DEFENSIVE FACTORS OF THE ANIMAL ORGANISM 201 



in 1898 that the serum of animals repeatedly injected with the defibri- 

 nated blood of another species exhibited the specific power of dissolving 

 the red blood corpuscles of this species. This was the first demonstration 

 of " hemolysis " — a phenomenon which, because of the ease with which 

 it can be observed in vitro, has much facilitated investigation. 



The knowledge that specific "cytotoxins" or cell-destroying anti- 

 bodies could be produced by injection of red blood cells naturally sug- 

 gested the possibility of analogous reactions for other tissue cells. It 

 was not long, therefore, before Metchnikoff ^ and, independently of 

 him, Landsteiner ' succeeded, by repeated injections of spermatozoa, in 

 producing a serum which would seriously injure these specialized cells. 

 Von Dungem ^ obtained similar results with the ciliated epithelium of 

 the trachea. Since then a host of cytotoxins have been produced with 

 the cells of various organs and tissues. Thus, Neisser and Wechsberg '' 

 produced leucotoxin (leucocytes) ; Delezenne,^ neurotoxin and hepa- 

 totoxin; Surmont," pancreas cytotoxin; and Bogart and Bernard,' su- 

 prarenal cytotoxin. 



One of the most interesting of the cytotoxins, moreover, is nephro- 

 toxin — produced by the treatment of animals with injections of emul- 

 sions of kidney tissue. 



In all cases it was supposed by those first working with these bodies, 

 that the injection of the sera of animals previously treated with any 

 particular tissue substance would produce specific injury upon the or- 

 gans homologous to the ones used in immunization. It need hardly be 

 pointed out how very important such phenomena would be in throwing 

 light upon the degenerative pathological lesions occurring in disease. 

 As a matter of fact, however, sera so produced have been shown to be 

 specific for certain organs in a limited sense only. The question of 

 specific cytotoxins has been of especial importance in the case of 

 nephritis, where Ascoli and Figari ' and others have suggested an 

 autonephrotoxin as the basis of the pathology of this disease. In 

 the hands of Pearce and others, however, the strict specificity of 



' Melchnikoff, Ann. de I'inst. Pasteur, 1898. 



2 Landsteiner, Cent. f. Bakt., i, 25, 1899. 



'v. Dungem, Munch, med. Woch., 1899. 



* Neisser und Wechsberg, Zeit. f. Hyg., xxxvl, 1901. 



° Delezenne, Ann. de I'inst. Past. 1900; Compt. rend, de I'acad. des sci. 1900. 



'^ Surmont, Compt. rend, de la soc. de biol., 1901. 



' Bogart et Bernard, ibid., 1891. 



' Ascoli and Figari, Berl. klin. Woch., 1902. 



