^m Immimity of the shin and mucous membranes 427 



Hihe object of demonstrating in suckling rabbits the precise part 

 played by these micro-organisms which prevent cholera, have not 

 given any satisfactory results. This we attribute to our very im- 

 perfect knowledge of the microbial population of the digestive organs. 



If the destruction by representatives of the normal intestinal flora 

 of the micro-organisms which penetrate into the intestines has not as 

 yet been satisfactorily demonstrated, the power of these latter to 

 destroy microbial toxins cannot be doubted. We^ have shown that 

 a great number of micro-organisms develop well in broth cultures of 

 the tetanus bacillus which contain a quantity of specific toxin. This 

 toxin is destroyed under the influence of this microbial vegetation, 

 but the production of antitoxin never results. Charrin and Mangin^ [448] 

 have observed similar facts. 



As the destruction of bacterial toxins by micro-organisms takes 

 place with great constancy and rapidity, it is quite natural to suppose 

 that the same phenomenon occurs also in the intestinal canal of living 

 animals in which pathogenic micro-organisms have succeeded in 

 secreting their toxic products. 



The liver having long been recognised as the purifying organ 

 of the products resulting from digestion, it has been asked if it might 

 not also play a part in the destruction of microbial poisons. Certain 

 facts point to its inhibiting influence on the action of nicotin, atropin, 

 and of certain other alkaloids, and we have other facts which 

 demonstrate the power of the liver to transform into urea the 

 ammoniacal substances arising from the activity of the digestive 

 glands. When Nencki, Pawloffj and their collaborators^ succeeded in 

 making the portal vein communicate with the vena cava, and thus 

 were able to suppress the purifying function of the liver, they found 

 that their dogs became poisoned in consequence of the accumulation 

 of ammonia in the animal organism. 



Guided by these data as to the protective role played by the 

 liver an attempt was made to apply them to the action of this organ 

 on bacterial toxins such as the diphtheria poison. The numerous 

 attempts undertaken in this direction have given negative results : 

 the liver was not found to be capable of destroying this toxin. 

 Bouchard, Charrin and Ruffer have studied the action of the liver on 

 the pyocyanic toxin. They thought that they could make out a 



1 Ann. de VIvst. Pasteur, Paris, 1897, t. xi, p. 802. 

 ^ Compt, rend. Soc. de bioL, Paris, 1897, p. 545. 

 3 jirch. de Sci. biol., St Petersbouig, 1892, t. L 



