The physiology of the circulation in plants : in the lower animals, and in man : being a course of lectures delivered at surgeons' hall to the president, fellows, etcof the Royal college of surgeons of Edinburgh, in the summer of 1872 . n the higher animals. Cirmlation in the Spicier.—In the spider a large dorsal vesselmakes its appearance, this being dilated posteriorly so as to resemblea heart. The great propelling organ in the circulation of animals isnow beginning to assume form. The dorsal vessel gives off lateralbranches which ramify through the body ; the venous blood beingcollected in
The physiology of the circulation in plants : in the lower animals, and in man : being a course of lectures delivered at surgeons' hall to the president, fellows, etcof the Royal college of surgeons of Edinburgh, in the summer of 1872 . n the higher animals. Cirmlation in the Spicier.—In the spider a large dorsal vesselmakes its appearance, this being dilated posteriorly so as to resemblea heart. The great propelling organ in the circulation of animals isnow beginning to assume form. The dorsal vessel gives off lateralbranches which ramify through the body ; the venous blood beingcollected in open spaces or sinuses on the abdominal surface. Thereis as yet only an arterial system of vessels, the venous one beingdeficient. The blood is aerated by tracheae or pulmonary cavities. Circulation in the Insect.—A similar account may be given ofthe circulation in the insect. Here the dorsal vessel is dividedinto a series of swellings, each of which is furnished with valves,and endowed with a pulsatile power, as shown at h of Fig. 46. 1 Anatomy Descriptive and Surgical, by Henry Gray, Esq., , p. 401. 2 Nerves are supplied to llie inferior cava, and cerebral veins; to the aorta,pulmonary artery, and many other PHYSIOLOGY OF THE CIRCULATION. 85 The dorsal artery receives lateral currents from various parts of thebody, aud is widened out posteriorly. The dorsal vessel opensand closes in parts (one part always opening when the other closes)with a vermicular or wave-like motion—this, in conjunction withthe valves (pa, r), determining the course pur-sued by the blood. The blood is returned by Fig. vessels situated on the ventral aspect ofthe insect (r); these, according to Cams andWagner, being in many cases absent, and theirplaces supplied by open sinuses, as in thespider. The dorsal and ventral vessels areunited anteriorly and posteriorly by loopswhich, in the immature or larval individual,extend into the antennae, fin-shaped caudalprocesses, the first
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectblo, booksubjectblood
