Capsules for frozen sectioning of small specimens.

It was necessary to make sections of small unfixed specimens which had been frozen while still immersed in their normal culture medium. The principal difficulty stemmed from the poor sectioning quality of the frozen culture medium. A capsule is described which has a narrow well in which the tissue specimen fits snugly within a small amount of culture medium. After freezing, the whole capsule is sectioned and the resulting sections, being nearly devoid of culture medium, are of good quality.