The optic nerve fibres and ganglion cells of the mammalian retina / by George Thin.

  • Thin, George
Date:
[1879]
Catalogue details

Licence: Public Domain Mark

Credit: The optic nerve fibres and ganglion cells of the mammalian retina / by George Thin. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    course of the fibre being marked by a line of deeply stained varicosities. The difference is more than one of degree, or than can be accounted for by the greater volume of the fibre at these points, and can, it seems to me, only be explained by supposing that there is accumulated in these swellings a substance which no longer at least exists in the intermediate parts of the fibre. The varicosities on these fine fibres are seen in another form. The fibre appears to open out for a short extent, so as to enclose a more or less elliptical or oval space. In this space a very finely granular substance can be observed. Sometimes the fibre remains perfectly straight and this space bulges out on one side like a pouch. A common form of this pouch is shown at the left extremity of fig. 4. The contents of the space do not stain by aniline blue. I have called special attention to these varicosities which do not stain in order to describe a peculiarity which I have observed in some of them, and which I have shown in figures 3 and 5. In a few instances I have been able, as is seen in the drawing, to trace the minute fibre through the centre of the varicosity, the appearance so produced having a certain analogy to that shown in the larger fibre drawn in fig. 2. These appearances bear directly on the question, whether the nerve fibres in the optic nerve expansion are, as they are usually described, naked axis-cylinders or whether they are not invested by a delicate membrane, but I concede that they are far from sufficient to settle it. Although the formation of varicosities takes place after death, and is in the present case determined as to its special form by the re-agents used, yet the constancy with which the same changes are observed suggests that they are determined by some structural peculiarity. As compared with the retina of the sheep, a large proportion of broad fibres are found in the retina of the cat, and as the cat's retina has not been so much an object of study as that of the sheep or ox, I have drawn examples of the fibres which are mostly found in it, in figures 6, 7, and 8. The ganglion cells shown in figures 9-23 have been drawn partly to show their various forms and sizes, and partly because they illustrate interesting points in connection with the cell processes.
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