280 



SPECIFIC MICRO-ORGANISMS 



unstable in solution but very stable when dried. Dry material 

 of which o.ooo ooo i gram is the fatal dose for a mouse is readily 

 obtained. The watery solution loses it toxicity when heated to 

 60 C. for 20 minutes, but when dry the toxin withstands 

 heating at 120 C. for an hour. 



Tetanus presents essentially the same picture in inoculated 

 animals as in the natural disease, which is indeed, as a general 

 rule, merely an accidental inoculation. The presence of insoluble 

 material and of other bacteria mixed with them in a wound favors 

 the development of tetanus bacilli. The tetanus bacilli always 



FIG. 1 13. Tetanus bacilli showing terminal spores. (After Kolle and Wassermann.} 



remain localized near the point of inoculation and may be hard 

 to find. The poison produced by the organisms is probably ab- 

 sorbed by the nerve endings 1 and transmitted to the central nerv- 

 ous system through the axis cylinders or in the perineural lymph 

 spaces of the motor neurones rather than through the blood 

 stream. The symptoms arise after the poison reaches the central 

 nervous system in sufficient concentration to stimulate the nerve 

 cells. In guinea-pigs and mice the spasm always begins near the 

 point of inoculation, but in man and the large mammals it often 

 begins in the muscles of the jaw and neck regardless of the location 



1 Von Lingelsheim, Kolle and Wassermann, Handbuch, 1912, Bd. IV, S. 766. 



