Glutaraldehyde Fixatives for Preserving the Chick's Inner Ear

Abstract
We preserved the inner ears of chicks in various concentrations of glutaraldehyde (2 to 3.5%) and cacodylate buffers (0.025 to 0.1 M). Buffer concentrations below 0.1 M caused osmotic damage that higher glutaraldehyde concentrations only partially counteracted. The combination of 3.5% glutaraldehyde and 0.1 M cacodylate buffer optimally preserved the different cell types and also eliminated problems of swelling and shrinkage. We further improved cellular preservation by immediately immersing the dissected specimen into chilled (4°C), aerated fixative. The improved fixation greatly increased the retention of cytoplasmic ground substances, particularly in supporting cells and nerve terminals.