Decalcification of Thin Sections for Electron Microscope Studies of Crystal-matrix Relationships in Mollusc Shells

This note reports a method for studying the relationship between crystals and the organic matrix in calcified structures by means of decalcification of single thin sections. The mollusc shell has been used in developing the method. Electron microscope studies of the organic matrix of the mollusc shell have been carried out by making replicas of the normal or etched shell surfaces (Gr5goire, 1957, 1959, 1961a, 1961b; Watabe and Wilbur, 1961), by thin sectioning (Wada, 1961; Watabe, unpublished), and following ultrasonic disintegration of the matrix (GrSgoire et al., 1955; Gr~goire, 1959, 1961b) after decalcification of the shell. These methods do not lend themselves readily to a detailed examination of the structural relationships between matrix and crystals. However, we have found that the relationships can be made clear by comparing normal and decalcified serial sections and through partial decalcification of individual sections of shell.