장음표시 사용
191쪽
nro in the superior degrest, and that they are so called in relation to those Whicli are in an inferior degree: that externalcauses are so called in relation to those Whicli are in a superior degree; so that causality has relation primari ly to soreos and substances of a superior and inferior degree. For When the spirituous fluid acts upon the motive fibre os a Vesset, muscle, Or gland, it acis Dom an internat cause; Whon the red bl ostacts ou the fame motive fibre, it acis DOm an externat cause; When hoWever the purer blood acis, it is Dom a cause Whicli is externat in relation to the spiritu ous fluid, and internat in relation to the rest blood, so that the puror blood is in the intermediate cause. A similar Observation applies to ali parallel cases. Internat causes there re proceed DOm a solantain Whicli is comparatiVely uni VerSal, pure, perseet, prior, and Superior: EXternalcauses proeeed Dom a fountain Whieli in iis nature is the reverse of the former. But in this artiolo enough has been suid on the subject os causes, inasmuch ns it enabies us to see to a certain extent, that causes repair the deficiency and wasto whicli hau been occasioned in the things caused, and that this cannot benecomptishod Without the subordination of vesseis of One degreeto vesseis Of a higher degree. 217. Moreoveri in order that the bratris may be continuat
producino this essect by the venoy of their own causes and si stprincipies, and also test, through continuity of communication,
arteries and veins which are proper to the body, and also those which are proper to the brains, form communications with eachother in a manner peculiar to themselves. The arteries of thebratus are tho internat carotid and the vertebral; the interualcarotid is properly the artery of the cerebrum; the vertebrat is properly the artery of the cerebellum, the medulla oblongata, and the medulla spinalis, inasmuch as it is reflected into thoanterior and posterior spinat arteries. All the Other arteries, hoWever numerous, helong to the rest of the body. It is Worthour While to enquire in What manner the arteries of the brain and those of the body communicate With each Other, because We may thetice inser the nature of the influx by Whicli one acts upon Or into the Other, through the medium solely of the blood. This hoWever is a subjeci reserved for another Ρari, and
192쪽
more particularly for that on tho Brain; stili as We are here Speaking os appetencies and aversiones, of those causos Os generalpressure Whicli alter the equilibrium and the circulation, aS Wellas of the means used in repatring any loss or deficiency in thethingS caused, We are under the necessity of So extending Our present argument as to include this subjeci. We shali reser toit, hoWeVer, Only in a cursory manner, inasmuch as in thesequel We shali have occasion to trent of the arteries, VeiΠS, Rudmotion of the brain, separately and distinetly. We learn Domanatomy, that the carotid artery, On entering the cavlty of thecranium, emancipates itself froin the insuetico of the liuartor the body, and places itself under the govertiment of thebrian Mone as iis sole moving poWer; for, I. The WholeCarotic Stem ascendS nos as a truuli, but res a branch, of thenorta. From the upper part of the arch of the aorta saysHeister, sand Ruysoli' asseris the fame thing, in the humansubjeci, most commonly three large branches ascend; the right branch then divides, more or less remotely DOm the trutili, intollio right si clavian and right carotid Rrte , kC. . . . Hen ethe norta cannot be dividen into an ascending and descenning trutili. But in dogs, calves, and Various Other beaSis, only one large ascending branch is generalty observed, and DOm this circumstance the error mentioned above namely, os dividing theaorta into an ascending and descending trunkJ appears to haveariseu D. 120). 2. As soon us this commoti branch arrivesnear the threstiold of the cranium, it divides in a remari ablemanner into an externat and internat branch; the externalhranoli is distribui ed to the externat paris Os the head, the internat paris of the bones, and especialty to the face and the Organs of the externat senses; the internat branch onfers the cranium through the foramen proper to it, in company With the inter- costat nervo. 3. It leaves belliud iis muscular tunio at the porch
this coat no longer has the character of a continued heari,notther does it promoto the circulation Or propagate the WaVe.
