372 



SIR THOMAS R. FRASER AND MR ALISTER T. MACKENZIE ON 



Experiment XLIX. — Two male frogs, each weighing 45 grams, were selected. The 

 Rana teiwpora/ria was used, as it had been noted in the course of the investigation 

 that the muscles of this species showed more marked fibrillary twitches than those of 

 Rana escidenta. One of the frogs received by subcutaneous injection into the dorsal 

 lymph-sac - 3 c.c. of a 1 percent, solution of curara. Half an hour afterwards, this frog 

 was paralysed. Both frogs were then pithed, and three nerve-muscle preparations were 

 made of the gastrocnemii and sciatic nerves. The preparations from the curarised frog 

 were designated A and B, and that from the non-curarised frog, C. 



Preparation A was immersed in 4 c.c. of Ringer's solution containing 0*001 gram of 

 curara to prolong the paralysis of its nerve-ends. 



Preparation B was simultaneously immersed in 4 c.c. of a solution of 1 part of the 

 extract of S. sarmentosus in 650 parts of Ringer's solution, also containing 0"001 gram 

 of curara. Preparation C was immersed at the same time in 4 c.c. of a solution of 

 1 part of extract in 650 parts of Ringer's solution, and this preparation, therefore, 

 was not subjected to the action of curara. 



The following table gives the results of the experiment : — 



Interval. 



Maximum Position of the Secondary Coil 



in mm. at which a Single-break Shock 



was effective. 



Notes. 



Muscles. 



Nerves. 



A. 

 mm. 



B. 



mm. 



200 



250 

 230 

 240 



260 

 290 



C. 



mm. 



A. 

 mm. 



B. 



mm. 



c. 



mm. 



After Immersion 

 hi Minutes. 



5 

 10 



15 

 20 

 25 

 30 

 35 

 40 

 41 

 45 

 46 



50 

 55 

 57 



60 



65 

 67 



170 



250 

 250 

 240 



... 

 260 



310 



200 



250 

 210 

 230 



270 

 300 









 



•■ 





 





 











 

 





 









430 



420 

 460 

 420 



380 

 410 



400 



i The curarised muscles, A ami B, did not respond 



< to break shocks even at zero, but responded 

 ( feebly to make shocks. 



< A and B do not respond to make shocks now. 



No fibrillary twitches in A, B, or C. 



Spontaneous fibrillary twitches in C. 



Do. do. 

 Coarse and frequent fibrillary twitches in C ; 

 none in A or B. 



Do. do. 



Spontaneous fibrillary twitches occur in C, but 

 they are less strong. 



A few feeble fibrillary twitches in C after stimu- 

 lation ; none in A or B. 



Feeble fibrillary twitches in C after stimulation. 



Spontaneous feeble fibrillary twitches in C ; 

 none in A or B. 



