1888.] 



NATURAL SCIENCES OP PHILADELPHIA. 



159 



sciatic nerves that would have been required to have filled up the 

 space, amounting in the case of the muscle to 2 cent, in length and 

 breadth and 1 mm in thickness, a smaller space was made use of in 

 the case of nerve, namely of 2 cent, in length 1 cent, in breadth and 

 0'5 mm in thickness. It will be observed from the tabulated results 

 given below of the resistance offered by muscle and nerve to the pas- 

 sage of an electrical current, that the resistance varied with the 

 amount of the resistance offered by that of the resistance box. At 

 first sight it might appear that such variations vitiated entirely the 

 result. It must be borne in mind, however, that the polarization due 

 to the passage of the current through the tissue offers a resistance 

 as well as the tissue itself and that this polarization varies with the 

 current, the latter varying in turn according to the resistance box. 

 Such being the case the variations in the resistance offered by the 

 same amount of tissue according as the resistance of the resist- 

 ance box is modified, may be attributed to the polarization set up in 

 the tissue. It may be mentioned incidentally in this connection that 

 in the absence of a round compensator the resistance of muscle, 

 nerve etc. can be determined, though not so conveniently or accurately, 

 by means of that form of resistance box in which the latter is provided 

 with the Wheatstone bridge arrangement as represented in Fig. 6 and 



which was made use of by the authors with the view of comparing the 

 results as obtained by it and by the compensator. After what has 

 been said as to the general theory of determining resistance it will he 



1 Pflugers Archiv. B and V. 



