To investigate the effects of fixation on the Gram reaction in the pituitary basiphil granules, frozen sections were made from fixed and unfixed glands, paraffin sections from frozen-dried glands, and paraffin sections in the usual way from whole glands, as well as from several pieces of glands embedded in one block. The fixatives were various well-known mixtures and single substances. Staphylococci were also studied, after treatment with some of the fixatives.
The basiphil granules were always Gram-positive after fixation in formaldehyde-saline, formaldehyde-Zenker, Zenker's fluid, and Zenker stock-solution. Frozen sections of unfixed glands, and sections of frozen-dried glands, were always Gramnegative; but such sections were usually Gram-positive if left in formaldehyde-saline for at least 12 hours before staining. All other fixatives studied gave negative results. The staphylococci were always Gram-positive.
These findings, and some questions arising from them, are briefly discussed.