Bouin’s fixative is a particularly good choice for worms because it penetrates dense tissues well and is extremely good for fixing antigens. Like all strong fixatives, however, it is unsuitable for some antibody-antigen pairs. In such cases, the length of time in the Bouin’s fixative can be shortened, or paraformaldehyde fixation can be used instead. - [Read Fixing Caenorhabditis elegans in Bouin’s Fixative Protocol]
The key preparatory steps. In-situ RT-PCR. Fixative. Protease Digestion. DNase digestion. One-step in-situ RT PCR Protocol. Gerard J. Nuovo - [Read RT In Situ PCR - Foundation of Success]