44 ELEMENTARY PHYSIOLOGY. VI. 



b. The brain of a frog is destroyed, the sciatic nerve 

 isolated out in the thigh, and the thigh except the nerve 

 ligatured in two places with a stout woollen thread. A 

 couple of drops of 1 p.c. curari are injected into the dor- 

 sal lymph sac. In 20 30 mins. pinching the skin causes 

 a reflex movement in the ligatured leg, but not in the 

 rest of the body. The experiment shows that at this 

 stage, though the curari has paralysed the nerve-end- 

 ings to which it has had access, it has not paralysed the 

 spinal cord. 



2. Action of veratrin. The fore brain of a frog is 

 destroyed and 3 or 4 drops of 1 p.c. veratrin are injected 

 under the skin. In about a quarter of an hour, when 

 the skin is pinched in the mid-line over the end of the 

 urostyle, the frog jumps, but it leaves the legs extended 

 for some time instead of drawing them up. 



