Zenker's stock solution contains which components?

• A. Mercuric chloride, Potassium dichromate, Sodium sulfate
• B. Formaldehyde, Picric acid, Acetic acid
• C. Osmium tetroxide, Potassium dichromate, Sodium sulfate
• D. Mercury chloride, Sodium sulfate, Formaldehyde

Answer: (A)

Zenker's stock solution is a mercuric chloride–based fixative that relies on heavy-metal reagents to preserve and harden tissue for good morphological detail. The mercuric chloride provides strong protein coagulation and fixation, while potassium dichromate acts as an oxidizing/hardening agent that improves tissue rigidity and nuclear detail. Sodium sulfate is included as a salt to help maintain osmotic balance and facilitate penetration of the fixing solution. This combination is distinct from fixatives that rely on formaldehyde, picric acid, acetic acid, or osmium tetroxide, which are used in other preparations and do not define Zenker's.