PROPERTIES OF ANTISENSITIZERS. 281 



Antisensitizers may be demonstrated in the blood of the animals 

 that have been vaccinated against a hemolytic serum. Following 

 the work of Camus and Gley and Kossel on the antitoxin to eel 

 serum, we demonstrated in 1899 * that the injection of an animal of 

 species A (rabbit) with the serum of species B (hen) gave rise to 

 a property in the serum of A that neutralizes the hemolytic effect 

 of serum B on the corpuscles of A, and we later studied in detail 

 the properties of such antihemolytic sera. On injecting rabbits 

 with specific hemolytic serum from guinea-pigs immunized against 

 rabbit blood we found that these rabbits formed an antiserum 

 that would inhibit the hemolytic effect of the specific guinea-pig 

 serum, and that, strangely enough, acted against both substances 

 necessary in hemolysis. In other words, it destroyed the charac- 

 teristic sensitizer, and was also antitoxic for guinea-pig alexin 

 (anti-alexic property). On account of its an ti-alexic property this 

 antiserum protected, not only rabbit corpuscles, but also other sen- 

 sitized cells, against guinea-pig alexin. For example, it was found 

 that sensitized cholera vibrios (treated with heated cholera serum) 

 could be subjected to fresh guinea-pig serum without showing 

 granular disintegration, provided a suitable dose of antiserum was 

 added. f In short, the addition of antiserum to guinea-pig alexin 

 prevented both its hemolytic and its bacteriolytic action. The 

 anti-alexin was found, moreover, to be strictly specific, having no 

 effect on the hemolytic or bactericidal action of sera from animals 

 other than the guinea-pig. 



The anti-alexic property of such antisera was later studied by 

 several observers. Wassermann in particular confirmed our 

 experiment on the antibactericidal effect of anti-alexin and in 

 addition noted an interesting modification. He neutralized the 

 alexin of normal serum by anti-alexin in vivo instead of in vitro; 

 he found that he could annul the bactericidal power of the peritoneal 

 exudate by injecting antiserum into the peritoneal cavity. 



The antisensitizing property has recently interested other experi- 

 menters. In the present article we shall consider the facts that 

 have been brought out concerning it. 



* Agglutination and dissolution of red blood cells by serum, p. 105. 



Hemolytic sera, their antitoxins, etc., p. 186. 

 t This antiserum, of course, had been deprived of its own alexin by heating to 55 

 degrees. This temperature does not effect the anti-alexin that protects the vibrios. 



