BACTERICIDAL PROPERTIES OF BLOOD SERUM 147 



resorted to an ingenious method of experimentation which yielded a 

 further important result, namely, the discovery that the injection of 

 antibodies into animals may give rise to "anti-antibodies." They 

 injected inactivated hemolytic serum into goats whose corpuscles 

 were sensitive to its action, and found that an "anti-isolysin" was 

 formed, which, mixed with hemolysin and sensitive corpuscles, pre- 

 vented hemolysis. Injection of such an isolysin into the goat from 

 which it had been obtained, however, did not yield anti-isolysin, and 

 it was therefore reasonable to suppose that its tissue cells possessed 

 no suitable receptors. This failure of the production of antibodies 

 by an animal against its own tissue cell has been spoken of by Ehr- 

 lich as "Horror Autotoxicus." 



These rather involved experimental data will be shown to have a 

 more than purely academic value when we come to speak of the 

 problems of cytotoxin formation, and although they seem to show 

 that auto-antibodies do not form, as a rule, exceptions to this gener- 

 alization have been observed. The most notable of these is the ob- 

 servation of Landsteiner and Donath 25 made in connection with the 

 condition of paroxysmal hemoglobinuria. It was found that in such 

 cases, in which hemoglobinuria follows exposure to cold, the blood 

 serum of the patient contains an "autohemolysin." If the blood of 

 such a case is taken into oxalate or citrate solution, and allowed to 

 stand at ordinary or incubator temperature, nothing occurs. If, 

 however, such blood is cooled to to 10 C. and then warmed grad- 

 ually to the temperature of the body, rapid hemolysis occurs. In 

 this case the "amboceptor" of the serum is apparently fixed or an- 

 chored by the blood cells only at a low temperature, the complement 

 becoming active as the blood is warmed. Although Landsteiner's 

 observations are undoubtedly accurate, it is likely that this mechan- 

 ism does not explain all such cases. The writer has had occasion to 

 examine carefully a number of clinically diagnosed cases of this 

 sort with a partially successful "Landsteiner" phenomenon in one 

 of them only. Other observers have, however, confirmed Land- 

 steiner' s observation in well-established cases of the condition. 



Before we leave the subject of iso-antibodies it will be interest- 

 ing to discuss for a moment the existence of isolysins in animals 

 other than' goats and more especially those occurring in human 

 beings, phenomena which have recently assumed considerable impor- 

 tance in view of the frequent therapeutic performance of blood 

 transfusion. 



The peculiar facts unearthed by Ehrlich and Morgenroth 26 indi- 

 cated specific differences between red blood cells of individuals in 

 the same species (goats), which could only be recognized by the 



25 Landsteiner and Donath. Munch, med. Woch., 1904, p. 1590. 



26 Ehrlich and Morgenroth. "tiber Hamolysine," Berl. kl. Woch 1900, 

 No. 21. 



