There is no coat of arms on the flask, but somewhere in one of Britain's hospitals a convalescent patient has some of the world's most exclusive blood flowing through his or her veins. The regal donor of the precious stuff was Prince Charles, 36, who has become the first member of the royal family ever to give blood, in his case, O Rh-negative. The unprecedented puncturing of royalty was to reassure Britons after a nationwide scare about AIDS caused a drop in donations. At the North London Transfusion Center, the Prince was asked whether he was homosexual, injected drugs into his veins or had had sex with anyone in those two groups. After those regulation indignities (and his negative answers), he had an apprehensive question of his own: "Is it going to hurt?" When the pint was finally drawn, Charles pretended to apologize because his blood was not blue: "I'm afraid it's red like anyone else's." Fancy that.