A method for quantitative estimation of mast cells in the bone marrow of the rat

Observations of thick smears of marrow obtained from the femur, tibia, humerus,sternum, and ribs (in rats), showed that in the first three bones, the number ofmast cells was much higher than in the latter two bones.

A method for the quantitative estimation of the total number of nucleated cellsand of mast cells in the bone marrow of rats is presented. The method involves dilution of the marrow, in a red cell pipet, with a 1:50,000 solution of toluidine bluein 3 per cent acetic acid. This method confirmed the results of mast-cell distribution obtained in the study of marrow smears.