385 



Nerves can not yet be traced from the ganglia of the sympathetic 

 trunks toward the heart, and there is no evidence of the migration of 

 cells from the ganglia of the sympathetic trunks into the anlagen of 

 the cardiac plexus. 



In embryos 16 mm in length cardiac nerves having their origin 

 in the ganglia of the sympathetic trunks, as well as vagus branches 

 may be traced into the ganglia of the cardiac plexus. Here again it 

 is interesting to note that while the vagus branches are apparently 

 free from migrating cells, the sympathetic cardiac nerves still contain 



Irn. - 

 Ivt. - - ^ 



' vtr. 



^^^ nb. 



ac. ■^- -»-!Ö._, ^ 



eg- 



Fig. 2. Transverse section through oesophagus, vagus nerves, and anlagen of 

 cardiac plexus of 12 mm embryo of the pig. y^ 110. ac. cells accompanying vagus 

 fibers, ao. aorta, cb. cardiac branches of the vagi. eg. anlagen of cardiac plexus. 

 Irn. left recurrent nerve. Ivt. left vagus tnink. mc. cells migrating from vagus trunks 

 around oesophagus, nb. neuroblast, oe. oesophagus, orr. origin of right recurrent nerve. 

 p. pulmonary artery, vtr. right vagus trunk. 



numerous cells which are apparently migrating peripherally along their 

 fibers. It is probable, therefore, that the cardiac plexus also receives 

 cells from the ganglia of the sympathetic trunks after the sympathetic 

 cardiac nerves have become established. 



This stage in the pig compares quite well with the human embryo 

 10.2 mm in length described by His jr. ('91). He also observed that 

 in this stage the vagus branches are comparatively free from cells 

 while the sympathetic cardiac nerves contain many cellular elements. 



Anat. Aaz. XXXV. Aufsätze. 



25 



