TETANUS. 241 



An interesting fact contributed to our knowledge of 

 the disease has been presented by Vaillard and Rouget, 

 who found that if the tetanus bacilli were introduced 

 into the body freed from their poison, they were unable 

 to produce any signs of disease because of the prompt- 

 ness with which the phagocytes took them up. If, how- 

 ever, their poison was not removed, or if the body-cells 

 were injured by the simultaneous introduction of lactic 

 acid or other chemical agents, the bacilli would imme- 

 diately begin to manufacture the toxin and produce 

 symptoms of the disease. 



The toxin is easily prepared, being readily soluble in 

 water. The most ready method of preparation is to 

 grow the bacilli in bouillon, keeping the culture-medium 

 at a temperature of 37 C., and allowing it to remain un- 

 disturbed for from two to four weeks, by which time it 

 will have attained a toxicity so great that 0.000005 c.cm. 

 will cause the death of a mouse. The toxin is very rapidly 

 destroyed by heat, and cannot bear any temperature above 

 60-65 C. It i s a ^ so decomposed by light. When pre- 

 served in the dark in a refrigerator it can be kept in- 

 definitely. The best method of keeping it is to add 0.5 

 per cent, of phenol, and then store it in a cool, dark place. 



By the gradual introduction of such a toxin into ani- 

 mals Behring and Kitasato have been able to produce in 

 their blood a distinctly potent and valuable antitoxic 

 substance. 



The method for the production of this tetanus anti- 

 toxic serum is very much like that for the diphtheria 

 antitoxic serum (q. v.\ except that a much longer time 

 is required for its production, that the doses of toxin are 

 of necessity smaller because its toxicity is greater, and 

 that trichlorid of iodin or Gram's solution will probably 

 need to be added to the toxin to prevent too powerful a 

 local reaction. Horses, dogs, and goats may be used. 



As tetanus cases are not very common, and the anti- 

 toxic serum when produced is not very stable in its prop- 

 erties, Tizzoni and Cattani have successfully prepared it 



16 



