A technique was devised for obtaining marrow-free trabecular bone so that the trabecular and cortical bone composition of dog, steer, monkey and man could be studied. Vertebral body was cut in the frontal plane into slices 2 mm thick with an electric band saw. The cortical bone encrircling each slice was trimmed off with a cleaver, leaving intact a lacy slice of trabecular bone. The marrow substance was washed away by fine and powerful jets of tap water obtained from an adjustable nozzle. Marrow washing was discontinued when no trace of red color was visible on holding the slice in front of a strong light source.

The quantities of water, volatile inorganic, organic and ash fractions in cortical bone was alike for all species. Likewise, the trabecular bone fractions of each was quantitatively similar. In general, density and amount of ash in cortical bone was higher than that in trabecular bone. The water and ash:organic ratio were higher in trabecular than in cortical bones.

Ratios of trabecular to cortical ash for the bones in an entire dog skeleton were also determined. Based on this, volume or mass of the various bone fraction may be estimated when the weight of the ash for any particular bone is known.