On the conduction of subnormal disturbances in normal nerve

Introduction. If a conducting tissue is cooled locally or anasthetised locally the response is lengthened in the affected part only. As the disturbance passes beyond the affected area it resumes its normal time relations and rate of conduction. This statement has been shown to hold good under the most varied conditions. The effects of local alteration of temperature on the electric response of the heart have been described by Page and Burdon Sanderson', on the electric response of nerve by Boruttau2 and Verwej3, and on the mechanical and electric response of muscle by Verwej. Boruttau and Fr6hlich have studied the effects of the local application of anesthetics on the electric response in nerve4, on the rate of conduction in nerve5, and on the mechanical and electric response of muscle6. In every case it was found that the change in the time relations and rate of conduction of the disturbance was strictly confined to the affected part and was not transmitted into the normal tissue beyond. It appears then that the time relations of the changes conducted through a tissue are determined solely by the local conditions and not by the conditions of other parts of the tissue through which the disturbance has passed. Can the same be said of the magnitude of the changes in each conducting element? If the disturbance is diminished locally does it remain small after it has left the affected area or does it recover its original magnitude when it recovers its original time relations ?