MEDICAL BATTERIES. 



63 



■were not perforated, the flannel wonlcl only be moistened at the edges, and 

 thus a great loss of power would be the result. 



" Copper gauze may be used instead of jjerforated copper plates."* — ' The 

 Qi;arterly Journal of Psychological Medicine and Medical Jru-isprudence/ 

 vol. i. pp. 62, 63.)—//. T.] 



(c). Galvanic chains of Golberger and of Puhermacher. — Of late 

 years the little voltaic instruments known as" galvanic chains have 

 been introduced. They rest on the same i^rinciples as the fore- 

 going; that is, they are formed of a great number of elements 

 having but small surface. 



The first chains of Golberger, which possessed no kind of pro- 

 perty, because the elements that composed them were not disposed 

 in the manner necessary to establish a galvanic current, soon gave 

 origin to the galvanic chains of Fulvermacher (figs. 20 and 21). 



Fig. 20. — Pulvermacher's galvanic chain. Fig. 21. — Another lorm of Pulvermacher's galvanic chain. 



These are admirably combined to produce, in small bulk, galvanic 

 currents of great pliysiological power, with but moderate calorific 

 action. They are arranged in the following manner. Each couple 

 is formed of a zinc wire, rolled in a close spiral, but with its coils 

 not in contact, around a cylinder of wood one-and-a-half or two 

 centimetres in length and five or six millimetres in diameter. 

 These couples are united together by little rings of copper, the 

 copper wire communicating with the zinc, and vice versa, forming 

 chains varying in length according to the intensity that is desired. 

 In this way may be formed batteries of 300 or 400 elements. 

 The chains, having been steeped in vinegar, yield currents, and 

 preserve this property for many hours; although they become 

 much weakened in a very short time. Pulvermacher's chain, which 



These batteries are manufactured by Messrs. Chester, of New York, 



