in vegetable Structures. 241 



de rupture d'equilibre des fluides : on observe surtout ces 

 phenomenes dans la capucine et dans \efra.vinelle." (p. 73.) 



Capucine, it appears, is the French name of the common 

 garden nasturtium (Tropae\>lum majus Lin.), of the electrical 

 properties of which I must confess my entire ignorance. The 

 Jt-axinelle, or Dictamnus albus, is stated, by other authors be- 

 sides those above referred to, to evolve free electricity. I am 

 not acquainted with any facts in support of this opinion, or 

 with any experiments which appear to countenance it; al- 

 though I think that the following observation of Professor 

 Lestiboudois will assist in throwing some light on this sup- 

 posed property of the Dictamnus, and serve, in some man- 

 ner, to explain the circumstance to which the opinion of its 

 electric properties is indebted for its origin : — " Dans les 

 temps chauds, la fleur (de la fraxinelle) repand une vapci/r 

 inflammable en si grande abondance, que si on en approche le 

 soir une bougie allumee, il paroit une Jlamme qui ne Vendom- 

 mage point?' (Botanog. Belgique, t. ii. p. 140.) 



To turn from this vague and unsatisfactory part of my 

 subject to one far more interesting, I would refer to some 

 experiments of an exceedingly talented philosopher, Dr. 

 Donne, who has devoted some time to the detection of elec- 

 tric currents in organic tissues, and has succeeded in de- 

 monstrating their existence in both animal and vegetable 

 structures. These currents are exceedingly feeble, and, of 

 course, of very low tension, as must necessarily be the case ; 

 for, if of considerable intensity, it is evident that they could 

 not be insulated by organic tissues, especially when moistened 

 by their proper juices; but would escape, as soon as formed, 

 to the earth, through the stem, which is always a sufficiently 

 good conductor for this purpose. This circumstance, I may 

 observe, en passa?it, militates most strongly against the pro- 

 bability of living vegetable tissues ever (unless by artificial 

 means) becoming so charged with electric matter as to afford 

 a spark, as stated by Babinet and Bailly. 



M. Donne inserted two pieces of platinum wire, connected 

 with a very delicate galvanometer, into different kinds of 

 fruits, one wire being always inserted near the apex, and the 

 other near the base, of the fruit : a deviation of the magnetic 

 needle always ensued, in different degrees, according to the 

 kind of fruit; sometimes even extending to 30°. In apples 

 and pears, the current of electricity appeared to be directed 

 from the base to the apex of the fruit ; whilst in peaches, apri- 

 cots, and plums, the current assumed an inverse direction. 

 No current whatever could be detected when the platinum 

 wires were plunged into the fruit at equal distance from the 



Vol. I. — No. 5. n.s. t 



