ENTOMOLOGY

398 SANITARY ENTOMOLOGYthrives only at temperatures from 16 0 to ~6° C. (610 to 79 0 F.) andis therefore unfitted to exist in the human body. This is further evidencethat the flagellate is a typical insect form. They have failed to find apostflagellate cystic form in. the stomach of the bug.Transmission by insects has not been demonstrated, although there isconsiderable evidence that it" l:!'an nbt be transmitted by the bite of thebedbug in which the organism normally flagellates. Cornwall and Menonclaim that there are only two possible means of transmission left; ruptureof a bug containing flagellates in the neighborhood of a puncture orabrasion, and passage of ~ystic forms into the feces, and there is nodirect evidence for either. They lean to the rupture theory because itseems to account for the peculiar distribution of kala azar. It is comparativelyrare and often localized in certain dwellings. The bug doesnot live on the person, but in buildings and furniture. It does not generallycrawl over the skin when feeding but attacks exposed parts from afairly safe position. It mu~t therefore be a comparatively rare event fora bug to be ruptured on the skin of its occasional host. They may betransported from place to place in fur.niture and clothing, and may gofrom house to house in search of food. The bug is also more or lesslocalized. As the bug would be sac:cificed in the act of transmission, it isclear that a human reservoir of the disease must be at hand if the bugs ina building are to remain dangerous. Knowles suggests the possibilityof hereditary transmission in the bedbug or in intestinal worms.Leishmania tropica (Wright), the cause of ORIENTAL SORE, isalso thought to be transmitted by insects. Wenyon found that the bedbugCimex lectularius could take up the parasites and that develop~mental stages were demonstrable in its gut. Patton (191~) obtaineddevelopment of the parasite into flagellate forms in Ci'mex hemipterus atlow temperature (!!~O to ~5° C.) and produces considerable evidencein favor of these species as the natural carrier.Mastigophora: Spirochaetacea: SpirochaetidaeSpiro8chaudinnia berbera (Sergent and Foley), the cause of .NORTHAFRICAN RELAPSING FEVER, is spread by the body louse. Sergentand Foley have obtained negative results with Cimex lectulariu8.Spiroschaudinnia duttoni (Novy and Knapp), the cause of TROP­ICAL AFRICAN RELAPSING F'EVER, is normally spread by ticks.Breinl, Kinghorn and Todd in 1906 and Nuttall in 1907, were unsuccessfulwith transmission experiments with Cimex lectulal;us.Spiroschaudinnia recurrentis (Lebert), the cause of EUROPEANRELAPSING FEVER, is normally t:ransmitted probably by the body