. excrements, and are scattered on the ground, either smgly or confined in the escaping segments of the tapeworm. Once upon the ground, they are easily washed along hy rain into the drinking water, ponds, or hrooks, or scattered on the grass. Upon heing swallowed with fodder or water, they arrive in the stomach of the inter- mediate host (cattle, sheep, etc.), where the egg- shells are destroyed and the embryos set free. The embryos then traverse the intestinal wall, and, according to most authors, arrive either ac- tively, by crawling, or passively, by being carried along by the blood, in the
. excrements, and are scattered on the ground, either smgly or confined in the escaping segments of the tapeworm. Once upon the ground, they are easily washed along hy rain into the drinking water, ponds, or hrooks, or scattered on the grass. Upon heing swallowed with fodder or water, they arrive in the stomach of the inter- mediate host (cattle, sheep, etc.), where the egg- shells are destroyed and the embryos set free. The embryos then traverse the intestinal wall, and, according to most authors, arrive either ac- tively, by crawling, or passively, by being carried along by the blood, in the liver or lungs, where they undergo certain transformations in structure. While still in the finer branches of the blood- vessels of the liver, which they transform into small, irregularly-shaped tubes about 12 to 15 mm. long and 1 to 1*5 mm. broad, the embryos lose their six hooks, and develop into small, round kernels, which are generally situated at one Fig. 139.—Egg of the marginate tapewonii (Tcenia marginnta), with six-hooked em- bryo, greatly magai- fied. (Stiles, Annual Eeport of Agriculture, 1901.)
Size: 2366px × 2113px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectveterin, bookyear1920
