Gently applying a cool cloth to the plants kernels as he cradled its frail stalk in his arms, Agriculture Secretary Tom Vilsack stayed up all night caring for a sick corn plant, sources close to the former Iowa governor confirmed Tuesday. There, thereyoure going to be all right, the fretful cabinet member said as he stroked the plants wilted leaves and browning tassels, feeding it spoonfuls of nourishing, nitrogen-rich fertilizer. Be brave for me, little one. Were going to make sure you get all better. At press time, sources reported that a tearful but determined Vilsack had mercifully snapped the corncob in half to put the dying plant out of its misery. 