306 DIGESTION. 



The direct influence of the facial nerve upon the secretion of 

 the parotid gland, the indirect action of the third branch of the 

 fifth pair (by inducing the movements of mastication), and the 

 reflex action through the glosso-pharyngeal nerve, have been 

 investigated in rabbits by llahn,* under the direction of Ludwig, 

 with all the acuteness of experimental criticism. 



Ludwig's admirable investigations afford some grounds for the 

 belief, that all those secretions which only appear at certain times 

 or in consequence of definite excitants, as for instance those of the 

 gastric juice and of the pancreatic fluid, are only produced under 

 the action of certain groups of nerves. The correctness of this 

 view, in reference to the two last-named animal juices, seems to 

 be confirmed by the observations recently repeated by Bidder and 

 Schmidt,f that the gastric juice is copiously effused into the 

 stomachs of dogs when flesh or any other attractive food is placed 

 before them while fasting. But although we certainly cannot deny 

 the influence of the nerves upon the secretion of the gastric juice, 

 we are entirely unable to determine upon which nerve this secre- 

 tion depends. It has generally Been referred to the pneumogas- 

 trics, and in recent times with more certainty, since Ed. Weber'sJ 

 admirable experiments (of which I was myself a witness) have 

 proved beyond a doubt that these nerves exert a direct influence on 

 the contractions of the muscular coat of the stomach. The direct 

 observations which have been made in reference to the secretion 

 of the gastric juice after the division of both the pneumogastrics 

 have, however, led to entirely opposite results. Whilst Arnold, 

 Reid, Leuret and Lassaigne, as well as Longet,|| following the 

 views of Joh. Mullerlf and Dieckhoff,** could not perceive any 

 change in the character of the secreted gastric juice in consequence 

 of the division of the pneumogastric nerve^ Bouchardat and 

 Sandras,tf and subsequently to them Bernard JJ and Frerichs, 

 believed that they had convinced themselves that no acid gastric 



* Zeitschr. f. rat. Med. N. F. Bd. 1, S. 285-292. 

 + Op. cit., p. 35. 



J Handworterbuch. der Physiologie. Bd. 3, Abt. 2, S. 41. 

 Edin. Med. and Surg. Journ. Vol. 51, p. 310. 

 || Arch. ge'n. de He'd. T. 15, p. 230, and Compt. red. T. 14, p. 266. 

 1T Handb. d. Physiol. Bd. 1, S. 459 [or English Transl.1839, Vol. 1, p. 597-] 

 ** De actione, quam nervus vagus in digestionem ciborum exerceat, Diss. 

 inaug. Berol. 1835. 



ft Revue me'd. Fe'br. p. 159-180. 



It Compt. rend. T. 18, pp. 783 et 995. 



Handworterbuch der Physiologie. Bd. 3, Abt. 1, S. 822-825. 



