loo Immunity 



In all these cases the neutralizing effects are either accomplished 

 or initiated by factors prepared experimentally, and forced upon 

 the animal in whose body their activities are manifested. 



EXPERIMENTAL INVESTIGATION OF THE PROBLEMS OF IMMUNITY 



Very important contributions were made by Ehrlich,* in his 

 work upon the vegetable toxalbumins, ricin, abrin, and robin, 

 that were found to be antigens capable of producing anti-ricin, 

 anti-abrin and anti-robin respectively, each antibody being capable 

 of neutralizing the efiect of its specific antigen. Kosself investigated 

 the reactions produced by toxic eels' blood and found that im- 

 munity could be established against their hemolytic action, and that 

 specific antibodies were formed. Phisalix and Bertrandf showed 

 that immunity could also be produced in guinea-pigs against the 

 action of viper venom, and that a specific antibody, " aniivenene" 

 was the source of the immunity. 



The investigation of other active bodies was soon begun. In 

 1893 Hildebrand§ studied emulsin and found that it produced a 

 definite reaction with the formation, in animals injected, of an anti- 

 emulsin. v. Dungern|| studied proteolytic enzymes of various 

 bacteria, and showed that when gelatin-dissolving enzymes were 

 repeatedly injected into animals, definite reactions took place, 

 and in the serum a body appeared that inhibited the action of the 

 ferment in a test-tube. Gheorghiewski** immunized animals to 

 cultures of Bacillus pyocyaneus, and found that the reaction pro- 

 voked caused the appearance in the serum of some body that pre- 

 vented the formation of the blue pigment so characteristic of the 

 organism. Morgenrothff applied the same principle to rennet, 

 finding that it produced definite reactions, with the formation of 

 an antibody inhibiting the coagulation of milk. Bordet and 

 Gengou|{ found that the fibrin ferment of the blood of one animal 

 was active in the body of another animal, producing an inhibiting 

 substance by which the coagulation of the blood of the first animal 

 could be delayed. 



The studies of Kraus§§ showed a new fact, that when filtered cul- 

 tures of the cholera spirillum were introduced into animals, the 

 serum of these animals, added to the filtered culture in a test-tube, 

 caused the appearance of a delicate flocculent precipitate, specific 

 precipitate. 



* "Deutsche med. Woch.," 1891, Nos. 32 and 44. 



t "Berliner klin Wochenschrift," 1898. 



t Atti d XI Congr. med. internaz. Roma, 1894, 11, 300-202. 



J"Virchow's Archives," Bd. cxxxi. 

 "Miinchener med. Woch.," Aug. 15, 1898. 

 "Ann. de I'Inst. Pasteur," 1899. 

 tt "Centralbl. f. Bakt.," etc., 1899, xxvi, p. 349. 

 ii "Ann. de I'Inst. Pasteur," 1903, xvii, p. 822. 

 §§ "Wien. klin. Woch.," 1897. 



