300 THE BEHAVIOUR OF HYLA AUREA TO STRYCHNINE, 



after the injection of the strychnine into the dorsal lymph sac, 

 the frog exhibited spasms. Four minutes later the frog was 

 completely paralysed. The sciatic nerve was exposed in the 

 thigh by an incision and was placed on electrodes. On stimu- 

 lating the nerve with single induced shocks or with the faradaic 

 current no contractions of muscles were seen. A standard Du 

 Bois Reymond inductorium and one bichromate cell were 

 employed. The secondary coil was placed directly over the 

 primary coil. On placing the electrodes directly upon the 

 muscles contractions were elicited even when the secondary coil 

 was separated 22 cm. from the primary coil. Five similar 

 experiments were carried out with exactly similar results. These 

 observations suggested that the strychnine was producing an 

 action upon the receptive substance* between the nerve endings 

 and the muscle fibres. Another experiment was therefore per- 

 formed. A frog which weighed 17 gm. was taken and the 

 cerebral hemispheres crushed with forceps. The right sciatic 

 nerve was exposed in the thigh and a ligature passed beneath 

 the nerve. The ligature was then tied around all the structures 

 of the thigh except the sciatic nerve. The ligature was placed 

 as near to the knee-joint as possible. The frog then received 

 1*7 mg. strychnine as sulphate hypodermically into the dorsal 

 lymph sac. After twenty-five minutes nerve-muscle preparations 

 (gastrocnemius-sciatic combination) were made from each leg. 

 On stimulation of the left sciatic nerve there was no response in 

 the gastrocnemius muscle even when the secondary coil was 

 pushed home. With the right sciatic nerve the minimal point of 

 stimulation of the right gastrocnemius muscle for single induced 

 break shocks was with the secondary coil 12 cm. from the pri- 

 mary coil. Contractions of the left gastrocnemius muscle were 

 first observed with single induced break shocks when the secondary 

 coil was 15 cm. from the primary coil. A Du Bois Beymond 

 standard inductorium and one bichromate cell were used in these 

 experiments. Repetitions of this experiment yielded like results. 



* Langley, Journ. of Physiol, xxxiii., 374, 1905. 



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