THE HEART. 285 



several of them in common. The endocardium is tolerably 

 well supplied with vessels in its layer of connective tissue, 

 whilst they are more scanty in the proper endocardium. In 

 the auriculo-ventricular valves a few vessels are readily seen, 

 not only in animals but also in Man, (vid. Luschka, 1. c, p. 182, 

 fig. 1), some of which enter them from the papillary mus- 

 cles, but chiefly from the basis of the valves, and are also 

 distributed, in part, though sparingly, in their proper endocar- 

 dial investment. The semilunar valves possess no vessels. 

 Only a few lymphatics are found in the external lamella of the 

 pericardium, whilst they occur in greater abundance on the 

 inner lamella on the muscular substance, and may there be 

 demonstrated readily enough, if the heart be placed for a few 

 days in water, as Cruikshank correctly observes. Their trunks 

 collect in the sulci, accompanying the blood-vessels, and termi- 

 nate in the glands, behind and below the arch of the aorta, 

 on the bifurcation of the trachea, to which the pulmonary 

 lymphatics also proceed. Whether the substance of the heart 

 and the endocardium are also furnished with lymphatics, as is 

 asserted by some, is not yet determined. The nerves of the 

 heart are numerous and proceed principally from the cardiac 

 plexus formed by the vagus and sympathetic, beneath and be- 

 hind the arch of the aorta. These nerves, forming the more 

 scanty plexus coronarius dexter, and the richer p. c. sinister, 

 accompany the vessels on the right and left ventricles and 

 auricles, run, in part with the vessels, in part crossing them in 

 various directions, toward the apex of the heart, and, whilst enter- 

 ing into numerous anastomoses with each other, usually at acute 

 angles, enter the muscular substance at various points, some even 

 in the coronary sulcus, in order to terminate, partly in the mus- 

 cular substance, and partly to reach the layer of connective tissue 

 of the endocardium. The cardiac nerves, in Man, are grey, and, 

 except the largest, contain only fine and very pale fibres j the 

 latter, however, in the greater number, and intermixed with not 

 very numerous nucleated fibres. Although the nerves, even in 

 the endocardium, retain their dark borders and are tolerably 

 numerous, it has not hitherto been possible to discover their 

 terminations in that situation, any more than in the muscular 

 substance. Ganglia exist, not only in the cardiac plexus in 

 various situations, but as Remak discovered in the Calf, also 



