2 1C) . NERVOUS SYSTEM. 



ments of the heart. 1 This assumption is too broad ; and 

 certainly it would not have been less accurate, and would 

 have answered a vital objection, if the nerve had been di- 

 vided and galvanization had been applied to its peripheral 

 extremity ; for it is well known that so long as the motor 

 nerves and the muscles retain their irritability, contractions 

 will follow their stimulation after they have been separated 

 from the centres. In the experiments just cited, there is 

 every reason to believe that the contractions of the oesoph- 

 agus and stomach were purely reflex. The remarks just 

 made concerning the experiments of Chauveau are equally 

 applicable to those of Yan Kempen, in which it is not stated 

 that the roots were divided ; 2 and, as far as we know, there 

 are no direct observations showing contraction of muscular 

 tissue following stimulation of the roots of the pneumogas- 

 trics, which cannot be explained by the principle of reflex 

 action, or by the supposition that the stimulation was ex- 

 tended to communicating motor filaments. In view of these 

 facts, we do not consider it necessary to discuss the question 

 more fully in detail, and will adopt, without reserve, the 

 conclusions of Longet, that the true filaments of origin of 

 the pneumogastrics are exclusively sensory, or, at least, that 

 they have no motor properties. 



Properties and Functions of the Auricular Nerves. 

 There is very little to be said with regard to the auricular 

 nerves, after the description we have given of their anat- 

 omy. They are sometimes described with the facial and 

 sometimes with the pneumogastric. They contain filaments 

 from the facial, the pneumogastric, and the glosso-pharyn- 

 geal. The sensory filaments of these nerves give sensibility 

 to the upper part of the external auditory meatus and the 

 membrana tympani. 



1 CHAUVEAU, Du nerf pneumogastrique, etc. Journal ck la physiologic, Paris, 

 1862, tome v., p. 193. 



2 VAN KEMPEN, Nouvelles recherche* sur la nature fonct'tonelle des racines du 

 nerf pneumogastrique et du nerf spinal. Journal de la physiologic, Paris, 1863, 

 tome vi., p. 284, et seq. 



