In going round the end of the hill I saw a lion sitting on a piece of rock about thirty yards off with a little bush in front of him. I took a good aim at him through the bush and fired both barrels into it. The men called out. “He is shot, he is shot.” Others cried, “He has been shot by another man too, let us go to him.” I saw the lion’s tail erected in anger and turning to the people said, “Stop a little till I load again.” When in the act of ramming down the bullets I heard a shout and looking half round I saw the lion in the act of springing upon me. He caught me by the shoulder and we both came to the ground together. Growling horribly he shook me as a terrier dog does a rat. The shock produced a stupor similar to that which seems to be felt by a mouse after the first gripe of the cat. It caused a sort of dreaminess in which there was no sense of pain nor feeling of terror though I was quite conscious of all that was happening. It was like what patients partially under the influence of chloroform describe: they see the operation but do not feel the knife. This placidity is probably produced in all animals killed by the carnivora and if so is a merciful provision of Creator for lessening the pain of death. As he had one paw on the back of my head I turned round to relieve myself of the weight and saw his eyes directed to Mebalwe who was aiming at him from a distance of ten or fifteen yards. His gun which was a flint one missed fire in both barrels. The animal immediately left me to attack him and bit his thigh. Another man whose life I had saved after he had been tossed by a buffalo attempted to spear the lion upon which he turned from Mebalwe and seized this fresh foe by the shoulder. At that moment the bullets the beast had received took effect and he fell down dead.
David Livingstone (1857). Missionary Travels (pp. 11-12). London: EW Cole.
Scottish explorer Livingstone, in his journey to discover the sources of the Nile, reported what is now known as stress-induced analgesia. Under conditions of extreme stress or in the adaptation to an extreme environmental challenge, an individual’s normal reaction to pain—reflex withdrawal, escape, rest, and recuperation—could be disadvantageous. In a dire emergency, these reactions to pain are automatically suppressed in favor of more useful behaviors. It turns out that we have a piece of software, the analgesia system, that automatically activates in these circumstances, with rather remarkable effects.