704 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



was still present, except that on the third day, the rate of the heart's contractions 

 had diminished to thirty-six in the minute. Death, with commencing rigidity, 

 occurred on the fourth day. 



The dose given in this experiment was greatly above the minimum fatal. "We 

 shall now describe the effects of a dose that was considerably below the minimum 

 fatal. 



Experiment XXXVIII. — The blood-vessels at the upper third of the right 

 thigh were ligatured in a frog, weighing 379 grains, and immediately afterwards 

 a solution of one-twentieth of a grain of sulphate of methyl-atropium, in four 

 minims of distilled water, was injected under the skin at the left flank. In three 

 minutes, the respiration had ceased, and the frog was lying on the abdomen, 

 perfectly flaccid and motionless in the poisoned region ; but retaining the normal 

 tone in the non-poisoned posterior extremity, where spontaneous vigorous move- 

 ments frequently occurred. Irritation of the skin of any region did not cause any 

 movement in the poisoned region, but it caused energetic contractions in the 

 non-poisoned. In ten minutes, the left (poisoned) sciatic nerve was subjected to 

 galvanic stimulation, with the result that no movement was thereby caused in the 

 left posterior extremity or in any part to which the poison had access, while ener- 

 getic reflex contractions were caused in the right (non-poisoned) posterior extremity. 

 The poisoned muscles freely contracted when directly stimulated. It was found 

 that the cardiac impulse was, at this time, powerful, while contractions occurred 

 forty-four times in the minute. Repeated observation showed that the conditions 

 of the poisoned heart, spinal cord, nerves, and muscles, and of the non-poisoned 

 nerves and muscles, described as being present at ten minutes after the injection, 

 continued unchanged during the succeeding three hours. On the following day, 

 the frog had resumed a normal posture. It moved and jumped about actively, 

 and there was now no symptom present. 



We have made experiments similar to these with iodide of methyl-atropium, 

 and the same general results were obtained. 



It has thus been shown, in the most satisfactory manner, that the salts of 

 methyl-atropium produce their paralytic effects in a very different manner from 

 atropia. The former substances do not appear to influence the sensory nerves or 

 the spinal cord, but they act solely on the motor nerves. We have seen that this 

 last action is possessed by atropia also, though in a comparatively feeble degree ; 

 and the experiment we have described confirms the opinion of previous observers, 

 that it is primarily restricted to the peripheral terminations of these nerves. The 

 evidence contained in the experiments we have narrated with sulphate of methyl- 

 atropium is in favour of the paralysis produced by this substance being likewise 

 due to an action on the peripheral terminations of the motor nerves, and the 

 following experiment clearly proves that such is the case. 



Experiment XLII. — The right gastrocnemius muscle of a frog, weighing 



