336 BACTERIOLOGY. 



animals still continues in force. Such heated 

 cultures have gained at the same time in place 

 of their toxic action, a protective power similar 

 to that shown by the serum of animals made 

 " specifically " tolerant of poison. In my lab- 

 oratory Bunzl-Federn treated culture fluids 

 with digestive ferments, and succeeded in the 

 case of pneumonia in obtaining protective sub- 

 stances of the kind that, according to Behring, 

 are supposed to exist only in the form of the 

 anti-substances of the blood-serum, in those 

 organisms that are tolerant of poison. Klem- 

 perer and Kriiger, and Nencki and Smirnow 

 reached the same result by making use of the 

 action of the electric current upon toxic bac- 

 terial cultures. The hypothesis is untenable 

 that in the latter experiments, which were con- 

 ducted outside of the body, antagonistic sub- 

 stances are produced from the poisons. As 

 with other bodies of this kind the poisons are 

 destroyed by the treatment ; the bacterial cell 

 substances which confer immunity simply 

 become modified, since the cultures thus de- 

 prived of poison are capable of bestowing im- 

 munity. 



The same result follows from other experi- 

 ments. The anti-substances vanish from out 

 of the blood v/ith relative quickness, and hence 

 protective inoculation with these substances 



