Daily tests of sera from bats of the species Carollia perspicillata, Phyllostomus panamensis and Eumops californicus which had been injected subcutaneously with yellow fever virus failed to demonstrate the presence of any virus in the blood stream. Similar tests on Molossus sp. and Phyllostomus panamensis which had been bitten by infected mosquitoes gave the same result.
When Phyllostomus panamensis was injected subcutaneously with massive doses of virus, the virus was demonstrable in the circulation after intervals of 30 and 60 minutes. Within three hours the virus concentration in serum had fallen to traces or had totally disappeared.