894 Chapter XII 



struggle on the part of the animal takes place under more favourable 

 conditions and even very susceptible animals may afford evidence 

 [414] that they offer a high resistance. Vaillard and Vincent 1 have 

 shown that if we inject living tetanus bacilli, or the spores of these 

 bacilli, deprived of free toxin, into guinea-pigs a great accumulation 

 of leucocytes, which prevent the production of infection and intoxi- 

 cation by devouring the bacilli and their spores, takes place. The 

 toxin contained in the ingested bacilli remains innocuous ; this afford- 

 ing evidence of the protective part played by the leucocytes against 

 the toxin. The same interpretation may be offered to explain the 

 survival of animals very susceptible to tetanus, when the tetanus 

 poison, mixed with pounded cerebral substance or with carmine 

 powder, is injected. In these mixtures the toxin, as mentioned above, 

 becomes attached to certain substances of the triturated brain or to 

 the grains of carmine. This fixation is very unstable, the toxin is 

 readily set free j-'butj" Vhen introduced into the body of the animal, 

 the mixture induces a great accumulation of leucocytes which seize 

 the cerebral particles and the grains of carmine and along with them 

 take possession of the toxin. Wassermann and Takaki's experiments 

 and those of Stoudensky are easily explained if we assume two 

 protective acts : the first of these consists in fixing the toxin, thus 

 preventing it from diffusing and rapidly reaching the living nerve 

 cells ; the second is the absorption of the toxin fixed by the leuco- 

 cytes, cells endowed with receptors for the haptophore group of 

 the toxin, but insusceptible to its toxophore group. When one 

 of the two factors is absent, tetanus cannot be prevented. It is for 

 this reason that in Courmont and Doyon's experiments with emulsion 

 of the frog's brain, mixed with tetanus toxin, the inoculated animals 

 died from tetanus in spite of an accumulation of leucocytes. This 

 fact affords additional proof that, under these conditions, the toxin 

 does not become anchored to the particles of the pounded cerebral 

 substance, this anchoring being a condition necessary for the effective 

 reaction of the leucocytes. 



The absorption of the tetanus toxin becomes evident when we 

 study in detail the phenomena produced in the experiments carried 

 out according to Vaillard's methods with tetanus spores and those 

 of Wassermann and Takaki with poison to which cerebral emulsion 

 has been added, or according to Stoudensky's method with grains of 

 carmine. When, however, it is desired to bring forward rigorous 

 1 Ann. de Flint. Pasteur, Paris, 1891, t. v, p. 1. 



