Some 38 hospitals are arrayed against the Department of Revenue in this case. The hospitals claim exemption from sales or use taxes on certain substances and machines because of the statutory exemptions for prescription drugs and prostheses. RCW 82.08.0281, 82.12.0275, 82.08.0283, 82.12.0277. The Department’s initial deficiency assessments for these taxes were affirmed by its Interpretation and Appeals Division and, on the hospitals’ appeal, by the Board of Tax Appeals. The Superior Court reversed, and the case is here on the Department’s appeal.