[Histonet] overprocessing   Formaldehyde fixes we assume by
creating cross links between proteins thereby creating a gel;
soluble proteins are bound and that gives strength to the gel
and helps to withstand processing. These cross links are between
basic acid lysine and other groups (amido, peptide, hydroxyl,
etc). Formalin is not a coagulant (precipitant) fixative but
it's an additive fixative; it does not harden and is reversible;
however it stabilises the proteins and prevents subsequent
hardening by alcohols.  Ethanol disrupts the hydrophobic bonds
which maintain the structure of proteins (coagulant fixative);
hydrogen bonds are more stable in ethanol than water and so the
structure is preserved. Both bound and unbound water molecules
will be replaced during fixation.  I can only conclude that
formalin is unable to prevent the damaging effects of processing
if the gel has not been allowed to form adequately or if it the
gel is disrupted by 'washing'.  I also assume that too much
'processing' collapses the