Section 7
SEC. 7. Failure to mark "Not negotiable."—A nonnegotiable receipt shall have plainly placed upon its face by the warehouseman issuing it "nonnegotiable," or "not negotiable." In case of the warehouse-man's failure so to do, a holder of the receipt who purchased it for value supposing it to be negotiable, may, at his option, treat such receipt as imposing upon the warehouseman the same liabilities he would have incurred had the receipt been negotiable. This section shall not apply, however, to letters, memoranda, or written acknowledgments of an informal character.