354 BIOLOGICAL EFFECTS OF RADIATION 



injection of the same filtrate (the " Schwartzmami reaction"), required 

 60 to 70 min. for its inactivation. 



Eberson's experiments (47) on the effect of ultra-violet light on the 

 antigenic properties of living cultures of different strains of meningococci 

 are principally of bacteriological interest. Brief irradiation (1 to 6 min.) 

 appeared to have increased, and longer exposures decreased the power of 

 certain strains to act as antigens in the production of agglutinins for other 

 strains; the author speaks of irradiation making the antigen "more 

 inclusive." The experiments are difficult to interpret from a photo- 

 chemical point of view. Additional controls would have been desirable. 



Reference should also be made to Hassko's (76) ultra-violet irradiation 

 of B. typhosus, B. enteritidis (Gartner), and B. dysenteriae Shiga with 

 partial loss of their specific agglutinability, and to Friedberger's (66) 

 report that ultra-violet irradiation of trypanosomes in diluted mouse 

 blood in vitro destroyed their antigenic property in 10 min. 



Friedberger also reports (66) that sheep erythrocytes irradiated 

 until slightly hemolyzed, still bound the corresponding amboceptor, 

 thus retaining their antigenic properties in a certain measure. 



Fiorini and Zironi (58) were unable, on the other hand, to detect any 

 effect of X-rays, either immediate or after one to two transplants, on the 

 agglutinability of B. typhosus by specific agglutinins. The dosage and 

 type of radiation are not clearly described. 



Protein Antigens. — Like the bacterial toxins studied by the same 

 author, ricin was found by Welch (162) to maintain its antigenic power 

 longer on exposure to ultra-violet radiation than it did its toxic and 

 agglutinating powers. 



Other proteins, such as egg white or foreign sera, do not ordinarily 

 display great toxicity on injection into normal animals but do have 

 considerable antigenic power leading to precipitin formation, sensitiza- 

 tion, etc. It is, however, their capacity to act in the role of precipitable 

 substance or "antigen" in the specific precipitin reaction which has been 

 studied in connection with irradiation. Fleischmann (60) found that 

 exposure of beef or horse serum or egg white to diffuse daylight led to 

 delay or to prevention of their precipitation, provided eosin, safranin, or 

 methylene azure was added before irradiation. 



The experiments indicate that only the precipitability, and not the 

 power to "bind" the correspondingly specific precipitin was affected. 

 Precipitins were also studied and found to be less stabile (cf. page 367). 



Doerr and Moldovan (44) obtained essentially similar results with 

 ultra-violet radiation (Kromayer lamp at 5 to 10 cm.), using sheep, ox, 

 and horse sera. They noted an increasingly rapid loss of precipitabihty 

 with increasing dilution. The power of these sera to produce anaphy- 

 lactic shock in sensitized animals was reduced at about the same rate 

 as the precipitate-forming power, Friedberger (66) and Scott (145, 



