ELECTRICITY AND LIFE. 527 



tricity peculiar to animals, as Galvani declared. It decides also that 

 electricity produced by external causes has an influence over animals, 

 as Volta taught. From profound study of the two orders of phenom- 

 ena, it deduces a system of procedure for the cure of very many 

 maladies by electricity. Consequently, an exposition of the relations 

 between electricity and life must begin with examining the electricity 

 that exists naturally, in the same way that heat does in animals, and 

 then go on to explain the action of the fluid on the organism, whether 

 in a healthy or a morbid state. Such a description will complete what 

 has been written in the Review respecting the relations of life with 

 light and heat relations that we may to-day consider as forming the 

 features of a new science. 



The most authentic witnesses to the existence of animal electricity 

 are fish. The torpedo, the silurus, the gymnotus, the ray, and other 

 fishes, develop spontaneously a more or less considerable quantity of 

 electricity. This fluid, the production of which depends upon the ani- 

 mal's will, is identical with that of common electrical machines ; it 

 gives the like shocks and sparks at a certain tension. The apparatus 

 for its formation consists of a series of small disks of a peculiar sub- 

 stance, kept apart by cells of laminated tissue. Fine nerve-end fibres 

 are scattered over the surface of these disks, and the whole represents 

 a sort of membranous pile, usually placed in the region of the head, 

 sometimes toward the tail. 



These fishes are the only animals provided with an appai-atus spe- 

 cially devoted to the production of electricity ; but all animals are elec- 

 tric, in this sense, that a certain quantity of that fluid is constantly 

 forming within their organs. The existence of electricity peculiar to 

 the nerves and muscles, and independent of their special modes of ac- 

 tion, has been settled by numerous experiments, particularly by those 

 of Nobili, Matteucci, and Dubois-Reymond. To prove the currents 

 of nervous electricity, it is sufficient to prepai-e 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 in- 

 strument then betrays the passage of a current. This muscular elec- 

 tricity 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 



