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, etc of the Royal college of surgeons of Edinburgh, in the summer of 1872 . d seventh layers embrace in their convolutions those immediatelybeneath them, while these in turn embrace those next in succession,and so on until the central layer is reached—an arrangementwhich explains alike the rolling movements and powerful action ofthe ventricles. It also accounts for the spiral shape of the ventri-cular cavities, and the fact that the b
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, etc of the Royal college of surgeons of Edinburgh, in the summer of 1872 . d seventh layers embrace in their convolutions those immediatelybeneath them, while these in turn embrace those next in succession,and so on until the central layer is reached—an arrangementwhich explains alike the rolling movements and powerful action ofthe ventricles. It also accounts for the spiral shape of the ventri-cular cavities, and the fact that the blood is literally wrung out ofthe ventricles during the systole. VII. The fibres of the right and left ventricles anteriorly andseptally are to a certain extent independent of each other ;whereas posteriorly many of them are common to both ventricles ;, the fibres pass from the one ventricle to the other—an arrange-ment which induced Winslow * to regard the heart as composed oftwo muscles enveloped in a third (Fig. 96). It will be evidentfrom this distribution of the fibres, that while the ventricles arefor obvious reasons intimately united, they nevertheless admit ofbeing readily separated (Fig. 101). Fig. 101. Fig. Fig. 101.—Right and left ventricles of mammal seen posteriorly (human). Shows how thefibres issue from the right and left auriculo-ventricular openings (c, d); the fibres romthe left opening passing from the left ventricle («) across septum (/) to the right ventricle(<?). Of these some curve in a downward direction, and disappear in the left apex: otherscurve round anteriorly and disappear in the anterior coronary groove Compare with b. Orifice of pulmonary artery.—Original. Fio. 102 shows how the two sets of external fibres (a b, c d) of the left ventricle curveround and form a be uitiful whorl prior to entering the left apex to become the two sets ofinternal fibres known as the musculi papillares, seen at m, n of Fig. 103. The fibres
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