That intravitam staining with basic dyes occurs more readily in alkaline than in acid solutions has long been known. Among the explanations which have been offered to account for this fact two deserve especial mention. The first is that originally proposed byOverton (1), accepted by Harvey (2), and supported in certain respects by the experiments of Robertson (3) (who, however, on other grounds...

Zeolites due to their structures can be used as molecular sieves for purification of materials and solutions. Zeolites with PHI and SOD structure are so common and applicable for this purpose. Hydroxy sodalite and phillipsite are the more abundant members of zeolites which display good selectivity for very small molecules and some ions such as Sr, Pb, Zn, Cu and Rb. There is not any pure natura...