360 PHYSIOLOGY CHAP. 



Halliburton noted that clioline, one of the toxic alkaloids of 

 animal origin, is decomposed by the intestinal bacteria into simpler 

 innocuous products. He therefore thinks it probable that if other 

 alkaloids are normally formed in the intestine by bacterial action 

 they are at once broken up, like choline, by other bacteria, or even 

 by those which produced them. 



Bouchard, in explanation of the toxicity of faecal extracts, gives 

 a predominating importance to the salts of ammonia and potash. 

 He found that on eliminating these salts from the alcoholic 

 extracts by means of tartaric acid, the toxicity of the latter 

 disappears to a very marked extent. It is also certain that the 

 stercobilin formed from the bile pigments, which is soluble in 

 alcohol, must contribute to the toxicity of the alcoholic extracts. 

 Probably, however, many other waste products of the body which 

 are soluble in alcohol, and have not yet been chemically differ- 

 entiated, contribute to the toxicity of the faeces. 



In fact this question, which is of great importance from the 

 clinical point of view, has hardly been attacked at present. Future 

 research must be directed towards determining not only the 

 chemical nature of the various substances that co-operate in the 

 toxicity of the faeces, but also their possible origin, i.e. whether 

 they are derived partly from alimentary residues, partly from the 

 metabolites of the body, or partly again from the toxins excreted 

 by the intestinal bacteria. We must confine ourselves to indicating 

 this possible threefold origin, without positive data as to which 

 of the three sources supplies most of the normal toxic products 

 of the faeces. 



Nor can we decide how far the excretory function of the 

 intestine is able to replace functional insufficiency of the kidneys. 

 Clinically we know that diarrhoea induced by strong purgatives 

 can diminish the toxicity of the urine, which means that part of 

 the toxic waste products normally eliminated by the kidneys may 

 be expelled with the water discharged from the surface of the 

 intestine (Bouchard). The urinary constituents excreted by 

 the intestine do not consist mainly of urea which is the most 

 important component of urine. According to Bouchard the 

 intestinal epithelium exerts no selective action on urea, which is 

 only excreted in the same proportions in which it is present in the 

 blood. Urea, however, is the least toxic substance of the urine, 

 perhaps because it has a pronounced diuretic action. To explain 

 the reduced toxicity of the urine after drastic purgatives, it is 

 therefore necessary to assume that other extractives of the blood, 

 which have a more toxic action than urea, may be excreted by 

 the intestines. 



A striking clinical phenomenon in reference to this excretory 

 function of the intestine, as a coadjuvant and vicarious agent for 

 the much more pronounced action of the kidneys, is exhibited in 



