It has been shown that by the cutaneous administration of simple chemical compounds in small quantities—2:4:6 trinitrochlorobenzene (picryl chloride) and 2:4 dinitrochlorobenzene, the latter a typical incitant of contact dermatitis in man—it is possible to induce true anaphylactic sensitization in guinea pigs, demonstrable by the intravenous injection of protein conjugates and by the Dale technique, using isolated uterine horns. This furnishes strong evidence for the formation of antigenic conjugates following application of substances of simple chemical constitution. Since the anaphylactic state is induced by the same method of administration that gives rise to cutaneous sensitivity, the assumption would appear justified, when one takes into account the chemical properties of the inciting substances, that the formation of conjugated antigens offers an explanation for the skin effects also.
In the experiments with picryl chloride, anaphylactic antibodies, and occasionally precipitins, have been demonstrated.
The differences between the cutaneous and anaphylactic types of sensitivity are discussed.