Maumené (1884) tested many food plants and concluded that some quantity of manganese is frequently present in potato, rice, barley, carrot, lentil, pea, beetroot, asparagus, chicory, most fruits, tea, and also in some fodder plants, as lucerne, oats, and sainfoin. Ricciardi (1889), Hattensaur (1891) also added to the list of plants proved to contain manganese. Guerin (1897) studied the manganese content of woody tissues. Sawdust was treated with distilled water containing 1% caustic potash, expressed, and filtered after two or three days. A brown coloured liquid was obtained, which when treated with a slight excess of hydrochloric acid gave an abundant flocculent precipitate. This precipitate proved to be soluble in pure water, so it was washed with slightly acidulated distilled water, and after further purification was analysed. No trace of iron was obtained, but about ·402% Mn was found. Guerin regarded the precipitate as a “nucleinic” combination, which he supposed to occur generally in wood and to contain the manganese present in the woody tissues of all plants. Schlagdenhauffen and Reeb (1904) detected manganese in a petrol extract of such cereals as barley, oats, and maize, and since inorganic salts of manganese are not soluble in such liquids as ether or petrol they concluded that the manganese must be present in the plant in organic combination, thereby upholding Guerin’s view. Loew and Seiroku Honda (1904) give a table of Mn₃O₄ in the ashes of certain trees. This is very high in some cases, rising to 11·25% in the ash of beech leaves, 6·73% in birch leaves, and 5·48% in chestnut fruits. Gössl (1905) gives lists of the distribution of manganese in plants, both Thallophytes and Phanerogams, indicating the presence of much or little of the element. As a rule, he states, marsh and water plants gather up more manganese than do land plants. The Gymnosperms seem to be particularly rich in their manganese content. Schröder (1878) tested for the element in firs and pines and found the following amounts of Mn₃O₄. In 100 parts ash. In 1000 parts dry matter. Fir Pine Fir Pine 33·18 13·46 2·76 ·77 He gave a table of detailed analyses showing the differing proportions of manganese in the different parts of the fir.