Fixation of foetal pig liver for electron microscopy. I. The effect of various aldehydrs and of delayed fixation.

Light and electron microscopic investigations of the ability of various fixatives to preserve foetal pig liver tissue (immersion fixed 5 min, 20 min, and 40 min after the death of the mother) gave the following results: 1) Fixation with 4% formaldehyde gives, in all circumstances, an unacceptable tissue presevation. 2)Fixation with 2.5% glutaraldehyde gives fair tissue preservation in a ca. 130 mu thick zone below the surface. 3) Fixation with a fixative mixture containing 2% formaldehyde and 1.25% glutaraldehyde or 2% formaldehyde, 1% glutaraldehyde and 1% acrolein gives good tissue preservation in a ca. 500 mu thick zone under the surface. 4) The addition of DMSO does not improve tissue preservation. 5) Delayed fixation of liver tissue removed from the foetus after the uterus has been placed in an incubator for 40 min has only a slight effect on tissue preservation.