4. It presently Winds into numerous gyres, as is it Seemed in
193쪽
this manner to Wish to shalio osy the yoke of the heart. This is sirst observabie in the osseous foramen itself. It is again Observabie When it has enterest the hollow of the cranium; againas it descenus into the receptacula cavernosa' as they are called
by Vieussens ) ; again While it is s ourning in this region; and again When having perforated the dura mater it climbs thebrain. 5. Not only does the artery divest itself of the musculartunio, but it places itself under the controi of the intercostat nerve, Whicli in tho body is in lieu of the cerebellum and
medulla spinalis,) and evo where ut the fame time under thecontroi of the dura mater; nor do these release it Dom their poWer and delivor it up to that of the brain, utitit it mounts thehemispheres of the brain, under Whose controi it thencelar-Ward is. 6. In certain animais, it spliis almost enthely intolit ilo tWigs; these it surrounds With membranouS prolongations derived Dom the dura mater, Dor does it again form njunction With the trutili excepi at the base of the brain. 7. Having at longili reached the cerebrum it ramisos and disseminutes itself around in such a manner that there is no portiori of the blood, ei ther in the trutili, in any branch, or in any Single OsDSet, Whicli is not common to ali the others. S. Thus ramified itfiualty extends itself to every individual spherule of the cortical
Substance, Whicli it circumvesis und construcis in a Wonderfulmanner Out of the inmost Or Iasi and most universat membrane
of the arteries of the body n. 145, 187, 188); hence the whole
cnSe, is Seen Dom the resolution Of the cortical substance by frequent immersion in Water, and Dom the connections be- tWeen the paris, as delinented by the above excellent authority. 9. This substance is, by means of the Same membrano, Continued in to the fibres, and thetice again descends into the vesseis of the body, Where it terminates iis Wondersul gyre n. 151-154). 10. Thus those arteries Whicli properly belong to thebody, and those Which properly belong to the brain, maintain With each other a communication peculiar to them selves; the arteries of the brain depending upon those of the body only so
194쪽
sar as is necessary to en te them to receive their due proportionos blood, although oven in this case the quantity and qualityof tho blood thus received is test to the decision of the brains, into Whose guardianship the body is committed. II. In brutennimais, hOWever, the casse is disserent. Indoed so great is thedisserenue, that moroly Dom a comparison of the determinationof the arteries, it is clear, that animais ure as much under therule of their body us of their bratus; Whicli is the reason thatthev never cense to destre Whatever their blood craves, and that according to the various changes and incitemenis CXPC-
the performance of the actions proper to them. In man, hoWever, an entirely disserent communication talios place; a communication manifestly of such a nature as to be able to Wardoir tho blood and dotain it at a distance Dom the cortices substances, test While the rational mirid is occupied in revolving iis reasons, the blood should too nearly approach, and interrupi iis judgmenis, besore the question is settied whether tho Will is to determine into aut the appeten cies excited by externat caUSeS, Orthose proceeding Dom the outWard Worid through the externa organs, and DOm the body through the medium of tho blood. But of this Wo shali spua in Vari II. 218. With a vies to accomptish this end in the humansrame, the arteries of the body and those of the brain are notgoverned by similar laWs. For, I. The arteries of the bodypush the bl ood Dom tho heari to the extremittes Successively. All the arteries, hoWevor, of the brain nre Opened and 8hut Simultaneousty and ut the fame moment With the vetus and SiΠUSeS. FOr there are as many animating corculi or littio hearisus there are spherules of the cortical substanco n. 177), Whichrequire this simultaneous motion, hecause they animate Simultaneously. 2. Thus the arteries of the body are dependentupori one great heari, but the arterius of the bra in are dependentupon an infinite number of cortical and cineritious spheruleS,
195쪽
pressed, and vice ver8α. 4. The arteries of the body and thoso os the brain agrest in this, that When the brain collapsos, Orcompresses itself, iis arteries distend, in the Same mannor asthose of the body When the heari is in iis systole; and vice
219. And their motions are dependent Von disserent origin8. For in Stanee, as We have just stated, the motion of the brain depends On the animation Os the spherules of the cortical f Stance, and upon the consequent animation of the medullarysubstance. The motion of the body depends on the systole and diastole os iis heari and arterius. For is the motion sowed Om the fame origin, and there Were no causes to retard, SHSpend, and intercepi iis continuous action in iis progress Domone Station to unother, the determinations of the brain Would necessarily arise DOm the motion of the body, and not the motion of the body Dom the determinations os the brain; ConSequently there Would be no Superior presiding over the inferior;
