364 BIOLOGICAL EFFECTS OF RADIATION 



hemolysis by sodium taurocholate, and this substance, or property, 

 to which no name is given, is quite rapidly destroyed by the same irradia- 

 tion. This work has been critically examined by Achard and Foix (2, 3) 

 who find similar results with blood serum, as to both hemolytic and 

 antihemolytic powers, when very long exposures are given. They also 

 criticize Danielopolu's method of titration. Obviously we are here 

 dealing with extensive photochemical changes which lie outside of the 

 realm of immunology. More purely chemical methods of study would 

 seem to be demanded. 



ANTIBODIES 



Antibodies may be defined as sera or other body fluids which have, 

 in response to the introduction of toxin or other foreign substances, 

 developed special properties, usually aiding to defend the body against 

 further introduction of the same agent. Sometimes by rapidly attacking 

 the agent they produce exaggerated reactions such as anaphylaxis. The 

 most important types include specific hemolysins, antitoxins, agglutinins, 

 the syphilitic antibody which, in the presence of an appropriate antigen, 

 "binds" alexin, precipitins, etc. 



Specific Hemolysins (Amboceptors). — When erythrocytes of one 

 species of mammal are intravenously injected into another, the serum 

 of the latter acquires, to a high degree, the power to hemolyze the 

 erythrocytes of the former. In the presence of an adequate concentra- 

 tion of alexin, i.e., any normal serum, small traces of serum from the 

 animal thus immunized will cause hemolysis in vitro of erythrocytes of 

 the donor species. Such a serum, usually heated to inactivate its own 

 alexin, is most often called amboceptor, from Ehrlich's concept of it 

 as a physical intermediary between alexin and the erythrocyte. Similar 

 amboceptors may be present in normal sera and are then distinguished 

 as normal hemolysins. 



These bodies have never been reported to be affected by visible light, 

 either with or without photodynamic sensitization, possible exception 

 being made of studies by Yanagihara (165). His brief note describes 

 the effects of acid and alkali on the inactivation of a hemolysin by direct 

 sunlight, eosin, methylene blue, or neutral red being dissolved in the 

 serum. Lack of details, especially as to the nature of the hemolysin, 

 make it impossible to tell whether it was alexin or a hemolysin which was 

 inactivated, or to be sure just what the results mean. Except for the 

 fact that when hydrochloric acid was added (pH not stated) methylene 

 blue was a relatively ineffective sensitizer, the data do not show any- 

 thing very convincingly. 



Definite negative evidence is given by Lichtwitz (105) who failed to 

 find any photodynamic effect on a specific hemolysin. 



