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

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and suntly separates into the umbilicat branches. So that this simple litile heari direcis iis sanguineous stream first os ali totho brain, and there collecis it res into a litile reservoir, in Orderthat it may be dri ven round by virtuo of the motion of thebrain and of the gone besore metitioned. It is shewn also thattho heari has iis origin by the fide of the spinal marroW, in ordor that it may bo lippi undor the influence of the motionthereos, Whicli is one and the sume With that of tho brain. Hence it is, as Lancisi says, that as soon as the motion Of the Corculum begitis, certain fine purpurascent lines Whicli prove tobe the umbilicui vesseisin aro fraced Dom tho horder, Or DOm thecircumserenue of the colliquamentum in this siluation, as Wesaid above,) to the centre of the cicatricula, Where they terminate, and becoming enlarged form those vesicles, Whicli are

alternately filled, elevatest und reddened by the influunt blood ;

bra in f, lihe the only tWO classes of citigens noW in exiStenee, give risu to nil the various Other members of the community. Thus also We see the conneetion belWeen the paris of the animalbody; sor ultimates Ought alWays to consociale themsolves With

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do nos oboy the influencos of tho principat hostri, Whicli is that of the body, but thoso os an infinito multitudo os littio hostris n. I77ὶ pertaining to the brain, Whicli is in the principies of allthe forces und actions of the body. From the nature os theconnection subsisting between the Organs, it may alSo be Seen, that tho pulsations of the arteries of the brain may Or maynot coincido With those of the heari, for their spheres of Rcti 'ity are separate, stud boundaries are placod belWeen them

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n. 217). This may be Seen much more eastly than in tho criso ostho motions of the lungs and the hears, Whicli aro stili more unitud, inasmuch as the right ventricle of the heari is continuod immediatoly into the arteries of the lungs, and the pulmonaryveius are continuod into the lest ventrictu of the livari. It is theresere possibi e that the motions of the brain and heari may Or may ΠOt be Synchronous. 2. But Whether the animations Osthe brain, under Whicli term I comprehend the cerebellum, themedulla Oblongata, and the medulla spinalis, coincide exactly With the respiratiotis of the lungs, is a question Whieli remaiusto be solvod. It is Woli linown that the brain cati Dei and will, cun determine iis Will into acis, and thus exercise pOWer OVerthe muscies of the bosty. Is uom it should bo demonstrated bynctunt saet that such a determination to nut is made by meansos particular elevations and constrictions os tho congerieS Ofthe cortical substance, Whicli in the part on that subject We shallcnil cortical tori or thalami, it Will sollow that it is in the poWcrand will of tho brain to expand aud constrict the whole of iis Substance, so that iis animation stiali bu ultogother subjuet to iis Will in the fame manuer as is the respiration os the lungs. Τhecase hoWever is not the fame With the pulsation of the heart. 3. ΤΟ ΡnSS OVer innumerable facis, and arguments munded uponsacis, it is plain froin the anatomy of tho brain, that the stirWhicli is received through the nostriis excites the brain to contraction at the moment in Whicli it is passing through the trachoato the lungs ;' for the olfactory nerves subtend a considerable portion of the base of the brain, and diffuso their radiclos through a large portion os iis medullary Substance; so that

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Other causes, sueti as the dura mater, the falx, the horigontal Septum, the arteries, the Veins, the sinuses Whicli are then extended anil compressed, and likeWise the nerves Whicli are Stimulat ed by any of these causes. For an infinite number Ofmeans conspire to the production Os one effeci, Whicli meansare providen to the enu that tho effect may never fuit of being produced. The motion proper to the brain is animato expan- Sion ; conStriction being a species of exanimation, Whicli is op-pOSed to expansion, as it is hunce also to lise. The case is the

Same as With the lungs, Whicli live by expansion, as the blood then traveis through tho arteries, but Whicli expire and die byconstriction. We may forni some idea of the fige of the pituitary membrano, Which is continuous With the meninx of thebrain, from the faci that it constitutes the membrane of the fixSinuSes; namely, the frontal, Sphaenoidat, and maxilla , and of the celis of the spongy and turbinated bones; Whence a ContactbetWeen the air and this membrane ean neVer be Wanting, nor consequently the effect of this contact; namely, a constrictionof the brain, Whicli constriction must thus arise 1 rom a multiplicity of causes. The truth of this assertion may be stili more plainly Seen si Om a consideration Of the externat causes of SDeeZing, an assection during Whicli the thorax and abdomen, together With the lungs, are expanded by a Species of convulSion, and the brain consequently beeomes constricted. Willis sup- poses it to be unquestionabie, that When persons SueeZe thedura mater is Strongly contracteil rebri Analome, cap. Vi.);he Would possibiy have suid the brain instead of the dura mater, had he not previolasty dented any motion to the brain. This

