Parboil a pair of sweetbreads twenty minutes; drain, cool, and cut in one-half inch cubes. Mix with an equal quantity of cucumber cut in one-half inch dice. Season with salt and pepper, and moisten with German Dressing. Arrange in nests of lettuce leaves or in cucumber cups, and garnish with watercress. To prepare cucumber cups, pare cucumbers, remove thick slices from each end, and cut in halves crosswise. Take out centres, put cups in cold water, and let stand until crisp; drain, and dry for refilling. Small cucumbers may be pared, cut in halves lengthwise, centres removed, and cut pointed at ends to represent a boat.