ENTOMOLOGY

DISEASES CAUSED OR CARRIED BY MITES AND TICKS 419organs, very seldom in the salivary glands, and not at all in the coxalfluid. Leishman in 1910 proved that the organism is voided in :M:alpighianexcrement while the tick is feeding, and, by means of an anticoagulincoxal fluid voided at the same time, is washed into the wound.Infection does not take place through the proboscis. Leishman's experimentswere completely checked and substantiated by Hindle (1911), whodemonstrated that the infection was due to the presence of the spirochaetesin the white Malpighian secretions, and entered the feeding punctureswith uninfected coxal fluid; and, furthermore, dissections provethat the salivary glands of these particular ticks were not infected, whilethe gut contents, sexual organs and Malpighian tubules were. Inoculationof these various organs gave incubation of spirochaetes in 7 to 9days.8piroBchaudinnia granulo8a (Balfour), cause of Sudanese or NorthAfrican FOWL SPIROCHAETOSIS, was proven by Balfour to betransmissible by A rga8 persicu8 (Oken) Fischer Von W aldheim.8piroBchaudinnia marchoua:i (Nuttall), the cause of Brazilian orSouth American Fe)WL SPIROCHAETOSIS, was shown by Marchouxand Salimbeni to be carried by Arga8 per8icuB. This has. been corroboratedby Nuttall, Hindle, and others. Shellack transmitted the diseaseby Argas refle:cus (Fabricius) Latreille. In experiments conducted atHamburg, Fiilleborn and Mayer transmitted the disease by Ornithodorosmoubata. Nuttall working with the Brazilian strain, found that whenthe spirochaetes first enter the tick they soon disappear from the gut;a certain number degenerate while others traverse the gut wall and enterthe coelomic cavity to circulate all over the body. They enter variousorgans, especially the cells of the Malpighian tubules and sexual organs,in which they break up into a large number of small particles or coccoidbodies which multiply by fission and give rise to large n.gglomerations.These coccoid bodies may also be found in the lumen of the gut and Malpighiantubules and in the excreta. According to Nuttall, the tick in theact of feeding occasi~ally voids excrement and exudes a few dropsof secretion from the coxal glands situated in the first intercoxal space,the fluid pouring out of a wide duct and being rapidly secreted from thefreshly imbibed blood serum. This fluid, as well as the salivary and intestinalsecretions of Argas, contains an anticoagulin. The coxal fluid dilutesthe escaped excrement and facilitates its getting into the wound inflictedby the tick. This is doubtless the usual mode of infection, the coccoidbodies in the excrement gaining access to the body of the host and afterwardsdeveloping into spirochaetes, though the latter development hasDot actually been followed. The bird begins to show symptoms after aperiod of incubation of about four days following upon the bite of theinfected tick.