Abstract
1. The effects of strychnine upon the nerve fibres of toads were investigated.
2. Strychnine had little effect on the myelinated portion, while it had markedeffects on the node of Ranvier.
3. The rheobasic voltage of the node was decreased by the application ofstrychnine solutions of lower concentration (from about10-17M to10-5M), butwas increased by higher strychnine concentrations (more than10-4M).
4. The rheobase of the node in Ringer solution rose by strychnization of theneighbouring node.
5. Thesholds for repetitive response to constant current was decreased bystrychnization of the fibre. The decreased threshold for repetitive response pro-duced by strychnization of the fibre was hardly possible to be restored to theinitial value by washing the fibre with fresh Ringer solution.
6. The relative refractory phase of nerve fibres became shorter than in thenormal, and the supernormality of the fibre was increased and prolonged by weakstrychnization, but the recovery process was depressed by strong strychnization.
7. The strychnine concentration, which was necessary to decrease therheobase of the fibre, became high by raising the room temperature over20°C.
8. Repetitive responses due to single shock stimulation were observed instrychnine-treated nerve fibres (from about10-7M to10-4M) at temperatureshigher than about20°C.
