. Biology. Biology. FIG. 84.—A single proglottid of Taenia solium enlarged to show the reproductive organs. (From Leuckart.) and stored up in the uterus of the proglottid, ready for develop- ment. When detached, a ripe proglottid then has thousands of embryos, each capable of giving rise to a new tapeworm. But these are deposited with the faeces, and before they can develop into a new Taenia must undergo partial development in the pig. In one way or other, they find their way into the food of a pig; the embryos are liberated by action of the pig's digestive fluids, and when liberated make thei
. Biology. Biology. FIG. 84.—A single proglottid of Taenia solium enlarged to show the reproductive organs. (From Leuckart.) and stored up in the uterus of the proglottid, ready for develop- ment. When detached, a ripe proglottid then has thousands of embryos, each capable of giving rise to a new tapeworm. But these are deposited with the faeces, and before they can develop into a new Taenia must undergo partial development in the pig. In one way or other, they find their way into the food of a pig; the embryos are liberated by action of the pig's digestive fluids, and when liberated make their way through the walls of the digestive tract into the muscles of the pig. Here their development is ar- rested, and, as cysticercids or bladder-worms, they give rise to what is called measly pork. rr"-~^- Such pork eaten in an uncooked state is a FIG. 85.—Trichina spiralis, encysted in source of human infection. The bladder- muscle tissue. (From r j . ,1 j. ,. i Hertwig after Boas.) worms are freed in the digestive tract, be- come attached as scolecids to the lining epithelium, and begin to bud out 'proglottids. Here, there is a very characteristic physiological adaptation, in which the difficulties of maintaining the species are balanced by the enormous number of embryos Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Calkins, Gary N. (Gary Nathan), b. 1869. New York, H. Holt and company
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