In this paper there is described a new method for the demonstration of antigen-antibody combination, as follows:
A rabbit sensitized a week previously to some animal protein receives a skin-preparatory injection of a potent bacterial filtrate. 24 hours after the skin preparation the rabbit is injected intravenously with the same animal protein. From 4 to 5 hours later there appears severe hemorrhagic necrosis at the prepared skin site.
The incidence of positive results is high. A single sensitizing injection and 1 week incubation period are sufficient. The test is highly specific unless repeated sensitizing injections of large doses of antigen are made. The necessary sensitization can be elicited with minute quantities of animal proteins.
It is also possible to elicit severe reactions in the prepared skin sites of non-sensitized rabbits upon separate intravenous injections of non-bacterial and bacterial antigens and homologous antibodies (i.e., passive transfer).
The relation of the phenomenon of local skin reactivity to bacterial filtrates to various fields of immunology is discussed in the light of the above observations.