A contribution to the anatomy of the amphibian and reptilian retina / by J.W. Hulke.

  • Hulke, J. W. (John Whitaker), 1830-1895.
Date:
[between 1870 and 1879?]
Catalogue details

Licence: Public Domain Mark

Credit: A contribution to the anatomy of the amphibian and reptilian retina / by J.W. Hulke. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    P4’0in a coinparisou with liis fi,t^urcs, 1 believe that tliis fibre, which I regard as the transformed inner segment of the rod- sheath, is identical with the fibre which Ritter describes in the axis of the rod-shaft, snrronnded by the other contents of the sheath in the manner of a medulla. He com})arcs it with the axis-cylinder of nerve, regards it as the true termination of Muller’s radial fibres, and considers it as valuable evidence in support of the nervous nature of the rods.* The axial situation of Ritter’s fibre has been coiifirmed by Manz, who considers it nervous.f Krause has also verified its existence in chromic acid preparations, but doubts its nervous nature, and even its original existence.| I submit that the true origin of the fibre is easily demonstra- ble by tracing its development through numerous intermediate phases which occur between the club-like and stalked vesicular transformations of the rods, and constitute a veiy regularly progressive series. Even in the club-like forms, where Ritter says its demonstratioii is not difficult, because the fibre is less closely embraced by the inner part of the rod and their separate outlines are better distinguishable, 1 have never seen the fibre pass inside the rod-sheath, its contour is always uninterruptedly continuous with that of the sheath.] Cones.—These are flask or bulb-like objects, smaller than the rods, and placed at regular intervals amongst them. They also have an outer and an inner segment, a shaft, and a body, the junction being marked by a bright transverse line, where they are very apt to break asunder. The shaft resembles a diminutive 7’od-sbaft, but ditfers from it in tapering slightly towards its outer end, in being ratner more persistent, and in shrinking less in chromic acid The bodv, larger than the shaft, is flask-shaped. Its outer end, narrow and truncated, contains the well known pale yellow bead, which lies just inside the line that marks the iunction of body and shaft. Its inner end is connected with an outer granule, in the same manner as we have seen the * Bitter A. f. 0. Bd. V, Abth., li S. 101. Taf. 4, F. 1-2C. T Manz. Henlc w. Pfeuffer’s Ztschr., 3 R., Bd. X., Taf. viii, S. 301. X Krause. Henle w. Pfeuffer’s Ztschr., 3 R., Bd. xi., S. 175.