168 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



For administration by the stomach, Ave dissolved this substance in warm dis- 

 tilled water, and introduced the solution through a gum-elastic catheter. We 

 found that as much as twenty grains could be thus given without any effect, and it 

 was not considered advisable to increase this dose. Its magnitude is apparent 

 when we recollect that it contains about seventeen grains of brucia ; and we have 

 already seen that when two grains of this alkaloid is introduced into the stomach 

 of a rabbit, the most violent tetanic convulsions are quickly produced, and death 

 soon follows. 



The short account we have given of a few of our experiments with iodide and 

 sulphate of methyl-brucium is sufficient to show that these substances have an 

 action that is very different from that of brucia itself. Brucia is a violent con- 

 vulsant poison, and it causes death by either exhaustion or asphyxia ; its methyl 

 derivatives never produce convulsions, nor do they even increase the reflex 

 activity ; and although they cause death by asphyxia, this asphyxia, in place of 

 being the result of prolonged and continuous muscular action, due to abnormal 

 nerve activity, is the result of muscular paralysis, due to partial or complete 

 absence of normal nerve activity. We have demonstrated the latter effect by the 

 following experiments, which further show that the influence of the methyl deri- 

 vatives of brucia is exercised on the terminations of the motor nerves. 



Experiment LVI. — The left iliac artery of a frog, weighing 608 grains, was tied, 

 after exposing it by removing a portion of the sacrum, and one-fifth of a grain of 

 sulphate of methyl-brucium, dissolved in ten minims of distilled water, was then 

 injected into the abdomen. In four minutes, every portion of the frog except the 

 left leg was paralysed. In five minutes and thirty seconds, weak interrupted 

 galvanism, applied to any portion of the skin, caused violent movements of the 

 left leg, and of it alone, every other part of the body remaining motionless. The 

 heart, as ascertained by its impulse, was contracting thirty times per minute. 

 In seven minutes, the right sciatic nerve was exposed— the incisions neces- 

 sary for which excited energetic reflex movements of the left limb — and on gal- 

 vanising it, strong contractions of the left limb occurred, but no movement 

 occurred in the right limb. The muscles were everywhere in a normal state, 

 and freely responded to direct galvanic stimulation ; and the heart still con- 

 tracted at the rate of thirty beats per minute. 



In a similar experiment, with half a grain of iodide of methyl-brucium, the 

 same effects were observed. It is, therefore, apparent that these substances do 

 not directly influence the action of the heart, of the muscles, of the spinal cord, 

 or of the sensory (afferent) nerves, but that the paralysis, which they so promi- 

 nently cause, is the result of an action on the motor nerves. In the above 

 experiment, the whole course of the sciatic nerve, from the pelvis to the extremity 

 of the left posterior limb, was protected from the influence of the poison. The 

 experiment does not, therefore show if the methyl-brucium compounds have 



