Principles of veterinary surGerv 451 



does not diffuse is not sufficient proof. They injected the 

 toxin into a part so poorly suppHed with blood that the punc- 

 ture could not be found at the autopsy, and found that it 

 diffused with great difficulty. This is so true that if toxin is 

 injected into the brains of animals rendered immune by anti- 

 tetanic serum it will be found that those that accidentally 

 bleed at the point of inoculation will not contract the disease 

 because of the flow of anti-toxic blood into the toxic focus. 

 It is as difficult for the toxin to dififvise as it is for the anti- 

 toxic blood to come into contact with it. Finally, and this 

 is particularly important, the injection into the brain short- 

 ens the incubation but does not eliminate it. How can we 

 explain the incubation period if the tetanic symptoms are 

 due only to the fixing of poison by the cerebral cells? And 

 even in the rat it requires more toxin to kill by cerebral than 

 by subcutaneous injections, and the period of incubation is 

 rather prolonged. All of these arguments demonstrate that 

 the theory that aims to explain the pathology of tetanus, by 

 simple physical phenomena — the fixing of toxin in the cere- 

 bral cells — is insufficient, as it can not explain all the pecu- 

 liarities of the mode of action of tetanus toxin, notably the 

 period of incubation. The others, — the chemical theories, — 

 admit a transformation and combination of the tetanic toxin 

 in the organism. Courmont and Doyon thought that the 

 toxin acts similarly to a soluble ferment. When introduced 

 into the organism it was supposed, to form a new tetanizing 

 substance, at the expense of the organism, that caused the 

 spasms. The period of incubation would then be explained 

 by the influence of the temperature, the disappearance of 

 the toxin during the period of incubation, the preventive 

 and non-curative action of the serum, etc. This would also 

 harmonize with the chemical characters of the toxin. Cour- 

 mont and Doyon have found the strychnizing substances in 

 the blood, the organs, the urine, etc. They have shown that 



