Distortion-Free Mounting of Frozen Sections by Handling on Paper Supports

Frozen sections are cut from the specimen until the level of interest is reached. A strip of paper (bond or similar writing paper) 5 cm long and about 1 cm wider than the specimen is moistened with water, closely applied to the surface of the specimen and frozen onto it. As the section is cut, the end of the paper strip above the knife is grasped and turned backward toward the other end of the strip. The section is then applied to an albumenized glass slide, firmed and thawed by finger pressure, and the paper removed. After thorough drying, the preparation is ready for further processing. When properly performed, mounted sections whose details coincide to those of the uncut block can be obtained. If thawing on the knife is prevented by cooling the knife, the technic can be performed without a cryostat, but it is also feasible to use a cryostat if a favorable temperature is maintained. The authors obtained 30 μ serial sections, suitable for stereotaxic mapping, from rabbit brain by this method.