ELECTRO-PHYSIOLOGY. 585 



connected. This forms part of the experimental circuit through 

 which a portion of the battery current is to be conducted. This cur- 

 rent is completed through a wire attached to a rider which slides 

 along the rheocord wire. The other portion of the current goes 

 through unpolarizable electrodes to a nerve lying across them. The 

 amount of current passing through the nerve varies directly with the 

 resistance of the deriving circuit, the rheocord. By increasing this 

 resistance more current is sent through the nerve, and on diminish- 

 ing, less. 



Fig. 220. Schema of Apparatus to Study Influence of Rapid 

 Variations of the Constant Current by the Rheonome of von FleischL 

 (LAHOUSSE.) 



P, Daniell cells. E, Key. A, B, Two pieces of zinc to which the wires are 

 attached. C, D, These two points are united by wires to the muscle M. 



Suppose, for example, that the resistance of the electrode and 

 ve is 100,000 ohms and the resistance of the rheocord 5 ' ohms, 

 100,000 5 



- n 7i AAK ^ the current passes through the rheocord and "T^TTTr/T^ 

 J-UU.uUo J.U\Jv/UO 



through the nerve. 



Rheonome of Von Fleischl. The rheonome of Von Feischl con- 



*ts of an ebonite plate with a circular groove on its upper surface. 

 is groove is connected at diametrically opposite points to the bind- 

 ing-screws. In the center of the ebonite plate is a vertical rod whose 

 >per extremity articulates with a piece of ebonite, which is mov- 

 e and has on its two surfaces two plates of zinc, which are curved 

 an archlike form. Their upper extremities are united to the bind- 



