Marrow

(mar'ro.) [A.S. mea rh. (Anat.) A substance of low sp. gr., filling the cells and cavities of the bones of mammals. In the long bones of a healthy adult mammal, the M. occurs as a yellow oily fluid, contained in vesicles like those of common fat, which are imbedded in the interspaces of the, medullary membrane, which is a highly vascular membrane lining the interior of the bones. This M. consists of 96 per cent. of oil and 4 of water, connective ti ue, and ve els. Its special uses are not very clearly known. [s. 580]