B. THE TOXIC DISEASES. 



CHAPTER I. 

 TETANUS. 



ONE of the most exquisitely toxic bacteria of which 

 we have any knowledge is the bacillus discovered in 

 1884 by Nicolaier, oblained in pure culture by Kitasato 

 in 1889, and now universally recognized as the cause of 

 tetanus. It is a peculiar organism, whose striking feature 

 is a considerable enlargement of one end, in which a 

 bright round spore is seen (Fig. 72). The bacilli which 



FlG. 72. Bacillus tetani; x looo (Frankel and Pfeiffer). 



are not sporiferous, are long, rather slender, have rounded 

 ends, seldom unite in chains or pairs, are motile, and 

 have no flagella. The bacilli stain readily with ordi- 

 nary aqueous solution of the anilin dyes, and also very 

 readily by Gram's method. 



The tetanus bacillus is a common saprophytic organ- 

 ism which can be found in most garden-earth, in dust, 



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