230 MANGANESE IN THE LEGUMINOS^ 



although the quantities have not been measured, the follow- 

 ing notes will serve to show their content of this element : — 



Miutoia titilis ... ... ... ... ... Traces 



Cicer arietitint)i ... ... ... ... ••• ,, 



Soja hispida ... ... ... ... ... ,, 



Vigiia Catjang ... ... ... ... ... Appreciable 



Phaseolus helvolus ... ... ... ... ... „ 



Canava/ta ensifoniiis ... ... ... ... „ 



Dolichos Inilbo^iHS ... ... ... ... ... ,> 



Arachis hypogaa ... ... ... ... ... Traces 



Voandzeia ... ... ... ... ... ... Appreciable 



Tephrosia Candida ... ... ... ... ... Traces 



Psophocarpus tetragonohbiis ... ... ... ... Appreciable 



It seems to be absent from the husks, as the majority 

 of our experiments have given negative results. This element 

 no doubt becomes localized in the seed while this latter is 

 maturing. 



According to the experiments already quoted the man- 

 ganese is seen to be dissolved by water and by very weak 

 acid solutions, and this occurs in soils from various localities. 

 Consequently we may conclude that the manganese in our 

 soils is easily assimilable, because, firstly, water and very 

 weak acid solutions are able to abstract it ; and secondly, 

 because plants assimilate it naturally, their ash often con- 

 taining fairly high proportions. It is difficult to specify the 

 states in which manganese is present in soils, as these states 

 are capable of being modified and the metal transformed into 

 soluble or insoluble salts. In certain soils it is possible that 

 the acids formed during the decomposition of organic matters 

 dissolve certain elements, such as manganese, and combine 

 ■with them. 



In the case of soil analyses bv treatment ^^ith aspartic 

 acid it has been noticed that, in many cases, an appreciable 

 quantity of manganese is liberated. This would tend to 

 prove that as this metal, in some states, is so easily attacked 

 by organic acids, no special effort on the part of the plant 

 is required to assimilate it. In such circumstances it may 

 be concluded that this metal has a physiological action on 

 the plant. 



