I suspect we could have done the whole thing on acid … except for some of the people; there were faces and bodies in that group who would have been absolutely unendurable on acid.

The sight of a 355-pound police chief from Waco, Texas, necking openly with his 290-pound wife (or whatever woman he had with him) when the lights were turned off for a Dope Film was just barely tolerable on mescaline – which is mainly a sensual/surface drug that exaggerates reality, instead of altering it – but with a head full of acid, the sight of two fantastically obese human beings far gone in a public grope while a thousand cops all around them watched a movie about the “dangers of marijuana” would not be emotionally acceptable.

The brain would reject it: The medulla would attempt to close itself off from the signals it was getting from the frontal lobes … and the middle-brain, meanwhile, would be trying desperately to put a different interpretation on the scene, before passing it back to the medulla and the risk of physical action.

Acid is a relatively complex drug, in its effects, while mescaline is pretty simple and straightforward – but in a scene like this, the difference was academic. There was simply no call, at this conference, for anything but a massive consumption of Downers: Reds, Grass and Booze, because the whole program had apparently been set up by people who had been in a Seconal stupor since 1964.

Hunter S. Thompson, “Fear and Loathing in Las Vegas”