444 PRINCIPLES OF VETERINARY SURGERY 



leaves 0.040 grams of a dry residuum containing 0.025 grams 

 of organic matter. Even if this last were pure toxin the con- 

 clusion would be that this amount is sufficient to kill a thou- 

 sand cavies or a hundred thousand mice. The fatal dose for 

 a cavy is therefore 0.000025 grams, and for a mouse 

 0.00000025 grams. And besides, this slight quantity of or- 

 ganic matter is not all toxin; it also contains foreign sub- 

 stances, showing the extraordinary activity of the poisons 

 liberated by the micro-organisms. 



What is the nature of this poison? It is a diastatic sub- 

 stance presenting in all of its biological properties, great 

 analogies to jequiritine, zymasis or soluble ferments, and to 

 the poisons of diphtheria. Knud Faber, Tizzoni and Cattani 

 and Vaillard and Vincent have shown the close relationship 

 of these poisons. 



The activity of the tetanus poison is markedly modified 

 bv heating to the temperature of 60^ for forty minutes. A 

 heating of thirty minutes at 65" in a closed vessel partly kills 

 it, although this same temperature will not kill the micro- 

 organisms. The temperature never completely suppresses 

 its action even at 80" or 90°. The toxin preserves its activ- 

 ity for years if kept in a closed vessel and out of the reach 

 of light. On the contrary, in the air and light it become rap- 

 idly inactive in consequence of the phenomenon of oxydation. 

 It is precipitated by alcohol, is soluble in water, is not modi- 

 fied by tartaric acid and it is not easily dialyzed. Like diph- 

 theria poison and diastases, it possesses the property of ad- 

 hering to certain precipit-ates produced in its solution. The 

 alumina, and above all the dibasic and tribasic phosphates 

 of lime, attract it, and when these precipitates are carefully 

 washed and inserted under the 'skin they produce fatal 

 tetanus. 



Its properties are utilized to obtain solid toxins. They are 

 precipitated with five to six volumes of alcohol and then 



