Prefer Is Considerably Faster Than Formalin, And Will Produce Superior Results In A Conveniently Short Time. Small Biopsies Will Fix In 45-60 Minutes, Larger Ones In 1-2 Hours. General Surgical Specimens No Thicker Than 4 Mm Will Fix Adequately In 2-4 Hours. Allow Longer Time When Fixing Gross Specimens. Notice The Exquisite Detail In The Gastric Biopsy (Figure At Left, Gastric Biopsy Fixed 45 Minutes In Prefer). Basement Membranes And Cell Membranes Are Clearly Defined. Nuclear Patterns Are Good.