Pfeiffer's Phenomenon 101 



Tchistowitch* found that eels' serum injected into animals 

 produced a reaction in which immunity to its poisonous 

 action was associated with the ability of their serum to pro- 

 duce a precipitate when added to the eels' serum. 



Closely connected with these various reactions are certain 

 others variously spoken of as cytotoxic, cytolytic, hemolytic, 

 bacteriolytic, etc. The first observation bearing upon these 

 was made by R. Pfeiffer,f who found that when guinea-pigs 

 received frequent intraperitoneal injections of cholera spirilla 

 and became thoroughly immunized, their serum behaved 

 very peculiarly toward the bacteria in the peritoneal cavity 

 of freshly infected animals, in that it caused them to become 

 aggregated into granular masses and subsequently to dis- 

 appear. This became known as "Pfeiffer's phenomenon." 

 The serum of the immunized animal was devoid of action 

 by itself, the serum of the infected animal was inactive, but 

 the combination of the two brought about dissolution of 

 the micro-organisms. Later it was shown by MetschnikoffJ 

 that the living animal was not a factor in the process, but 

 that what was seen in the peritoneal cavity could be re- 

 produced in a test-tube, though not quite as well. 



Bordet made frequent injections of defibrinated rabbits' 

 blood into guinea-pigs, and obtained a serum that had a 

 solvent action upon the rabbit's corpuscles in -vitro, and 

 showed that the induced hemolysis resembled in all points 

 the bacteriolysis. 



Ehrlich and Morgenroth|| studied the hemolytic action 

 of the serum of goats that had been frequently injected with 

 the defibrinated blood of sheep and goats, and were able to 

 point out the mechanism of the corpuscle solution or hemo- 

 lysis. It was found to depend upon two associated factors, 

 one of which, the lysin or solvent, was present in normal 

 blood, and was called "addiment" or "complement," and 

 another present only in the serum of the reactive animals, 

 called the "immune body" or "intermediate body." 

 The former was labile and easily destroyed by heat, the 

 latter stabile and not affected by heat up to the point of 

 coagulation. The experiments were confirmed by von 

 Diingern and many others. It is to be observed in passing 



* " Ann. de 1'Inst. Pasteur," vol. 13. 



t "Deutsche med. Wochenschrift, 1896, No. 7. 



t "Ann. de 1'Inst. Pasteur," 1895. Ibid., xn, 1898. 



|| " Berliner klin. Wochenschrift," 1899. 



