214 



On Reflex Inhibition of the Knee Flexor. 



followed by inhibitory relaxation. In these respects, therefore, both these 

 sets of afferents conform with that type of afferent whose reflex reactions, as 

 Fr. Frohlich* has pointed out in the frog, are analogous to the reactions given 

 by the nerve of the opening muscle of the arthropod claw. A paradigm of 

 the results may be drawn up thus : — 



Afferent limb -nerve. 



Muscle. 



Intensity of stimulation. 



Weak. 



Intermediate. 



Moderate. 



Strong. 



Contralateral 



Extensor 

 Flexorf 



ExtensorJ 



+ * 



+ 

 + — 





+ 



+ signifies reflex contraction. 

 — signifies reflex relaxation. 

 H — signifies reflex contraction followed during the stimulation by reflex relaxation. 



* Under the circumstances mentioned previously in the text. 



t Sherrington, ' Journ. Physiol.,' 1910, vol. 40, p. 28. 



t Ibid. 



As briefly summarised in the above table it might appear that the sole 

 factor determining whether, in these cases, reflex contraction or reflex 

 inhibition ensued is the intensity of the stimulation. It was shown, 

 however, in the more detailed descriptions supplied earlier in this and the 

 previous paperf that that is really not the case. Another important 

 determining factor appears to be the degree of the intensity of the reflex 

 background at the time when the intercurrent reflex is tested. 



* F. Frohlich, Verworn's ' Zeitschr. f. Allgem. Physiol.,' 1909, vol. 9, p. 55. 

 t Sherrington and Sowton, loc. cit. 



