272 THE RETINA, BY MAX SCHULTZE. 



bly followed out ophtlialmoscopically, are still only sparingly present.* 

 In addition to this form of pigmentation, leading to impairment of 

 vision, is another of a less serious nature, which consists in the 

 development of stellate pigment cells (pigmented connective-tissue cells) 

 in the supporting tissue and adventitia of the vessels, which is a fre- 

 quent occurrence in animals, as has been particularly observed by me 

 in the case of Ruminants. 



3. THE CONNECTIVE-TISSUE FRAMEWORK OF THE RETINA. 



In addition to the nervous tissues that have hitherto been under 

 consideration, almost all the layers of the retina are interpene- 

 trated by a tissue occupying a considerable space in many parts, 

 and this is the supporting connective tissue. Though continu- 

 ous with that of the optic nerve,-f- it forms a very peculiar kind 

 of framework in the retina, varying in its character according to 

 the various nervous constituents of the several layers by which 

 it is surrounded. This form of connective tissue is closely allied 

 structually to that of the brain and spinal cord, and has, like it, 

 been named Neuroglia by Virchow. We have applied the term 

 " spongy connective tissue " to it, and distinguish as several 

 parts belonging to it the two limiting layers limitans interna 

 and externa ; the radial fibrous bands, or supporting fibres, 

 in opposition to the radial nerve fibres ; and 'the finer and 

 coarser plexuses connecting the supporting fibres, which, from 

 their resemblance to a sponge, have given their name to the 

 whole tissue. The membrana limitans interna (limitans 

 hyaloidea of Henle) immediately invests the vitreous humour, 

 to which it is often intimately connected ; whilst the limitans 

 externa divides the layer of the external granules from the 

 bacillar layer. Stretched between these two limiting layers, as 

 columns between a floor and a ceiling, stand in great numbers 

 the radial supporting fibres. 



* Donders, in Grafe's Archiv, Band iii., p. 139. Schweigger-Seidel, 

 ibidem, Band v., Heft i., p. 96. Leber, ibidem, Band xv., 1869, Heft 

 iii., p. 1. There is also an excellent illustration of the affection in 

 Leibreich's Atlas, Taf. vi., fig. 1. Iwanoff describes, in Grafe's Archiv, 

 Band xi., Heft, i., p. 153, a deposition of pigment along the radial 

 fibres. 



t. Klebs, Virchow's Archiv, Band xix., p. 321. 



