172 M. M. McCooL 



Leclerc (1872) found small amounts of this element in the various soils 

 that he studied, and recent work has shown that some types of soil contain 

 unusually large quantities. The data for soils from certain sections of 

 Hawaii are particularly significant, as the following table from Kelley 

 (1908), for black soils of the Wahiawa district, indicates: 



Volatile matter. 



MnsOi 



FesOa 



AI2O3 



K2O 



CaO 



P2O5 



Percentage 



17.70 

 9.74 

 19.65 

 15.50 

 0.83 

 1.39 

 0.21 



OCCUREENCE OF MANGANESE IN PLANTS 



The earliest report of the existence of manganese in plants which the 

 TVTiter has been able to obtain is that of Heropath, which Rousset (1909) 

 cites. Heropath found this element in the ash of radish, beet, and 

 carrot. Liebig (1851) reported the presence of manganese in tea. Leclerc 

 (1872) concluded from his analyses that manganese occurs in most species of 

 plants, the percentage being rather high in forest trees. Wolff (1870-1880) 

 also reports analyses which show that manganese is present in the wood, 

 bark, and leaves of various forest trees. Maumene (1884) found that no 

 trace of manganese occurs in the parenchymatous tissue of cabbage 

 leaves, but the veins contain relatively large quantities. 



The analyses of Pichard (1898) likewise reveal a wide distribution of 

 manganese in seed plants. The leaves, actively growing parts, and repro- 

 ductive organs contain the greatest amount. 



THE ROLE OF MANGANESE 



The role of manganese in plant nutrition is not fully understood, but the 

 researches of Bertrand (1897) established the fact that it is important in 

 the action of the oxidases. Bertrand analyzed the ash of the oxidase- 

 containing material obtained from different samples of laccase, and found 

 the percentage of manganese to be rather high. He studied the oxidizing 



