OF ELECTRICITY AS A CONDITION OF VITAL ACTIVITY. 95 



effects of even the feeblest current are equally obvious. The agency of 

 Electricity in producing Chemical change is the more powerful, in pro- 

 portion as there is already a predisposition to that change ; thus, the 

 largest collection of oxygen and hydrogen gases, or of hydrogen and 

 chlorine, mingled together, may be caused to unite by the minutest elec- 

 tric spark, which brings into the condition required for their active 

 exercise, the mutual affinities that were previously dormant. Hence it 

 cannot but be inferred, that its agency in the Chemical phenomena of 

 living bodies must be of an important character : but this may probably 

 be exerted rather in the way of aiding decomposition, than of producing 

 new combinations, to which (as we have seen) Light appears to be the 

 most effectual stimulus. Thus it has been shown that pieces of meat, 

 that have been electrified for some hours, pass much more rapidly into 

 decomposition, than similar pieces placed under the same circumstances, 

 but not electrified. And in like manner, the bodies of animals that have 

 been killed by electric shocks, have been observed to putrefy much more 

 readily than those of similar animals killed by an injury to the brain. 

 It is well known, moreover, that in thundery weather, in which the 

 electric state of the atmosphere is much disturbed, various fluids con- 

 taining organic compounds, such as milk, broth, &c., are peculiarly dis- 

 posed to turn sour ; and that saccharine fluids, such as the wort of brewers, 

 are extremely apt to pass into the acetous fermentation. 



143. The actual amount of influence, however, which Electricity exerts 

 over a growing Plant pr Animal, can scarcely be estimated, it would, 

 perhaps, be the most correct to say, that the state of Electric equilibrium 

 is that which is generally most favourable ; and we find that there is a 

 provision in the structure of most living beings, for maintaining such an 

 equilibrium, not only between the different parts of their own bodies, 

 but also between their own fabrics and the surrounding medium. Thus 

 a charge given to any part of a Plant or Animal, is immediately diffused 

 through its whole mass ; and though Organized bodies are not sufficiently 

 good conductors to transmit very powerful shocks without being them- 

 selves affected, yet a discharge of any moderate quantity may be effected 

 through them, without any permanent injury, and this more especially 

 if it be made to take place slowly. Now the points on the surfaces of 

 Plants appear particularly adapted to effect this transmission ; thus it 

 has been found that a Ley den jar might be discharged by holding a blade 

 of grass near it, in one third of the time required to produce the same 

 effect by means of a metallic point ; and an Electroscope furnished with 

 Vegetable points has been found to give more delicate indications of the 

 electric state of the atmosphere, than any other. Plants designed for 

 a rapid growth have generally a strong pubescence or downy covering ; 

 and it does not seem improbable that one purpose of this may be, to 

 maintain that equilibrium between themselves and the atmosphere, which 

 would otherwise be disturbed by the various operations of vegetation, 

 and especially by the process of evaporation, which takes place with 

 such activity from the surface of the leaves. 



144. There appears to be sufficient evidence that, during a highly 

 electrical state of the atmosphere, the growth of the young shoots of 

 certain plants is increased in rapidity ; but it would be wrong thence to 



