78 THE SECRETION OF GASTRIC JUICE. [BOOK II. 



secretion of Richet also observed 1 , in the case of gastric fistula 

 the gastric w hich he has submitted to elaborate investigation (that 

 fluenced 8 by ^ Marcelin N.), that when the patient, who had an 

 the nervous absolutely impassable stricture of the oesophagus, chewed 

 system. savoury articles of food, there was, simultaneously with 



an abnormal secretion of saliva, a copious flow of gastric j uice. 



These facts would lead one at first to conclude that the gastric 

 glands are under the closest influence of the nervous system, but, 

 as is remarked by Heidenhain, who draws attention to them, the 

 results observed may be explained by assuming an action exerted pri- 

 marily on the muscular movements of the stomach, or upon the blood- 

 vessels of the stomach. 



Section of the pneumogastric nerves has long been known to 

 influence in an important manner the functions of the stomach. 

 It has been asserted, by some, that after division of these nerves the 

 secretion of gastric juice, as well as the movements of the stomach, 

 cease permanently ; by others, that secretion of the gastric juice is 

 stopped for a time, and then becomes re-established. The bulk of the 

 evidence which is most to be relied upon clearly shews, indeed, that 

 the pneumogastric nerves only affect gastric digestion by their influ- 

 ence upon the movements of the organ, and that after their division 

 secretion of gastric juice of normal constitution takes place. 



It has been similarly shewn that the sympathetic nerve-trunks 

 connected with the stomach may be destroyed without stopping the 

 secretion of gastric juice. The stomach therefore, unlike many 

 secreting organs, is not known to be dependent on the control of 

 secretory nerves passing to the organ from the great nerve-centres. 

 It cannot, however, be regarded as definitely proved that there are no 

 secretory nerves running from the central nervous system to the 

 gastric glands. Since the gastric glands secrete when cut off from 

 the central nervous system, we have to inquire whether this is 

 brought about by a peripheral nervous mechanism or by a direct 

 stimulation of the gland centre. The abundant nerve ganglia and 

 nerve plexuses which are found in the submucous coat of the stomach 

 may probably represent the secretory centres, and the secretory nerves 

 which preside over the secretion of the gastric juice, but yet another 

 possibility presents itself. 



It is conceivable, argues Heidenhain, that just as in the vegetable 

 Drosera the secretion of the digestive glands is brought about by 

 mechanical irritation without the intervention of a nervous me- 

 chanism, so, in the animal stomach, secretion of gastric juice may 

 follow the direct application of a stimulus to the secreting epi- 

 thelium. 



von Nahrungsmitteln die Absonderung des Magensaftes zu vermehren vermag, wovon 

 wir uns bei Thieren mit unterbundenen Speichelgangen vielfach iiberzeugt haben.' 

 Bidder u. Schmidt, Die Verdauungssafte und der Stqff'wechsel, p. 35. 



1 Ch. Richet, 'Recherches sur 1'acidit^ du sue gastrique de l'homme...faites sur une 

 fistule gastrique.' ^Comptes Eendus, Vol. LXXXIV. p. 410. Journ. de Pharm. et Chimie, 

 Vol. xxv. p. 427. Le sue gastrique chez Vhomme et les animaux. Paris, 1878. 



