Hybrid guinea pigs weighing about 300grams were used for the test. Egg-album in antiserum was injected immediately after the whole body irradiation of X-ray. The same was done on the 5th, 7th, 14th, 21st and the 28th days. Twenty four hours later, the antigen was administered to observe the passive anaphylactic shock. The results were as follows: 1) The passive anaphylactic shock was restrained 5-7 days after the x-irradiation of 200r. It returned to normal after 14 days. After 28 days the reaction seemed to turn stronger. 2) By x-irradiation of 200r, the time of incubation to typical shock showed a tendency to prolong. The duration to death by shock also seemed to prolong. 3) Concerning the reduction-rate of the compliment no particular result was obtained. 4) The drop of body temperature was uncertain in case of 200r irradiation. 5) The dilation of the lung after the shock in guinea pigs has a mortal effect. By 200r irradiation, the lung dilation was moderate on the 7th day after the irradiation. 6) As for the clinical signs after 200r irradiation, no serious condition showed on the 7th day. The condition on the 5th day succeeded while they advanced after the 14th, the 21st and the 28th days. 7) After the 7th day of irradiation, the anaphylaxis of guinea pigs did not appear apparently in 100r irradiation but showed stronger in case of 50r and 25r irradiation.
Thus the author concludes that the effect of irradiation on the serological reactivity of guinea pigs was mostly restrained around one week after the irradiation in case of passive anaphylaxis by egg-albumin antibody as an indicator.