368 DR THOMAS R. FRASER ON STROPHANTHTJS HISP1DUS. 



nerve no longer produced any contraction ; but it was also found that direct galvanic 

 stimulation of the exposed muscles of this (left) thigh and calf was not followed by any 

 contraction of the muscles stimulated. For at least an hour longer, stimulation of the 

 right sciatic nerve, and even of the spinal cord, produced well-marked contractions of the 

 right (ligatured) pelvic extremity, but none elsewhere. At the end of this time, all the 

 muscles to which Stropbanthus had direct access were rigid and acid in reaction. On the 

 following day, 25 hours after the administration of Strophanthus, the right sciatic nerve 

 was no longer able to conduct motor impressions ; but the muscles of the right pelvic 

 extremity still contracted, though feebly, when they were directly stimulated, and, in 

 contrast with the muscles in every other part of the body, they were non-rigid and 

 alkaline in reaction. 



This experiment, as well as others already described, shows that if a direct action be 

 exerted on motor nerves, the part acted upon is not the nerve-trunk, but the peripheral 

 terminations in the muscles. The experiment further shows that in the regions to which 

 Strophanthus was conveyed by the blood-stream, not only do the motor nerves become 

 unable to produce contractions of the muscles, but also that the muscles lose their 

 contractility at about the same time as the motor nerves fail to excite muscular 

 contractions on being stimulated. 



Further, complete paralysis of the muscles was preceded by their enfeeblement, 

 rapidly increasing until complete paralysis occurred ; and this enfeeblement might alone 

 be a cause, before complete muscle-paralysis had been produced, of the inability of the 

 motor nerves to excite contractions. 



It is, therefore, difficult to decide by such experiments as have as yet been described 

 whether Strophanthus actually paralyses the motor nerve terminations. 



Other experiments were accordingly made for the purpose of determining this point. 



Experiment XLIX. — To a frog, weighing 410 grains, 0*004 grain of extract of Stro- 

 phanthus was administered by subcutaneous injection. In 8 min., the anterior extremities 

 were maintained in an unduly extended position. In 48 min., the frog was resting on 

 the abdomen and thorax, respiratory movements had ceased, the pupils were contracted, 

 and spontaneous fibrillary twitches were occurring over the back. In 51 min., the frog 

 remained on the back, after a little resistance, and no cardiac impulse could be seen. 

 In 1 hour and 16 min., the fibrillary twitches had almost ceased, and reflex movements 

 could no longer be excited by irritation of the skin, even when severe. The left sciatic 

 nerve and thigh muscles were now exposed, and from time to time stimulated by an 

 interrupted galvanic current. The minimal stimulations required to cause contraction, 

 when applied to nerve and muscle respectively, are recorded below : — 



