. The Biological bulletin. Biology; Zoology; Marine biology. 128 GEORGE FRED SUTHERLAND. separated as if by a recent outburst of cerebrospinal fluid, and deeply-staining rounded and fragmenting nuclei are seen. In the second preparation, the deeply-staining nuclei are all small. Fig. 8. Sagittal section through the end ot the spinal cord fourteen hours after the operation. This shows the epidermal layer, the plasma layer, and the knob- like extension of the central canal, caused by the outward pressure of the cerebro- spinal fluid, ep, epidermis; cc, central canal; pi, plasma layer; ntc, notoc
. The Biological bulletin. Biology; Zoology; Marine biology. 128 GEORGE FRED SUTHERLAND. separated as if by a recent outburst of cerebrospinal fluid, and deeply-staining rounded and fragmenting nuclei are seen. In the second preparation, the deeply-staining nuclei are all small. Fig. 8. Sagittal section through the end ot the spinal cord fourteen hours after the operation. This shows the epidermal layer, the plasma layer, and the knob- like extension of the central canal, caused by the outward pressure of the cerebro- spinal fluid, ep, epidermis; cc, central canal; pi, plasma layer; ntc, notocord. (330 diameters.) and fragmentary. In other words no more nuclei seem to be starting to degenerate. At fourteen hours, plasma and epidermis cover the spinal cord though the plasma is pushed outward by the cerebrospinal fluid (Fig. 8). There are nuclear fragments in the cord and de- generating nuclei in the plasma. Another preparation of the same period shows the nerve cord still open to the exterior, as well as the nuclear appearance of an earlier stage. At twenty-four hours, only a few of the nuclei are slightly smaller and darker than the normal. At this time there appear near the end of the spinal cord, granular leucocytes containing pigment granules and fragments which closely resemble the fragments of degenerating nuclei. It may be that the leucocytes appear at this time and dispose of nuclear fragments. After one day, the degenerating nuclei are too rare to be significant. The degenerative process which the foregoing facts seem to show, may be indicated diagrammatically as follows: fragments â> disposed Cells directly cut â> broken nuclei â> rounded nuclei of by outbreak of cerebro-spinal fluid, or by leucocytes. Cells just in front of those cut â> angular nuclei â» rounded nuclei â» disposed of by leucocytes. â fragments. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectb, booksubjectzoology
