TETANUS BACILLUS 1 71 



with tetanus bacilli, then sealed, colonies will develop, as perfect 

 anaerobic conditions are thus obtained. Often the organism grows 

 best in the presence of saprophytic ones. Strongly pathogenic 

 organisms do not grow well in culture media, while comparatively 

 non-virulent ones grow very well. 



Pathogenesis. Tetanus may follow any wound, no matter how 

 insignificant, though deeply punctured ones, caused by nails or 

 splinters, are more often followed by tetanus infection, especially 

 if the puncture is sealed by blood clots or pus, and so creating an 

 anaerobic condition necessary for growth. If the wound is on the 

 face or hand, tetanus symptoms more quickly supervene, while if 

 the wound is on the foot, these are apt to be delayed. The sooner 

 the symptoms appear after the reception of the injury, the more 

 likely will the disease be virulent and fatal. If spores are washed 

 free from toxin, according to Viallard and Rouget, and then injected 

 into a susceptible animal, they do not cause tetanus, but are taken 

 up by the phagocytes. In other words, the rods not the spores 

 produce toxin. Necrotic tissue in wounds favors infection with 

 tetanus, since it helps to fulfil anaerobic conditions, and in some 

 way hinders phagocytosis. Aerobic bacteria favor tetanus infec- 

 tion by absorbing the free oxygen which prevents the growth of 

 tetanus organisms. Free oxygen never kills the organism or its 

 spores, but merely prevents their development. Wounds that have, 

 apparently healed, may be the cause of tetanus. The toxin is 

 produced rapidly in wounds, or what is more likely, some is intro- 

 duced with the bacilli and other dirt. Kitasato found, in the case 

 of mice, that if bacilli were introduced in the skin, near the tail, and 

 in an hour the whole area was excised, and the wound cauterized, 

 fatal tetanus nevertheless supervened. 



Rheumatic tetanus follows pulmonary infection. As related in 

 the chapter on toxins, the mode of disease production is as follows: 

 The toxin is conveyed from the wound by means of the motor nerves 

 to the central nervous system affecting the motor elements. It 

 causes microscopic degeneration of the fibers and cells of the motor 



