Licence: Public Domain Mark
Credit: The circulation. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![masj Ited th fay; bn GiSnwi Miraculous cures are soughj^ Tacobins, philosophers ioubt had their mo every month of tin reigned a century tember may have Saint Bartholome still the Parisian) Lutetia is G6u6v pictures, may embi is in the hearts o which is stronger t the nineteenth centur centuries, is the incantatn Isis of the Holy Mountain. The blue and white banner spangled with stars, of the saiute, still makes thousands of eyes sparkle in the city of the Seine, and the invocation still thrills many souls whenever it is heard : Sancta Gcnovefa IJrbis et Galliic Patrona, ora pro Charles Dlclcens.] UtM.l kneel, the taper, ton - ,™..enr.,,r,,o«!rht.^Mt!».Ue ‘“Jor “rial e,stent, and the venon, or sanguinary system. ‘ , But, said Galen, when you open an artery, gjood flows from it. Either, therefore, blood s contained in it, or has come into it from other source. But if it comes from vie of SI sacres g.vs an s, an ther names, But sbgg ■ovflMK^L'he §#fe ther where, if the artery contains air alone, e contained air ought to issue from it he- re the blood ; which is not the case. There „ ,~sues blood, and not a particle of air. Therefore, the arteries contain blood only. Galen made another experiment. He inter- cepted a portion of an artery between two ligatures ; he then opened the portion be- tween them, and found nothing but blood. Again, therefore, the arteries contain blood, and nothing else. “ But,” argued the partisans of Erasistra- tus, “ if the arteries contain blood, how can the air which is inspired by the lungs, pass Holy GdnCvieve, patroness of the city and country throughout the whole body • of Gaul, pray for us! i “It does not pass throughout it, answered ' ' Galen. “ The air drawn in, is sent out again. j It serves the purposes of respiration, by its temperature, and not by its substance. It THE CIRCULATION. To arrive at a truth, it is often necessary to hew the way through a thicket of error ; and one man’s labour does not always suffice to do the work. Sometimes, when the screen is nearly removed by the efforts of several successive pioneers, a few remaining tangled cools the blood, and that is the only use of respiration.” It is true that this is far from what we know about respiration at the present day ; it is even contrary to the fact. Instead of cooling the blood, respiration warms branches will still serve to intercept a clear' it, being the only source of animal heat, view of the important fact about to be re-: IN’evertheless, relatively to Erasistratus, who vealed. So it was with tiie discovery of the asserted that the air traversed the arteries in circulation of the blood, which Harvey had totality, in mass, in substance, exactly as it the honour of finally inaugurating, though passes down the windpipe ; that it was air numerous predecessors had put their hand j which distended the arteries, which made to the achievement. The task was spread ! them beat, which was the cause of the pulse : over more than a single epoch. Among the | Galen’s idea was au advance in science, and ancients, Galeu began by refuting Erasistratus; such an advance that the whole force of phy- whilst in modern times, the student Fagon risked an audacious act which, at that date, could only he undertaken by a young man, and only justified by great success. He main- tained in a thesis the circulation of the blood ; and the old doctors allowed that he defended this strange paradox with a talent worthy of a better cause ! Three important errors had to be swept away, before Harvey could arrive at his grand conclusion. Erasistratus, the author of the first, believed that the arteries contained not blood, but air only. According to his ideas, we breathe for no other purpose than to fill the arteries with air. The arteries were air-channels, whence their name, derived from two Greek words, signifying to draw air. The air, drawn in by the lungs, reached them by the trachea-artery, properly so called; from the trachea, it passed into the venous artery (now called the pulmonary vein) ; from the venous artery, it passed into the left ventricle, and from the left ventricle, it (always the air) passed into the arteries, which carried , , l t , it to the members. What we now call the nay, even saw that there was a passage j siology could not set a step further without the aid of modem chemistry. Haller still believed that respiration cooled the blood. Galen, therefore, demolished error the first; he was less fortunate with the remaining two. Still he proved that the arteries con- tain no air, but blood only, like the veins. An entire half of the sanguineous system, de- tached from that system by a mere hypo- thesis, was restored to it ; and as the circu- lation is no other than the movement which incessantly carries the blood from the heart to the arteries, from the arteries to the veins, and by means of the veins brings it back to the heart—the discovery of the circulation of the blood was impossible, so long as the arteries were supposed to be filled with air alone. Until the step which Galen made, any other progress was impracticable. Error the second. The partition, or dia- phragm, which separates the two ventricles of the heart, is not pierced with holes, minute or large; there is no passage through it. How, then, did it happen that Galen believed,](https://iiif.wellcomecollection.org/image/b22461498_0003.jp2/full/800%2C/0/default.jpg)
