Phase-contrast microscopy of the animal vitreous body.

A STUDY of the structure of the vitreous body has been made by means of phase-contrast microscopy. Shortly after work began, Schwarz and Schuchardt (1950) described the structure of the vitreous of various animals using this method as well as dark-ground illumination. However, it was thought worth while to continue our study as we were specially interested in trying to determine the chemical nature of the fibres and membranes seen, and their distribution within the vitreous body. The chemistry of the vitreous was not investigated by Schwarz and Schuchardt (1950). Later, however, following its examination with the electron microscope, Schwarz (1951) and Matoltsy and others (1951) concluded that one type of fibre from the vitreous body is probably a primitive collagen. This confirms the chemical analyses of the residual protein by Pirie, Schmidt, and Waters (1948). The work described in this paper has been mainly concerned with the vitreous body of the ox. No wide investigation of other animals has been attempted, but it seemed worth while examining the vitreous body of birds as there is evidence that its embryological origin is different from that of mammals (Mann, 1949). We also examined the vitreous of the monkey, since that of man is almost impossible to obtain fresh and in the normal state.