Intelligence and Miscellaneous Articles. 579 



toward the superior and inferior faces. In numerous Cactuses, it 

 is from the neighbouring parts toward the centre of the eye. 



6. The currents are feeble in flowers, and in the buds during 

 winter, whilst they are very marked in succulent fruits and in several 

 species of grain. 



7. In fruits, the direction of the axial currents varies with the 

 species. The lateral currents proceed, in the greater number of 

 cases, from the superficial jjarts to the subjacent organs. 



8. Mushrooms exhibit in general two feeble currents ; one directed 

 from the cap to the base of the stipes, the other laterally from the 

 centre to the periphery. 



9. A similar lateral current occurs in tubers. 



10. The strength of these different currents depends on that of 

 the vegetation, and the abundance of sap which bathes the parts of 

 the plant under examination. It is in general greater in spring than 

 at any other period. 



1 1 . When the soil and any part of a plant, visible or underground, 

 is placed in the circuit of the rheometer, we find a current directed 

 from the plant to the soil, which is thus positive with relation to it. 



12. The superficial layers of the soil are frequently positive rela- 

 tively to those which surround the spongioles. 



13. Currents are manifested also when two distinct plants are 

 placed in the circuit of the rheometer, either by inserting an unoxi- 

 dable needle into each of them and connecting by a platina wire the 

 earth with the different vessels in which they vegetate, or by making 

 a communication between the plants by means of the wire, and pla- 

 cing in the mould the terminal needles of the apparatus. 



14. The galvanometric deviations obtained by inserting platina 

 needles into the vegetable organs are often very considerable; but they 

 diminish with rapidity, and in the end generally become almost null. 

 They result first from an electro-chemical action between the liquid 

 substances brought into contact by the tearing of the tissues. The 

 weak residual current (which is the normal cuiTcnt) owes its origin 

 to the interposition of the porous vegetable walls between juices of 

 different concentration, and proceeds through them from the densest 

 to the least dense liquid. 



15. The vegetable currents form very probably closed circuits. 

 The radical extremities of one part, and the foliaceous terminations 

 of the other, establish the continuity of the perijiheric ascending 

 current with the central descending one. The similarity of the lateral 

 electric state of the wood and the external part of the bark results 

 perhaj)s from an action of the medullary rays, which convey to the 

 surface a part of the ascending sap, and thus dilute the external 

 descending juices. 



16. The electric state of the soil, and probably also the exhalation 

 which takes place by the organs furnished with stomata, influence 

 the electricity of the ambient atmospheric strata. 



Tlie majority of these proj)ositions were announced in a memoir 

 read to the Soci^te de Physique, at its general sitting of the '20th of 

 December 1849. 'I'hey have been publicly reproduced in the winter 



