116 Mr. K. Sassa and Prof. C. S. Sherrington. Myogram of the 



stage of the grading of reflex response to a single-shock is, with the 

 flexor nauscle, much less extensive in the decerebrate than in the spinal 

 preparation. 



6. To summarise, we find that in the spinal preparation a single break- 



FiG. 5.- — Reflex contraction of tibialis anticus in response to single break-shock stimulus 

 of afferent nerve trunk compared in the decerebrate (top line) and spinal (second 

 and third lines from top) conditions respectively, and with a maximal twitch from 

 motor nerve (bottom line) ; the coil at 12'5 cm. in the top line, and at 15 cm. in 

 third and bottom line ; at 55 cm. in the second line from top. Time in O'Ol". 



shock, whether applied to a bared afferent nerve or to local skin, evokes when 

 the shock is considerably above threshold value a reflex contraction which is 

 both stronger and more prolonged than is the maximal twitch evoked from 

 the motor nerve itself, and that this is so whether or no the muscle retains 

 its own intrinsic proprioceptive reflex arc. This excess of the reflex con- 

 traction over the maximal twitch indicates that summation of successive 

 contraction-waves is present in the reflex contraction. So, further, does the 

 occurrence, not unfrequent, of a more rapid up-gradient of tension develop- 

 ment, despite less abrupt first onset of tension development, in the reflex than 

 in the maximal twitch. In other words repetitive discharge from the reflex 

 centre occurs in response to a single induction shock stimulus applied to an 

 afferent nerve or to local skin connected with that centre. 



It may be that the stimulus applied to the afferent nerve or to the skin sets 

 up a local change which, before it subsides, originates there not merely one 

 but a short series of nerve impulses. We are examining this possibility 

 further. If it be so it is remarkable that the similar stimulus supplied to the 



