Zenker and Helly fixatives share which components?

• A. Mercuric chloride and potassium dichromate
• B. Formaldehyde and acetic acid
• C. Formalin and methanol
• D. Osmium tetroxide

Answer: (A)

Zenker and Helly are historical heavy-metal fixatives that preserve tissue by cross-linking proteins with metal ions. They share mercuric chloride and potassium dichromate as the active fixing components, which work together to stabilize cellular and tissue structures rapidly and deeply. This combination is what defines both formulations, distinguishing them from fixatives based on formaldehyde or osmium tetroxide, which use different chemistry.