710 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



right (non-poisoned) leg, but no movement occurred in any part of the poisoned 

 region. It was likewise observed that frequent spontaneous movements of an 

 energetic character occurred in the right (non-poisoned) leg. In twelve minutes, 

 the symptoms were as last described, and the heart's contractions occurred 

 thirty-eight times in the minute. - In thirteen minutes, the left sciatic nerve Avas 

 exposed, and on being stimulated by galvanism, it was found that the conductivity 

 of its motor fibres was suspended, while that of its sensory fibres continued; no 

 movement occurring in the left (poisoned) posterior extremity, although the 

 muscles of that limb yet retained their contractility unimpaired, while vigorous 

 reflex movements occurred in the right (non-poisoned) posterior extremity. 



The occurrence of these reflex movements shows that the reflex function of the 

 spinal cord is not destroyed by the direct action of this poison. It is obvious, 

 from the details we have just given, that the sensory nerve fibres and the striped 

 muscles are likewise unaffected ; while the motor nerve fibres are powerfully 

 affected. The paralytic effects of iodide of ethyl-atropium, like those of iodide 

 and sulphate of methyl-atropium, are, therefore, caused entirely by an action on 

 the motor nerves. The last experiment further shows that the trunks of the 

 motor nerves are unaffected, while their peripheral portions are paralysed. It 

 will be seen from the next experiment that the ultimate terminations of these 

 nerves in the muscles are the portions of the periphery that are affected. 



Experiment L. — In a frog, weighing 450 grains, the left gastrocnemius 

 muscle was carefully dissected from all its connections, excepting its origin and 

 insertion and the nerve fibres that entered it ; and its blood-vessels were ligatured 

 and divided. Two-tenths of a grain of iodide of ethyl-atropium, dissolved in ten 

 minims of distilled water, was then injected under the skin at the right flank. 

 In ten minutes, the frog was completely flaccid and motionless ; and, when the 

 skin anywhere was irritated, no movement occurred in the poisoned region, 

 while well marked movements occurred in the left leg and foot. In twelve 

 minutes, the right sciatic nerve was subjected to galvanic stimulation, with the 

 result that while no movement occurred in the right leg, vigorous contractions 

 occurred in the left. The left sciatic nerve was then similarly stimulated, and 

 vigorous movements followed in the left leg, but nowhere else. It was seen that 

 these movements were due solely to contractions of the left gastrocnemius muscle, 

 which was protected from the direct action of the poison. 



The results we have obtained from these experiments are of an extremely 

 interesting character. They clearly prove that the ammonium bases derived 

 from atropia possess an action which is very different from that of atropia itself. 

 The latter substance produces paralysis chiefly by affecting the motor centres and 

 the sensory nerves ; it produces convulsions by stimulating the spinal cord ; and 

 it produces diuresis and catharsis by influencing the urinary apparatus and the 

 intestinal functions. The salts of the ammonium basis possess none of these 



