. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 454 SPECIFIC MICRO-ORGANISMS Opalina Ranarum.—This is a common, parasite in the in- testine (cloaca) of the frog. It reaches a large size, 600 to Soo/j. in diameter, is flattened and somewhat irregular in outline. The ectoplasm is striated and there are very many nuclei in the in- terior of the cell. In the springtime, as the frogs enter water to spawn, the parasites divide rapidly and give rise to cysts 20 to 40/^ in diamete
. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 454 SPECIFIC MICRO-ORGANISMS Opalina Ranarum.—This is a common, parasite in the in- testine (cloaca) of the frog. It reaches a large size, 600 to Soo/j. in diameter, is flattened and somewhat irregular in outline. The ectoplasm is striated and there are very many nuclei in the in- terior of the cell. In the springtime, as the frogs enter water to spawn, the parasites divide rapidly and give rise to cysts 20 to 40/^ in diameter. These escape into the slime and are ingested by the growing tadpoles. In the cloaca the cells escape from the cysts. They are differentiated into male and female gametes and A B. Fig. 21S.—Opalina ranarum, showing the numerous vesicular nuclei. A, Ordinary form. B, Dividing form. {From Doflein after Zeller.) fuse to^ form one cell which grows and multiplies in the developing frog. Balantidium Coll.—This parasite of the human intestine was described by Malmsten in 1857. Its normal habitat seems to be in the large intestine of swine, where it is commonly found in large numbers. The cell is a short oval, 50 to 70/1 wide and 70 to loofj. long, rarely larger. Jts surface is covered with active cilia, and there is a short oral groove at the anterior end. The cytoplasm contains drops of fat and food vacuoles, often red blood cells and leukocytes of the host. The principal nucleus. 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 MacNeal, Ward J. , 1881-1946; Williams, Herbert Upham, 1866-. Philadelphia, P. Blakiston's Son & Co.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbacteri, bookyear1920
