Which constituents are found in Orth fixative?

• A. Formaldehyde and potassium dichromate
• B. Paraformaldehyde and picric acid
• C. Acetic acid and picric acid
• D. Formaldehyde only

Answer: (A)

Orth fixative is defined by its two main chemical components: formaldehyde and potassium dichromate. The formaldehyde provides aldehyde crosslinking that preserves protein structure and overall tissue morphology, while the potassium dichromate acts as an oxidizing agent that enhances fixation and helps to preserve cellular details more deeply. This specific combination distinguishes Orth fixative from other fixatives that use picric acid or acetic acid, or from formaldehyde alone. So, the constituents are formaldehyde and potassium dichromate.