferior. Thespinul marrow therelare contributes to tho continuation of the action and pressure of the blood of the two cavae, und thus continuos the circulation as it Were Dom a li Ving Spring, Πay, almOSt carries it on to iis termination. In Order to malle this appear We must bear in miud that 563. The spinal marroW is so connected With the cere-

bellum, and in faet With the cerebrum, that it is put in motion Systallidalty With each, and at the moment of such motion transmits iis oWn proper blood, of Whicli it is the mover, intoboth venae cavae, inferior and superior; into the Superior, throughthe Vena agygos, When the bratus transmit their blood throughthe jugular vetiis. And in ordor that there may be a continuouschain os causus horti the sirst to the last, the agygos is a single Vein, and unites With the superior vena cava beside the right auricle, and is lied up to the trachea. Thus as long as the Spines marroW animates synchronousty With the brains, and theliings With both, the motion of the heari is necessarily continued. Let us noW consider these poSitionS. 564. The spinal marroW is so connected With the cere- bellum, and in fact With the cerebrum, that it is put in motion systallicatly With each.-This may be inferred DOm the continuity of the medullary and cineritious substance, and Dom thecontinuity of the membranes and of the blood vesseis. It maybe inferred, We Sari Dom the continuity of the medullary substance of the brain; for this substance, crossing through the annular protuberance, passes Straight to the anterior part of the spinal marroW, and that Whicli comes out under the sirst processos the cerebellum, near the testes, descends also to the posterior part of the fame. It may be inferred froin the continuity of the cortical substance; for this is continued, distributed, and interWOVen throughOut the medulla oblongata, aud finalty is concentraled into the axis of the medulla spinalis, Ultore it does not terminate illi it arrives at the second lumbar vertebra. The same Observation holds With regarit to the cerebellum, nil the

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three prouesses of Whicli run to the spinal marrow: the firAt si Om the region of tho testes round tho sides of the laurili Ventricte : the second froin the annular protuberance, Where itfuriis in orner to descend: the third or restiform proceSS TUBSd0Wn evidently to the fides of the calamus scriptorius. ΤhiSProeeSS does not pass out of the vertebrat shoath tili it has Rrri Ved ut the os sacrum, Whonce it goes more especialty to the members dedicated to generation, as shewn by a Variety Ofproose. It may be inferred Dom tho continuity of the membrane'ns of the pia mater of the cerebrum and cerebellum, Whichtogether With the arachnoid membrano proximatoly involves the Same medulla: in the fame mannor it may bo inferren from thedura mater, Whicli extends to the ultimate apex of the os coecygis. It may bo inferrest Dom tho continuity of tho blood vesseis, forthe anterior spinat artery runs doWn froin the vertebrat uni ted with it, and whicli is callen the cervical, or Dom One Ofiis crura, to the second lumbar vertebra und farther; consequently Dom the thalamus Where the medullae of the cerebrum and cerebellum unite. The posterior artery also runS dOWn om the laurili ventricle and choroid plexus. MoreOver thevertebrat Vein is common to both the medulla oblongata and to the Superior region of the medulla spinalis; it passes likeWise into the Superior cava. Hence it solioWs, that such a connexion is established belween the spinal marrow and the brains, that theformer cannot be put in motion except synchronousty With thelaiter. What the nature os iis motion is, or of iis expanSion and constriction, is abundantly evident Dom iis connection; that isto say, it is toWard the posterior but nos toWard the anterior part of the spine; sor belWeen iis pia and dura mater there extends Dom the large foramen of the occipiat a Space into Whicli it can be expanded. There is also a groove or chinii Whichruns through the dorsal region, and there the posterior spinat artery and vein are in their descent variousty folded together, divided, and reunited. The netion of the annular protuberanceis immediately inflected toWard the posterior region, Where thelaurili ventricle is, the expansion Os Whicli produces an effectupon the posterior part of the medulla spinalis, and lest this effect should extend to the anterior pari, the precautionary meariS