The development of the posterior elastic lamina of the cornea or membrane of descemet / by E. Treacher Collins.

  • Collins, E. Treacher (Edward Treacher), 1862-1937
Date:
[1892]
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Licence: Public Domain Mark

Credit: The development of the posterior elastic lamina of the cornea or membrane of descemet / by E. Treacher Collins. 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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    [Eeprmted from the Royal London Ophthahnie Hospital Reports, Vol. XIV, Part ?.] THE DEVELOPMENT OF THE POSTEEIOR ELASTIC LAMINA OF THE COENEA OR MEMBRANE OF DESCEMET. By E. TeeaCHER Collins, Assistant Surgeon to the HospitaL The development of the cornea in the chick has been described as follows* :—*' The substantia propria corneas first appears in the chick as a thin homogeneous layer lying immediately within this epithelium (the surface epithelium). Into this homogeneous layer mesoblastic cells pass from the margin, greatly thickening it, and producing eventually the regular layers of fibrous tissue which are characteristic of the cornea. No cells pass into the most anterior or into the most posterior stratum, which remain homogeneous (anterior and posterior homo- geneous lamellae of Bowman). The epithelium of the posterior homogeneous lamella or membrane of Descemet is derived from mesoblast cells, which grow in like the corneal corpuscles from the margin, and spread themselves over the posterior surface of the cornea, thus separating this from the iris and anterior surface of the lens. Witkregard to the origin of the homogeneous layer which first separates the lens vesicle from the surface epithelium in the chick, and which remains ultimately as the anterior and posterior elastic laminae, two different views have been put forward. Kessler regards it as a secretion of the epidermis, and Kolliker as of mesoblastic origin. In mammals, this homogeneous layer has not been met with.f Hertwig says :— As soon as the lens vesicle in mammals is fully constricted off, it is already enveloped by a thin sheet of mesenchyma with few cells, which separates it from the epidermis. The thin layer is rapidly * Quain's Anatomy, lOth edition, vol. i, Pt. 1, p. 87. t Text-Book of Embryology, Translation of 3rd German Edition, p. 477.