394 Dr. C. S. Sherrington. Experiments on the Value of 



on a table near, but not on that on which the kymograph observation 

 was in process. In order to be sure that all was ready, I closed the 

 electric key and touched the vibrator of the inductorium. The harsh 

 rattling noise of the vibrator lasted a few seconds, and I then stopped 

 it by re-opening the key. Turning thereupon toward the arterial 

 record, I was a little disappointed to see that a marked oscillation had 

 suddenly upset the already somewhat undesirably irregular line that 

 had to serve as starting level for the vasomotor reflexes I was wishful 

 to study. It was clear that one would have to wait for greater 

 quietude to re-establish itself again. I waited ; the disturbance of the 

 arterial pressure subsided ; the previous fairly equable cardiac beat, 

 despite somewhat disquiet respiration, returned. A few minutes 

 later I again started, by force of habit, trying the inductorium for 

 a couple of seconds preparatory to proceeding to excite and observe 

 the vasomotor reflexes. Again, on turning toward the trace running 

 on the kymograph, I was met by a sudden disturbance that had 

 altered it. This time it occurred to me that the sudden whirring noise 

 of the magnetic interrupter might have caused the reaction. This 

 supposition I proceeded to test, and soon found that each time the 

 noise was repeated the disturbance of the circulation followed. If the 

 reaction had become less, as it frequently did after a number of repeti- 

 tions, it was only necessary to wait for ten minutes or a quarter of an 

 hour in order to re-obtain it in its original extent. 



I then remembered that in examining the limits of the cutaneous anaes- 

 thesia in this animal from week to week, I had at several times employed 

 the inductorium ; sometimes the electrodes had in making the delimi- 

 tation been applied to points of skin still sentient, and no doubt had 

 there caused sensations of unpleasant quality. The recurrence of the 

 sound to the awakening animal occasioned now emotional anxiety. 

 But in this animal the vasomotor centre cut off" by the spinal section 

 from practically the whole of the rest of the vasomotor mechanism 

 was quite unable to aff'ect the arterial pressure.* Hence that rise of 

 pressure observed by Couty and Charpentierf to occur under emotion 

 of fear was impossible in this case. All the more obvious and un- 

 complicated for that reason appeared the inhibitory action exerted on 

 the heart. The heart that had been beating at the rate of 180 per 

 minute, suddenly fell for twenty seconds to a rate of 54 per minute. 

 The respiratory rhythm was easily seen to be also altered, but no 

 graphic record of the respiratory movement was being employed. A 

 slight elevation of the mean arterial tension immediately preceding the 



* Some description of the spinal reflex and other vasomotor reactions obtained 

 from these animals I hope to give in the ' Journal of Physiology ' ; they are not 

 necessary to the argument here. 



t " Effets cardio-vasculaires des excitations des sens," fig. 4. * Archives de 

 Physiologic normale et pathologique,' 1877, p. 560. 



