[Immunofluorescence investigation of formol-paraffin material]

Immunohistochemical methods were employed for the investigation of bioptic and necroptic material fixed in formol and embedded in paraffin after it had produced very little or no fluorescence at all in the use of routine immunofluorescence techniques. Partial digestion with pepsin or trypsin or both enzymes in succession mostly facilitated positive immunohistological reaction. This particular procedure gives more scope to the methodological possibilities of histological material examination in that it offers an opportunity for the immunohistological investigation of even old material not specially preserved for immunohistological purposes but routinely fixed in ordinary formol. The simplification adds general availability to the method.