Can Xylene act as a substrate for the second part of the mannich reaction during formalin fixation? Under the mannich reaction, after the initial amine-formaldehyde reaction, could xylene act as a substrate to stabilize the reaction if the reaction does not stabilize during or prior to dehydration and clearing? In synthetic chemistry, amine-formaldehyde reaction products can attack ring structures, is this possible under the FFPE processing conditions?