PATHOGENIC ANAEROBIC BACILLI. 537 



to ascertain whether their blood serum would also neutralize the 

 tetanus poison; the result was negative. 



That the tetanus poison is present in the blood of individuals who 

 die from tetanus has been proved by Kitasato by injecting a small 

 quantity (0. 2 to 0. 3 cubic centimetre) of blood from the heart of a 

 fresh cadaver into mice; the animals develop typical tetanic symp- 

 toms and die in from twenty hours to three days. 



Tizzoni and Cattani have (1891) reported results similar to those 

 obtained by Kitasato. By repeated inoculations with gradually 

 increasing doses of the tetanus poison they succeeded in making 

 a dog and two pigeons immune, and found that blood serum from 

 this immune dog, in very small amount, completely destroyed 

 the toxic power of a filtrate from cultures of the tetanus bacillus 

 one to two drops of serum neutralized 0. 5 cubic centimetre of filtrate 

 after fifteen to twenty minutes' contact. They also ascertained that 

 small amounts of blood serum from this immune dog injected into 

 other dogs or white mice produced immunity in these animals ; but 

 they were not able to produce immunity in guinea-pigs or rabbits by 

 the same method. 



In a later communication (May, 1891) Tizzoni and Cattani give 

 an account of their experiments made with a view to determining 

 the nature of the substance in the blood serum of an immune animal 

 which has the power of destroying the toxalbumin of tetanus " tet- 

 anus antitoxin/' They found, in the first place, that this antitoxin 

 in blood serum is destroyed in half an hour by a temperature of 68 

 C. ; further, that it does not pass through a dialyzing membrane ; 

 that it is destroyed by acids and alkalies. As a result of their re- 

 searches they conclude that it is an albuminous substance having the 

 nature of an enzyme. 



Vaillard has succeeded in producing immunity in rabbits by re- 

 peated injections into the circulation of filtered cultures in all 

 twenty cubic centimetres which had been exposed for one hour to 

 a temperature of 60 C. At a temperature of 65 C. both the toxic 

 and the immunizing action is destroyed. 



186. BACILLUS CEDEMATIS MALIGNI. 



Synonyms. Bacillus of malignant oedema ; Vibrion septique 

 (Pasteur). 



Discovered by Pasteur (1877); carefully studied by Koch (1881). 

 This bacillus is widely distributed, being found in the superficial 

 layers of the soil, in dust, in putrefying substances, in the blood of 

 animals which have been suffocated (by invasion from the intestine), 

 in foul water, etc. 



It may usually be obtained by introducing beneath the skin of a 

 38 