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tho brain Oxpuls the pituita that clogS the elatratices, On the expulsion of Whicli the brain compOSeS itSelf, and reduces the cortical tori to their proper Order, Whicli it could not do Without a deos contraction and sudden expansion. The character of thonaturat expansion Of the fibriis or Origi iis of the mammillaryprocesses, is evident in brutes; for Wheu tho mammillary processes are inflated, the whole brain sWelis up, because these fibriis ure dissominated throughout ali iis iobes. But in manthe case is disserent, because the mammillae are Sm alter, und

against external light, shews DOm under the la8hes a glimpse OfWhat is passing Within, contracis his cheelis, lips and breast, brenthes floridy und tacitly, elevates the lungs higher as it vere, reciprocates them When but litile elevated, test by too great a collapso they should asterWards latch tOO deep a breath; and respires through the mouth, and not alWays through the nostriis,a habit Whicli is peculiar to man. While the minu therefore is intently pondering on the disserent relations of things, the brain in generat With the lungs is comparatively quieScent, in Ordor that iis teisuro may be undisturbed; heiace it avolds draWingbreatli through the nostriis, or exciting the olfactOry nerVeS, ODWhicli account these nerves ure smaller in man thun they are in brutes. It is unnecessary to notice, in addition to What is herostatest, the phenomena of gaping, Whicli are themselves also

modes of elevating the fleepy and indolent brain. I Deed also say nothing of laughter, of stretching the limbs, and Other natural media coinciding With the lungs, and by a Lind of instinct

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to the medulla spinalis, und from the medulla spinalis to the medulla oblongata, the cerebellum and the cerebrum; in Milichchnin Os connection, necording as One link is moved, So is theother. The sphere of the heari's activity cannot be extendeditito tho vertebrae through the arteries; for the anterior spinalnrtery takes iis riso Dom the vertebrat artery after it has e tered the cranium, and above the medulla oblongata, Dom Whicli iti8Sues doWnWnrds; While the posterior spinat artery tines iis riso Dom the vertebrat artery Without the cranium, namely, si Om the norta und lumbar artery; although at the sume time itin part arises DOm the vertebrat artery Within the cranium, neartho laurili ventricie. But me branches traverse the Same nOtches through Which the spinal nerves pas8, Where they are neceSSurilyreduced by mutuat contiguity into the determination Os anothermotion. This is essected by n most Wonderfui contrivance, in the folloWing manner: the notuli os the inferior vertebra is

into the first buginnings of the Derves, nud into the Sursace Ofthe medulla spinulis, Whicli are ali in the fame stream Os motionas the medulla spinalis; so that the sphere of the activity or vibrations of the heari extends isseis Only to the vertebrae, and not beyond. 5. In confirmation of this synchronism and concordance of the cerebrat and pulmonary motions, We might deriVe arguments Dom numerous other paris, both of the bratri

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and os tho body; as Dom the intercostat nervo, Whicli in thebody is the substitute for the cerebellum, and surrounds nil thobranches of the agygos : Dom the par vagum, Whicli in liliumn nor is an Ossset Os the cerebellum, and does iis generat be-husis in the hody. The clearest possibie arguments may be

nected With respiration at the fame moments that the medulla spinalis constricis iiseis. For in Gur Ρart on the Motion of the

Brain, it Will bo fhewn that Whon the medulla spinalis, by iis

bo deducod froin the nitith pair of the nervos of the hered, a salso from the socotid patr; the former of Whicli principalty serves the longue for the purposes of speech, Whicli it could not do is the animations of the lungs and the bratris did not coincide.

continuation os essecis from sirst causes through intermediates, I cannot at present dilate farther on this part of the subjeci, and I reserve it theresore for Ρari II., On the Motion os tho Brain. 6. The anatomy of the Silh-WOrm, as given by Μal-pighi, obviousty leads to the fame concluSion; for the cineritious substance of iis brain and spinat mari OW, contained Within prolongations of the medullary Substance, and divided into globules, acts principally upon the tracheal pipes of the lungs; sortite medullary substance Surrounding it at every nodule gives ossiWO nerves expre88ly to the tracheal pipes; und this substancodoos tho liko where it is contained Within the cranium, Whithor the topinosi tracheat ramification alSO enters. Wo must bear iti

