286 CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 



lu two families, during the past eighteen years, there has been, within the knowl- 

 edge of this board, microscopic identification of trichiure in the human subject. 



During the past ten years five deaths attributed by attending physicians to trichi- 

 niasis have been re]>orted to this board : one in 1875, one in 1878, one in 1880, and two 



in 1881. 



The secretary of the board of health of Brooklyn, N. Y., says that five 

 cases of trichiuiasis have occurred iu that city, of which a full history 

 may be found in the ])roceedings of the Medical Society of Kings County 

 for 1879. 



North Carolina.— The secretary of the State board says that an equiv- 

 ocal case of trichiuiasis occurred in Wilmington, in that State, but no 

 microscopical examination was made. It was iu the person of a boy of 

 German parentage, habituated to using raw ham. 



West Virginia. — The health ofi&cer of the city of Wheeling reports 

 five cases — father, mother, and child of same, aged two and one-half 

 5^ears, and two females of other families. All ate of same meat — raw 

 smoked ham — on March 4, 1870. No microscopic identification was 

 made in the human subject. 



Wiseonshi. — The secretary of the Wisconsin State board of health 

 says that some cases of trichiuiasis have occurred in Milwaukee, but 

 does not give the number or dates. 



CAUSE AND PREVENTION OF TRICHINA IN SWINE. 



The worm known as the Trichina spiralis has no stage of its existence 

 outside of the animal body, and cannot multiply or even remain alive 

 for any considerable time, so far as has ever been ascertained, after it 

 quits its host. Every infected animal must become infected either by 

 eating the muscular tissue of another animal which has i^reviously ob- 

 tained the parasite in the same way, or possibly by taking food which 

 has been soiled by the excrement of an animal recently infected. It is 

 geuerallj^ admitted that eating flesh which contains the parasite is the 

 most frequent, if not substantially the only, way in which trichiupe find 

 their way into the body. A few cases have been advanced to show that 

 pastures and feeding places may be infected and be dangerous for a con- 

 siderable time ; but, according to our present knowledge of the natural 

 history of this parasite, it may be doubted if many instances of this kind 

 occur. 



When meat containing trichinaj is taken into the stomach the capsule 

 or cyst which surrounds the worm is dissolved by the digestiv^e liquids, 

 the i>arasite is set free, develops into its mature form, the females are 

 impregnated, and each gives birth to one thousand or more young. The 

 young trichinai penetrate the intestinal walls and find their way into 

 the various nuiscles of the body, while the mature worms, and doubtless 

 many of the young as well, are voided with the excrement. Now, it 

 may be admitted that a large number of the mature parasites will be 

 passed from the bowels before they have brought forth their young, and 

 that if taken into the stomach of another animal the act of reproduction 



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