Also a heap of loving to make a house a home, and a spoonful of sugar to make the medicine go down. At 65, movieperson Kanin, who has always had his finger on the pulse of popular taste, now has it affixed to his own coronary artery. His point--which is well taken, but not particularly well made--is that superannuation should not be determined by age. The trouble is that virtually every cutesy-poo example he's collected to prove that old people can, indeed, function as useful members of society is an old saw (worse, already seen on the Johnny Carson show). Miss Maggie Kuhn of Philadelphia, aged 72, president and organizer of the Gray Panthers. Dr. Benjamin Spock, who divorced his wife of 48 years to marry a young thing (Kanin says it was because he believes in the institution of marriage). E. B. White, who took on the Xerox Corporation and convinced them that the underwriting of magazine pieces was immoral. Kanin thinks that White's effort was remarkable because he was 76 at the time, and that he was the only one in America to raise his voice. We think Kanin is remarkable because he thought it was more remarkable for White to protest at 76.