GENUS BACILLUS 331 



to a characteristic odor, resembling putrefying organic mat- 

 ter. This odor is due largely to H 2 and methyl mercaptan. 



Milk. It grows readily in milk but does not produce any 

 appreciable change. 



Life conditions and properties. Bacillus tetani is an ob- 

 ligatory anaerobe although Ferran 7 and others have succeeded 

 in having subcultures grow under aerobic conditions. Smith, 

 Brown and Walker 8 found that by the addition of suitable 

 carbohydrates and of fresh sterile liver tissue to the media its 

 absolute anaerobiosis was weakened. It produces a soluble 

 and one of the most powerful toxins known. It is stated that 

 0.000,005 cc. of the filtrate of a broth culture will prove fatal 

 to mice of ten grams weight. This toxin when in solution is 

 very sensitive to heat. Two toxins have been named according 

 to their action, tetanospasmin and tetanolysin. Tetanolysin 

 was discovered by Ehrlich. 9 It has the power to cause hemo- 

 lysis of the red blood corpuscles of various animals and is an 

 entirely separate substance from tetanospasmin which pro- 

 duces the familiar symptoms of the disease. Tetanolysin may 

 be removed from cultures of tetanus by mixing red blood cor- 

 puscles with it. Tetanolysin when injected into animals pro- 

 duces an anti-hemolysin. Different cultures possess different 

 ability to produce toxin. In the inoculated animal, the toxins 

 are produced at the point of inoculation and are taken through 

 the nerves to the motor cells of the anterior horn of the spinal 

 column where the changes characteristic of tetanus occur, and 

 which give rise to the symptoms. 



Resistance. The vegetative forms of the tetanus bacillus 

 are quite sensitive to heat or chemical agents. The spores, 

 however, are quite resistant, but not so much so as those of 

 anthrax. They are destroyed by exposure to live steam at 

 110 C. They resist 5% solution of carbolic acid for many 

 hours, but if %% hydrochloric acid is added they are de- 

 stroyed in two hours. They are killed when acted upon by 



7 Ferran. Centralbl. f. Bak., Bd. XXIV (1898) p. 28. 



8 Walker. Jour, of Med. Research, N. S. Vol. IX (1906) p. 173. 

 8 Ehrlich. Ber. Klin. Woch., 1898. 



