In 1919 Arkwright and Bacot and Duncan (1) removed 150 lice (Pedicinus longiceps) from a typhus infected monkey (Macacus rhesus) just before death, which were inoculated subcutaneously and intramuscularly to another monkey of the same species. After an incubation period of 7 days this animal developed a febrile disease.
Dissection of the lice nourished on the infected monkeys indicated from 4–16% with rickettsiae in the digestive tract. In 1922 Atkin published the results of experiments made with Bacot in 1920 and 1921 at the Lister Institute in London, using a Polish and Irish virus (2). In this important work the authors demonstrated that the infected lice could not transmit infection by biting; a few experiments of experimental infection of Pedicinus longiceps on macaca monkeys are also reported.
Atkin and Bacot first took the intestinal tract of 36 Pedicinus from a M. rhesus on the 12th day of typhus, emulsified in normal saline, inoculating into the thigh of a macacus of the same species.
Director, Pasteur Institute of Morocco.
Major, Medical Corps, U. S. Army attached to the United States of America Typhus Commission.