Absorption of Moisture by Gelatin in a Saturated Atmosphere

A great deal of work has been done to determine the relation of colloidal matter to water, gelatin being a favorite substance for such studies.However, one finds but few attempts to determine the water relations established when the colloidal material is exposed to an atmosphere saturated with water vapor.The earliest observations of a difference in behavior of colloids toward water and water vapor are credited to Volbehr (5).The main work dealing with this subject is a paper by von Schroder (3), who claims that gelatin absorbs much more water when placed in liquid water than when exposed to a vapor-saturated atmosphere.The data presented in his paper were afterwards used as a basis for a theoretical discussion by Bancroft (1), who attempted an explanation of the observed phenomena, but without any apparent attempt to verify von Schréder's results.One finds in the recent literature occasional reference to these papers, as in * Calculated on absolute dry weight of gelatin disc, 0.679 g. 1 Contributions from the Botanical Laboratories of the University of Kentucky, No. 3.