Electricity and Galvanism. 249 



to the great nervous centres. Thus becoming charged, the brain is 

 supposed to excite the action of any organ, by giving a spark to the 

 nerve supplying it. The electricity thus transmitted to the muscles 

 forms around their fibres a kind of atmosphere. Becoming similarly 

 electrified, the fibres repel each other, separately in the middle of the 

 muscle, and thus by approximating their ends cause the structure to 

 contract. This very pretty theory has unfortunately no support 

 beyond the fertile imagination of its ingenious author. 



Sir John Herschel, in his exquisite Discourse on the Study of 

 Natural Philosophy, has beautifully expressed the possible relation 

 between galvanic electricity and the vis nervosa, and hints at the 

 brain being either the organ of secretion, or at least of the applica- 

 tion of this agent ; adducing in illustration the dry piles, as they are 

 termed, of De Luc and Zamboni, and remarks, that " if the brain be 

 an electric pile constantly in action, it may be conceived to discharge 

 itself at regular intervals, when the tension of the electricity reaches 

 a certain point, along the nerves which communicate with the heart, 

 and thus to excite the pulsation of that organ." By the " dry pile" 

 a ball may be kept in motion for many years, without any obvious 

 waste of power, and some analogous arrangement would constitute 

 the most constant and economic primum mobile of a moving organ 

 which the resources of limited human reason can suggest. Dr. 

 Arnott has also hinted at some such cause being the active agent 

 which keeps up the regular pulsations of the heart. 



It is indeed remarkable what an enormous quantity of electricity 

 of high tension is developed by the piles here alluded to. I have 

 one before me consisting of 1200 alternations, made by superposing 

 400 pieces of paper covered on one side with tin foil, and on the 

 other with black oxide of manganese. The upper end of this is 

 always charged with negative and the lower with positive electricity ; 

 and this little apparatus will for many years remain a constant source 

 of free electricity. 



Founded on the general law that bodies similarly electrified repel 

 each other, an hypothesis has been broached that the circulation in 

 the capillaries was greatly aided by the electric state of the blood. 

 It has been long known that if a vessel containing water, having a 

 very small hole in its base, be connected with the prime conductor of 



1 K 



