370 



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



induction apparatus, the minimum stimulus required to cause contraction of each muscle 

 (a) through its nerve and (b) on direct stimulation of the muscle was noted repeatedly 

 before and after immersion, as in the following experiment. Only single-break shocks 

 wore used. 



Experiment XLVIII. — Immediately after pithing a frog (Rana temporaria) weigh- 

 ing 50 grams, two nerve-muscle preparations were made. In the following table these 

 preparations are designated A and B. The nerve of A and the muscle of B were each 

 immersed in 3 c.c. of a 1 in 500 solution of extract in Ringer's solution. Before 

 immersion the normals were recorded. 





Minimum Single-break Shock required. 





Muscles. 



Nerves. 



Interval. 









Notes. 



A. 



B. 



B. 



A. 





mm. 



mm. 



mm. 



mm. 





Be/ore Poisoning. 













10 minutes . 



190 



200 



500 



500 





5 



200 



200 



500 



500 







Control 



Poisoned 



Control 



Poisoned 



Muscle B and nerve A were immersed in 



After Poisoning. 











a solution of the extract (1 in 500) in 

 Ringer's solution. 



3 minutes 



220 



280 



500 



490 





7 „ . . 



250 



270 



500 



500 





12 „ . . 



240 



270 



500 



500 





15 „ . 



250 



290 



500 



500 





20 „ . . 



240 



260 



500 



500 





25 ,. . . 



240 



260 



500 



500 





30 „ 



190 



240 



420 



410 





35 „ . . 



180 



170 



380 



350 





40 „ 



150 



120 



310 



310 



Stimulation caused fibrillary twitches in 

 the poisoned muscle. 



45 „ 



140 



150 



320 



290 



Spontaneous fibrillary twitches occurred in 

 the poisoned muscle. 



50 „ . . 



120 



110 



310 



280 





55 „ 



110 



110 



280 



260 



Spontaneous twitches, coarse in character, 

 occurred in poisoned muscle. 



60 „ . 



120 



110 



280 



260 





65 „ . . 



130 



130 



260 



300 





70 ., 



130 



120 



320 



350 



Twitches have ceased. 



75 „ 



140 



140 



280 



290 



Do. 



80 „ 



160 



130 



360 



300 



Do. 



85 „ 



170 



140 



330 



320 



Do. 



90 „ . . 



160 



150 



310 



340 





95 „ 



180 



120 



370 



480 





100 „ 



190 



110 



Zero 



270 





105 „ 



220 



120 



Zero 



200 





110 „ . . 



200 



110 



30 



190 





115 „ 



200 



120 



Zero 



140 



Twitches have ceased. 



120 „ 



200 



130 



40 



130 





125 „ . . 



220 



120 



30 



150 





130 „ . 



210 



120 



30 



140 





140 „ . . 



200 



120 



50 



160 





