Cryostat sectioning of formalin-fixed brain: further attempt to improve section quality by previous infiltration with O.C.T. compound.

We previously reported that in non-brain and formalin-fixed specimens, one can obtain frozen sections of markedly improved quality not only by supporting specimens with O.C.T. compound as usually done, but by infiltrating them with the medium prior to embedding. In the present paper we show that this technic also proved to be quite effective in the cryosectioning of brain tissues, which so far has been difficult because of the liability of sections to shattering, particularly when one attempts to obtain a thick section. The present paper also discusses about the reason why sectioning is improved by the procedure, and aims to establish the optimal temperature for cryostat sectioning in relation to section thickness.