Histochemical properties of the "crystal ghosts" of calcifying epiphyseal cartilage.

The crystal ghosts represent a crystal associated organic material which is stained by acidic phosphotungstic acid, periodic acid-silver methenamine and periodic acid-thiosemicarbazide-osmium, and is reactive with cations and with colloidal iron at pH 2.0, and unreactive after methylation and saponification. These results suggest that crystal ghosts are, or derive from, proteoglycans of calcifying matrix.