128 BACTERIAL POISONS. 



very variable in its virulence, some cultures having been 

 obtained which are wholly without effect upon animals. 

 From cultures of this kind Briegee and Frankel pre- 

 pared a non-poisonous albumin differing in its ultimate 

 composition and in many of its chemical reactions from the 

 poisonous one. 



Frankel has been unable to secure immunity in ani- 

 mals against diphtheria by the employment of small doses 

 of the " toxalbumin." If the dose is large enough the 

 animal dies. If it is smaller, the animal seems to become 

 more susceptible and succumbs more readily to inoculations 

 with the germ. While this is true of the filtered culture, it 

 is not the case with that which has been sterilized by heat. 

 FrInkel finds that if from 10 to 20 c.c. of a cul- 

 ture of the bacillus three weeks old, which has been 

 heated for one hour at from 65° to 70°, be injected under 

 the skin of the abdomen of guinea-pigs, immunity against 

 subsequent inoculation with the virulent germ is secured, 

 provided that the inoculation is not made earlier than the 

 fourteenth day after the treatment with the sterilized 

 culture. He thinks that the culture contains two specific 

 albumins, one of which is poisonous, while the other gives 

 immunity. The former is destroyed by a temperature of 

 from 65° to 70°, while the other retains its characteristic 

 properties. He admits the possibility that the poisonous 

 albumin may be converted into the other form by the high 

 temperature. He finds that the modified culture, which 

 gives immunity, is of no service for therapeutic purposes, 

 and that if an animal be treated with it directly after inocu- 

 lation with the germ, death is not retarded, but is hastened. 

 From these experiments he concludes that the vaccination 

 albumin at first lessens, and subsequently increases the 

 resistance of the animal. 



Sprotjck and his students have confirmed the above 

 statements concerning the toxicity of the germ-free cultures 

 of this bacillus. They have also called attention to the 

 albuminuria following the employment of this poison. lu 

 the urine they find casts, white, and sometimes red, blood- 

 corpuscles. Microscopic examination of the kidney after 



