CHAP. XII.] 



INTESTINAL CONCRETIONS. 



467 



by the bacterial decomposition of cellulose (Hoppe-Seyler 1 , Tappeiner 2 , 

 Henneberg and Stohmanu 3 .) 



The nitrogen is in part doubtless a diffusate from the blood, but 

 is certainly in part derived from the bacterial decomposition of the 

 proteids (Hiifner 4 , Kunkel 5 .) 



The following are the results of analyses of the gases of the 

 human colon, made by Huge. 



Results of Analysis of the Gases of the Large Intestine of Man. 



Ruqe 6 . 



SECT. 8. INTESTINAL CONCRETIONS 7 . 



In addition to gall stones, which are very frequently excreted 

 with the faeces per anum, or which, remaining impacted in the small 

 intestine occasionally are the cause of fatal intestinal obstruction, 

 intestinal calculi are sometimes met with in the colon of certain of 

 the lower animals, and much more rarely of man. In man, these 

 calculi are usually very small, having a diameter of 0'2 1 mm. 

 (intestinal gravel), but occasionally, though rarely, they attain the 

 size of a hazel nut. Intestinal concretions are comparatively frequent 

 in Scotland, owing to the large use made of oatmeal porridge as an 

 article of diet. Such calculi present the appearance of brown balls 

 and resemble, in structure and composition, calculi which are very 



1 Hoppe-Seyler, 'Ueber Gahrung der Cellulose und Bildung von Methan und 

 Kohlensaure,' Zeitsch.f. phys. Chemie, Vol. x. (1886), p. 201 et seq. and pp. 401440. 



2 H. Tappeiner j ' Untersuchungen iiber die Gahrung der Cellulose insbesondere iiber 

 deren Losung im Darmcanal,' Zeitsch.f. Biol., Vol. xx. (1884), pp. 52 134. 



3 Henneberg and Stohmann, 'Ueber die Bedeutung der Cellulosegahrung fiir die 

 Ernahrung der Thiere,' Zeitsch. f. Biol, Vol. xxi. (1885), pp. 613624. 



4 Hiifner, 'Ueber ungeformte Fermente und ihre Wirkungen &c.,' Journ. f. prakt. 

 Chemie, Vol. x. (1874), p. 1. Maly's Jahresber., VoL iv. (1875), pp. 262274. 



5 Kunkel, see Note 4 on preceding page. 



6 Ruge, Sitzungsber. d. Wien. Akad. d. Wiss., Vol. XLIV. (1862), p. 734. 



7 In preparing this section the Author has made use of the account given under 

 the heading 'Darmconcremente ' at page 174 of Professor Karl B. Hofmann's Lehrbuch 

 der Zoochemie, Wien, 1879, as well as of the information contained in Hoppe-Seyler's 

 Physiologische Chemie, under the heading 'Darmconcremente' (see p. 356 et seq.). 



302 



