Cartilage-staining technique for the examination of unskinned fetal rat specimens previously processed with alizarin red S.

A novel staining technique has been devised that permits a cartilage examination of unskinned fetal rats that have been previously processed for skeletal examination with alizarin red S. The procedure consists of rinsing alizarin red S-stained specimens in distilled water and placing the specimens in a 3% acetic acid solution. A transfer of the stain from bone to adjacent cartilage occurs, producing purple-stained cartilaginous structures that can be differentiated from still-discernible bone structures.