48 Mr. W. A. Jolly. Reflex Times in the 



but at summer temperatures the rhythm is one of at least 30 per second. 

 This author considers that these waves are of central origin. 



Fig. 6. — Electrical variation evoked i-eflexly from the muscles of the hind-limb of the 

 decerebrate frog by mechanical stimulation of the homonymous toes. The curve 

 shows waves occurring before stimulation at a rate of 54 per second. Eoom tempera- 

 ture. 19° C. Time marker and signal as in figs. 2 and 3. 



The reflex responses to stimulation exhibit, in addition to waves of similar 

 rate to the foregoing, other waves of greater rate, which occur especially at 

 the commencement of the electrical charge. Tig. 7 is an example of this. 

 The initial waves have here a rate of 206 per second, at a room temperature 

 of 20°. Other rates observed are 277 at 21-8° 145 at 23°, 137 at 16°, and 

 128 at 21°. We are remmded of the two varieties of oscillations described 

 by Miss Buchanan (9) in strychnine tetanus as waves and wavelets, but the 

 rapid initial oscillations shown here are of much greater rate than these 

 wavelets, which occur at a rate of 40 to 100 per second, and which Miss 

 Buchanan regards as of peripheral muscular origin. A muscular rhythm so 

 high as 277 per second has, so far as 1 know, never been suggested, even for 

 the muscles of warm-blooded animals, and we must look for some explana- 

 tion other than peripheral muscular rhythm. The wicks of the electrodes 

 are placed in these experiments round the thigh and knee, so that the action 

 currents of various muscles which take part in the flexion reflex can show 

 themselves in the electrical response. 



I have been struck, in studying the oscillations of the higher rate which 

 appear in the reflex response of the decerebrate frog, with the similarity of 

 the intervals between the deflections and the period which we have seen 

 reason to believe represents the delay at a synapse. Thus, in Experiment 

 fig. 7, the intervals between the rapid deflections at the beginning of the 

 curve are 4-3 o- and 4cr. In another experiment the interval is 3-6 o-, while 

 the average of the periods in the other cases above mentioned is 7-3 <r, the 

 double of the delay at a synapse. If this is more than a coincidence, it 



