Volume 1

The microscopic anatomy of the human body, in health and disease. Illustrated with numerous drawings in colour / By Arthur Hill Hassall, M.B.

  • Hassall, Arthur Hill, 1817-1894.
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: The microscopic anatomy of the human body, in health and disease. Illustrated with numerous drawings in colour / By Arthur Hill Hassall, M.B. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    surface of the choroidal epithelium, and the tails disposed in an opposite direction. Although these cells adhere together with sufficient firmness to constitute a distinct membrane, it would appear that they possess a certain power of movement upon each other, tor it is only on such a supposition that we can explain satisfactorily the fibrous appearance which this membrane frequently presents when viewed in extenso. (See Plate LXVII. Jig. 9.) The tunica Jacobi, although certainly not a nervous struc- ture, is yet properly enumerated as one of the layers of the retina, since it never adheres on the removal of the latter to the choroidal epithelium, but always to the second or granular layer of the retina itself: on account of its extreme frailty and delicacy, this membrane is only to be satisfactorily studied in extremely fresh eyes. A few hours after death the cells separate from each other, and the heads of the cells become disjointed from the tails, so that in the course of a short time not a vestige of the membrane remains. Each cell of the stratum bacillosum bears not an inexact resemblance to a human spermatozoon, than which it is how- ever less considerable in size. The granular layer consists not of granules merely, as the name implies, but of numerous nuclei imbedded in granular matter, and each of which contains several dark spots which reflect the light strongly. This layer is of considerable thick- ness, and is described in the “Physiological Anatomy” as being divided into two, of which the inner is much the narrower, by a pale stratum which can only be seen by very careful manipulation. The nuclei of which it is composed bear much resemblance to those which occur in the convolutions of the brain, and are most probably of the same nature. (See Plate LXVII. Jigs. 5, 6.) The next is the ganglionary layer: this appears to have been hitherto altogether overlooked; its discovery supplies a desideratum in the anatomy of the eye, and clearly shows the really nervous character of the granular and vesicular strata of the retina, which many persons have been much disposed to doubt.