364 DR THOMAS R. FRASER ON STROPHANTHUS H1SPIDUS. 



0/1 grain of extract was then injected under the skin of the left flank. In 9 min. after 

 the injection, the heart's ventricle was motionless, small, and pale, the contractions having 

 previously been imperfect, only portions of the ventricle having dilated during diastole. 

 In 28 miu., the auricles had also ceased to contract, but the frog was still able to jump. 

 In 1 hour 42 min.— that is, in 1 hour 33 min. after the ventricle had ceased to con- 

 tract — irritation of the skin anywhere caused pretty active reflexes in the two pelvic 

 extremities, though none in the thoracic extremities, which already were slightly rigid. 

 In 2 hours 7 min., however — or 1 hour 58 min. after the ventricle had ceased to contract 

 — neither mechanical nor galvanic stimulation was able to produce reflex movements in 

 either (poisoned or non-poisoned) pelvic extremity or elsewhere. Both sciatic nerves 

 were as yet active, and contractions of each extremity could be caused by stimulating 

 the sciatic nerve supplied to it. 



In other four experiments, in which the heart had been exposed previously to the 

 subcutaneous injection of extract of Strophanthus, it was found that the intervals which 

 elapsed between standstill of the ventricle and loss of reflex function were 1 hour 13 min., 

 1 hour 26 min., 1 hour 25 min., and 1 hour 8 min. It must be admitted that the blood 

 supply of the cord would become insufficient at some period before the heart's ventricle 

 had been brought to complete standstill ; but no important addition can on that account 

 be made to the interval of time elapsing between the two events, as in all the experi- 

 ments referred to the ventricular paralysis occurred in less than ten minutes after the 

 administration of Strophanthus. 



In order to determine how soon after mere stagnation of the circulation the reflex 

 function of the cord is destroyed, the heart of a frog was ligatured at its base, and it was 

 found that the spinal reflex function had not disappeared at the end of three hours.* 

 The inference appears warranted that Strophanthus paralyses the reflex function of the 

 spinal cord by a direct and primary action, although this action, relatively to others that 

 are produced by Strophanthus, is but slight and unimportant. 



Sensory or Afferent Nerves. 



The circumstances, already described (pp. 362-3) and illustrated (Experiments XL., 

 XLL, and XLIL), that when Strophanthus is administered to a frog having one limb 

 protected from its contact action, stimulation of this nerve-trunk or of any part of the 

 protected limb does not cause reflex movements after stimulation of nerve-trunks, or of 

 other parts to which Strophanthus had direct access had ceased to do so, are sufficient to 

 indicate that no general or powerful action is exerted upon sensory or afferent nerve fibres. 

 As a more concentrated contact might, nevertheless, be capable of disordering the normal 

 conditions of these nerve fibres, several experiments were made in which such contact was 

 effected with both the nerve-trunk and its peripheral terminations. 



* During this experiment the temperature of the laboratory was nearly the same as during the immediately fore- 

 going experiments. 



