Publisher's Synopsis
Excerpt from The Vitreous Body: Its Origin, Development, and Structure as Observed in the Eye of the Pig
The origin of the vitreous body of the eye has long been in doubt. Even the numerous and thorough investigations of the first decade of the present century, although clearing up many difficulties and correcting false notions, have failed to bring a satisfactory answer to the question, "Is the vitreous body of the eye a derivative of the outer or middle germ layer; is it an ectodermal or mesodermal formation?" A glance at some of the latest and most widely used textbooks, chosen at random, reveals the uncertainty existing among modern authors as to the origin of this interesting structure of the eye. Says Parker (page113), "Mesoderm also makes its way into the optic cup, through the choroid fissure, and becomes the vitreous humour." Lillie, on the other hand, maintains (page275) the "researches of the last few years have demonstrated that the vitreous body is primarily of ectodermal origin, its fibers arising as processes of cells of the inner layer of the optic cup and the matrix as secretion." Again, Prentiss and Arey assert (page381) that "the vitreous body may be regarded as a derivative both of the ectoderm and the mesoderm."
The reasons for this diversity of opinion among biologists may be reduced to the following: 1. The very delicate nature of the vitreous body, which differs so widely from all other tissues, renders its study extremely difficult. It requires special methods of technique not ordinarily employed in histological investigations. The difficulties of obtaining perfect sections of the eye in all its stages of development have been regarded by some investigators as almost insurmountable; 2. The extreme complexity of the mammalian eye, its very rapid development, especially in early embryonic life, the appearance and disappearance of an intricate vascular system in the course of development with its concomitant radical changes - all this obscures the origin and growth of the vitreous body and renders its study as difficult as it is interesting.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
