Edgar Douglas Adrian, a dominating figure of 20th century electrophysiology, published in 1912 a study on the effects of the conduction block induced by application of alcohol vapours to small segments of nerves from which he derived the conclusion that nerve signals regenerate along the nerve fibre during the conduction process. This conclusion was based on results of experiments in which the time required to produce a conduction block was found to decrease as the length of the nerve segment treated was increased. These results could not be confirmed when similar experiments were performed about 10 years later by Gen'ichi Kato, a leading figure of Japanese physiology and founder of one of the great schools of Japanese electrophysiology. Directly or indirectly, the Adrian–Kato controversy was at the inception of two of the most important advancements of 20th century neurophysiology: the elucidation of the mechanism of nervous conduction in squid giant axon by Hodgkin and Huxley and the discovery of the saltatory conduction in myelinated nerve fibres by Tasaki, Takeuchi, Huxley and Stämpfli. This controversy is also interesting for its epistemological aspects, which is important now to re-evaluate.