(concurring):
In rejecting petitioners’ application for a zoning variance which would enable them to continue to use their building at 2019 R Street, N.W., for law offices, the Board was dealing with a piece of property which has not been occupied solely for residential purposes for a period of more than 45 years; one owner opening a dentist’s office *309there in 1928; his successor using it for the practice of medicine; and a third converting it into the chancery annex of a foreign government. The building in question is situated in a city block where there are several parcels devoted to nonconforming uses. While the Board finds support in the Zoning Regulations for distinguishing between law offices and medical offices, I find this distinction lacking in any rational support. In view of the restraints imposed by our own rules of decision1 upon particular divisions of this court, however, I agree that the disposition of this case is controlled by Clouser v. David, 114 U.S.App.D.C. 12, 309 F.2d 233 (1962).
. M.A.P. v. Ryan, D.C.App., 285 A.2d 310 (1971).