74 DR. C. F. SONNTAG ON THE VAGUS AND 



branches to the solar plexus (c.S.P.). It is continued into the 

 superior mesenteric plexus (S.M.P.), one branch in particular 

 being thick and reaching the csecum (Oa). These sympathetic 

 plexuses even if traversing the vagus cord have come from the 

 solar plexus. 



In Canis thous the ventral cord runs along the lesser curvature 

 of the stomach to the pylorus, but it does not give off the hepatic 

 plexus. The dorsal cord supplies the dorsum of the stomach, 

 communicates with the solar plexus by a large cord, and sends 

 many branches into the solar ofishoots. Many branches can be 

 traced through the superior mesenteric plexus to the caecum. 



In Gynictis penicillata the right vagus replaces the ventral cord 

 in the species described above, but has a similar course. The 

 left one runs through the dorsal aspect of the oesophageal opening 

 in the diaphragm, supplies the stomach, and breaks up into fila- 

 ments which pass to the offshoots of the solar plexus. 



It is now believed that the A.rctoid Carnivora have genetic 

 relations to the Oetacea, and Swan (1) described the conditions 

 in PhoGcena communis as follows : — ''"In the porpoise the par 

 vagum communicates with the sympathetic, but is otherwise 

 separate from this, as in the baboon, rabbit, and others ; it gives 

 off a small recurrent which winds round the subclavian artery 

 on the right side, and tlie arch of the aorta on the left ; it sends 

 filaments to the oesophagus; it gives several branches to the 

 heart, and copiously supplies the lungs ; it then passes to the 

 oesophagus, where its branches are more deeply imbedded in 

 the m.uscular fibres than in other animals ; the greater portion 

 corresponding with the posterior trunk supplies the first, or 

 cuticular, and the second, or villous, stomach ; after forming a 

 corona or ring on the lower part of the oesophagus, it sends fila- 

 ments to the diaphragm and to the left semilunar ganglion ; it 

 also sends branches towards the other three stomachs or duodenal 

 pouches, a branch to the liver, and others to communicate with 

 branches from the coeliac plexus on the branches of the coronary 

 artery passing to the stomachs, and with some of the branches of 

 the hepatic plexus as this passes to the liver; the smaller portion 

 corresponding with the anterior trunk passes down and sends 

 some filaments to the lower portion of the oesophagus and the 

 first stomach, but its principal part divides to join both semilunar 

 ganglia." 



It is, therefore, evident that there is a greater degree of com- 

 munication between the vagi and solar plexus in the porpoise 

 than in the Arctoid Carnivora, both trunks being connected to 

 the semilunar ganglia. Complications are inti'oduced owing to 

 the differences in the characters of the stomach. 



The Sympathetic Nervous System. 



The superior cervical ganglion (text-figs. 1, S.0.G.-3, S.C.G.) is 

 absent in Atilax paludinosus, Ictonyx zorilla, and Canis thous, 



