436 Prof. C. 8. Sherrington and Miss S. C. M. Sowton. [| Dec. 30, 
BL co hee Ne AN ee SEN EE Ce a ae Ee ae) eae Ce 
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59 
(x4) 
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Fig. 2. 
1.—Isolated Vasto-crureus Muscle ; decerebrate preparation. Galvanic current 
(strong, ascending), applied to ipsilateral afferent (popliteal) nerve ; electrodes non- 
polarisable. Time above in seconds; signal below. Descent of the myogram line 
means relaxation ; ascent means contraction. The make of the current evokes a 
marked inhibitory relaxation of the muscle; this is followed by a rebound with 
heightened tonus during the passage of the current. The current is then cut off, and 
the break excites a second marked inhibitory relaxation of the muscle. 
2.—Isolated Vasto-crureus Muscle ; decerebrate preparation. Ascent of the 
myogram line means contraction of the muscle ; descent means inhibitory relaxation. 
Time above in seconds; signal below. During the period marked by the downward 
notch in the signal line a series of brief galvanic currents, each lasting 0°04 second 
and succeeding each other at the rate of 12 per second, were delivered in the 
ascending direction through the central stump of the severed ipsilateral popliteal 
nerve. Both records are from the same experiment with only a few minutes’ 
interval between them. The strength of current was quite weak in the left-hand 
record (5 cm. divisions of 60 cm. platinum-iridium wire rheochord used as a 
potentiometer), and was quite strong in the right-hand record (59 cm. divisions of 
the rheocord similarly used). The weak stimulus evokes reflex contraction ; the 
stronger stimulus reflex inhibition. 
