66 ON THE MOTION OF THE BLOOD. 



were therefore called triglochine or tricuspidal: they 

 adhere to the fleshy pillars, or, in common language, 

 the papillary muscles. • 



105. In a similar maimer, the limits of the posterior 

 auricle and ventricle are denned by a ring of the same 

 kind, constituting two valves, which, from their form, 

 have obtained the appellation of mitral. * 



106. At the opening of the pulmonary artery f and 

 aorta J are found the triple semilunar or sigmoid valves,§ 

 fleshy and elegant, but of less circumference than the 

 mitral. 



107. It is obvious how these valves must prevent 

 the retrocession of the blood into the cavae. They 

 readily permit the blood to pass on, but are expanded, 

 like a sail, against it, by ^aiy attempt at retrograde 

 movement. 



108. The texture of the heart is peculiar : fleshy, in- 

 deed, but very dense and compact, far different from 

 common muscularity. || It is composed of fasciculi of 

 fibres, more or less oblique, here and there singularly 

 branching out, curiously contorted and vorticose in 

 their direction, lying upon each other in strata, closely 

 interwoven between the cavities, and bound by four 

 cartilaginous bands to the basis of the ventricles, which 

 are thus supported and distinguished in their texture 

 from the fibres of the auricles. ** 



* Eustarhius, Tab. xvi. fig. 6. 



f Eustuchius, Tab. *• i. fig. 4. 



X Eustachius, Tab. xvi. fig. 5. Morgngni, Adars. Anat. i. Tab. iv. fig. 3. 

 Santorini, 1. c. 



| Consult Huutcr, who treats very minutely of the mechanism of these 

 ralres in his work On the Blood, dec. p. 159. 



|| Leop. M. A. Caldani, Mcmvie Ultc nelF Acad, di Padava. 1814. p. G7. 



•• Casp. F. Wolff, Act. Acad. ScicHtiar. Pctropol. for the year 1 780 sq. 



