Billeder på siden
PDF
ePub

world of Homer must mean, in Mr and academies before we venture on Gladstone's apprehension, those it.

,

. more subtle and very disputable de- A university education, which ends ductions which he, and the like in- at the age of twenty-one, cannot ungenious men, may still draw from dertake to lead men through all the the verses of the poet. Such subtle high and intricate discussions which matter is not, and cannot be, the may very easily be gathered round subject for academical study. We the poems of Homer. It can only assign no limit to genius or to learned prepare them for such discussions, labour; there may be much yet to if they should have the requisite be seen in Homer which the eyes of ability or leisure to pursue them in scholars and historians have not hither their mature years. And that only todetected; but academic institutions which has already obtained some cannot outstrip, or keep pace with, measure of general assent is fit for the man of genius. That only which scholastic teaching: If a profeshas stood the test of examination can sorial chair were endowed at Oxford be made the groundwork of scho- to expound this inner and innermost lastic training. The only study of world of Homer, whom should we inHomer which Mr Gladstone, on re- vite to fill it? Whoever filled it, he flection, would find to be defective, would have continually to discuss is that study which must be pur- and contend, rather than to teach. sued by the solitary individual, Certainly, for our part, it is not Mr bringing all the knowledge he has Gladstone himself" that we should acquired from other sources, all his invite to occupy such a chair. We philosophy, his theology, his history, much prefer that he should still rehis critical faculty, to bear on the main the learned Member for the poems of Homer. It is the study University of Oxford, than that he of the mature mind, it is the study should transfer those talents which of the author. Along this path render him so eminent in the House we must go one by one. We have of Commons to a chair of philosophy acquired all we can from schools and historical criticism.

CIRCULATION OF THE BLOOD : ITS COURSE AND HISTORY.

Did Harvey discover the circula- ing: Erudite prejudice has done tion of the blood ? To many, the its worst in this direction, and its question will sound like an impertin- worst has only set Harvey's merits ence. To those who have critically in a clearer light. examined the historical evidence, the Harvey discovered the fact of the question wears another aspect, and circulation ; but he did not discover the answer will run somewhat thus : the course of the circulation, nor the Harvey did, and he did not, make the causes of the circulation. He knew discovery; he made a very great dis

that the blood was carried from the covery, which has given an imperish. heart through the arteries to the tisable glory to his name, but it was not sues, and from the tissues through precisely that which is popularly at- the veins and lungs back again to tributed to him. In endeavouring to the place whence it started. But he mark clearly out that which he dis- knew not how the blood passed from covered, and that which he did not arteries to veins ; he knew not why discover, no attempt will be made the blood thus moved. In our day here to diminish the fame England science is in possession of the exact is justly proud of, by ransacking the course of the circulation, but the archives of science to detect stray exact causes are still under question. passages of meaningless vagueness, We know that the circulating system wherein older authors may have in consists of heart, arteries, capillaries, dicated something like the truths veins, and lymphatics. Harvey knew which Harvey established on the not the capillaries and lymphatics; firm basis of experiment and reason- so that his knowledge of the course

a

taken by the blood was necessarily story whose episodes extend over not incomplete. To put the reader in less than seventeen centuries; and possession of what is now known on the two centuries that have elapsed this subject, and to enable an esti- since the discovery, have not sufficed mate to be formed of what Harvey entirely to complete it. Seventeen discovered, we will first take a rapid centuries is a vast span of time for view of the circulation.

