Kopeloff and his associates1 gave many injections of normal horse serum or egg white to Macacus rhesus monkeys. These investigators found that their blood serums contained precipitins and that the animals had become sensitized, since they could be shocked to death by subsequent injections of the specific antigen.
Recently, a report was made of the results of the clinical use of horse serum scarlet fever antitoxin from which the factor causing serum sickness had been removed.2 If monkeys sensitized to normal horse serum according to the methods of Kopeloff and his co-workers are given injections of this type of scarlet fever antitoxin, which lacks the factor causing serum reactions in man, they should have no reactions.
METHODS AND MATERIALS
The plan of the work reported on here was to give monkeys injections either of concentrated scarlet fever antitoxin or of normal horse serum until sensitization occurred, that is,