GALVANISM. 



particularly described, is, for general use, 

 the, most convenient, and in other re- 

 spects, the best battery yet introdu- 

 ced. 



The next thing- to be considered, is the 

 management of the galvanic battery. 

 First, all of the cells of the trough must 

 be filled, within about half an inch of the 

 top, with a liquid, composed of water, 

 with about one twenty-h'fth part of the 

 muriatic or the nitric acid The plates of 

 the trough are shorter than the depth of 

 the trough by about three-fourths of an 

 inch ; so that the trough may be leaned 

 on one side in the filling, for the purpose 

 of letting the liquid run equally into all 

 the cells. 



If a number of troughs are to be con- 

 nected together, the communication must 

 be made by arcs of metal, which are in- 

 serted into the liquid of one cell of each 

 trough, as represented in fig. 1, atC. In 

 making the connection, it is to be observ- 

 ed, that the zinc surface of one trough 

 must correspond with the copper one of 

 another, and the zinc of the latter with 

 copper of a third, and so on. This ar- 

 rangement may be better conceived by 

 placing them in the same order, and 

 to end in such a way, that all the zinc 

 surfaces may face one way, and the 

 copper ones the other. After all the 

 troughs are connected together, let the 

 two unconnected ends, at which the ex- 

 periments are to be made, be as near to- 

 gether as possible. 



A connection being now formed be- 

 tween the two ends, one of which we 

 shall term the zinc end, and the other the 

 copper end, the united energy of the 

 whole will be transmitted through .the 

 connecting medium. 



EXPERIMENTS. 



The most striking and the most com- 

 mon experiments are those which consist 

 in the galvanic energy upon the organs of 

 animals. If two metallic rods, or, what 

 is equally convenient, two silver spoons, 

 be grasped, one in each hand, the skin of 

 the part being previously moistened with 

 a solution of salt, and one of the spoons 

 be brought in contact with one end of the 

 battery, the moment the other comes in 

 contact with the other end of the battery 

 the shock is perceived. Fifty compound 

 plates will give a shock which will be felt 

 in the elbows. One of a hundred will be 

 felt in the shoulders. A greater number 

 of plates give so forcible a shock to the 

 muscles, as to be dreaded a second time. 



VOL. V. 



The shock appears to depend upon the 

 number of plates. The stun, or first im- 

 pression, is much the same, whatever 

 may be the size of the plates; at least, 

 from the size of two inches square to that 

 often ; the surfaces befog as four to one 

 hundred. The effect upon the muscles, 

 as well as upon the cuticle itself, is very 

 different from large plates, when the se- 

 ries is the same. It appears that the 

 shock, or first impression, is as the series, 

 which is also as the intensity of th elec- 

 tricity. If the shock b received from the 

 same number of large plates, the same 

 species or' commotion is produced, in the 

 first instance, as with the small plates ; but 

 if the contact be still kept up, a continua- 

 tion of the effect is perceived, which is 

 felt through the whole arini, producing a 

 vast tremor, attended with a sensation of 

 warmth. If the plates be from eight to 

 twelve inches square, this effect may be 

 perpetually kept, while the acid in the 

 cells is expended. 



Though small plates have been recom- 

 mended for medical purposes, we think 

 large ones will be found more likely to 

 have a good effect. If the medical advan- 

 tage is to be derived from the stimulus of 

 galvanism, the effect of a perpetual and 

 regular current of that stimulus must cer- 

 tainly be preferable to the rapid transmis- 

 sion of a small quantity. 



The galvanic shock may also be conve- 

 niently given, by immersing the hands or 

 the feet into vessels containing a solution 

 of salt, and bringing wires from each end 

 of the battery into the liquid. If any other 

 part of the body is intended to be ope- 

 rated upon, a sponge, moistened with salt 

 water, fastened to a metal plate connect- 

 ed with one end of the battery, may be 

 applied to the part, and the hand or foot 

 put into a vessel of the same liquid, con- 

 nected by a wire with the other end of 

 the battery. Small bits of sponge or 

 bits of leather may be fastened to the 

 end of the connecting wires, and made 

 more or less moist, as the delicacy of the 

 part may require. This contrivance is 

 very useful in operating upon the eyes 

 or ears. 



When galvanism is used medically, it 

 should first be "applied very feebly, and 

 the effect gradually increased, as the sus- 

 ceptibility of the part will admit. If the 

 part has, from disease, become so languid 

 and insusceptible, as not to be sensible of 

 the effect, it should be scarified, or by 

 other means have the cuticle removed. 

 This is sometimes the case with languid 

 tumours, and some cases of paralysis. 



LI 



