Abstract
1. The slow potential which occurs in the dorsal column-root preparation has been recorded on Japanese toads (Bufo vulgaris japonica).
2. The shapes of the slow potentials depend upon the position of the recording electrodes and change in a definite way.
3. The phenomena of spatial and temporal summation and occlusion areexhibited by the slow potential.
4. The slow potential acts as a generator potential when the preparation is kept in cold Ringer solution for some time.
5. Antagonism is observed between potassium-and calcium-effects on the slow potential.
6. The slow potential is strikingly augmented and prolonged by veratrine.Similar but much less effects are observed by T. E. A. B.(Tetraethyl ammonium bromide), as well. Nicotine can not abolish the slow potential.
7. Similarities are observed between the slow potential and the negative after-potential in the peripheral nerve. This indicates that the slow potential has some connections with the restorative process.
8. Some dorsal column-root preparations have been microscopically examined after experiments. No internuncial neurons have been discovered in them. The slow potential of the spinal cord can be produced without internuncial neurons.
9. The slow potential is shown not to be cardinally originated from the cut-ends of nerve fibers in the dorsal column, though some minor part of it may be so.
10. The origin of the slow potential is explained to be due to the potential change in the interstitium of the dorsal column after an impulse is conducted.
11. The origin of the positive potential is stated in the same way.
