THE WORK OF THE DIGESTIVE GLANDS. 



we found enormous quantities of sawdust in the stomach, as much as 

 half a pound weight; obviously the dog had licked the wound from 

 adherent sawdust, which it then swallowed, together with that sticking 

 to its nose. And yet these particles of sawdust of themselves, which 

 certainly acted as mechanical stimuli, never caused a secretion. It 

 appears to me that this long series of facts ought to suffice to carry the 

 supposition to its grave, that by direct mechanical stimulation, one is able 

 to set the neuro-secretory apparatus of the stomach into activity. 



And yet the feather and the glass tube continue the even tenor of 

 their ways to this moment, and function in some text-books, yea, even 

 in articles which specially treat of gastric secretion, as exciters of the 

 gastric glands. There are, it is true, a few physiologists who hold 

 mechanical stimulation, in relation to gastric secretion, not to be very 

 effective, and give it a subordinate position in the series of exciting 

 agencies, but as yet I know of no other physiologist who has wholly 

 denied its influence, and who has not held it possible to obtain at least 

 some juice by it. 



To conclude this lecture, we will take into consideration a question 

 connected with the matter we have just discussed. Since the contact 

 of food with the gastric mucous membrane has no direct influence on 

 the secretion, is its entry into the stomach devoid of all connection with 

 the secretory process? 



It can hardly be doubted that, under normal conditions, the stomach 

 is the seat of certain definite sensations, that is to say, its surface has a 

 certain degree of tactile sensibility. This sensation is, as a rule, very 

 weak, and the majority of people become accustomed to pay no heed to 

 it in the normal course of digestion. They obtain their sensations of 

 general well-being, and especially of satisfaction from the enjoyment of 

 food, without taking cognisance of the factors contributing to them. 

 The feeling of general hunger, however, is referred solely to the stomach. 

 On the other hand, all of us have met with men who could describe 

 exactly and with gusto, fcow they were able to follow a special tit-bit, or 

 a mouthful of a favourite wine, the whole way through the oesophagus 

 down to the stomach, especially when the latter happened to be empty. 

 Naturally the gourmand, who directs his attention continuously to the 

 act of eating, can in the end distinctly perceive sensations and even 

 call them up to consciousness, which in other people are normally masked 

 by other sensations and impressions. We may therefore take it that 

 the satisfaction derived from eating, is caused not only by stimulation 

 of the mouth and throat, but also by impulses awakened by the 

 passage of the food along the deeper portions of the oesophagus and by 

 its entry into the stomach. In other words, food which merely passes 

 through the mouth and throat produces less enjoyment and excites, 



