Ethanol Artifact
Processing tissues with inadequate fixation can have serious and uncorrectable consequences. In most cases the dehydrant is ethanol. Ethanol is also a fixative as well as a dehydrant, and quite a poor one at that. Unfixed or inadequately fixed tissues will have fixation completed by the ethanol during processing. If this is done with a modern processor in which the reagent temperatures may be increased, the negative effects of ethanol fixation will be exaggerated, and the results may well be unacceptable. This artifact is often erroneously referred to as overfixation or as the parched earth effect, but the appearance is simply due to unfixed tissue being fixed and dehydrated with (warm) ethanol. Unfortunately, the effects are permanent and reprocessing usually does not correct the results of this artifact. The brittleness of the tissues may be overcome to some degree by using a very sharp knife, setting the section thickness to the thinnest possible and sectioning very slowly and evenly. Soaking the block face in ice cold water may also help.
