Vital Resistance 



389 



In bouillon containing sugar considerable gas is formed in 

 the fermentation tube. Both CO 2 and 

 H 2 S are formed 



Gelatin. The growth occurs deep 

 in the puncture, and is arborescent. 

 Liquefaction begins in the second 

 week and causes the disappearance of 

 the radiating filaments. The lique- 

 faction spreads slowly, but may in- 

 volve the entire mass of gelatin and 

 resolve it into a grayish-white syrupy 

 liquid, at the bottom of which the 

 bacilli accumulate. The growth in 

 gelatin containing glucose is rapid. 



Agar-agar. The growth in agar- 

 agar punctures is slower, but similar 

 to the gelatin cultures except for the 

 absence of liquefaction. 



Milk is favorable for the develop- 

 ment of the tetanus bacillus. There 

 is no coagulation. Litmus milk is 

 acidified. 



Potato. Upon potatoes under strict 

 anaerobic conditions the bacilli grow 

 but slightly. 



Vital Resistance. The tetanus 

 spores may remain alive in dry earth 

 for many years. Sternberg says they 

 can resist immersion in 5 per cent, 

 aqueous carbolic acid solutions for ten 

 hours, but fail to grow after fifteen 

 hours. A 5 per cent, carbolic acid 

 solution, to which 0.5 per cent, of 

 hydrochloric acid has been added, 

 destroys them in two hours. They 

 are destroyed in three hours by 

 i : looo bichlorid of mercury solu- 

 tion, but when to such a solution 

 0.5 per cent, of hydrochloric acid is 

 added, its activity is so increased that 

 the spores are destroyed in thirty 

 minutes. According to Kitasato,* ex- 

 posure to streaming steam for from five to eight minutes is 

 * "Zeitschrift fur Hygiene," xn, p. 225. 



Fig. 121 . Tetanus 

 bacillus ; glucose-agar 

 culture, five months old 

 (Curtis). 



