The author's paper consists mainly of a Table exhibiting certain of the positive results of many hundred experiments on the colouring matters contained in or educible from Lichens. The experiments in question are partly a repetition, and partly an extension on a more systematic and complete scale, of a series of researches made by the author between 1852 and 1855, the results of which were originally submitted to the Botanical Society of Edinburgh. The present series of experiments includes the whole family of the Lichens. The Table represents mainly the effects of chemical reagents on solutions of the lichen colouring-matters, or colorific principles, in boiling alcohol or water. The nomenclature of the Colour-reactions is that of Werner and Syme.