Is there a way for a 19th century scientist to prove that the octopus doesn't revive? Say a sophiscated scientist in the 19th century noted that applying soy sauce on a dead octopus leads to movement of the legs, as a...--prophetes.ai

Is there a way for a 19th century scientist to prove that the octopus doesn't revive? Say a sophiscated scientist in the 19th century noted that applying soy sauce on a dead octopus leads to movement of the legs, as a result of the voltage differences resulting from the salt in the soy sauce. (For example, see this video) Is there a way for that scientist to prove, using only the methodologies available at that time, that the decapitated octopus doesn't regain the functions that a octopus brain normally has, for even a few seconds, when the soy sauce is applied?

Yes. The scientist could cut a small piece of the octopus's tentacle and perform the experiment again. If the same result is observed, no other organs are involved.