Incidentally, as part of the above inquiry, experiments were carried out on monkeys. Two were used. The first was made drunk with new whisky and was seen to become quarrelsome, no doubt due to the fusel oil (which was well-known for making men fighting drunk), and the second was intoxicated with 'fine old whisky' with the result that it became 'markedly hilarious', the maturity and the lack of toxic ingredients obviously agreeing with the chimp. Once sobered-up, the experiment was reversed, causing the quarrelsome beast to cheer up somewhat and the contented one to become aggressive. The conclusion drawn was that new or freshly distilled whisky did have an adverse effect, at least on monkeys, and that its storage to allow maturation appeared to be beneficial.

From Bad Whisky: The Scandal That Created The World's Most Successful Spirit, by Edward Burns