CURARA EXPERIMENT. 



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2. Cool the muscle by filling the cylinder with water at 

 the required' temperature. Take successive tracings at 8, 6, 

 4, and 2 C. 



3. Warm the muscle, taking tracings at every 3 C rise, 

 above 10 C. Inscribe these curves upon a portion of the 

 recording surface immediately below the record of No. 2. 



Curara experiment. Direct excitability of muscle. 



Required: No recording. Inductorium, 2 Leclanche cells, 2 keys, 

 3 ordinary and 2 thin wires, hand electrodes, waxed paper, narrow tapa 

 and a 1 P- C - solution of curara in water (filtered). 



13 



FIG. 42. P Poisoned limb. L Seat of ligature. W Waxed paper under the 

 nerves. C Commutator, less cross wires ; wired to S circuit, outleads M to muscle, 

 H to hand electrodes. 



Decerebrate the frog and plug the opening into the skull 

 firmly to prevent bleeding. Having ligatured the middle of 

 one thigh firmly with tape (unpoisoned limb), so as to stop 

 the circulation, but not to crush the nerve, inject 5 drops 

 of curara solution into the dorsal lymph sac, half or three- 

 quarters of an hour before required. Wait until the poison 

 has produced its effect, i.e., until reflexes excited in the 

 poisoned limb are absent. 



Expose both sciatic nerves throughout their whole lengths, 

 and remove the urostyle ; carefully introduce beneath both of 

 them as high up near the spinal column as possible a piece 



