Another distinctive property of soap-is that it forms what are called colloidal solutions—that is, solutions in which the actual mole-criles of soap remain in aggregates in the solution, and are not completely separated as is the case with a solution of, say, common salt. It is a property of colloidal solutions that they have the power of adsorbing other particles of matter, and it is suggested that the groups of soap molecules in a soap solution adsorb small particles of dirt. This is partly confirmed by the fact that other colloidal solutions. such as glue and gelatine, have some detergent properties, though none are as effective as soap.
Text read from the printed page and cleaned; old type leaves the occasional error.