<276 0N THE IRRITABILITY OF VEGETABLES. 



*' but that the vessels had really lost the faculty of contract- 



" ing and of expelling the sap which they contained." 



Sennebier Sennebier, to account for these phenomena, observes, that 



b U o*wtng to a " electricity stops the passage of the juices in the branches 



destruction of " exposed to its action by the shock which it occasions in 



the organiza- lt ^g^ wn ich may derange their motions, and produce 

 tion : . . - 



f* some change in the juices themselves. However strong 



" the sparks, which suspend the flowing of the juices, I 



" have suspected, that this suspension was produced by the 



" disorganization of the parts of plants which experienced 



" its action, and that the extravasated juices were diffused 



" into the spongy parts, which retained them. I commu- 



«' nicated this suspicion to Van Marum, who answered me, 



" that an electric torrent could not destroy any thing by 



" passing through a less perfect conductor, such as plants 



" are, but especially when it was divided in such a manner 



" that the light of the electric fluid could not be perceived ; 



*' yet I insisted on his recalling to mind, whether he had 



" seen any manifest disorganization in his experiments; and 



*' I desired him to make the experiment, and observe the 



" electrified parts with a magnifying glass." Physiol. 



Vegetal. tomeV, p, 111. 



but this was Agreeably to this request Van Marum repeated the ex- 



not the fact, . ° J . * r 



pertinent, and answered sennebier, that he saw no apparent 



rupture (disorganization) in the organs of the vegetable. 

 Sennebier then confesses, that he regards the experiments 

 of Van Marum as the most favourable argument for the ir- 

 ritability of vegetables, and as the only one against which 

 • he has nothing to oppose. 

 The milky j n setting out with experiments of this kind it is neces- 



pkms^iouheir sa, T to know, that what has been called the sap by both the 

 sap, but ape- authors quoted is now thought to be a peculiar secretion, 

 cuharsecre- D r> Smith, [ n \ } \ s introduction to botany, has placed the 

 milky juice both of the fig and spurge along with the se- 

 creted fluids of plants; and mentions, that Dr. Darwin has 

 shown this fluid, quite distinct from the sap, to be, like ani- 

 mal milk, an emulsion or combination of a watery fluid with 

 oil or resin. 

 If the-vessels . Of whatever nature the juice of the euphorbia is, I do not 

 containing it mean a t present to inquire; for this fluid must be contain- 

 ed 



