48 THE WORK OF THE DIGESTIVE GLANDS. 



Several workers had observed disturbances of the secretory activity 

 of the stomach which concerned the quantity or properties of the 

 gastric juice, as often as the vagi, the chief anatomical nerves of the 

 organ, were divided in the neck. But only very few were convinced 

 that the vagus stood in intimate relationship to the secretory activity of 

 the stomach. As is well known, division of the vagi on both sides of 

 the neck is an operation which is accompanied by the severest conse- 

 quences to the animal, and is usually followed by death after a few 

 of tenest after two to three days. If this operation in the course of such 

 a short time brings the whole functions of the organism to a standstill, 

 it is not to be wondered at, that, amongst other things, the action of 

 the gastric glands is also disturbed. It was consequently hazardous to 

 conclude from such an experiment that the vagus bore a direct relationship 

 to the gastric glands. (This is a good illustration of the second rule given 

 above, relative to the experiment of nerve-division.) Such a cautious 

 attitude towards the experiment seemed all the more justified because 

 Schiff * was able without difficulty to preserve his dogs in good health 

 and nutrition after division of both vagi beneath the diaphragm. The 

 animals increased in weight, and the younger dogs grew and thrived as 

 if nothing had happened. 



These experiments of Schiff have had decided weight with many inves- 

 tigators against the recognition of any secretory innervation whatever, 

 and unfortunately the view is still extant. But one can raise two impor- 

 tant objections to the experiments. First, the survival of the animals 

 cannot be taken as a proof that no deviation in the activity of the 

 gastric glands from the normal had occurred. We become more and 

 more convinced every day that the animal body is governed on the 

 principle of mutual help and defence by the several organs. In this 

 case it should have been boi-ne in mind that the sympathetic nerve also 

 sends fibres to the stomach. Schiff, moreover, had made no precise and 

 detailed comparison of the secretory activity of the stomach before and 

 after vagotomy. (This is a good example of the importance of the first 

 of our rules for nerve-division experiments.) 



Secondly, the subdiaphragmatic division of the nerves takes no cog- 

 nisance whatever of the possibility that the secretory fibres of the vagus 

 may enter the wall of the digestive tube above the diaphragm and 

 course down to the stomach along its deeper layers. 



The results of excitation of the vagus nerve proved to be also 

 uncertain, perhaps even more doubtful. Hardly any of the authors, 

 no matter where or how they stimulated the nerve, could claim a 

 result which recalled a secretory effect. The few and not very 



* Schiff, Lpqons K-nr hi physiologic de la digestion, isi!7. 



