Structure and composition of oolitic granules (Milk of calcium)

Abstract

Milk of calcium collections, recognized by a sharply outlined horizontal level in X-ray films taken with the patient in an erect position (1), were believed to be an opaque fluid or a paste-like material. Somacarrera and Alonso (2) provided, for the first time, scanning electron microscope (SEM) images of very small sandy granules which are the elemental unities of the „milk of calcium“. In a previous work, we made a structural study of these granules under the polarizing microscope (3). We found that small calcium phosphate calculi can be composed of a clustering of milk of calcium granules, cemented together, and surrounded by a common envelope of organic material and apatite. This kind of structure was earlier described by us (4) as similar to that of the pomegranates („Granatähnliche Struktur“) and a “milk of calcium“ granule may be composed of a cluster of one hundred or more microgranules, each measuring from 50 to 100 μm (Fig. 1).