250 INFECTION AND IMMUNITY 



of immunity by the investigations of Nuttall, 25 v. Fodor, Buchner, 

 and others, who not only demonstrated the power of normal blood 

 serum to destroy bacteria, but also showed that this property of blood 

 serum became diminished with age and was destroyed completely by 

 heating to 56 C. The thermolabile substance of the blood serum 

 possessing this power was called by Buchner, 26 alexin. 



Soon after this work, Behring, in collaboration with Kitasato 27 and 

 Wernicke, 28 in 1890 and 1892, made further important advances in 

 the elucidation of the immunizing processes by showing that the blood 

 sera of animals actively immunized against the toxins of diphtheria 

 and tetanus would protect normal animals against the poisons of 

 these diseases. He believed, at the time of discovery, that such sera 

 contained substances which had the power of destroying the specific 

 toxins which had been used in the immunization. He called these 

 bodies antitoxins. While Behring 's first conception of actual toxin 

 destruction soon proved to be erroneous, his discovery of the presence 

 in immune sera of bodies specifically antagonistic to toxins was soon 

 confirmed and extended, and stands to-day as an established fact. 



Ehrlich, 29 soon after Behring 's announcement, showed that specific 

 antitoxins could also be produced against the poisons of some of the 

 higher plants antiricin, antikrotm, antirobin), and Calmette 30 pro- 

 duced similar 'antitoxins against snake poison (antivenin). Stimulated 

 by these researches, other observers have, since then, added exten- 

 sively to the list of poisons against which antitoxins can be produced. 

 Kempner 31 has produced antitoxin against the poison of Bacillus 

 botulinus, and Wassermann, 32 against that of Bacillus pyocyaneus. 

 Antitoxin has been produced by Calmette 33 against the poison of 

 the scorpion, and by Sachs 34 against that of the spider. Thus a large 

 number of poisons of animal, plant, or bacterial origin have been 

 found capable of causing the production of specific antibodies in the 

 sera of animals into which they are injected. 



25 Nuttall, Zeit. f. Hyg., 1886. 



26 Buchner, Cent. f. Bakt., i, 1889. 



27 Behring und Kitasato, Deut. med. Woch., 1890, No. 49. 



28 Behring und Wernicke, Zeit. f. Hyg., 1892. 

 ^Ehrlich, Dent. med. Woch., 1891. 

 ^Calmette, Compt. rend, de la soe. de biol., 1894. 

 31 Kempner, Zeit. f. Hyg., 1897. 



*' Wassermann, Zeit. f. Hyg., xxii. 



83 Calmette, Ann. de 1 'inst. Pasteur, 1898. 



34 Sachs, Hofm. Beit., 1902. 



