MANIFESTATIONS OF ELECTRICITY. 433 



uscle, as to receive the influence of this current. And a much more 

 werful current is produced, when the muscle is thrown, by a stimu- 

 us applied to its own nerve, into a state of energetic contraction. The 

 explanation of the constant direction of the current, from the interior 

 towards the exterior of the muscle, seems to be, that the changes con- 

 nected with the nutrition and disintegration of the muscular tissue go 

 on more energetically in its interior, than they do nearer its surface, 

 where the proper muscular fibres are mingled with a large proportion 

 of areolar and tendinous substance. 



776. It was observed by Galvani that there exists in the Frog, 

 during its whole life, a continual current of Electricity passing from 

 its extremities towards its head; and as no such current has been detect- 

 ed in any other animal, it has been termed the courant propre, or pe- 

 culiar current, of the Frog. It bears this curious analogy to the elec- 

 tric discharges of Fishes, that it is not manifested if the connexion be 

 made between corresponding points of the opposite sides, but that it 

 shows itself when the communication is made between points higher or 

 lower in the body, whether on the same or on opposite sides. There 

 now seems reason to believe, however, from the observations of Mat- 

 teucci, that this " proper current of the frog" is but a special case of the 

 ordinary muscular current, depending upon the peculiar arrangement of 

 the muscular and tendinous elements in this animal. Both currents are 

 alike influenced by agents which affect the vitality of the muscle ; and 

 it is curious that poisoning with sulphuretted hydrogen should almost 

 immediately put an end to each, although ordinary narcotic poisons 

 have very little influence. 



777. Manifestations of Electricity may be produced, in most animals 

 having a soft fur, by rubbing the surface, especially in dry weather ; 

 this is a fact sufficiently well known in regard to the domestic Cat. 

 Some individuals of the Human race exhibit spontaneous manifestations 

 of electricity, which are occasionally of very remarkable power. There 

 are persons, for instance, who scarcely ever pull off articles of dress 

 that have been worn next their skin, without sparks and a crackling 

 noise being produced, especially in dry weather. This is partly due, 

 however, to the friction of these materials with the surface, and with 

 each other. But the case of a lady has been recently put on record, 

 who was for many months in an electric state so different from that of 

 surounding bodies, that, whenever she was but slightly insulated by a 

 carpet or othir feebly-conducting medium, sparks passed between her 

 person and any object which she approached. When she was most 

 favourably circumstanced, four sparks per minute would pass between 

 her finger and the brass ball of a stove, at a distance of 1 J inch. Va- 

 rious experiments were tried, with the view of ascertaining if the Elec- 

 tricity was produced by the friction of articles of dress ; but no change 

 in these seemed to modify its intensity. From the pain which accom- 

 panied the passage of the sparks, this condition was a source of much 

 discomfort to the subject of it. 



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