580 Ldelligence and Miscetlaneuus Ariicles^ 



course of 1^49-50, which I delivered tb'the Faculty of Scje^cesj pif 

 our Academy, and I have verified them at' different iiitervals .d'uri^^ 

 the summer -wliich has just terminated. 



M. Becquerel has also been engaged since last May in observa- 

 tions analogous to the foregoing (which were not known to him) ; 

 the conclusions he comes to are the following* : — 



There is a production of derived currents in the stems of vege- 

 tables, by the aid of platina needles inserted into the bark and into 

 the wood, directed from the parenchyma to the pitht- ■ •■k 



A production of derived currents proceeding from the cambiuxi(i 

 to the pai-enchyma, and directed, consequently, in an inverse direction 

 to the preceding J. 



The sap, or the liquid in the* cortical parenchyma, kept for some 

 instants in contact with the air, experiences such a modification, that 

 on putting it again in contact with the sap contained in the green 

 part of the parenchyma of the bark, it becomes negative and the 

 other positive §. 



Currents from the pith and the wood to the bark, by the media- 

 tion of the roots. 



These last currents show, that, in the act of vegetation, the earth 

 acquires continually an excess of positive electricity ; the parenchyma 

 of the bark and a part of the wood, an excess of negative electricitj', 

 which is transmitted to the air by means of the vapours of exhaled 

 water. _ i 



The leaves act like the green part of the parenchyma of the bark ; 

 that is to say, the sap which circulates in their tissues is negative 

 with relation to the wood, to the pith, and to the earth, and positive 

 with regard to the cambium. 



The distribution of the ascending sap and the liquid of the cortical 

 parenchyma lends to the belief that currents continually circulate in 

 vegetables from the bark to the pith. 



Chemical actions are the first causes, it cannot be doubted, of the 

 electric effects observed in vegetables. 



The electric eflfects which occur in vegetables are very variousy 

 and it is not possible. as yet to observe more than a small number. . 



The opposite electric states of vegetables and the earth give reason 



* Comptes Rendus, sitting of November 4, 18.50, vol. xxxi. p. (J34. 



t This derivation is effected, not by the galvanometer, but laterally be- 

 tween the parts ]ilace(l in the circuit of the instrument. This is the result 

 indicated in ray fourth conclusion. 



J For these currents to be derived, the cambium (or the organs of its 

 circulation) and the cortical parenchyma would require to be traversed by 

 inverse a.xial currents, which observation does not confirm. 



§ Admitting that, on the contact of the air, the liquid of the denuded 

 part is concentrated by evaporation (or by some phenomenon of oxidation), 

 the fact in question is explained by means of the general jirinciple which I 

 have just cited. It accounts also for the derangement of direction of the 

 lieripherical cuiTcnt which is manifested sometimes when the needles in- 

 serted into the bark, one more deeply than the other, remain there during 

 a certain time. 



