Non-tuberculous guinea pigs after treatment with eggwhite react to the intracutaneous injection of varying amounts of egg-white with a quickly developing large swelling, which disappears in twenty-four to forty-eight hours. This reaction corresponds to the reaction called “immediate” by Zinsser.
In tuberculous guinea pigs after treatment with eggwhite there appears first a sensitiveness similar to that of the non-tuberculous guinea pigs, but usually in a few days it gives place to a persistent necrotic reaction. After a shorter or longer period the evanescent reaction may reappear.
The hypersensitiveness of tuberculous guinea pigs demonstrated with the necrotic skin reaction is similar to the Arthus phenomenon of rabbits. Subcutaneous injections cause very extensive necrosis, but do not kill the animal. Precipitins are present in large amount in the blood serum. Anaphylaxis against eggwhite is also present.
In general there seems to be a parallelism between the precipitin content of the blood serum and the sensitiveness. But in four tuberculous guinea pigs of the two first series which produced precipitins only slightly, two were very sensitive, and several with strong precipitin production were only slightly sensitive.
Sensitiveness and precipitins appear about the same time—around the seventh day after treatment. Very small amounts of eggwhite are needed for the production of both.
The complement fixation has no direct connection either with the sensitiveness or precipitation. In no case did we observe complement fixation with crystalline egg albumin.
Desensitization is possible with larger doses of eggwhite given subcutaneously. The tuberculin reaction is only slightly affected.
The sensitization with the eggwhite is mainly against the egg globulin. With egg globulin the sensitization is as successful as with the eggwhite. With egg albumin we obtained necrotic skin reaction only after more prolonged treatment.
After treatment with timothy pollen we obtained in two animals a strong necrotic skin reaction, and in two others a moderately strong reaction. The formation of precipitins and complement fixation antibodies were observed only in the tuberculous animals. With typhoid bacilli we obtained in the tuberculous animals neither sensitiveness nor increased agglutinin formation.