The Determination of Copper in Biological Materials.*

Many early workers detected copper in certain plants, but attached no significance to its occurrence. Bucholz (1) and Meissner (2) in 1816 were probably the first definitely to establish the presence of copper in plant life. Sarzeau (3), in 1830, found copper in numerous plants, and since then many workers have reported the occurrence of this element, but most of them, as reviewed by Chevreul (4), have offered no explanation for its presence. More recently other investigators (5, 6) suggested that copper should be placed in the group of catalytic elements found in plants. Maquenne and Demoussey (7) in 1920 noted that copper was found in greater amounts in the more active organs of the plant; e.g., young shoots and leaves. They concluded that copper in some way aided in the vital functions of the plant. McHargue (8) suggests that copper, together with other minor elements, plays an important rBle in life processes. Allison, Bryan, and Hunter (9) report that the additions of copper sulfate to the raw peat soils of the Florida Everglades stimulated the growth of a considerable number of agricultural plants. Whether this stimulation is due to the direct utiliaation of copper by the plant, which would indicate that copper was essential to plant growth, or to some indirect action of the element, remains to be determined. The occurrence of copper in certain animal tissues was also recognized by early workers. Its function in marine organisms has been definitely established and has been reviewed by Rose and Bodansky (10). In the higher forms of animal life the rBle of copper has received little attention,