No. 83-1375. Argued October 6, 1983. Decided February 8, 1984. William L. Rikard, Jr., Charlotte, N.C. (I. Faison Hicks, Grier, Parker, Poe, Thompson, Bernstein, Gage Preston, Charlotte, N.C., on brief), for petitioner. Ernest S. Delaney, III, Samuel M. Millette, Charlotte, N.C. (Delaney, Millette, DeArmon McKnight, Charlotte, N.C., on brief), for respondent. Before WIDENER and ERVIN, Circuit Judges, and BRYAN, Senior Circuit Judge. WIDENER, Circuit Judge: Ralston Purina Company (Purina), defendant