A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . to one-eighth of the totalnumVjer of corpuscles. The diminution after thisis less rapid, but it is only at about tlie time of birththat they disappear from the blood altogether. The question of the manner in which the nucleatedred corpuscles become converted into the non-nucleated variety, typical of mammalian blood, is amuch disputed one. Howell and others claim tohave observed the extrusion of the nucleus in a freecondition, and this theory is supported by
A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . to one-eighth of the totalnumVjer of corpuscles. The diminution after thisis less rapid, but it is only at about tlie time of birththat they disappear from the blood altogether. The question of the manner in which the nucleatedred corpuscles become converted into the non-nucleated variety, typical of mammalian blood, is amuch disputed one. Howell and others claim tohave observed the extrusion of the nucleus in a freecondition, and this theory is supported by the factthat free nuclei which have presumably been extrudedfrom corpuscles are frequently seen in sections, andthat cells in all stages of nuclear extrusion may beobserved in specimens procured after extensive bleed-ing when there is a rapid regeneration of the blood con-stituents. Malassez thinks that the original nucleatedcells persist throughout life and that tlie non-nu-cleated discs arise by the setting free of a portion ofthe pigmented cytoplasm by a process of budding andsubsequent constriction. The view which to-day. Fig. 695.—The Manner in Which the Nucleus Escapes fromthe Nucleated Red Corpuscles, according to Howell. 1, 2, 3, 4,represent different stages of extrusion noticed upon the livingcorpuscles; a, specimen from the circulating blood of an adultcat, bled four times; 6, specimens from the circulating blood of akitten forty days old, bled twice; c, specimens from the blood ofa fetal cat nine centimeters long. Others from the marrow of anadult cat, two of the figures showing the granules which have beeninterpreted bv some as a sign of the disintegration of the nucleus.(After HoweU.) claims the most adherents, however, is that by Kolliker and later extended somewhatby Neumann. According to this view the nucleusbecomes small, more homogeneous, and later notchedor indented, while the cell as a whole graduallybecomes flattened. As a later stage
Size: 1671px × 1495px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbuckalbe, bookcentury1900, bookdecade1910, bookyear1913
