Specific spindle cells and globular substances in enamel knot.

In the course of the previous study entitled " Chronological Study of Enamel Knot with Special Reference to Mitoses in Enamel Knot" the present author noticed the presence of (1) specific spindle cells with nuclei stained darkly with hematoxylin in the vicinity of the enamel knot as well as (2) small granules or globular substances of brownish black or yellowish brown in color in the enamel knot. They appeared only in the early cap stage. Since there was no previous report of these structures in the tooth germ, the author conducted a histological study on human and mouse fetuses using various staining methods, and these results are herein reported.