2 LECTURES ON IMMUNITY 



are therefore not toxins. On the other hand, extracts from 

 the seeds of Ricinus communis contain a toxin called ricin, 

 against which we possess an antitoxin called antiricin. In 

 the same way antitoxins are known corresponding to abrin 

 and robin, extracted from the seeds of Abrus prcecatorius 

 and of Robinia pseudacacia. It is not only against poisons, 

 but also against wholly or nearly inoffensive bodies, that 

 animals produce antibodies. Furthermore it seems that if 

 we introduce nearly any type of cell into the veins of an 

 animal, its blood will contain after a time an antibody 

 which destroys the particular variety of cell. Even after 

 the injection of rennet, the ferment of the coagulation of 

 milk, we obtain an antibody called antirennet, which 

 hinders the coagulative power of rennet. 1 It is very diffi- 

 cult to draw a distinction between enzymes or ferments and 

 toxins. Like rennet, many others of these substances are 

 found to yield antibodies after injection into the blood of 

 different animals. Thus, for instance, v. Dungern 2 pre- 

 pared in this way antibodies against proteolytic enzymes 

 from pathogenic microbes. Hildebrand 3 obtained in a simi- 

 lar way an antibody against the ferment emulsin. Gessard 4 

 found it possible to prepare an antibody against tyrosi- 

 nase, an oxydase extracted from mushrooms ; and Sachs 6 

 showed that the serum from a goose which had been in- 

 jected with pepsin contained antipepsin. 



A. Schutze prepared " antilactase " by injection of "lac- 

 tase from kefir" into rabbits or hens; other antibodies 



1 Morgenroth : Centralblatt f. Bakteriologie, Abt. I, Vols. 26 and 27. 



2 v. Dungern: Centralblatt f. Bakteriologie, Thl. I, Vol. 24 (1898). 

 8 Hildebrand: Virchovfs Archiv, Vol. 131 (1893). 



4 Gessard: Annales de Vinstitut Pasteur, 15. 607 (1901). 

 6 H. Sachs: Fortschritte d. medicin, 20. 425 (1902). 



