CHAPTEK IV 



DISEASES PRODUCED BY BACTERIA WHICH 

 SECRETE TRUE TOXINS 



Tetanus, or Lockjaw.— Causal organism— the B. 

 tetani — was discovered by Nicolaier in 1884. The 

 bacillus, in the form of spores, is widely distributed 

 in nature, being commonly found in manure and soil 

 which has been manured. It is also frequently found in 

 the intestinal contents of horses and cattle. Entering 

 the body by means of a wound in the skin or mucous 

 membrane, the bacilli do not become generalised, but 

 remain localised at the point of infection, where they 

 produce their toxins. These are taken up by the 

 peripheral nerves and are carried along the axis- 

 cylinders to the central nervous system. 



Meyer and Kansom, as the result of many experi- 

 ments, consider that it is only by the peripheral 

 nerves that the poison can reach the spinal cord or 

 brain. Poison circulating in the blood is taken up by 

 the nerve endings, and so passed on to the central 

 portions of the nervous system, but it does not 

 penetrate directly into the latter from the lymph. 



They thus explain the incubation period met with 

 in poisoning with tetanus toxins. They point out 



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