Handsheets were made by a carefully standardized technique from one lot of Douglas-fir bleached sulphate pulp. These were dried normally, by freeze-drying, or after water displacement by an organic solvent or by an aqueous solution of surface-active agent. At least 10 handsheets were made in any one series and broken or submitted to cycling on the Instron tensile testing machine. Reduction of the surface tension during drying either by a surfactant or freeze drying resulted in large drops of sheet strength as found earlier by other investigators. The presence of nonpolar liquids during drying also greatly reduced sheet strength. An interesting observation was made that such sheets when exposed to high relative humidity (85per thousand) over long periods of time increased in strength to about the value obtained for a water- formed and normally dried sheet. The results are discussed from the standpoint of hydrogen bonding between cellulose fibers.