378 BIOLOGICAL EFFECTS OF RADIATION 



Buchner's experiment (30) on X-irradiation of mice vaccinated against 

 Trypanosoma hrucei or T. equiperdum showed similarly a decreased 

 mortality from subsequent infection on the part of irradiated mice, but 

 the author recognizes the result as statistically unconvincing. It may 

 correspond to a real effect, although it is less marked than the protection 

 against pneumococcus infection which Lippmann claimed to have been 

 afforded by injections of thorium X into mice. Lippmann's findings (106) 

 do not appear to have been confirmed. 



Effects of visible plus ultra-violet irradiation on certain cutaneous 

 immune reactions in tuberculosis have also been recorded (Miiller, 123; 

 Hirschmann, 86). The explanations of all these phenomena are entirely 

 unknown. 



RESUMfi 



Reviewing the work of the last three or four decades on the effects of 

 irradiation on toxins and immune bodies one might hope to be able to 

 give answers to at least the following questions: (a) How sensitive to 

 irradiation are these immune bodies, either absolutely or relative to better 

 defined substances? (5) What is the relative photolability of the different 

 individual bodies or classes of them? (c) What are the relative effects 

 of different types of radiation, both corpuscular and electromagnetic in 

 relation to wave-length or quantum energy? (d) What are the mecha- 

 nisms and reactions involved in different cases? (e) What information is 

 afforded as to the nature of toxins and immune bodies? To none of these 

 questions can we give satisfactory answers. The prime difficulty is 

 obvious as soon as we try to answer the first question. 



a. An approach could be made by using monochromatic radiation of 

 known energy flux, with appropriate irradiation chambers so that we 

 could know how much and what kind of energy was being absorbed. But 

 even then we would have no guarantee that the energy was being absorbed 

 by any one chemical species, either the "body" being studied if that be a 

 chemical individual, or any other which might be responsible for its 

 inactivation. Until we do use appropriate irradiation conditions and can 

 isolate the immune body free from other substances which absorb and 

 dissipate energy, we shall have to content ourselves with something like 

 the following answer: 



All the substances in question, so far as they have been studied, are 

 affected by irradiation, especially ultra-violet. The effect is usually 

 inactivation, although in the case of alexin there is ground for suspicion 

 that under some circumstances increased activity may result from brief 

 irradiation. The dosage required is in general rather small, even where 

 serum is used undiluted so that there is a great deal of light absorption by 

 presumably inert components, i.e., components unrelated to the property 

 measured. In general, we may hazard an estimate that toxins, alexin. 



