CHAP. XII.] PUTREFACTIVE PROCESSES IN THE COLON. 455 



observations of Dr Bischler 1 , to a most energetic fermentation, in 

 which are formed ethylic alcohol, acetic acid, and dextrogyrous para- 

 lactic acid 2 . As was stated in discussing the micro-organisms of the 

 small intestine, the Bacterium lactis aerogenes has an intense action 

 on sugar, developing alcohol and according to Frey dextrogyrous 

 paralactic acid. When grown in the absence of air it decomposes 

 sugar with the production of a mixture of gases, containing 72'38 vol. 

 p.c. of CO 2 and 27'61 of H. 



It is the Streptococcus liquefaciens coli and the other putrefactive 

 bacteria to which reference has been made, which are the cause of 

 the putrefactive fermentation which attacks the proteids. That this 

 produces small quantities of peptones and other soluble products of 

 the putrefactive decomposition of albumin, as Marckwald shewed, and 

 that these are absorbed, is likely enough, but the part which they play 

 in reference to the nutrition of the body must be a very limited one. 



The action of these organisms is, however, able to convert into 

 faeces the residual matter left after the absorption of a large part of 

 the water and of the soluble constituents which the intestinal contents 

 possessed on entering the colon. The alkalinity of the mucous secre- 

 tion of the colon is such as more than to neutralise the organic acids 

 which are the products of the action of the bacterium commune coli, 

 &c., and the alkaline reaction, which is so favourable to true putre- 

 faction, is established. 



The putrefactive process, which attacks the residues of the diges- 

 tive process, is one in which the proteid bodies are decomposed with 

 the production of characteristically stinking products, amongst which 

 skatol is the chief 3 . The nascent hydrogen, which is evolved during its 

 progress, acting on the bilirubin, which had retained its individuality, 

 now converts it into hydrobilirubin, the characteristic colouring matter 

 of the faeces. Yet, even when the putrefactive changes are complete, 

 the faeces have, under normal circumstances, to sojourn a while in 

 the rectum, where the absorption of water and perhaps even of other 

 diffusible substances goes on until they are expelled from the body. 



It is a strange, and a somewhat puzzling, fact that the hydro- 

 bilirubin, the indol, the skatol, the phenols, which are the result of the 

 putrefactive process, which goes on in preponderating measure, if not 

 exclusively, in the large intestine, should in great measure be absorbed 

 and, after entering the portal blood and making their way through the 

 liver, be excreted, somewhat modified or in new combinations, in the 

 urine/ That these bodies play a part in influencing the metabolic 



1 Original observations communicated to Dr Blachstein. See his Contribution a la 

 Biologic du Bacille Typhique,' Premier Memoir, p. 11. 



- See also A. Baginsky, 'Zur Biologic der uormalen Milchkotbakterien,' Zeitsch. /. 

 phys. Chem., Vol. xin. (1889), p. 353. 



3 Zumft, in a recent research conducted in Nencki's laboratory at St Petersburgh, 

 found no skatol- carbonic acid in the contents of the colon. See Zumft 'Sur les 

 processus de putrefaction dans le gros intestin de I'homme,' &c. Archives des Sc. Biol, 

 St Petersburg. Tome i. (1892), p. 497. 



