1. Primary poliomyelitic infection in the monkey, as a rule, is characterized by no significant increase in the body temperature during the incubation period until 48 or 24 hours before the onset of clinical symptoms, when a critical rise of the temperature occurs.
2. The temperature curve of recovered monkeys on intracerebral reinoculation shows an almost immediate and marked febrile reaction during the first 24 or 48 hours after inoculation. A similar accelerated febrile reaction may be obtained in recovered animals after subcutaneous injection of killed virus. In case the previous infection is of very recent date, reinoculation may lead to no demonstrable reaction whatsoever.
3. Monkeys, which have received a number of parenteral injections of live virus, respond to intracerebral infection with a precocious and prolonged febrile reaction on the 3rd or 4th day after infection which may last until the onset of symptoms.
4. The altered response to reinoculation of monkeys which have previously been in contact with the virus, suggests a close analogy with the accelerated reactions observed in allergic phenomena.