. Protozoo?logy. Protozoa; Protozoa, Pathogenic. w > I ,1 V rf'f ^ —. Regression and merozoite formation (parthenogenesis) in Plasmodium vivax. (After Schaudinn.) A, macroganietocyte in blood with nucleus differentiating into a denser and a lighter part; B, the denser part of the nucleus now divides preparatory to schizogony, C, D, while the paler portion with a part of the original cell degenerates; D, numerous merozoites formed about the divided nucleus. cytes, undergo a process of parthenogenesis (Fig. 113), whereby the vitality is again renewed and with this the ability to withstand the
. Protozoo?logy. Protozoa; Protozoa, Pathogenic. w > I ,1 V rf'f ^ —. Regression and merozoite formation (parthenogenesis) in Plasmodium vivax. (After Schaudinn.) A, macroganietocyte in blood with nucleus differentiating into a denser and a lighter part; B, the denser part of the nucleus now divides preparatory to schizogony, C, D, while the paler portion with a part of the original cell degenerates; D, numerous merozoites formed about the divided nucleus. cytes, undergo a process of parthenogenesis (Fig. 113), whereby the vitality is again renewed and with this the ability to withstand the natural or acquired immunity of the host. Craig, on the other hand, describes the conjugation of two schizonts within the human blood cell, an observation which Ewing ('01) and Wright ('01) had also made, although in the last two cases in connection with the normal infection and not with recurrence, while the occurrence was stated as rare and exceptional. Craig ('05 and '07), however, claims that the union of schizonts is a normal process inevery infection, and sees in this fact a means by which the organisms renew their vitality and thus bring about recurrence. Minchin doubts the interpretation of this fusion as given by Wright and by Ewing, and regards it as a process of plasto- gamy without sexual significance. Craig's view is certainly enticing, but we must not forget that plastogamy is a very common phenom- enon throughout the group of protozoa and occurs frequently when. 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 and Philadelphia, Lea & Febiger
Size: 1575px × 1586px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorkandphiladel
