Identifier: practiceofmedici00tyso (find matches)
Title: The practice of medicine; a text-book for practitioners and students, with special reference to diagnosis and treatment
Year: 1913 (1910s)
Authors: Tyson, James, 1841-1919
Subjects:
Publisher: Philadelphia : P. Blakiston's
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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ulva at anterior fifth of body; viviparous. Lance:when born, 90.-100. microm. in length, obtuse anteriorly, posteriorly prolonged to apointed tail; when encysted as muscle trichinie the larva; measure about i. mm. longand 0.04 mm. in thickness, tapering anteriorly, more thick and obtuse posteriorly, withcomplete organization as in the adult and showing the characters of the different sexes. This important parasite in its adult, sexual stage infests for a briefperiod the intestinal tract of man and a number of animals (mainly mam-mals), gives origin to a large ntmiber of larval worms after which the adults TRICHINIASIS 223 die; the larvaa make their waj^ into the muscles of the same host and passan indefinite encysted stage in this situation until transferred to the nexthost by the ingestion of the infested flesh by the latter. The species wasfirst established by Owen in 1835, from encysted larvse in the muscles ofhtiman anatomical subjects; in 1846 Leidy announced the discovery of the
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Fig. 64.—Trichinella spiralis: a, gravid female intestinal trichina L embryos; G,vulva; Oa, ovary; 6, adult male intestinal trichina; T, testicle^ c joung larva i, larvain musculature; e, encapsulated larva in muscle. (Braiin, after Claus.) encysted larvas in pork; but it was not until i860, mainly through Zenker,that the full relation with the intestinal form and the development of theworm were understood. Besides in man the worm is commonly found in the hog (domestic andwild), in rats, and in mice; it has also been met in rabbits, guinea-pigs, cow, 224 INFECTIOUS DISEASES sheep, horse, dog, cat, fox, marten, badger, bear, raccoon, mole, skunk, hedge-hog, hippopotamus, hamster, and in birds as hen, pigeon, and duck. It ismost common in man, hog, rat, guinea-pig, and rabbit. Man commonly acquires trichiniasis by eating infected ham insuffi-ciently cooked. The capsules are digested and the trichina? set free; thejpass into the small intestine and there develop into the sexually matue

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