162 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



general paralysis ; but the special characteristic of curare-poisoning is, that this 

 paralysis is the result of an impairment or destruction of the function of the 

 peripheral terminations (end-organs) of the motor nerves. It is impossible to 

 demonstrate such an action without undertaking experiments of a special 

 character. We, accordingly, extended our research for the purpose of examining 

 this question. 



Experiment XXVIII. — The sciatic artery and vein were tied at the knee of a 

 frog, and one-tenth of a grain of sulphate of methyl-strychnium, dissolved in 

 distilled water, was injected under the skin of the back. Eight minutes after- 

 wards, the frog was lying in a perfectly flaccid state, and, in ten minutes, irrita- 

 tion of any portion of the skin produced energetic movements of the tied limb, 

 below the -points of ligature, but nowhere else. The sciatic nerve of the untied 

 limb was now exposed, and on stimulating it with a weak, interrupted galvanic 

 current, movements occurred in the tied limb only, not the slightest effect 

 occurred in any part to which the poison had access. At the same time, the 

 muscles were everywhere active, and freely contracted when directly stimulated. 

 The sciatic nerve was then exposed in the tied limb, above the points of ligature, 

 and on stimulating it, energetic movements occurred below the knee of that 

 limb, and there only. The heart was, at this time, acting at the rate of fifty per 

 minute. 



This experiment was repeated with one grain of iodide of methyl-strychnium, 

 and the same general results were obtained. The evidence that was thus acquired 

 in favour of an action on the peripheral terminations of the motor nerves was 

 strengthened by a modification of this method of experiment. 



Experiment XXIX — The right gastrocnemius muscle of a frog was carefully 

 dissected from its connections, excepting that its origin and insertion, and the nerve- 

 fibres entering it, were untouched, and that all its blood-vessels were ligatured. 

 One-tenth of a grain of sulphate of methyl-strychnium, dissolved in five minims of 

 distilled water, was then injected under the skin of the back. Twenty minutes 

 afterwards, the animal being in a perfectly relaxed and motionless condition, the 

 two sciatic nerves were exposed. Galvanism of the left produced no movement 

 in the left limb, while galvanism of the right produced energetic movements of 

 the right limb, which were seen to be due solely to contractions of the right gas- 

 trocnemius muscle, the other muscle remaining motionless. At the same time, 

 direct stimulation by galvanism caused contractions as freely in the poisoned 

 muscles as in the non-poisoned right gastrocnemius. 



In an experiment, in which iodide of methyl-strychnium was substituted for 

 sulphate, the effects were the same. We have, therefore, demonstrated that the 

 methyl-strychnium derivatives produce paralysis and death by destroying the 

 function of the motor nerve end-organs, and that their mode of action is, there- 

 fore, identical with that of curare. This conclusion is an extremely curious and 



