Chromatography in self-coated tubes. II. Testing of the coated tubes Chromatotubes, coated by means of a home-made coating apparatus with cellulose, silica gel, aluminium oxide, kieselguhr, magnesium silicate and polyamide with and without an admixture of plaster of Paris, starch or fluorescence indicator, were tested for application in chromatography. Sudan Red G, Dimethyl Yellow and Indophenol were separated on these layers with benzene, Fast Red E, Chrysoine SGX and Indigotin I with n-propanol—ethyl acetate—water (6:1:3), sorbic acid, salicylic acid and p-hydroxybenzoic acid ethyl ester with n-pentane— n-hexane—acetic acid (10:10:3) (admixture of fluorescence indicator). The reproducibility of the R F values and the size of the spots correspond to those obtained with commercial chromatotubes. Development times, spot sizes and medium errors of mean values of layers coated with alcohol or acetone as suspending medium are given.