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mind that the silk-worm has many tracheas Or lungS,' RS Wellas many hearis). MoreOver, the very blood-vesseis, Whicli runOVer the Whole extent of the spinal marrow With iis distinctglobules, expand exstetly upon the tracheal pipes of the Same iung8 De Bomb., p. 16, 20, 21.) Hence the notion of the bratus, that is to say, of the globules of the cineritious substance, bein ggranted, an immediate effect 1lows into the proximate trachealpipes or lungs. This being manifest upon a very Slight eXamination of Malpighr's figures,' mere conjecture is ni an Oud. Since theti there are three generat Duntatus of motion n. 279), and the motions of the brutiis are the sirst, und those of thel ungs are the last, hetico by the consociation of the sirst audiast motions, the intermediate motion os the heuri, and ali theother Sub ordinate motions, ure constantly kept in their eventenor and Order. The faeis and arguments here adducod are indoed feW, but the render Will hereaster sud Our position esta-blished by a multitude os data. In the meantime I may Observe, that there is nothing but tendes to confirm this viow of the Subjeci; as is alWays the case, Where What is advanced is the

284. The only phenomenon that might at sirst seem to militate against the faut of the concordance of the motions of the lungs and brains, is, that When We lay Our fingers iapon the fontanelle in insanis, W0 feel that the longitudines sinus of the dura mater exhibiis a movement synchronous With the pulse of tho heart. But is me look into this matter more closely, it Willbe found, that it is nos the sinus that pulsates, but the luxuriant arteries of the perieranium und dura mater, Whicli traverSethis part at this period of existence. It is olearly shewn in oneos RuyscIds Figures, es. Anat. V., tab. it., fig. 4, in that tWolitile arteries ruti tengthWise under the fontanelle, and numerOUS arteries brendthWiso; a d since they do so in company With theother arteries of the dura mater, that is, of the lamella thereos that eouers the sinus above, and of the other lamellae that formitie sinus lateralty, hetice a pulsation is produced apparently asof the sinus iiself, and heuce of the cerebrum; an appenYRI CO

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anatomy of this sinus in Pari II. With respect to the factabove related by Ridley n. 28 I), Who discovered, as he sayS, that the Systallic motion of the bratiis exactly corresponded With the vibrations os the heari, I do not deny that such a motion might

exist in a dog, so fastened With a ligature us to have iis trachen Or throni constricted, and the motion Os iis lungs entirely intercepteti, as We Shali presently hRVe OceaSion to observe . 285. IV. But that it again conjoius itself With the motionos the heari Wheneuer it returiis into a state similar to that offormation, Or Whenever the Iungs cense to respire While thelieari continues to beat, as in cases of droWning, Suffocation,

ever, from varisus causes, the lavs cea8e to respire, while the heari continues to beat. For hom that moment the Voluntary actionos the brain tapon iis muscies censes : the Sensation Os the Organsis likowisu deprivsed os iis life and lost in Obscurity. An appenrance of night supervenes, and there is a return as it mere tolliat stato of the body and brain Whicli existed during their

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I OrVOus and muscular fibros, Or upon illo spirituous fluid, and the lungs together With the bratus give force to the muSeles, nudat the sume time incito the vessuis of the puror blOOd to motion, Rud con Sequently promoto the universat circulation sit. I 54);whilo the heuri promotos merely the subordinate circulation, Orthat of tho red blood. 287. But me have furthor to consider that tho motion Os thebrain should be conceived os as taking place according to the partition Os iis SubStances, Or, RS generat, Spectat, particular, and lieneo variousty subdividod. Thus tho brain is dividon into hemispheres, the hemispheres into Jobes, the iobes into serpentine rid gos, the rid ges into tori, the tori into clusters racemos , the clusters into spherules, and the spherules into tesser undieast spheriales. FOr this reason the brain possessos the facultyos expansion in generat, in special and in particular; sor thewholo bratu may be uia ided, or a single Iobe, Or Only a portion os the cortical substance. Hence, is in consequence of any serious Obstruction, One half Or One hemisphere shouid becometorpid, the brain could neverthel ess uti id iis other hemisphere; is a single iobe should become so, stili the Other might experi- ence an alternate motion; is this iobe should lose iis action, then One Or the Othor Os the serpentine tumuli might be brought into play; should the whole cerebrum become quiescent, thentho cerebellum and euch medulla might be made to aut, e8pecialty in the human subjeci. In the sciences of physius and cosmology it is Well knOWn, that a mass Or volume Of one and the fame body may DXperience a generat, R JeSS generat, R PRY-ticular, and uti individunt motion, Simultaneously, and yet thatone motion shali not intersere With the other. It is known thattho generat motion in relation to the subdivided or particularmotion, in Whicli and under Whicli ulso the more particularmotion subsisis, is or appears to be as none, and has the Sem-blance Os a state of rest; as in the casu of undulations Withiuundulations, modifications Os auras Within modifications. This induod is the actuat statu both of the universe itself and of alliis living machines. The whole heaven may be perpetually' revolving in a vortex. The planeis of this heaven may revolve

Roturi et volvi.