128 CONTENTS OF THE INTESTINAL CANAL. 



In addition to the fluid and solid contents of the intestinal 

 canal, we must also refer to the gases occurring there. Unfortunately, 

 however, the very few observations which we possess regarding 

 these elastic fluids are not altogether trustworthy, since the investi- 

 gations made regarding the gas contained in the intestines in cases 

 of disease, have usually not been instituted till twenty-four hours 

 after death. Magendie and Chevreul* are the only experimentalists 

 who have examined the gaseous contents of the stomach and the 

 small and large intestines of men immediately after their execution ; 

 and even these investigations cannot be regarded as altogether 

 conclusive, since a person's knowledge that he is going to be 

 executed in a few hours must probably somewhat disturb his 

 digestive functions. 



In the stomach of a man, after execution, Magendie and 

 Chevreul found a gaseous mixture, consisting of atmospheric air 

 in which a portion of the oxygen had been replaced by carbonic 

 acid; and, besides this, they found a little hydrogen. (According to 

 volume, this air was composed of 14-g- of carbonic acid, 11^- of 

 oxygen, 71*45 $ of nitrogen, and 3'55 of hydrogen.) Moreover, 

 it can hardly be doubted that this air was for the most part con- 

 veyed into the stomach from without. We have already men- 

 tioned that, in the insalivation of the food, a very appreciable 

 quantity of air is mixed with it, and this is probably the most 

 common mode by which atmospheric air finds its way into the 

 stomach, although, in certain respiratory movements some air may 

 be driven or pressed through the oesophagus, as, for instance, in 

 the efforts which precede vomiting, as has been shown by 

 Budge : some persons, however, possess the power of swallowing 

 air at will, and of exciting vomiting by swallowing large quantities. 



The diminution of the oxygen, and the considerable augmen- 

 tation of the carbonic acid, may be referred with more probability 

 to the interchange of these gases with those of the blood, than to 

 processes of fermentation ; this interchange is, at all events, a 

 physical necessity, while processes of fermentation are always 

 indicative of something abnormal in the stomach. In the case 

 examined by Magendie and Chevreul, there certainly seems to 

 have been a fermentation, as evidenced by the presence of 

 hydrogen, although in small quantity, in the air. 



In the dead bodies of healthy men and animals, the quantity of 

 air found in the stomach is always extremely small ; but there are 

 various conditions in which there is an abnormal accumulation of 

 * Berzelius, Lehrb. d. Ch. Bd. 9, S. 338-340. 



