An inaugural dissertation on the congenital malformations of the heart / by John Paget.

Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: An inaugural dissertation on the congenital malformations of the heart / by John Paget. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    VASCULAK SYSTEM. complex. * At a very early period the bulb of the aorta, as the vessel continuous with the heart is then named, divides into five pairs of vessels, which pass back to certain fissures 'tn the sides of the oesophagus, called branchial clefts, as the vessels pas- sing to them are called branchial arteries, from the close analo- gy they bear to the structure of the adult fish, or the young of the BatrachicB. Each of these vessels opens posteriorly, into the two vessels we have mentioned as lying along the spine, and which never unite higher than the middle of the dorsal region. The upper ones of these branchial arteries, undergo nearly the same changes as the vessels of the tadpole when its branchice become obliterated; and the vascular system of this animal bears a very close analogy to that of the foetus of mam- malia, at this early period. The first pair of vascular arches become the carotids; the second and third are said to unite to form the subclavians ; the ftmrth constitute the aortas, (per- manently double in reptiles as far as the middle of the dorsal region ;) while the fifth form the pulmonary arteries. In birds the arch of the aorta is single, and is formed by the fourth ves- sel oil the right side; in mammalia, on the contrary, the fourth on the left side constitutes the aortic arch. The ductus arteriosus, or ductus Botalli of continental au- thors, is formed by the persistence of the communication between the fifth arch or pulmonary artery and the systemic aorta. In the turtle and many other reptiles, this communication remains open on both sides through life ; in birds it has been clearly seen on the right side ; and in mammalia there can be little doubt that it is formed on the left in a similar manner. On this point, how- ever, there has been some difference of opinion. Meckel,and in this he has been followed by Dr Allen Thomson, \ supposes it to be formed by the division of the bulb of the aorta into the ])ulmonary artery and aorta proper, when a small channel of I)r A. Thomson on the Dcvclopemcnt of the vascular system in the fosliis of Vertebrated Animals, part 2d. Edin. New Phil. Journal, January 1831; and the translations of the writings of Baer and Ratlike on Foetal Developement in the Re- pertoire Generale d'Anatomie, &c. Tomes vi. vii. and viii. ■\ Memoire sur rilistoirc du Developpcment du Coeur, &c. Journal Couipl. Tome i. p. 259. } Kdinb. Kew I'liil. Journal, Jan. 1831, p. 75.