ELECTRICITY AND LIFE. 157 



action, has been settled by numerous experiments, particu- 

 larly by those of Nobili, Matteucci, and Du Bois-Reymond. 

 To prove the currents of nervous electricity, it is sufficient 

 to prepare a frog's muscle, and touch it at two different 

 points with the two ends of a nerve-filament of the same 

 animal. The muscle then undergoes contraction under the 

 influence of the nervous current. Another experiment, as 

 simple, proves the existence of the muscular current. In 

 an animal living or just killed, a muscle is exposed and 

 cuts made in it perpendicularly to the course of the fleshy 

 fibres, and communication effected by the two wires of a 

 very sensitive galvanoscope between the natural surface of 

 the muscle and the surface made by incision. The needle 

 of the instrument then betrays the passage of a current. 

 This muscular electricity may be obtained in tolerable 

 quantity by placing a number of slices of muscle together 

 in the form of a pile. The positive pole of the system 

 will be the natural surface of one of the terminal slices, 

 and the negative pole the cut surface of the other. Such 

 a battery acts upon galvanic instruments, and can even ex- 

 cite contractions in other muscles. 



Independent of these nervous and muscular electric cur- 

 rents, other sources of this fluid exist in the animal econ- 

 omy. Currents ,are produced between the outer and inner 

 surfaces of the skin, in the blood, in the secreting vessels, 

 in fine, almost throughout the whole organism. The ex- 

 periments, as delicate as original, to which Becquerel has 

 for several years devoted all the activity of his green old 

 age, authorize him now to assert the preponderance of 

 electro-capillary phenomena in animal life. According to 

 this accomplished physicist, two solutions of different na- 

 ture, both conductors of electricity, separated by a mem- 

 brane or a capillary space, compose an electro-chemic cir- 

 cuit ; and, if we reflect on the anatomical elements of the 

 various tissues, cells, tubes, globules, etc., in their connec- 



