Zenker's and Helly's fluids work by denaturing proteins and stabilizing cellular structures, thus preserving tissue for microscopic analysis. The mercuric chloride component is particularly effective in coagulating proteins, while the potassium dichromate and sodium sulfate help to maintain the structural integrity of the cells. The acetic acid in Zenker's fluid and formalin in Helly's fluid assist in the penetration and fixation process, ensuring comprehensive preservation.
