Ulander’s results have been confirmed by those obtained by K. Müller[760]. In _Cladonia rangiferina_, Müller found that the cell-membranes of the hyphae contained, as hemicelluloses, pentosans in small quantities and galactan, but no lichenin and very little chitin. In _Evernia prunastri_ hemicelluloses formed the chief constituents of the thallus, and from it he was able to isolate galactan soluble in weak hot acid, and everniin soluble in hot water, the latter with the formula C₇H₁₅O₆, a result differing from that obtained by Stüde[761] who has given it as C₉H₁₄O₇; chitin was also present in small quantities. In _Ramalina fraxinea_, the soluble part of the thallus (in hot water) differed from everniin and might probably be lichenin. _Cetraria islandica_ was also analysed and yielded various hemicelluloses, chiefly dextran and galactan, with less pentosan. No chitin has ever been found in this lichen. In testing minute quantities of material for chitin, Wisselingh[762] heated the tissue in potash to 160° C. The potash was then gradually replaced by glycerine and distilled water; the precipitate was placed on a slide and the preparation stained under the microscope by potassium-iodide-iodine and weak sulphuric acid. Chitin, if present, would have been changed by the potash to mycosin which gives a violet colour with the staining solution. It has been stated by Schellenberg[763] that these lichen membranes may become lignified. He obtained a red reaction with phloroglucine test for lignin in _Cetraria islandica_ and _Cladonia furcata_. Further research is required. _c._ CELLULOSE. Several workers claim to have found true cellulose in the cell-walls of the hyphal tissues of a few lichens; but the more careful analyses of Escombe[764], Wisselingh[762] and Wester[765] have disproved their results. The cell-walls of all the gonidia, however, are formed of cellulose, or according to Escombe of glauco-cellulose, except those of _Peltigera_ in which Wester found neither cellulose nor chitin. Czapek[766] suggests that the blue reaction with iodine characteristic of the cell-walls in some apothecia, of the asci and of the hyphae in cortex or medulla in a few instances, may be due to the presence of carbohydrates of the nature of galactose. Moreau[767] in a recent paper terms the substance that gives a blue reaction with iodine at the tips of the asci “amyloid.” In _Peltigera_ the ascus tip is occupied by such a plug of amyloid which at maturity is projected like a cork from the ascus and may be found on the surface of the hymenium. B. CONTENTS AND PRODUCTS OF THE FUNGAL CELLS