It will be recalled that Nicolle1and his associates recently have greatly advanced our knowledge of typhus fever by two achievements. First, it was shown that the disease could be transmitted to the chimpanzee by the injection of the blood of human patients, and in a similar way from the chimpanzee to the macacus monkey (Macacus sinicus). Strangely they were not able to infect the macacus directly with virulent human blood. Their second important result consists in the transmission of the disease from macacus to macacus by means of the ordinary body louse (Pediculus testamenti). From the epidemiologie conditions which prevail in Tunis they were able to rule out the flea and the bedbug as carrying agents. When the moneky has once been infected with the louse, they attempted to transfer the disease from animal to animal by means of injection from the first monkey, but the experiments resulted