40 Voltaic Induction. 



shock is not at all in proportion to the intensity of the current ; for 

 the second arrangement which affected the galvanometer to the ex- 

 tent of 70°, gave scarcely any sensation to the tongue ; whereas that 

 in, fig. 6, hardly moved the needle of the galvanic multiplier and yet 

 occasioned shocks as disagreeable as those produced by an active 

 galvanic battery of fifty plates, four inches square. I do not think 

 that the distinctions of intensity and quantity will solve the difficulty ; 

 for, if the want of action upon the galvanometer and the power of 

 giving shocks, be owing to the passage of a fluid, great in quantity 

 but of weak intensity, then we should expect to find common elec- 

 tricity in circulation, and this was my own opinion when I first noti- 

 ced the phenomenon, but the gold leaf electrometer was not in the 

 slightest degree affected by the arrangement of fig. 6. It is nothing 

 unusual to have shocks following the sudden interruption and renew- 

 al of common or voltaic electricity, but, in all such cases, the preex- 

 isting forces are powerful and proportionate to the effect. Upon a late 

 occasion, while performing the usual galvanic experiments upon an 

 executed criminal, I had an excellent opportunity of proving this fact 

 in relation to muscular action. The prostrate arm, by the first im- 

 pulse, suddenly became elevated, but fell down as rapidly although 

 still under the full influence of the uninterrupted current; yet, when, 

 by quickly tapping the circuit wire against an extreme plate of the 

 battery, a succession of impulses was created, the lifeless arm pre- 

 served, vigorously, its upright posture. It is probable, therefore, 

 that the nervous fluid, supposing it the same as the voltaic, occasions 

 muscular action less by quantity or intensity than by the distinct rep- 

 etition of its impulses, the rapidity of which must be inconceiva- 

 bly great even during its ordinary action, but infinitely more so when 

 it sustains those tremendous convulsive efforts which characterize 

 Opisthotonos and other tetanic diseases. Another physiological con- 

 clusion suggests itself, as more akin to our subject, and which might 

 almost induce one to become a convert to the doctrine of animal 

 magnetism. It has been fully proved by Dr. Davy and others, that 

 the voltaic current, generated by those animals which possess the 

 power of giving shocks, is constantly accompanied by the transverse 

 magnetic forces. If, therefore, the nervous power which occasions 

 ordinary muscular motion and the different operations of secretion, 

 be considered the same as the voltaic, it would follow, that every 

 nerve possess a tangential magnetic force j and, further, that, upon 

 the supposition that an uniform current proceeds from the brain down 



