PRESENT STATE OF ORG.VNIC ELECTUICITY. 311 



tlirough the liareiichyma, the upper electrode indicating posi- 

 tive, the lower negative electricity. M. liecquerel accounts 

 for the relative electrical conditions of the green parenchyma 

 from the leaves downwards l-»y the removal of oxygen. 



But the observations of ^I. Becquerel on the relative elec- 

 trical conditions of the plant and soil indicate the existence 

 of a descending current passuig from the stem through the 

 roots into the earth, which therefore becomes positive around 

 the plant. 



M. "NVartiiiann, in the notice already (quoted,* states that 

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

 there exist a centml descending current, and a i)eripheral 

 ascending one, which he denominates axial cuiTcnts ; antl that 

 the galvanometer indicates currents from eveiy part of the 

 Ijlant, 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 cm-rents exist in the 

 dicotyledonous plant, in the course of the circulation of its 

 sap, but in an opposite dii'ection to it. 



Currents passin/j front within outwards, and from without 

 imvards in the horizontal section of the Dicotyledonmis 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 layei"s, or into the bark, the needle 

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



gftlvauomcter, tho cum-iit which travi-rsi'S its win-, iiiid which lU-tlect-s the 

 magnetic ueiiUe, is convi-ntioually said to pass from the positive to the nega- 

 tive electrode ; while in tl»e electro-motor portion of tho circuit — e.g. a portion 

 of vegetable structure — tho current is said to jwiss in the opiwsite direction. 

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

 whatever fonu the diHchiirge may take, or whatever part of the circuit »>r 

 current is referri'd to, as much iKwitive force as is then' > v it, I in cm. din < ti.iii. 

 80 much negative force is there exerted in tho otliur. ' 



• Bib. Univ. dc Ooi&tx, tom. xv. p. 30± 



t Loc. cU. p. 44. 



