466 THE GASES OF THE LARGE INTESTINE. [BOOK II. 



In individuals suffering from the cystine-diathesis, the quantity 

 excreted in the urine is comparatively large, as much as one- 

 fourth of all the sulphur which should be excreted in the oxidised 

 condition passing out of the system as cystine. There can be no 

 doubt that this depends upon an abnormal decomposition of the 

 proteids, and facts render it probable that this is dependent on the 

 intervention of abnormal fermentations in the alimentary canal. 

 Neither the faeces nor the urine of healthy human beings contain 

 any trace of diamines (so-called ptomaines). Baumann and Udransky *, 

 as well as Brieger and Stadthagen 2 , have found that when cystine 

 occurs in the urine, both the faeces and the urine contain cadaverin, 

 putrescin and another diamine, which is isomeric with pentamethylen- 

 diamine or cadaverin (perhaps neuridin or saprin). It therefore seems 

 very probable that the cystine diathesis depends upon an abnormal 

 ferment process, having its seat in the intestine and due to yet 

 unknown micro-organisms. 



SECT. 7. THE GASES OF THE LARGE INTESTINE. 



The large, like the small intestines, are always more or less 

 distended by a mixture of gases which, in part, have diffused out of the 

 blood, but in part are the products of the action of micro-organisms 

 on carbohydrates and to a less extent on proteids. The evolution of 

 gases is, however, in the normal condition, a very limited one. An 

 analysis of the gases obtained from the rectum shews them to be 

 composed of a mixture of carbonic acid, marsh gas, nitrogen, and 

 hydrogen. In the strictly normal* condition of digestion, unless 

 substances are consumed in considerable quantities which either 

 contain free sulphur, or easily decomposed sulphur compounds, the 

 gases of the large intestine contain no sulphuretted hydrogen. 



Origin of the The C0 2 is in part derived from the blood, in part 

 individual ^ e p ro( j uc t o f th e bacterial decomposition of the carbo- 

 themixedgases hydrates and proteids. The H is a product, as we have 

 of the colon. already shewn, of the action of various bacteria on 

 sugars 3 , in part it is produced during the putrefaction of 

 albuminous bodies. 



The methane (CH 4 ) is the product both of the fermentation of 

 carbohydrates and proteids (Kunkel) 4 . It is formed in large quantities 



1 E. Baumann and L. v. Udransky, 'Ueber das Vorkommen von Diaminen, soge- 

 nannten Ptoma'inen, bei Cystinurie,' Zeitsch. f. phys. Chem., Vol. xm. (1889), pp. 

 562594. 



2 L. Brieger and M. Stadthagen, 'Ueber Cystinurie nebst Bemerkungen iiber einen 

 Fall von morbus maculosus Werlhofii,' Berliner kl. Wochensch., 1889, no. 16, and 

 Maly's Jahresbericht, 1890, p. 453. 



3 The abundant evolution of H and C0 2 during the butyric fermentation is well 

 known ; see Victor Paschutin, 'Einige Versuche iiber die buttersaure Gahrung, ' Pniiger's 

 Archiv, Vol. vin. (1873), p. 352. 



4 Kunkel, ' Ueber die bei der Pancreasverdauung auftretenden Gase,' abstracted in 

 Maly's Jahresber., Vol. iv. (1875), pp. 274276. 



