268 DIGESTION. [CHAP. xxv. 



or absent, the fetid odour of the discharges from the bowels 

 becomes greatly increased, as in jaundice from obstruction, and 

 Asiatic cholera. It is not improbable that some of the intestinal 

 glands may secrete a peculiar odoriferous principle, which may be 

 modified by the bile. Foyer's glands may perform this office ; and 

 this idea derives support from the fact, that in certain cases where 

 these glands are diseased, as in fever and phthisis, the foetor of 

 the faeces is increased considerably. 



Certain gases are generated in the course of the intestinal canal. 

 These are partly set free during the changes which the alimentary 

 matters undergo in the intestine ; and partly they are products of 

 secretion from the mucous membrane. They consist of carbonic 

 acid, hydrogen, carburetted and sometimes sulphuretted hydrogen, 

 and nitrogen. A certain quantity of these gases seems, by its 

 distending action, to favour the vermicular movement of the bowels, 

 and so to promote the passage of their contents. Within certain 

 limits, therefore, the formation of gases in the bowels may be pre- 

 sumed to favour health ; but, it is well known, that under the in- 

 fluence of emotion, or of irritation, or of certain kinds of food, gases 

 are generated in the stomach, as well as in the intestines, to an 

 enormous extent. Tympanitis shows itself in hysteria under the 

 influence of strong emotion; and sometimes a few minutes will 

 suffice to generate a quantity of gas sufficient to distend the whole 

 canal. Also, in fever, the formation of gases in the intestines is a 

 prominent symptom, giving rise to that state of meteorism which 

 is known to be an unfavourable sign in that disease. 



On the subjects discussed in this chapter the reader is referred to the list 

 of writers at the end of the last chapter, and to those quoted in the foot- 

 notes ; also to the following : Berzelius, art. Galle in Wagner's Handworter- 

 buch ; Bernard, du Sue Pancreatique, etc., Arch. Gen. de Med. 1849 ; Bernard, 

 de 1'origine du sucre dans reconomie animale, Arch. Gen. de Med., 1848, and 

 translated in Banking's Abstract for 1849. Frerichs' art. Verdauung, in 

 "Wagner's Handworterbuch, a most able essay, which did not reach us until 

 this chapter had been some time in type ; Bouchardat and Sandras, Comptes 

 Rendus, 1845 ; Dr. Allen Thompson's paper on the Intestinal Glands, in 

 Goodsir's Annals of Anatomy and Physiology. Part i. 1850. 