the elaboration of the discovery of a The heart, as the great centre, shall fact which, now we know it, seems be our point of departure. It is com- so obvious that our marvel is why it posed of four cavities: two ante- was ever unknown; and the moral of chambers, or auricles, and two the story lies precisely there, teachchambers, or ventricles. Into the ing, as it does, the remarkable serright auricle the blood is poured by vility of the mind in the presence of the veins ; it passes thence into the established opinions, and the diffiright ventricle, and is driven there- culty which is felt, even by eminent from, by a strong contraction, along men, in seeing plain facts, so hoodthe pulmonaryartery* into the lungs. winked are we by our preconceived Here it comes in contact with the oxy- notions. To those who are unfamiliar gen of the atmosphere, and changes with the practical parts of science, it from venous into arterial blood. It seems singular that men should connow passes along the pulmonary tinue acquiescent in errors so baseless veins into the left auricle of the that they vanish immediately they are heart, thence into the left ventricle, challenged : and to men who have from which it is driven, by a power- never trained themselves in the diffiful contraction, into the arteries. cult and delicate art of Observation, The pulsing torrent rushes through it seems singular that facts, extremethe arteries to the various tissues, ly simple when observed, should conwhere it passes into the network of tinue to be overlooked. But the truth capillary vessels, described in our is, observers are at all times rare, belast Paper. Having served the cause new observation requires singupurposes of Nutrition, the blood con- lar independence of mind; and, untinues its course along these capil- happily, those who never made an laries into the veins. Here the stream observation themselves, are always is joined by that of the lymphatics, ready to dispute the accuracy of new which, like the roots of a plant in observations made by others. the earth, absorb lymph from the In the case now before us, there organs in which they arise. This were three capital errors, which for confluence of streams hurries on till seventeen centuries masked the fact the blood is emptied into the right of circulation; and the reader will auricle, from which it originally probably learn with surprise what started; and thus is the circuit com- those errors were.

The first error pleted.

was, that the arteries did not conThe story of this discovery is one tain blood. The second error was, of the most interesting and instruc- that the two chambers of the heart tive in the whole range of science, communicated with each other by and it has recently been re-written means of holes in the septum dividing by M. Flourens in a very agreeable them. The third error was, that the style.t He declares that before him veins carried the blood to the various no one had accurately narrated it. parts of the body. How was it posIn some sense this is true; but there sible that errors so flagrant as these are important omissions in his own could have maintained their ground account; and while availing, our- a single day after men began seriously selves of his labours, we shall en- to examine the subject ? It was obdeavour to complete them. It is a vious that air did enter the body, and

Although the blood is still venous, this vessel is called an artery; for vessels do not receive their names from the nature of the blood they carry, but from the nature of their distribution. Those which carry blood from the heart are called arteries ; those which carry blood to the heart are called veins.

+ FLOURENS: Histoire de la Découverte de la Circulation du Sang. 1854.

[ocr errors]

entered it by the trachea, or windpipe. the ancients had a very vague idea The conclusion was natural, in the of the necessity and the nature of early days of science, that the air, proof; so long as an opinion was thus entering by the trachea and logical and plausible, it was held to be bronchial vessels, should continue its irresistible. The spirituous element course through other vessels. When was supposed to be formed in the left the arteries of a dead body were ex- ventricle of the heart; but inasmuch amined, they were found empty, and as even venous blood requires some consequently the arteries were chosen of this spirit for the purposes of as the veritable channels : hence their nutrition, it was necessary that the name (“air-containers,” from anp and two bloods should mingle ; and, to tnpew). It never occurred to the phi- meet this necessity, holes were aslosophers that air and blood might sumed in the partition dividing the both be carried along the arteries ; and two ventricles. So deeply impressed when Galen demonstrated the fact were anatomists with reverence for that the arteries did carry blood, he what Galen had said, and what theory felt bound to deny the presence of air. required, that they one and all saw the What, then, becomes of the air in- holes-- which do not exist. Berenger spired ? Galen said it did not enter de Carpi had, indeed, an uneasy doubt the parts of the body, but was thrown on the subject, which he naïvely exout again after performing its office, pressed in the admission that they that office being to cool the blood. were only to be seen with great diffiIf you open an artery, said Galen, culty-cum maxima difficultate vidblood will issue, but not air: whencé entur ; but, by straining the eyes the conclusion seems inevitable, that sufficiently, he doubtless saw what the arteries do not contain air, and do Galen required him to see—as thoucontain blood. Modern science has sands daily see what they believe they proved that atmospheric air is not ought to see. The first man who had contained in the arteries, but only sufficient strength of mind to use his the oxygen thereof, with a slight eyes, and say what he saw, was Vesaamount of nitrogen, and a certain lius* the father of modern anatomy, amount of carbonic acid gas. But as for whom Titian drew the figures the composition of the atmosphere which illustrate his work. was not suspected in the days of Thus was the second error overGalen, the presence of blood, and the thrown in 1543. The third errorabsence of air, were facts so firmly namely, that of the veins carrying established by him, that, in spite of the blood to the tissues-was someall antagonists, they finally assumed what more complex. If the venous the place of incontestable truths. and arterial bloods do not mingle in

