Differential staining of cartilage and bone in whole mouse fetuses by alcian blue and alizarin red S

The procedure described by Inouye ('76) for the staining of full-term mouse fetal skeletons has been adapted for use with mouse embryos and fetuses of days 14-18 of gestation. The main adaptations for younger specimens involve a longer time in acetone, in lieu of skinning, and omission of the aqueous KOH step. These adaptations require more time but result in consistently good staining of intact specimens.