DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



379 



In this experiment, as in the previous one, the muscles, whose motor nerves had 

 been paralysed by curare, were not affected by fibrillary twitchings ; while the muscles 

 supplied by non-paralysed motor nerves exhibited these twitchings in a marked form, 

 and for a long period of time. 



Experiments LV. and LVI. have, therefore, clearly shown that the spontaneous 

 fibrillary twitches of the muscles, which constitute so marked a feature among the 

 symptoms produced by large doses of Strophanthus, are caused by an action on the 

 terminations of the motor nerves in the muscles. 



C. Action on Skeletal Muscles. 



In many of the preceding experiments, and especially in Experiments VI., VIII. , IX., 

 XVIIL, XXVIIL, XXXIIL, XXXV., XXXVL, XL., XLL, XLVIIL, and XLIX., evidence 

 has been given of the circumstance that the skeletal muscles are markedly affected by 

 Strophanthus. The action on these muscles is definite, conspicuous, and direct ; it places 

 in the background the other actions as yet specially considered, which, relatively, are slight 

 and obscure ; and it is of much importance in its immediate and secondary consequences. 



Under the influence of Strophanthus the muscles become enfeebled, somewhat rigid, 

 affected with fibrillary twitchings, whose production has already been discussed, and, 

 finally, non-contractile, pale and hard ; and then, or soon afterwards, it is found that their 

 reaction has been changed from the normal alkaline to an acid reaction, and that lactic 

 acid can be separated in considerable quantity from the muscles. In fact, Strophanthus 

 paralyses the muscles chiefly by diminishing their capability to relax, and it then rapidly de- 

 stroys this capability by producing a condition indistinguishable from that of rigor mortis. 



It is a significant confirmation of the view that the final pharmacological effect is the 

 production of a true rigor mortis, that this effect may be postponed for many hours by 

 steeping the muscle in a weak solution of chloride of sodium, and also that such treat- 

 ment delays not only the paralysis and rigidity of the muscle, but likewise the change 

 from the alkaline to the acid reaction (see Experiments LI., LIL, and LIIL). 



As has already been stated, the heart is early paralysed by such moderately large 

 lethal doses of Strophanthus as are necessary to display prominently the effects on muscle. 

 In order to determine whether the cardiac standstill has any causal relation to any of the 

 special effects produced upon the skeletal muscles, the following experiment was made. 



Experiment LVIL- 



-Two frogs were selected — one, A, weighing 266 grains, and the 

 other, B, weighing 268 grains. 





A. 





B. 



Jan. 12. 

 1.15 

 1.20 



The heart was exposed. 



Heart's contractions 12 per 30 sec. 



Jan. 12. 

 1.21 

 1.23 

 1.25 



The heart was exposed. 



Heart's contractions 12 per 30 sec. 



A ligature was drawn tightly round the base of the 

 heart so as completely to stop the circulation. Im- 

 mediately the respirations became interrupted by 

 long pauses, at the end of which struggles occurred. 



