Abstract
A critical assessment is made of the crystallographic data for and against the concept of mosaic structure and crystallites in bromo-iodide emulsion grains. It is considered that all the data studied support this concept.
The finding of a low number of dislocations in such grains, by the convergent-beam technique, is examined and found to be somewhat uncertain. Even so, simple arguments are given which suggest that mosaic structure and low dislocation densities are quite compatible.