A method for orienting cryostat sections for three-dimensional reconstructions.

Tissue for cryostat sectioning is embedded together with reference tissue impaled on the needles of a specially constructed trident. To maintain spatial orientation, reference and experimental tissue are frozen in Tissue-Tek O. C. T. compound in the manner usual for enzyme histochemistry using a simply constructed carrier. The trident is removed by heating its handle, thus leaving holes in the reference tissue which in turn are used as reference points to orient successive sections with respect to each other.