154 THE WORK OF THE DIGESTIVE GLANDS. 



and conclusively be decided that the second or chemical period of 

 gastric secretion is determined by a reflex proceeding mainly from the 

 inner surface of the stomach. If chemical excitants (solutions of meat 

 extract and so on) be alternately introduced into the large stomach and 

 into the duodenum, a full secretory effect is only obtained from the 

 small stomach in the former case. In the latter the secretion is very 

 scanty. 



On the other hand, the inhibitory effect of fat originates chiefly 

 from the surface of the duodenal mucous membrane and not from that 

 of the stomach. 



With the same dogs we were able, without difficulty, to demonstrate 

 a new form of auto-regulation on the part of the stomach, which 

 concerns the secretion of hydrochloric acid. It appears that the acid 

 prevents the further secretion of gastric juice when it has accumulated 

 in any considerable quantity within the cavity of the organ. It is 

 moreover of the greatest interest that other acids, for example, phos- 

 phoric, &c., do not exert this inhibitory action. Butyric acid, on the 

 contrary, strongly excites gastric secretion, a matter which is probably 

 connected with the fact that hydrochloric acid strongly inhibits butyric 

 acid fermentation. What could be more striking as an instance of the 

 selective excitability of the mucous membrane of the stomach ? 



I have only brought forward a few of the results which we obtained 

 by our new method, and would merely remark, in addition, that the 

 experiments on such dogs were characterised by an astonishing degree 

 of accuracy and constancy in the results. It might seem that the 

 cutting out of the influence of the movements of the food, and of the 

 effects of the different exciting substances, from these parts of the 

 digestive canal, would make it otherwise, but this was not so. 



I turn now to the bile. You all know, gentlemen, that the greater 

 the number of remedies recommended for a disease, the less is the real 

 efficacy of any one of them. The reason of this is quite plain. When 

 we possess a really good remedy we want no other. The same criterion 

 may be applied to our knowledge of the organs of the body. When a 

 number of insignificant functions are assigned to any organ, it means 

 that we do not know its real function or have not properly appreciated 

 it. So it is with the bile. In every text-book one can straightway 

 learn the functions of the gastric juice, of the pancreatic juice, and so 

 on. But when we come to the bile we have to read whole series of 

 sentences about its supposed uses, and perhaps will not even then learn 

 its chief function. Mention will be made of the emulsification of fat, 

 of the moistening of the intestinal wall, of the promotion of peristaltic 



