CHEMICAL CONSTITUTION AND PHYSIOLOGICAL ACTION. 727 



extremity, and there were no respiratory movements whatever. In nine minutes, 

 stimulation of the skin in any region was followed by energetic reflex movements 

 in the right posterior extremity, but no movements occurred in the poisoned 

 region. In fourteen minutes, the left sciatic nerve was stimulated by an inter- 

 rupted galvanic current, and, although active reflex movements of the right 

 (non-poisoned) posterior extremity were thereby excited, no movement occurred 

 in the left (poisoned) posterior extremity, or in any other part of the poisoned 

 region. The heart's impulse was, at this time, found to be of fair strength, and 

 occurring forty-two times in the minute ; and the muscles contracted vigorously 

 on direct stimulation. In three hours, the condition of the frog was the same as 

 last noted, excepting that the rate of the heart's contractions had diminished to 

 thirty-eight in the minute. The observations were now interrupted until the 

 following morning, when the frog was found dead and in rigor. 



In many other similar experiments with different doses of this substance, 

 the symptoms and mode of action were exactly the same as in the last experi- 

 ment. They show that the paralysis produced by dimethyl-conium is dependent 

 on an action on the motor nerves, primarily restricted to the peripheral termina- 

 tions. Even after the administration of a fatal dose, we have never observed 

 any action on the spinal cord, beyond its necessary implication in the progress 

 towards death. On the other hand, in experiments where doses below the mini- 

 mum fatal, and therefore considerably smaller than in Experiments CVII. and 

 CVIIL, were given, the condition of complete paralysis of the peripheral termina- 

 tions of the motor nerves existed along with retained functional activity of the 

 spinal cord and sensory nerves, for periods protracted over many hours. Thus, 

 in an experiment where the dose was equivalent to the ^Voth °f the frog's weight 

 (Experiment CIIL), the poisoned motor nerves remained completely paralysed for 

 more than twenty-six hours, while, during this time, the poisoned sensory nerves 

 and the spinal cord retained their functional activity. 



We conclude from our experiments, that in physiological action iodide of 

 dimethyl-conium differs from conia and methyl-conia in being entirely free from 

 spasmodic and spinal-paralysing actions. 



It is shown in the following Table of minimum fatal doses, that iodide of 

 dimethyl-conium is much less active than either conia or methyl-conia : — 



