WITH NERVOUS INFLUENCE. 27 



meter (an instrument adapted for the detection of slight currents 

 of electricity) amounting to fifteen or twenty degrees, when 

 the liver and stomach of a rabbit were connected with the 

 ends of a galvanometer ; an action, which was not due to the 

 different chemical properties of the secretions, for it ceased 

 with death ; and more recently, Professor Zantideschi and 

 Dr. Favio assert that, in all warm-blooded animals there are 

 two Electro- Vital or Neuro-Electric currents; one external 

 or cutaneous, which directs itself from the extremities to the 

 cerebro-spinal axis, and the other, internal, going from the 

 cerebro-spinal axis to the internal organs. These currents grow 

 weaker in proportion as life ceases, or as pain is felt ; while the 

 convulsive or voluntary movements give a strong current, or 

 increase the discharge. 



Many other experiments which tend to confirm the identity 

 of nervous force and electricity may be cited. Dr. Prevost, of 

 Geneva, has succeeded in magnetizing very delicate soft iron 

 needles by placing them near the nerves, and it is a well known 

 fact that this property is communicated to soft iron or steel, by 

 a current of electricity transmitted at right angles to it. Vaus- 

 seur and Berandi have likewise succeeded in rendering needles 

 magnetic, by passing them through the nerve of a living animal, 

 while division of the cord, they say, destroys this property, but 

 the inhalation of oxygen increases it. M. David also reports 

 that he has seen a galvanometer deflected when its poles were 

 inserted into the bared nerve of an animal, and it was made to 

 move, and that there was no motion when the spinal cord was 

 divided. 



But supposing that we had never yet detected a current of 

 electricity traversing the nerves during functional activity, we 

 are not therefore to conclude that there is no traverse of an 

 electric current. We should bear in mind the great effects which 

 our weakest, and otherwise almost inappreciable currents, are 

 capable of producing on the living muscle ; and to detect a cur- 

 rent of as weak tension as must be that of the nerves, we ought 

 to possess galvanometers as delicate as living muscle. Matteucci, 

 indeed, has lately made use of this, and the result is perfectly 

 B 2 



