. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. MORPHOLOGY AND CLASSIFICATION 163 the growing parasites do not divide into merozoits but become differentiated into male and female cells (gametocytes). The male gametocyte gives rise to a large number of elongated motile microgametes, one of which approaches and penetrates the ripened macrogamete. The nuclei of the two gametes fuse and the fertilized cell quickly forms a protective wall around itself and then divides into ei
. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. MORPHOLOGY AND CLASSIFICATION 163 the growing parasites do not divide into merozoits but become differentiated into male and female cells (gametocytes). The male gametocyte gives rise to a large number of elongated motile microgametes, one of which approaches and penetrates the ripened macrogamete. The nuclei of the two gametes fuse and the fertilized cell quickly forms a protective wall around itself and then divides into eight cells which are enclosed in pairs within secondary cysts known as spores. This form of the organism passes out of the host, and after a passive existence in the external. Pig. 81.—Porms in the asexual cycle of Plasmodium falciparum, the parasite of tropical malaria. A, Multiple infection of a red blood cell; B to E, various forms of the growing parasite; B and C show also the Maurer granulations; F, full-grown parasite with many nuclei; G, Segme^ntation. The pigment is shown in E, F and G. {After Doflein.) world may gain entrance to a new host, whereupon the spore wall ruptures and the enclosed cells, sporozoits, emerge to penetrate new host cells. The —Plasmodium includes the malarial parasites, forms parasitic in red blood cells and closely analogous to the coccidia in the asexual cycle. The gametocytes are also similar to those of Eimeria except that the gametes are not formed within the mammalian host, but only after the blood has been drawn. The sexual cycle of development takes place in a definite secondary. 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
