The Polysaccharide of the Vitreous Humor

Since the work of Miirner (1) the existence of a mucoid in the vitreous humor has seemed well established. All subsequent workers used his method of preparation: the precipitation of the diluted native vitreous humor with dilute acetic acid. In his recent book on the nature of the vitreous body (2), Duke-Elder gives its concentration as 0.021 per cent, or about 30 per cent of the total protein present. The only analysis we were able to find on this mucoid is that of Miirner: N, 12.27 per cent; S, 1.19 per cent. The stability of a typical mucoid, as, for example, egg mucoid, toward splitting into its polysaccharide and protein components is very remarkable. Thus Levene and Mori (3) state that the egg white must be hydrolyzed on the steam bath with 10 times its volume of 10 per cent barium hydroxide for 7 hours. In an effort to prepare the supposed vitreous mucoid for other studies, we obtained, by very gentle methods, a free polysaccharide acid of high molecular weight, which is apparently in the vitreous humor in a salt-like combination. It appears to be a substance unique in higher animals, and may be best compared with some of the specific polysaccharides of bacteria.