

CIRCULATION. 



681 



and sometimes the secretions, natural growth 

 of parts, and reunion of wounds have been 

 found to be little impaired by injuries of the 

 nerves. We may therefore form the conclu- 

 sion, that although the circulation in the small 

 vessels is obviously liable to be modified by 

 the state of the nerves in their neighbourhood, 

 or perhaps by affections of the nervous system 

 in general, there is no reason to consider the 

 capillary circulation as more immediately de- 

 pendent on nervous influence than the action 

 of the heart. 



BIBLIOGRAPHY. We have deemed it advisable 

 to reserve our historical sketch of the discovery of 

 the circulation and the knowledge of that impor- 

 tant portion of physiology to this part of the article, 

 thereby consulting brevity in uniting it with the 

 literature of the subject. 



The Chinese have been conceived to have enter- 

 tained correct notions of the circulation before they 

 had any intercourse witli Europe, a supposition, 

 the erroneousness of which is sufficiently demon- 

 strated by their description of the commencement 

 of the circulation of the radical humours and vital 

 heat at three o'clock in the morning, their passage 

 through the lungs in the course of the day, and 

 termination in the liver at the end of twenty-four 

 hours, as well as by the different manipulations 

 practised by them in the operation of venesection. 



In the time of Hippocrates and Aristotle, al- 

 though the principal bloodvessels were described 

 apparently from dissection of animals, the course 

 of the blood appears to have been wholly un- 

 known. 



Towards the end of the second century Galen 

 describes accurately the distribution of many of 

 the bloodvessels in the lower animals. He ap- 

 pears also to have known the anastomoses of the 

 arteries and veins, and the structure and uses of 

 the foramen ovale in the foetus, but his works 

 afford no evidence of his having known the course 

 of the blood in either the pulmonic or the systemic 

 circulations. He described the arteries as arising 

 from the heart, the veins from the liver ; and some 

 of those passages of his works in which it is 

 alleged that the circulation of the blood is pointed 

 out, are either inconsistent with one another, or 

 are believed to have been introduced at a later 

 time than Galen's. Galen believed that the blood 

 passed through the septum of the ventricles ; he 

 knew that the arteries contained blood, but he 

 believed its motion to be of an oscillatory kind. 

 (De usu partium, 1. iv., vi., & vii., and his trea- 

 tise on the question an sunyuis in arteriit ruitura 

 continetur ?) 



The authors of a more recent date, in whose 

 works it has been supposed that the circulation was 

 described, are Servetus, Columbus, and Caesal- 

 pinus. After the revival of letters, the great ana- 

 tomist Vesalius of Brussels, in 1542, had examined 

 more minutely than his predecessors the connec- 

 tions of the arteries and veins : he mentions the 

 valves of the veins, the difference between the 

 veins and arteries, and describes the valves of the 

 heart. He seems to have known that the blood 

 was propelled into the arteries by the heart, and 

 demonstrated by a more direct experiment than 

 Galen's, that the arterial pulse depends on the 

 systole of the heart. (De corporis humani fabrica, 

 fol. ; and Opera Omnia, cura. Boerhaave.) 



Servetus, the victim of religious persecution in 

 1553, is one of those in whose writings we find the 

 first dawn of part of the discovery of Harvey, for 

 he very distinctly at one place refers to the pulmo- 

 nary circulation. The vital spirit (blood) passes 

 by the arteries into the veins by their anastomoses. 

 The blood cannot pass from the right into the left 

 auricle on account of the closed nature of the sep- 



VOL. I. 



turn auricularum ; in the adult it must go through 

 the lungs, where it is charged with the vital spirit 

 obtained from the atmospheric air, and then returns 

 to the heart. He further held that the pulmonary 

 artery and vein from their large size must have 

 some other use than the nourishment of the lungs 

 merely. De Trinitatis Erroribus. Basil, 1531. 



Columbus, Professor at Padua and Rome, six 

 years after the publication of the work of Servetus, 

 published the discovery of the lesser circulation as 

 his own. He describes it more clearly than Ser- 

 vetus does, and held that the blood returning from 

 the lungs is not mixed with vital spirit, but is quite 

 pure. Libri xv. De re anatom. Venetiis, 1559. 



Caesalpinus of Arezzo, Professor at Pisa, gave, 

 in 1583, a more detailed description of the pul- 

 monary circulation than any of those who preceded 

 him, and in two parts of his work expresses him- 

 self in such a manner as to shew that he had some 

 idea of the systemic and double circulation. Other 

 passages in his works are, however, quite incon- 

 sistent with a correct knowledge of the course of 

 the blood, and, although we find this course more 

 nearly indicated in the writings of Caesalpinus 

 than in any others before the time of Harvey, he 

 does not seem to have added much, if any thing, 

 to the knowledge possessed by those who preceded 

 him, but rather to have applied, and without 

 acknowledgement, the observations of Vesalius, 

 Fallopius, Servetus, and Columbus, to the expla- 

 nation of the circulation. 



The foetal circulation seems to have been ex- 

 amined with great attention by the anatomists of 

 the sixteenth century. Galen had already been 

 acquainted with the foramen ovale, and also knew, 

 though less perfectly, the ductus arteriosus. Fal- 

 lopius described the ductus arteriosus exactly, 

 so also did Vesalius and .Ar.tn/ii; and after this 

 Botallus appropriated to himself the discovery of 

 both the foramen ovale and ductus arteriosus. 

 Vesalius discovered the ductus venosus which was 



r" red by Fabricius and Eustachius. Fabricius 

 Aquapendente made the discovery of the valves 

 of the veins and published it in 1603 : it is sur- 

 prising that knowing their structure so perfectly as 

 he did, he should have continued ignorant of their 

 uses, and stricily attached to the older erroneous 

 opinions regarding the circulation. 



Dr. William Harvey was born at Folkstone in Kent, 

 and studied under Fabricius at Padua from 1598 

 to 1602. Learning from his master the structure 

 of the valves of the veins, he engaged in experi- 

 mental researches after returning to England, with 

 the view of determining their uses, and in 1619, 

 according to his own statement, taught publicly for 

 the first time the doctrine of the double circulation 

 of the blood, which he had demonstrated by his 

 investigations. He did not publish any history of 

 this discovery until after the lapse of nine years, 

 during which he had carefully examined his doc- 

 trines and experiments. This appeared in the 

 Excrcitaiio Anatomica de Motu Cordis et Sanguinis 

 in Animalibus. first published at Frankfort in 

 1628. 



Among the contemporaries of Harvey who sup- 

 ported his views, the following authors are re- 

 markable. 



Werner Rolfink, Professor at Jena, one of the 

 first to adopt the new view, published two years 

 after the publication of Harvey's work. 



DesCartesupon two occasions supported Harvey's 

 views, viz. in 1637 and 1643, having been answered 

 by Plempius. 



John Walaeus, Professor at Leyden, may be 

 regarded as one of the most original of those who 

 adopted and defended the new view. In 1640 he 

 published two letters, addressed to Thomas Bar- 

 tholin. 



Herman Conring of Hermstadt. 



James de Back, Amsterdam, 1649. 



John Trullius 1651, Rome. 



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