4oo 



Tetanus 



tire mass of gelatin and resolve it into a grayish-white 

 syrupy liquid, at the bottom of which the bacilli accu- 

 mulate. The growth in gelatin con- 

 taining 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. 



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 : 1000 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. Exposure to stream- 

 ing steam for from five to eight 

 minutes is certain to kill them. 



Toxic Products. Bouillon cul- 

 tures of the tetanus bacillus contain 

 a powerful toxin in solution. 



The most ready method of pre- 

 paring it for experimental study is 

 to cultivate the bacilli in bouillon, 

 at a temperature of 37 C., and then 

 filter the culture through porcelain. 

 Field* found the highest degree of 

 toxicity about the sixth or seventh 

 day. It may attain a toxicity so 

 great that 0.000005 c - c - will cause the 

 death of a mouse. I found the aver- 

 age toxicity such that o.ooi c.c. was 

 fatal to a guinea-pig. The toxin is 

 very unstable and is easily de- 



Fig. 121. Tetanus 

 bacillus ; glucose-agar 

 culture, five months old 



(Curtis). 



"Proc N Y. Path. Soc.," Mar., 1904, p. 18. 