196쪽
22I. By what method os nature is the procres of secretisn
the blood, euch staminute is draWn, ut every diastole and EXPRΠ- Sion of the artery, into the parent artery, and forins in the arteryitself a larger excipulum Or orisce, into Which the serOSity Se
tending Dona iis parent artery; the Stamen being noW relaxed; and lience the serosity projecis itself Out of it. The same operation tulies place in ali the other secernent vesseis, and this continually. For is the fibraled membrano together With the inmost be continued into the secretory tufis, and is by the transflux of blood the artery be at the fame time dilated and elongated, the effect produced, is, that the lusis dram them- solves bach into the expanded mater into Whicli their tunios are continued, and immediately after, extending themselves, Hecttheir contenis. Henue the whole of the mechanism effectingilie secretiou dependes on the circulation of the blood, and the circulation, upon the generat equilibrium Os pressure. 222. Ly what method do the veins reabsorb the suids which are conveyed to their flamina and orifces That there are stamina Whicli depend froin the litile veitis similar to those Whicli depend Dom the litile arteries, is a fact Woll known. NON is tho fibraled, together With the inmost membrane of the litile artorios, be continued into these stamina, but in an inverse order; that is to say, is the membrane Which Was the inmost of the artery beeomes the Outermost of the Vein, and consequently also, ns anatomisis inserm us, the outermost of the stamen Whicli is extended froin the velit; it solloWs, that ut every diastole orexpansiou of the artery Whicli is in continuity With iis velit, tho externat membrane of the stamen so eXtended, is draWn upon; consequently the stamen itself opens With everted lips, unddips With open mouth in the passing Stream. Again, When
197쪽
tho litile artery is contra ted or relaxed, thon the stamen With convoluted and compressed lips draWs iis liquid into the voin, into vhicli probably the stamen is entirely received, and dis-chargos iis milli. For is the inmost membrane Of the arterybecome the Outermost of the vein, then the mouth of the ab-SOrbitory Stamen annexed to the vein is expanded and widened by the samo force of circulation Whicli stratiens the secretoryStamen Of the artery; sor While the artery acis iapon the inmost membrane os iis stamen, it neis at the Same time upon theoutermost membrane of the vein in continuity With it, and uponthe Oufermost membrane of the stamen depending Dom theuein. Heuce it folio , I. That the artery expels iis liquid, notat the fame, but at the alternate moments in Whicli the vein
imbibes iis liquid. 2. That tho reabsorption of the liquid
by the Vein depends on the litile arte , and hetice On thecirculation of the blood, While the circulation depends on thegenerat equilibrium os pressure: that consequently On this equilibrium os pressure deponds the uviole of the natural chemistry ; Whicli cannot be performed Without the continuationos the artery into the vetus. 3. That inasmuch as the vetusare pa8Sive, it cannot be predicated of them that they conveytheir own liquid into themselves, since this effect is continu- Ous Dom the efficient cause of tho artery. 4. That for this
ther With the artery constituto the vein. The first boginningsos a vein are thus the smallest vesseis, and iis end the right auricle of the heari, just as the end of the pulmonary vetus istho lust auricle of the heart. 223. By what method Ges the arterial blood pass into theveinsy Let iis suppose the case Os a litile interstice, Where the inmost tunic of the artery is the Only one, and Which by achange Os siluation becomes the outermost tunic os tho littio voin. It Will solioW, that When the artery is contracted longitudinalty and latitudinalty, the outermost tunic Of the Veinbeing draWn upon, assords a Dee necess and open chanuel to thoblood, and immediatoly offers itsulf as a receptacle to the blood which has como Dom the arteries; thus the Ossico Of the v in is Only to receive the wave Whicli the artery projecis into it, and
198쪽
to aci only Dom tho motion Whicli it receives Dom the artery. Consequently, When the blood is received by the vein, then as
minglos itsulf With tho Waves educen through the stamina; thus tho litile canes distonds, and is iis intumescetice be relativelygreatur thau that of the branch or the trutili, then, accordingto the law of the naturat equation os fluids, this intumescetice dis-charges iiself Over the valves, in Order that the Vein may acquiretis equipoise of impletion; While On the other haud, the valvesare immediately closed by the pressure of the waVe, WheneVerthoro is in the branches a smaller quantity than in the trutilis, proportionalty to their capaci ty and faculty of extension.
