174 CUEBENT ELECTRICITY CHAP. XII. §. m. 



action, and also those circumstances which are likely 

 to influence the normal result, before drawing our 

 final conclusions. 



From these results we may deduce the following 

 conclusions : 



1st, That when the electrodes of a galvanometer 

 are brought into contact, one with the external 

 surface of the spongioles of a plant, and the other 

 with the sap ascending from the roots, the sap and 

 the external surface are in opposite electric states: 

 and, 2dly, That the eflfeets which are observed virith 

 the galvanometer may, in the majority of instances, 

 be due to ordinary electro-chemical actions, but that, 

 in some instances, the effect cannot be referred to 

 these actions, but may be referred to the organic 

 changes which occur in the fluids in the roots 

 during vegetation. 



Sect. III. On the Mardfestation of Electric Currents 

 in the Petals of Flowers during Vegetation. 



According to Wabtmaiw", " the currents are 

 feeble in flowers." 



Circuits were formed between the surfaces of the 

 petals and the sap from the peduncles, in the follow- 

 ing plants : Geraniums, various ; nasturtium ; bal- 

 sams, single and double; fiichsia; hollyhock; con- 

 volvulus; vegetable marrow; and cucumber. The 

 effects obtained were but slight, and in many in- 

 stances null. Whenever the effects were obtained, 



" Loc. cit. 



