gray substance n.
See gray matter.
Then those next above, the gray substance retreating with what seemed to be pouting reluctance.
I saw the gray substance that stopped the entrance of the little metal vial disappear.
If it simply lay within the skull the first fall would mash the gray substance against the side of the cavity.
Daniel Webster's brain had gray substance to the depth only of one sixteenth of an inch.
All the faculties which we call the soul are nothing but functions of this gray substance, of this mass of intestines.
Great masses of the gray substance still clung to the top of their cabin, like sticky tar.
This gray substance lies in folds or convolutions, the furrows or sulci, dipping deeply into the interior of the brain.