. Animal parasites and human disease. Insects as carriers of disease; Medical parasitology. 312 PILARIS AND THEIR ALLIES may attain a length of four feet or more, though the^average length is about three feet, while the diameter is less than j\ of an inch. The body is smooth, cylindrical and milky-white in color, with the tip of the tail sharply hooked. The male worms are believed to be much smaller than the females. When ready to bring forth her young, the guinea-worm is instinctively at- tracted to the skin, especially to such parts as are likely to, or frequently do, come in contact with co
. Animal parasites and human disease. Insects as carriers of disease; Medical parasitology. 312 PILARIS AND THEIR ALLIES may attain a length of four feet or more, though the^average length is about three feet, while the diameter is less than j\ of an inch. The body is smooth, cylindrical and milky-white in color, with the tip of the tail sharply hooked. The male worms are believed to be much smaller than the females. When ready to bring forth her young, the guinea-worm is instinctively at- tracted to the skin, especially to such parts as are likely to, or frequently do, come in contact with cold water, such as the arms of women who wash clothes at a river's brink, or the legs and backs of water-carriers. The worm pierces the lower layers of the skin with the front end of her body and the outer layers of the skin form a blister over the injured spot. The blister eventually breaks, revealing a shallow ulcer, about as large as a dime, with a tiny hole in the center. When the ulcer is douched with water a milky fluid is exuded directly from the hole or from a very deli- cate, transparent projected structure which is a portion of the worm's uterus. This fluid is found to contain hordes of tiny coiled larvse with char- acteristic straight projecting tails. The larvse (Fig. 131) are from to mm. (about 35 of an inch) in length. An hour or so later a new washing with cold water will bring forth a fresh ejection of larvae and so on until the supply is exhausted, a little more of the uterus being extruded each time. After each ejection of the larva; the protruded portion of the uterus dries up, thus sealing in the unborn larvse. This process can be looked upon only as a wonderful adaptation for the pres- ervation of the race. As we shall presently see, the tiny larvae utilize various species of Cyclops (Fig. 132), small fresh-water crustaceans, as intermediate hosts. If the larvae were not de- posited in water, or if they were all poured at once into any bit of water
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmedical, bookyear1918
