474 DR T. R. FRASER ON SOME UNDESCRIBED TETANIC SYMPTOMS 



I performed the following experiment to ascertain how far the mere division 

 of the cord affects reflex excitability. 



Experiment LV. — In a healthy male frog the reflex excitability was tested in 

 various ways, and found to be normal. The spinal cord was then divided imme- 

 diately below the brachial enlargement, with the loss of only one or two drops of 

 blood. Except that some general quivering occurred at the time of the division, 

 and for a few minutes afterwards, the frog remained quietly in a normal posture, 

 and showed no symptoms of exaggerated reflex activity until the second day. 



On the second day — at twenty-one hours after the division of the cord — 

 slight stimulation of an ankle was followed by a series of feeble twitches of 

 various muscles in both legs, lasting for three seconds. These twitches were 

 so slight that they caused no movements of either posterior extremity, and during 

 their occurrence both posterior extremities remained normally flexed. Similar 

 series of twitches were produced other three times by stimulating each ankle 

 alternately at intervals of a minute ; but when the same stimulation was repeated 

 for the fifth time, no effect whatever followed. 



On the third day, the posture of the frog was still perfectly normal ; but stimu- 

 lation of an ankle excited merely a feeble twitch in both posterior extremities. 



On the fourth and fifth days, stimulation of a more energetic character was 

 required to excite similar feeble twitches in the posterior extremities ; but such 

 series of twitches as appeared on the second day could not be caused by even 

 powerful excitation. 



The experiment was now terminated. 



It is therefore apparent that, in Experiments XLIX., L., and LI., the tetanic 

 symptoms that were present in the posterior extremities after division of the 

 spinal cord were not caused by the division. 



We have thus obtained most satisfactory evidence in favour of the con- 

 clusion that these convulsive symptoms are due to a direct action of atropia on 

 the spinal cord. 



Moreover, the results of some further experiments made to test this conclusion 

 are entirely confirmatory thereof. Two of these may be briefly described. 



Experiment LVI. — Immediately after dividing the left sciatic nerve in the 

 thigh of a frog, weighing 360 grains, I injected a solution of seven-twentieths of 

 a grain of sulphate of atropia, in four minims of distilled water, under the skin 

 of the right fl ank. 



On the third day, the frog was lying on the abdomen, with the anterior 

 extremities rigidly arched, with the right posterior extremity stiffly extended, 

 and with the left posterior extremity flexed and somewhat flaccid. A touch 

 anywhere, except in the left posterior extremity below the middle of the thigh, 

 excited a violent tetanic convulsion, in which the left leg took no part. Galvanic 

 stimulation, when applied to the cut end of the distal portion of the left sciatic 



