While I have been out of action, a technology-world friend named Michael Jones has generously added to the world's store of knowledge on the Frog Question. He has the floor:
Goltz work inspired George Henry Lewes--actor, philosopher, friend of Dickens, bigamous partner of Marian Evans (George Eliot) and of note, literary critic--to extend the slowly-boiled brainless frog oeuvre
by slowly-boiling frogs with partial brains or with their spinal cords
severed at various locations. Lewes published his findings four years
and many frogs later as Sensation in the Spinal Cord in Nature, Dec. 4, 1873. He summarized the story this way:
"Goltz observed that a frog, when placed in water the temperature of which is slowly raised towards boiling, manifests uneasiness as soon as the temperature reaches 25° C., and becomes more and more agitated as the heat increases, vainly struggling to get out, and finally at 42° C., dies in a state of rigid tetanus. The evidence of feeling being thus manifested when the frog has its brain, what is the case with a brainless frog? It is absolutely the reverse. Quietly the animal sits through all successions of temperature, never once manifesting uneasiness or pain, never once attempting to escape the impending death."