Here, then, we see one error re- the heart, where do they mingle? moved. The others still remained. We know it is in the lungs that Galen, and all his successors, main- the one passes into the other; but it tained that the two chambers of was an immense discovery to make; the heart communicated directly by and there is something piquant in means of holes in their septum; an the fact that it was first divined by opinion perfectly intelligible when a restless and daring theologian, we learn that it rested on a theoreti- whom Calvin burned, with affeccal assumption. Theory wanted the tionate zeal, for speculations of anfact, and men saw the fact they other kind. Michael Servetus was wanted. Theory distinguished be the first to announce the existence of tween venous blood, and spirituous the pulmonary circulation; and he or arterial blood. The venous blood announced this in the Christianismi nourished all the coarser organs, Restitutio, a work which was burned such as the liver. The spirituous by the theologians. Two copies of blood nourished all the delicate or- this work exist : one, still reddened gans, such as the lungs. In our day and partly consumed by the flames, we should demand some proof, be- is in the Royal Library of Paris ; fore accepting such a theory; but and copious extracts from it are

VESALIUS : Opera Omnia, edit. 1725, i. 519.

[ocr errors]

vein." *

.

It was

printed by M. Flourens in his “His- seen in the fact of its being also tory.” Nothing can be less equivo- made by Cæsalpinus, the great bocal than the description given by tanist, who does not seem to have Servetus of the passage of the blood been aware of what Colombo had from the heart to the lungs, “where written, since he makes no menit is agitated, prepared, changes its tion of him, and as M. Flourens obcolour, and is poured from the pul- serves, le grand mérite est toujours monary artery into the pulmonary probe. Cæsalpinus, moreover, was

the first to pronounce the phrase This idea was as novel as it was circulation of the blood.” I true; but we cannot agree with M. Here the reader may ask, What Flourens in regarding this as a dis- further remained for Harvey to discovery, in the strict sense of the cover ? and it may surprise him to term; for although Servetus had hear the answer : Everything! Such some notion of the anatomical evi- is pretty nearly the fact. The puldence furnished by the large calibre monary circulation takes place only of the pulmonary artery, which en- through a small arc of the great ables it to carry a far greater quan- circle traversed by the blood. Betity of blood than could be needed sides this arc, there is the other greater for the nutrition of the lungs, yet arc, through which the systemic, or we have only to read the passages in general circulation, takes its course; which he describes this pulmonary and of this no one except Cæsalpinus circulation to perceive that he had had even a suspicion. Every one no accurate idea of it: he speaks supposed that the veins carried the confidently of the nerves being con- blood to the tissues, and nourished tinuations of the arteries, and de- them ; no one suspected that this scribes with grave precision how the function was reserved for the arteair passes from the nose into the ries, and that the veins carried the ventricles of the brain, and how the blood only to the heart. devil takes the same route to lay thought that the arteries had their siege to the soul. All we can say is, origin in the heart, and the veins in that Servetus made one lucky guess the liver; from the liver the veins among his numerous guesses by no carried the blood to every part. A means of the lucky kind. He an- single fact, familiar to every surgeon, nounced the fact of the pulmonary and to every barber who ever opencirculation, and may receive from ed a vein, ought to have revealed History the whole credit of such the error ; since every tiine a ligature priority; he also guessed rightly was applied, the operator must have that in the lungs, and not in the seen that the vein swelled below the liver, the blood received its elabora- ligature, and not above it, from which tion, passing from venous into arte- the deduction seems obvious that the rial. But whatever merit may be blood in the vein Howed to the heart, assigned to Servetus, no influence and not from it. But here, as in so can be attributed to his discovery, many other cases, familiar facts were since both he and his treatise were not observed ; they were seen, but roasted by Calvin, and no one heard not interpreted. Ciesalpinus was the of the pulmonary circulation. Six first who observed it; but he has years afterwards, Realdo Colombo only the merit of having suspected rediscovered the pulmonary circula- the cause to be the current setting tion ;t and that the discovery was towards the heart. His suspicion ready to be made on all sides, is was not a demonstration; and we are

1 * “ Fit autem communicatio hæc, non per parietem cordis medium, ut vulgo creditur. Sed magno artificio a dextro cordis ventriculo, longo per pulmones ductu, agitatur sanguinis subtilis : a pulmonibus præparatur, flavus efficitur, et a vena arteriosa in arteriam venosam transfunditur.”

