370 BIOLOGICAL EFFECTS OF RADIATION 



the idea that the process of inactivation of opsonin by a-radiation follows 

 "rigorously" the course of a unimolecular reaction. Nevertheless, in 

 view of similar findings in the case of alexin (Brooks, Lundberg) and 

 various venoms, toxins, and immune bodies (Dreyer and Hanssen), this 

 observation of Chambers and Russ seems significant. 



Anaphylaxis. — Presumably when serum from a specifically sensitized 

 animal is injected into a normal animal and induces the same type of 

 anaphylactic sensitization in this animal, the effect is to be attributed to 

 something analogous to an antibody. Doerr and Moldovan (44) 

 irradiated the serum of a rabbit sensitized to egg white, and found that it 

 had lost this power to confer passive sensitivity. This effect of ultra- 

 violet radiation was rather slow, complete destruction requiring several 

 times as long an irradiation as for the anaphylactic toxicity of the same 



serum. 



Antitoxins. — Sera which protect animals against toxins, either from 

 actual infections or injected, are called antitoxins. They appear to com- 

 bine with toxins in vitro with resulting detoxication, and there is con- 

 siderable evidence that the combination is stoichiometric. 



Photodynamic inactivation of antitoxins was briefly mentioned by 

 Tappeiner and Jodlbauer (155), and Huber reported inactivation of 

 diphtheria and tetanus antitoxins by 4 hr. exposure to sunlight, eosin 

 being present; free oxygen was necessary as for the corresponding toxins, 

 already mentioned. 



Ultra-violet radiation inactivates diphtheria antitoxin (Baroni and 

 Jonesco-Mihaiesti, 13; Scott, 146). Particular interest attaches to 

 Scott's experiment which was made in the hope that the danger of 

 anaphylactic shock as a result of injecting antitoxic sera might be reduced 

 by ultra-violet irradiation of the antitoxin. It transpired, however, that 

 the antitoxic property was destroyed first, leaving the serum still able to 

 produce anaphylactic shock. Scott (145), in an abstract of a paper read 

 before the Pathological Society, gives several further details as to coagu- 

 lability, salting out, and ionization of the serum proteins, particularly the 

 globulin fraction. The report is so condensed as to make undesirable 

 an extended consideration of the hypotheses advanced. 



Lusztig (HI) failed to find any significant effect of X-rays on tetanus 

 antitoxin, even when 10 erythema doses were given. 



Fermi (55) allowed direct sunlight to act on horse antirabies serum for 

 10 to 100 hr. He found that the longer the serum was irradiated, the 

 more quickly after infection of mice with rabies virus was it necessary to 

 inject the antiserum in order to keep the mice alive. Insolation for 

 100 hr. made the antirabies serum totally inactive. 



IRRADIATION IN VIVO 

 The irradiation of animals may have either direct or indirect effects 

 upon the immune properties of their blood plasma. Earlier workers in 



