Sections obtained from lymphoid tissues fixed immediately after biopsy in Bouin's fluid and embedded in paraplast may be used to visualize the immunosecretory cells with classical direct immunofluorescence. A comparative study of the same fragments processed according to the frozen section method followed by acetone fixation or according to Sainte-Marie's method confirms the value and the advantages of the proposed technique. Early fixation of thin fragments seems to be the main point.