. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . rectly(by the ductus venosus), or, after first passing to the liver (bythe venae advehentes, and returning by the venae, ),and proceeds, mingled with the blood returning from the lowerextremities, to the right auricle. This blood, though far frombeing as arterial in character as the blood after biith, is the bestthat reaches the heart or any part of the organism. After arriv-ing at the right dammed back by the Eustachianvalve, it avoids the right ventricle, and
. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . rectly(by the ductus venosus), or, after first passing to the liver (bythe venae advehentes, and returning by the venae, ),and proceeds, mingled with the blood returning from the lowerextremities, to the right auricle. This blood, though far frombeing as arterial in character as the blood after biith, is the bestthat reaches the heart or any part of the organism. After arriv-ing at the right dammed back by the Eustachianvalve, it avoids the right ventricle, and shoots on into the leftauricle, passing thence into the left ventricle, from which it issent into the aorta, and is tben carried by the great trunks of thisarch to the head and iipper extremities. The blood returningfrom these parts passes into the right auricle, then to the corre-sponding ventricle, and thence into the pulmonary artery; but,finding the branches of this vessel unopened, it takes the line of Pulmonary Art Foramen Ovale Eustachian Opening. fc\%!. / *%. Bladder. Pulmonary Auric. ■ , Hepatic Vein. Branches of theUmbilical Vein, .to the Liver. Ductus Venoms. Internal Iliac 13-1.—Diagram of the foetal circulation (Flint). THE DEVELOPMENT OP THE EMBRYO ITSELF. 127 least resistance through the ductus arteriosus into the aorticarch beyond the point where its great branches emerge. It willbe seen that the blood going to the head and upper parts of thebody is greatly more valuable as nutritive pabulum than the rest,especially in the quantity of oxygen it contains; that the bloodof the foetus, at best, is relatively ill-supplied with its vital essen-tial ; and as a result we find the upper (anterior in quadrupeds)parts of the foetus best developed, and a decided resemblance be-tween the mammalian foetus functionally and the adult forms ofreptiles and kindred groups of lower vertebrates. But
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1890