other ingredients Were rejected to the parietes of the vesset, and Wore received by the mouilis and litile lacunae of the artery n. 22I), they Would only, by reason of their uncongeniat nature, Wear and tear, pricli and cut, iis smooth and sensitivo inferior coat; or is accidentalty intruded, in consequence of any of the secretortes being Obstructed, the litile venous canal Would checli their ad vance by convulsive contractionS; Or haring SWHlowed, Would vomit them out again ;' OtherWise a vesset so immoderately strutched aud inflamed, Would every time becomethe sent of a diminutive an eurism. For this reason it is, that
a clot of blood concreted in a vesset stud bloching it up, and then gradually the cloi Was perforated by the constant stroke orimpulse of the ad vaticing current, utitit at last it transmitted athread-like stream through the middie of it, and in fact acted
' Canaliculus talis crebro singultu illa castigaret et excuteret, seu deglutita
199쪽
blood, Serum, lymph, animal Spirit, saliva, the mucus of themouth, bile,-the liquor of the panereas, Stomach, inteStineS,MSophagus, brain, eyes, thorax, peri cardium, abdomen, tunica vaginalis testis,-semen, the liquid of the prostate glands, themucus of the nose, tonsil8, joinis, urethra, uterus, Vngina, and Fallopian iubes, he humor of the ova, and that in Whicli the
226. That suci, an incalculable number of disserent Secretions may be producud Dona the blood, is clear Dom the solioWing considerations. I. That the blood in iis progress throughthe largest und least artery, continuatly projecis to iis fides sirst
n. 157, 162 . 4. Τhat consequently at oue poliat in the line os
200쪽
or celi, composed os vessela os a three id ordor, or of the redand pollucid blood-vesseis and fibros, that even this is sussicient lar supplying the sirst principies sor the concoction Of any liquor. To this We may add, 7. That in tho organs of their respective laboratori es, as in the litile serpentine bladders, pipes, and phials, or in the severat receptucles and pores, One fluid is mixed up With another, tWO, three, Dur timeS, Or Oftener; RS in the brains, mammae, stomach, liver, and everyWhere elSe; and this, in the ordor in Whicli euch procoeds, either in an in-Ward Or OutWard direction, to iis oWn proper destination, as in the case of the testicles, prostate glands, urethra, &c. 8. Τhat the fluids whicli are thus mixed, are again conducted throughfillers, and after being percolatud and discriminatod in disserunt Ways, are again united, tili sinalty they are formed into somo
recondite substance Whicli the animal poli ty requires for thesi ply of iis necessities, USeS, Or contingent emergencies. Oneos these substances beeomes excreted; another is reabsorbed by tho litile vetiis; a third is destined for the nutriment and renovation Os textures; a laurili, for the preparation os a fluidWhicli is to serve some use Within the circle os iis Lingdom. NoWhere does nature exhibit SO Wonderfui an aspect as here, Whore sile is in the exercise Os nil her ari: Where indeed, SO Wonder ut are her operations, that to the contemplative mind scarcoly
subjeci hoWever can be attained only by a mastery of the Sciences os anatomy and pathol Ogy; nor even then cati it beconsiderest complete Without a thorough proficiency in the entire chemistry and physios of the wOrid and iis Lingdoms. 227. Whilo I have boen dWelling on these StupendoUS mySteries of the animal Lingdom, and endeavoring to reduce iis particular aud specific modes of Operation to a seW general
Et videtur tanquam nihil ei a principiis et per suos ordines progrediente invium