THE HEART. 671 



readily enough, if the heart be placed for a few days in water, as Cruik- 

 shank correctly observes. Their trunks collect in the sulci, accompany- 

 ing the bloodvessels, and terminate in the glands, behind and below the 

 arch of the aorta, on the bifurcation of the trachea, to which the pulmo- 

 nary 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 behind 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 entering into nume- 

 rous 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 muscular substance, and partly to 

 reach the layer of connective tissue of the endocardium. The cardiac 

 nerves, in Man, are gray, and, except the largest, contain only fine and 

 very pale fibres ; the latter, however, in the greater number, and inter- 

 mixed 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 in the muscular substance of the auricles 

 and ventricles, which is likewise true of man and other animals. These 

 ganglia are best known in the Frog, in which they are situated, espe- 

 cially in the septum, and at the junction of the auricles with the ven- 

 tricle, and contain apolar and unipolar cells (Ludwig, Bidder, R. Wagner, 

 myself). The minute fusiform enlargements on the external nervous 

 branches, especially noticed by Lee, are not ganglia, being merely thick- 

 enings of the neurilemma. 



With respect to the particular direction of the muscular fibres of the 

 ventricles, the following remarks may be offered. On the external sur- 

 face of the ventricles there is a layer, J-l line thick, which, on the left ven- 

 tricle, runs obliquely downwards from the pulmonary artery, the anterior 

 longitudinal sulcus and the left transverse sulcus, and in the middle of 

 the wall of the ventricle, descends very abruptly, almost vertically. 

 On the right ventricle, these fibres are oblique only on the conus arteri- 

 osus, whilst on the sides and posteriorly they are almost or quite trans- 

 verse. At the longitudinal sulci, the superficial fibres are continued 

 from one ventricle upon the other, so that a small portion of those of the 

 left ventricle arise from the anterior side of the ostium venosum dextrum 



