PRESENT STATE OF ORGANIC ELECTRICITY. 311 



through the parenchyma, the upper electrode indicating posi- 

 tive, the lower negative electricity. M. Becquerel accounts 

 for the relative electrical conditions of the green parenchyma 

 from the leaves downwards by the removal of oxygen. 



But the observations of M. Becquerel on the relative elec- 

 trical conditions of the plant and soil indicate the existence 

 of a descending current passing from the stem through the 

 roots into the earth, which therefore becomes positive around 

 the plant. 



M. Wartmann, in the notice already quoted,* states that 

 in the roots, the stem, the branches, the petioles, and peduncles, 

 there exist a central descending current, and a peripheral 

 ascending one, which he denominates axial currents ; and that 

 the galvanometer indicates currents from every part of the 

 plant, aerial or subterranean, to the soil, which is thus positive 

 in relation to the plant. 



From these observations of Becquerel and Wartmann, little 

 doubt can be entertained that electrical currents exist in the 

 dicotyledonous plant, in the course of the circulation of its 

 sap, but in an opposite direction to it. 



Currents passing from within outwards, and from without 

 inwards in the horizontal section of the Dicotyledonous Plant. 

 According to Becquerel,t if one electrode be inserted into the 

 pith, in a clean horizontal section of a young poplar, and the 

 other into one of the woody layers, or into the bark, the needle 

 is deflected 5, 10, 15, or more, according to the delicacy of 



galvanometer, the current which traverses its wire, and which deflects the 

 magnetic needle, is conventionally said to pass from the positive to the nega- 

 tive electrode ; while in the electro-motor portion of the circuit e.g. a portion 

 of vegetable structure the current is said to pass in the opposite direction. 

 But "there is never one current of force, .or one fluid only." " In a current, 

 whatever form the discharge may take, or whatever part of the circuit or 

 current is referred to, as much positive force as is there exerted in one direction, 

 so much negative force is there exerted in the other." 



* Bib. Univ. de Geneve, torn. xv. p. 302. 



t Loc. at. p. 44. 



