CHAPTER XIII 



TETANUS, INFLUENZA, BUBONIC PLAGUE 



Tetanus (lockjaw) is an acute infectious disease, 

 caused by Bacillus tetani, which is characterized by 

 frequent and long-continued spasms of the voluntary 

 muscles, and which is nearly always fatal. 



Bacillus tetani belongs to the small group of anae- 

 robes, that is, the class of microorganisms which 

 . grow best in the absence of free oxy- 



' I / gen, and is found in abundance in 

 // ^ \ cultivated soil, in street dust, and in 



/ / I the droppings of horses and other 



Fig. "m. — Baoillus auimals. 



The tetanus bacillus was discovered 

 by Nicolaier in 1884, who first observed it in pus 

 taken from mice which had been inoculated with 

 garden soil. Nicolaier did not succeed in growing 

 it in pure cultures, and it was not until 1889 that 

 Kitasato, by the use of anaerobic methods, obtained 

 cultures which were free from other organisms, and 



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