344 Mr Carpenter on the Differences of the Laws 



tlon of electric action. The seed may indeed be considered an 

 electro-negative system, retaining the bases and rejecting the 

 acids ; and it has been accordingly found that grains applied 

 to the negative extremity of a voltaic pile, germinate much 

 more rapidly than those uninfluenced ; and that positive elec- 

 trical influence retards the process. In like manner slightly 

 alkaline solutions accelerate, and acids delay or altogether 

 check it. In the later periods of vegetable growth, the con- 

 temporaneous chemical changes are by no means uniform in 

 character ; and it is probably from this cause that artificial 

 currents of electricity do not seem to assist the growth of 

 plants, although atmospheric electricity, which is undoubted- 

 ly much connected with the processes of vegetation, appears to 

 accelerate it. That there is constant electric disturbances du- 

 ring the growth of plants, has been fully proved by the expe- 

 riments of Pouillet ; and by many writers, the changes pro- 

 duced by the exhalation of fluid, and the gaseous alterations 

 eff^ected by the leaves, are believed to be the main source of the 

 constant variations in the electric state of the atmosphere. 



The connection of capillarity with electric action has been 

 already noticed ; but some other facts may be briefly stated. 

 Various substances having minute porous structure, possess the 

 power of occasioning the union of oxygen and hydrogen at 

 comparatively low degrees of heat ; thus spongy platinum will 

 produce this effect at common temperatures, and charcoal or 

 porcelain biscuit at about 300°. It does not seem very clear 

 to what this power is to be attributed ; and we are almost 

 equally in the dark regarding the phenomena of endosmose, in 

 which electricity would appear to have some share, the known 

 laws of capillary action not being adequate to explain some of 

 the recently observed facts.* 



Many facts corresponding with those to which we just now 

 alluded as having been obtained with regard to the electrical 

 state of different organs of animals, have been remarked in ve- 

 getables also. Thus it has been ascertained that wires passed 

 into the pith and applied to the bark indicated opposite elec- 

 trical states ; and the same is true of the two extremities of 



• Cyclopedia of Anatomy, p. 110. 



