556 MUSGRAVE, CLEGG, AND POLK. 



of infection or noninfection is almost entirely due to the mode of life of any 

 given individual or community. In other words, it is a question of exposure, 

 which in the vast majority of instances occurs only in those who are ignorant, 

 or whose personal hygiene is otherwise very faulty. In a sense, it seems to us, 

 that the prevalence of ivhip-ivorm infections in a community is, to a certain extent at 

 least, an index of the intelligence and cleanliness of its citizens. This statement 

 makes the assumption of what is probably a fact, that physiologic predisposition 

 to infection with this parasite (except perhaps in children), if it exists at all, 

 surely does so to a very minor degree. 



Stiles and Garrison in discussing the question of physiologic predisposition in 

 females state that "the relative frequency of a given parasite, or of helminthiasis 

 in general, among males and females is apparently not so much a question of 

 physiologic predisposition of the sex toward the parasite, as it is a question of 

 the relative intimacy existing between the average daily life of the sex and the 

 more concentrated infectious material." 



In the case of whip-worm infections it seems to us that this statement applies 

 not only to a question of sex, but that it explains many of the differences noticed 

 under predisposing causes. Carrying this statement to its logical conclusion, 

 we may say that race, sex, occupation, etc., as such, probably are not factors in 

 the incidence of the infection, except to the extent in which they harmonize with 

 the person's exposure to sources of infection under a given mode of life. 



TEICHUEIS. 2 



This genus is easily recognized by its peculiar whip-worm shape; the thick- 

 posterior portion and the long, slender anterior portion representing the stock and 

 the lash respectively. The anterior extremity bears a small, round, mouth opening, 

 behind which lies a small, funnel-shaped oral cavity. The long, thread-like 

 oesophagus extends throughout the greater portion of the anterior, slender part 

 of the body and enters the intestine which, in a folded course, reaches the posterior 

 extremity of the body to find exit at a terminal anus in the female, and at the 

 common genito-anal orifice in the male. The cuticle is striated transversely, 

 except on the ventral surface where a longitudinal band, set with minute papillae, 

 extends from the anterior to the posterior extremities. The thick posterior por- 

 tion of the body contains the intestine and the genital organs. In the female it 

 is straight or slightly bow-shaped; in the male it is more or less closely coiled. 



Male organs. — The testicle is single and consists of a long, coiled and folded 

 tube which fills the greater part of the caudal portion of the body. A short, broad 

 vas deferens turning abruptly eaudad from the anterior end of the testicle enters 

 a dilated portion of the genital tube (vesicula seminalis) which, in turn extends 

 posteriorly to the cirrus or spicule. The spicule is single, highly developed and 

 lies in a sheath or cirrus pouch, both sheath and spicule being protrusible for a 

 considerable distance through the cloacal orifice. 



Female organs. — The ovary is simple, tubular, with its extremity attenuated 

 into a slender oviduct which enters the posterior end of the more expanded uterus. 

 From the anterior extremity of the uterus, the slender, more or less coiled vagina 

 leads to the genital pore which is situated on the ventral surface at about the 

 junction of the slender, anterior and the thick, posterior portions of the body. 



2 These diagnoses of this genus and species, furnished by Dr. Philip E. Garrison 

 of this laboratory, are taken from various authors, chiefly Leuckart, with the 

 purpose of furnishing for medical men a description of the parasite, not too 

 technical, but rather more detailed than that usually given in medical publications. 