+ COLUMBO : De re Anatomica, edit. 1572, p. 325.

I CESALPINUS : Quæst. Peripitet., edit. 1593, lib. v. p. 125. Flourens gives the passage, as well as that from Colombo.

§ “Quia tument venæ ultrà vinculum, non citra. Debuisset autem opposito modo contingere, si motus sanguinis et spiritus a visceribus fit in totum corpus.” Quæstiunum Medicarum, lib. ii. p. 234.

-a

surprised to find De Blainville saying, Harvey having had a clear idea of “ that the circulation was known to the true theory, no one had even acCasalpinus, although he had not de- curately conceived the true theory of monstrated' it.” In science, the dif- pulmonary circulation; for although ference between a guess and a de- Servetus, Colombo, and Cæsalpinus monstration is as great as that be- knew that the blood passed through tween the fame which an unwritten the lungs, they fancied only so much poem may achieve, and the fame passed as was necessary for the rewhich a great poen has achieved. If ception of the vital spirits," guesses counted as achievements, the quantity which their predecessors temple of fame would be thronged fancied took its course through the with the statues of heroes. De perforated septum of the heart. But Blainville says, that the reason why they had no conception of the entire Haller and others have denied the mass of blood traversing the lungs; claim of Cæsalpinus, is because they and even had they known so much, did not read what he had said in they would have been wholly at a loss his work On Plants. * Now, if to say whence it came, and whither we turn to the passage in ques- it went. It was necessary to undertion,+ we shall see how far the stand the whole circulation before any writer really was from the truth, and part of it could accurately be underyet how near his guess went to the stood. truth. In animals, we see the food The discovery that the veins had carried by the veins to the heart, as valves, opening and closing like to a centre of innate heat; and there, doors, brought the discovery of the having acquired its final perfection, circulation within compass. It was it is distributed over the whole body made in 1574 by Fabrice d'Acquathrough the arteries, by the agency of pendente, under whom Harvey studthe spirit, which is engendered in the ied at Padua. These valves, preheart by this same food.” Easy as it venting any flow from the heart, is for us to read into this passage al- but admitting the flow to the heart, most all that we understand by the ought to have suggested to their discirculation, a close historical criticism coverer the true interpretation of detects in it nothing but a guess; their use. But five-and-forty years and, as Bérard remarks, we ought elapsed before any one arose, who not to confound two such vague had the sagacity to perceive the real statements as these, themselves re- value of this anatomical structure in quiring demonstration, and by Cæs- respect to the blood-currents; and alpinus himself subsequently contra- during these five-and-forty years, dicted, with the clear ideas, and everything that had been discovered imposing proofs, on which Harvey or surmised respecting the circulaestablished his discovery. The con- tion, was familiar to every anatomist vincing evidence of Harvey's origi- of the great Paduan school in which nality is, that not only was this Harvey studied : nevertheless, when guess advanced by Cæsalpinus with- Harvey, promulgated his theory, it out any influence on the theories of was vehemently opposed. In 1619 that day, in spite of his deserved he first publicly taught what he had authority; but when Harvey promul- discovered ; and in 1628 he publishgated his theory, he found, all over ed, for the benefit of Europe, bis ceEurope, the greatest difficulty in lebrated treatise, Exercitatio Anatogetting it accepted. Bérard main- mica de Motu Cordis et sanguinis, tains, that so far from any one before which may justly be called the basis

* DE BLAINVILLE: Hist. des Sciences de l'Organization, ii. 227-a statement repeated by ISIDORE GEOFFROY Sr Hilaire : Histoire Générale des Règnes Organiques,

+ CÆSALPINUS: De Plantis, i., c. 2, p. 3.-—"In animalibus videmus alimentum per venas duci ad cor tanquam ad officinam caloris insiti, et adeptâ inhibi ultimâ perfectione, per arterias in universum corpus distribui agente spiritu, qui ex eodem alimento in corde gignitur.”

IBERARD : Cours de Physiol., üi. 581. Milne EDWARDS : Leçons sur la Phys.et l'Anat. comparée, üi. 20.

i. 44.

« ForrigeFortsæt »