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 — > disposed 



Cells directly cut — > broken nuclei — > rounded nuclei 



of by outbreak of cerebro-spinal fluid, or by leucocytes. 



Cells just in front of those cut — > angular nuclei — » rounded nuclei 



— » disposed of by leucocytes. 



■ fragments 



