PATHOGENIC ANAEROBIC BACILLI. 



533 



and the cultures give off a characteristic odor " brenzlichen Ge- 

 ruch " (Kitasato). 



According to Kitasato, blood serum is not a very favorable me- 

 dium for the growth of the tetanus bacillus, and contrary to the 

 statement of Kitt, Tizzoni, and others 

 it does not cause liquefaction of this 

 medium. 



The spores of the tetanus bacillus re- 

 tain their vitality for months in a desic- 

 cated condition, and are not destroyed in 

 two and one-half months when present 

 in putrefying material (Turco). They 

 withstand a temperature of 80 C. main- 

 tained for an hour, but are killed by 

 five minutes 5 exposure to steam at 100 C. 

 They are not destroyed in ten hours by 

 a five-per-cent solution of carbolic acid, 

 but did not grow after fifteen hours' ex- 

 posure in the same solution. A five- 

 per-cent solution of carbolic acid, to 

 which 0. 5 per cent of hydrochloric acid 

 has been added, destroys them in two 

 hours ; in sublimate solution containing 

 1 : 1,000 of mercuric chloride they are 

 destroyed at the end of three hours, or 

 in thirty minutes when 0.5 per cent of 

 hydrochloric acid is added to the solu- 

 tion. Kitasato succeeded in obtaining 

 pure cultures from the pus formed in 

 the vicinity of inoculation wounds, by 

 destroying the associated bacilli after 

 the tetanus bacilli had formed spores. 



This was effected by heating cultures from this source for about an 

 hour at a temperature of 80 C. The spores of the tetanus bacillus 

 survived this exposure, and colonies were obtained from them in flat 

 flasks especially devised for anaerobic cultures ; from these colonies 

 pure cultures in nutrient agar or gelatin long stick cultures or in 

 peptonized bouillon were easily obtained. 



Brieger (1886) first succeeded in obtaining from impure cultures 

 of the tetanus bacillus a crystallizable toxic substance, called by him 

 tetanin, which was found to kill small animals in very minute doses 

 and with the characteristic symptoms of tetanus. More recently 

 Kitasato and Weyl have obtained the same substance, by following 

 Brieger's method, from a pure culture of this bacillus. From a 



Fio. 163. Culture of Bacillus tetani 

 in nutrient gelatin. (Kitasato.) 



