Volume 1

Lectures on the parts concerned in the operations on the eye, and on the structure of the retina ... To which are added, a paper on the vitreous humor; and also a few cases of ophthalmic disease / By William Bowman.

  • Sir William Bowman, 1st Baronet
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on the parts concerned in the operations on the eye, and on the structure of the retina ... To which are added, a paper on the vitreous humor; and also a few cases of ophthalmic disease / By William Bowman. Source: Wellcome Collection.

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    meability, or chemical constitution of the vitreous substance in the two situations. Or it may possibly depend on the different access of the solution to the two parts. But however such variations may be explicable, they are proved, I think, by the last-cited experiments, not to depend on any difference in the number or thickness of actual membranes in the two situations. ‘The fine, close lines in fig. 8 and 9, and the equally fine ones in the same region of fig. 1] 0, traverse the vitreous substance in directions too dissimilar for us to imagine them to be the exponents of an anatomical lamination ; but they are im both cases parallel to the surface previously exposed to the salt. The frozen vitreous humor.—In his later paper, Briicke draws an argument for the existence of the concentric layers as a true structure from the condition of the vitreous when frozen ; but in this I confess he appears to me to have been warped by the idea previously in his mid. He says that when the thawing of the frozen mass commences, thin flakes of ice may be picked off from the surface, as though the ice had taken the form of the concentric lamellee while freezmg. For my own part [ have been unsuccessful in finding any indication of the concentric flakes in this way. ‘The ice appears to shoot in the substance of the vitreous ina crystalline form, quite irrespective of any structure existing there, and as it melts, layers and angular fragments may be got off it in a varicty of directions. I feel sure that the ice never takes the figure of the cup-shaped lamellee supposed. Vitreous humor of the bird.—I have examined the vitreous humor of the eye of the common fowl after a month’s immersion in the solution of chromic acid. After this period of immersion, short as compared with that recommended by Hannover, the vitreous—as shown in the annexed wood-cut, fig. 15*—was found throughout rendered slightly opaque; no con- centric lamellee or layers, in any respect parallel to each other, were discovered ; but a very evident arrangement of more opaque fibres * Fic. 15.—Fresh eye of a common fowl, immersed during three weeks in dilute solution of chromic acid; section carried obliquely through, and parallel to, the plates of the pecten; strie are seen proceeding from the summit of the pecten, chiefly towards the ciliary body, but also towards the lens; others ap- pear to pass from the ciliary body towards the lens.
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