A CRYSTALLOID INCLUSION IN THE RABBIT BLASTOCYST

Abstract
Elongated crystalloids measuring 0.5 to 10 u in length and 0.1 to 1 u width were found in the cells of the 5 1/2 day rabbit blastocyst. They were found to contain polysaccharides (PAS reaction) but no detectable RNA (azure B). Under electron microscope they gave a striated appearance in longitudinal sections, and in cross-sections showed a hexagonal packing of units each about 100 A in diameter, with a light center 70 A across.