438 



THE GASES OF THE SMALL INTESTINE. 



[BOOK ii. 



The formation of butyric acid from dextrose is represented by the 

 equation 



C 6 H 12 6 = C 4 H 8 2 + 2C0 2 + 2H 2 . 



But butyric acid may also be developed by the action of ferments 

 on lactic acid, thus : 



2 (C 3 H 6 3 ) = C 4 H 8 2 + 2C0 2 + 2H 2 . 



SECT. 3. THE DECOMPOSITION OF THE FATS IN THE SMALL IN- 

 TESTINE, UNDER THE INFLUENCE OF BACTERIAL ACTION. 



Whilst there can be no doubt that under the influence of putre- 

 factive organisms fats may become rancid, i.e. be decomposed into 

 fatty acids and glycerin, there does not appear evidence to support 

 the view that such a process occurs, or at least attains a perceptible 

 figure, in the small intestine 1 . Lecithin is said to be decomposed 

 into glycerin-phosphoric acid and choline, the latter substance being 

 further decomposed into carbonic acid, marsh gas and ammonia 2 . 



SECT. 4. THE GASES OF THE SMALL INTESTINE. 



The small intestines are always more or less distended with 

 gases, which are composed of carbon dioxide, hydrogen, and nitrogen, 

 marsh gas being absent. The following are the results of the gases 

 of the small intestine of the dog made by Planer 3 . 



K. B. Hofmann also analysed the gases of the small intestine of 

 the dog and rabbit, and found them to be composed of a mixture of 

 CO 2 , H and N, neither O nor CH 4 being present 4 . 



1 Macfadyen, Nencki u. Sieber, op. cit., p. 347. 



2 Hasebroek, Zeitsch. f. physiol. Chemie, Vol. xn. (1888), p. 148. 



3 Planer, Sitzungsber. d. Wien. AJcad. d. Wiss., Vol. XLII. (quoted at second hand). 



4 K. B. Hofmann, ' Ueber die Zusammensetzung der Darmglase,' Wiener med. 

 Wochenschrift, 1872, No. 24 ; Maly's Jahresbericht, Vol. n. (1874), p. 226. 



