The laws and mechanics of circulation, with the principle involved in animal movement . en upon the lung surface, passingthrough and through the lung substance for this purpose(Fig. 24, a, e), the air being admitted to the very bones them-selves ; and in birds of powerful flight penetrating even be-tween the muscles of the neck and limbs. And it is easy to per-ceive how the action in the abdomen and chest should increasethis circulation also by expanding and contracting the air-sacs correspondingly, at the same time compelling the air intoand out of the bones with afflux and efflux of air in t
The laws and mechanics of circulation, with the principle involved in animal movement . en upon the lung surface, passingthrough and through the lung substance for this purpose(Fig. 24, a, e), the air being admitted to the very bones them-selves ; and in birds of powerful flight penetrating even be-tween the muscles of the neck and limbs. And it is easy to per-ceive how the action in the abdomen and chest should increasethis circulation also by expanding and contracting the air-sacs correspondingly, at the same time compelling the air intoand out of the bones with afflux and efflux of air in the lungs,and enabling them to readily inflate the sacs for buoying themin the media when swimming or flying, by diminishing thebody-density, and increasing surface correspondingly. It isneedless to extend the matter. In conclusion : It is manifest, from this relation of the parts PORTAL CIECULATIOlSr. 81 in the abdomen, that the pumping action in respiration shouldincrease the portal circulation correspondingly. Thus, theliver substance being spread out, as it were, against the firm. Pig. 34.—Lungs, Heart, and Great Vessels of Buteo Vulgaris.— Gegenbaur. tr,trachea ; i, crop ; ae, communication between the air-sacs and the lungs ; 6, bursaf abricii ; ao, aortic arch : aad, art. anonyma destra ; aas, art. anonyma sinistra ;ps, art. pulmonalis sinistra ; c, carotid ; am, visceral artery; vci, commencementof the inferior vena cava : vcm, vena coccygeo-mesenterica. 82 PORTAL CIRCULATION. ventriculus (Fig 22, B, A), with the other viscera resting uponthem, must necessarily undergo a degree of compression withevery expiration, and increasing till the end of this, whichwould tend to force the blood through the open hepatic veins,the aspiratory force in the heart, which is close to the organ, beingadded to this ; while during inspiration the organ, by spring-ing back again to the original shape, should produce a suction-force upon the portal blood, at the same time the suction forc
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Keywords: ., bookcentury1800, bookde, booksubjectblood, booksubjectrespiration
