FLEXOR EEFLEXES 113 



than the knee, and a heavy clip- weight attached to the foot so as to keep the 

 foot out of the way of the thread to the myograph. Knee and hip are placed 

 in fairly full flexion (PI. IX, fig. 7). 



IV. Open wound in left thigh. Lift by its thread the prepared proximal 

 stump of tibial nerve, and arrange it on the bare standard-carried electrodes, 

 assuring complete air insulation. [Place that electrode which is kathodal 

 for the break-shock higher up, i. e. proximal on the nerve-trunk.] [Or, if the 

 sheathed electrodes are used (PI. IX, fig. 7), place the nerve in the split glass 

 tube provided, fixing it into that by jamming the thread attached to distal 

 end of the nerve-stump between the wall of the end outlet of the tube and the 

 rubber cork which fits it. Insert the electrodes provided through the distal 

 of the two side-openings in the glass tube, in such a way that the platinum 

 terminals lie against opposite sides of the nerve-trunk and do not touch the 

 glass. A stitch to adjacent tissue may be required to keep the glass tube 

 carrying the electrodes in position. See that the edge of the glass where the 

 nerve emerges from the tube does not compress or bend the nerve-trunk.] 



V. Bring the operation table to the myograpli table. Tie the thread 

 from the myograph-lever to the thread attached to tibialis anticus tendon. 



The vertical standard carrying the writing-lever rotates and at a certain 

 place its further rotation is checked by a stop at the base of the standard 

 (see text-fig. 37). Rotate the standard up to this check : then place the 

 standard so that the lever-point writes lightly on the drum ; see that the arc 

 described by the lever's writing-point is aligned to the drum-surface and 

 that the point can write lightly but clearly over a good vertical height of the 

 dinim-surface. This position of the lever having been arranged, clamp the 

 base carrying the myograph standard to the table ; the base should not be 

 moved again. Similarly the position of the drum should not be moved again. 

 Arrange that thread from tendon to lever is just taut ; this is best done by shift- 

 ing the operating table or the screw for ' after-loading ' the writing-lever. 

 Then rotate the lever-standard slightly in a direction carrying it away from the 

 check-stop and the writing-point away from the drum-surface ; the thread 

 from tendon to lever will have its tension altered by this, but will return to 

 previous tightness when the standard is rotated back to the stop for the record. 

 Adjust the tightness of the rubber-band resistance of myograph suitably. 

 Set the after-load support so as to just support the lever in this position. 



VI. Rotate the vertical standard carrying the myograph-lever so that the Obs. 83. 

 writing-point does not touch the recording-drum. Screw down the after-load i*roprioceptive 

 stop from under the writing-lever so that the latter is no longer supported by anticus. 



