TETANUS 275 



the vicinity of the point of inoculation. In inoculated 

 animals, and in tetanus in man resulting from acci- 

 dental infection, the bacillus may be obtained in the 

 vicinity of the inoculation wound, but is not present 

 in the blood or in the various organs of the body. 

 The presence of the deadly tetanus toxin may, how- 

 ever, be demonstrated by injecting the blood of a 

 victim of the disease into a mouse, which dies with 

 the characteristic tetanic symptoms after such an in- 

 oculation. The fatal dose of this toxin is so small 

 that, according to the Japanese bacteriologist Kita- 

 sato, the amount of a culture, from which all living 

 germs have been removed by filtration, which is re- 

 quired to kill a mouse is not more than one hundred- 

 thousandth of a cubic centimetre (o.ooooi c.c.). The 

 tetanus poison is destroyed by five minutes' exposure 

 to a temperature of 65 C. It is also destroyed by 

 exposure to direct sunlight, but it may be kept inde- 

 finitely in a cool dark place. The German chemists, 

 Brieger and Cohn, have obtained the toxin in a pre- 

 cipitated and comparatively pure state, in the form of 

 yellowish transparent scales, which are readily soluble 

 in water. They report that this purified toxin will 

 kill a mouse in the dose of 0.00000005 gram, and 

 they estimate that 0.00023 gram would be a lethal 

 dose for a man. Comparing this with the most deadly 

 vegetable alkaloids known, it is nearly six hundred 



