My"e*lin (?), n. [Gr. marrow.] Physiol. Chem. (a)
A soft white substance constituting the medullary sheats of nerve fibers, and composed mainly of cholesterin, lecithin, cerebrin, albumin, and some fat.
One of a group of phosphorized principles occurring in nerve tissue, both in the brain and nerve fibers.
© Webster 1913.