. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LUNG FLUKES 221 tissues through which the parasite tunnels out its burrows and in which it deposits its eggs (Fig. 70). These excavations in the lung connect with the bronchial tubes, through which the blood, parasite eggs and other products are voided, thus causing the characteristic blood-spitting. The expectorations, resembling those of pneumonia, are of a peculiar brownish red color, due in part to the blood corpuscles present and in part to the dark brown fluke eggs, which are often very abundant.
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LUNG FLUKES 221 tissues through which the parasite tunnels out its burrows and in which it deposits its eggs (Fig. 70). These excavations in the lung connect with the bronchial tubes, through which the blood, parasite eggs and other products are voided, thus causing the characteristic blood-spitting. The expectorations, resembling those of pneumonia, are of a peculiar brownish red color, due in part to the blood corpuscles present and in part to the dark brown fluke eggs, which are often very abundant. Occasionally the lung fluke bur- rows in other organs and glands fig. 70. Eggs of lung fluke of the body, such as the liver, contents of cyst in lung of hog. X spleen, muscles, intestine and ^''°"* ^°- (After stlies and Hassaii.) brain. Musgrave found in the Philippines that sometimes many parts of the body are infested at once, and in one case he found over a hundred mature parasites in a muscular abscess. When they burrow in the brain they cause epileptic fits and usually in time cause death. The eggs of the lung fluke (Fig. 71 A) when immersed in fresh water for several weeks develop within themselves typical ciliated embryos or miracidia (Fig. 71B). The latter burst away the little cap at the end of the egg and emerge as free-living animals. Fig. 71. A. freshly passed egg Nakagawa has recently shown of lung fluke; B, egg of lung fluke that if these miracidia are placed with fully developed embryo. X • . •,. j. • • r 250. (After Katsurada.) 1" ^ater With certain species of snails, particularly Melania liber- tina, the miracidia swarm about the snails and burrow into them, shedding their cilia as they go. The entire cycle of development in the snail has not been worked out but it is probably very similar to that of Schistosoma. Sporocysts of various sizes occur in the liver and other tissues of the snail, and it is probable that these produce the cercarise
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