110 THE WORK OF THE DIGESTIVE GLANDS. 



by a septum formed of mucous membrane in a way similar to that 

 described in our operation for making the miniature stomach. In this 

 dog a gastric secretion could be set up when the exciting substance 

 was introduced either into the stomach or into the intestine. 



But a remote possibility may still exist that the food (apart from its 

 reflex effect) could act also in a more immediate and direct manner 

 upon the glands. We must confess that this hypothesis, which for- 

 merly, when nothing was known concerning gastric innervation, was of 

 necessity admitted, appears now quite inconceivable. To accept it, one 

 had to admit that the food, in order to excite the gastric glands, 

 was able to penetrate into the thick mucous membrane. How little 

 physiological this idea sounds ! Now, however, the supposition becomes 

 all the more improbable since according to the latest investigations the 

 absorbing capabilities of the inner surface of the stomach are very limited. 

 Moreover, it must not be forgotten that even a long-sustained absorption 

 might not of necessity lead to a penetration of the substances into the 

 peptic glands. Nor can one even admit that the substances gain entry 

 into the mouths of the glands, because during secietion the stream of 

 fluid is directed from the lumen of the gland towards the cavity of the 

 organ. In support of the view for which we are contending, the 

 analogy of insect-eating plants has been brought forward, but this 

 analogy is scarcely justified. In plants the nervous system has not 

 yet been differentiated into a separate tissue or factor ; its functions 

 are shared by all the cells ; in our case, however, the gastric glands 

 have placed at their disposal the services of a very intricate nervous 

 mechanism. Unfortunately, one cannot, so far as I see, disprove 

 this improbable hypothesis by direct experiment. It will only gradually 

 die outj by giving way before the discovery of other neuro-glandular 

 phenomena, which certainly will attract ever more and more attention 

 to themselves. 



Now that I have shown you that the secretory activity of the 

 stomach, as a whole, depends on nervous processes, I must present the 

 matter once more to you as a working hypothesis of the inner- 

 vation apparatus of the gastric glands. In the immense majority 

 of cases gastric digestion begins with a strong central (automatic ? ) 

 excitation of the secretory and trophic fibres of the glands. Sooner 

 or later after the taking of food the influence of the reflex excitant 

 comes into play, while the automatic psychic effect gradually dies out. 

 If meat have been eaten, the secretory centre will still be strongly 

 excited in a reflex manner from the stomach and intestine, whilst 

 at the same time the trophic centre receives only weak impulses 

 from the peripheral terminations of the nerves in question. When 

 bread, however, is eaten, the reverse effects happen. After the cessa- 



