PRINCIPLES OF VETERINARY SURGERY 433 



by a dose of one cubic centimeter. The frog can be tetan- 

 ized, especially at the .temperature of 30" to 35'' C. 

 Marie claims to have caused tetanus at a temperature of 

 12" to 13° C. after a long period of incubation, and chiefly 

 with the grey frog, but the experiments of the Italians, of 

 Ehrlich and of Morgenroth fully confirm the previous de- 

 duction as to the surrounding temperature. The sheep and 

 the hog are highly susceptible. 



The question as to what becomes of the bacilli reveals 

 the fact that they remain at the point of inoculation, and 

 that they become fewer and fewer, and finally leave only 

 their spores behind. The disease is therefore only local. 

 If the tails of twelve mice are inoculated with fatal doses 

 of the culture and then cut off five, ten, fifteen and thirty 

 minutes after, only the last one will die from already having 

 absorbed sufficient poison to cause deaths although all of 

 the micro-organisms have been removed by the amputation. 

 It is the tetanus poison that kills. 



PATHOGENESIS.— The bacillus of tetanus inoculated 

 alone, that is to say without toxin, is not pathogenic. Thus, 

 cultures in gelatine at 20 degrees have no toxin until four 

 or five days. They may be inoculated with impunity on 

 the third day. The spores can also be separated from the 

 poisons elaborated by the bacilli by washing" or by heat 

 without impairing its potency. The poison is sufficiently 

 deteriorated by a temperature of 80° for three hours 

 to render possible the inoculation of considerable numbers 

 of spores without producing serious intoxication. Cultures 

 thus purified when inoculated into \'ery sensitive animals, 

 like the cavy, in doses of one-half or one-third of a cubic 

 centimeter, give negative results. Rabbits have been given 

 30, 40 or even 65 cubic centimeters of purified spores con- 

 tained in broth cultures without exhibiting any tetanic symp- 

 toms. These facts demonstrate clearly that the spores are 



