Page:The Journal of Tropical Medicine, volume 6.djvu/230
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THE JOURNAL OF TROPICAL MEDICINE. {June 15, 1903.
Areprint.
FILARIA PERSTANS. By Grorce C. Low, M.A., M.B., C.M.
Medical Superintendent and Tutor, Tropical Medicine.
(Continued from page 182.)
Tue ParentaL or Apuut Forms.
The parental forms of the embryonic Filaria perstans, first discovered by Daniels in British Guiana, resemble fine coiled threads, the males being shorter and finer than the females. In both sexes the head is club- shaped; the neck, narrower than the head, joins the body, which tapers somewhat as it approaches the tail, the latter organ having the cuticle thickened over it, forming two triangular appendages.
A well-marked, musculo-cutaneous, non-striated layer encloses the body cavity, in which the viscera and generative organs are placed. The alimentary canal begins with a simple circular mouth, and extends almost throughout the entire length of the worm, ending on the concavity of the curve formed by the tail. Fia 1.—Tail of Filaria perstans ¢ (slightly diagrammatic), x 525. ap, anal papille; ¢ t, cuticular thickening at tip of tail, one of the triangular appendages only seen. In the female the anus opens at the apex of a slight bulge or papille on the cuticle; in the male it opens at the general level of the outside of the body, but has four pairs of papillee placed in front of it (pre-anal papille) and one pair behind it (post-anal papille), and two unequal spicules may sometimes be seen protruding from the orifice. The two uterine tubes almost com- pletely fill up the body cavity of the female, these being packed with eggs posteriorly and with embryos anteriorly, the latter escaping into the vagina, which unite and open externally some distance behind the
head.
London School of The adults inhabit the connective tissues at the base of the mesentery and may be found readily if some | time is expended on the research. The best method — to adopt is to remove the whole of the mesentery from _ the intestines and the tissues at its base en bloc, and then to place them in 2 per cent. formalin. This is Fic, 2.—Tail of Filaria perstans ¢ (slightly Aingeaemaniey x 525. ap, anal papille; tip of tail not seen.
then dissected piecemeal at one’s leisure, and with good eyes a lens is unnecessary. The worms when found may be placed in 2 per cent. formalin, and after measur- ing them, they should be mounted for permanent preparation with or without staining in glycerine jelly. —
TABLE III. MEASUREMENTS OF AN ADULT FEMALE AND MALE F2/arta perstans FROM UGANDA.
Length... 50 mm. 34 mm. Grectest thickness o°160 mm, o'104 mm. Diameter of head.. o'080 mm. 0'064 mm. Diameter of neck.. i 0°072 mm. ' 0°054 mm. Distance from head of 1°22 mm. ;
vaginal orifice Distance of commence- 1°60 mm. ment of uterus from head Distance of end of uterus 0°600 mm. from tail Distance of anus from tail... o'160 mm. o'r20 mm. | Anal papillee None Four pairs of pre anal papillse, on pair of posterio Cuticle thickened | Cuticle thicken to form two tri- | to form two tt angular appen-| angular appel dages dages. Termination of tail Tue IyterMepiate Host. Analogy leads one to suppose that the embryo fila 1 must be sucked out of the blood by some insect in whieh /
the peculiar distribution of the parasite and its ass0o- ciation with dense tropical forests suggests some insect with a similar distribution. To determine the point