I PAUSE reading this book and hear a voice in my head with a Kelvinside accent saying: “A half an hour later, I was beginning to feel definite effects.”

Patter theft, I know, but many of the historical figures in Mike Jay’s splendid history of pharmacological experimentation recall Larry Forsyth, the hapless character created by comedian Brian Limond, seen fired up by various stimulants. Larry may be the funniest Scottish psychonaut, but he certainly wasn’t the first.

“Psychonaut” is a term coined by novelist Ernst Jünger, a man who tried to tame his own internal demons (survivor of the trenches, insider knowledge of the Holocaust) with hallucinogens. Jay tells us that other early psychonauts were a ragbag bunch of “renegades, autodidacts, bohemians and mystics”. They dropped a tab alongside a select gang of professional, more establishment types.

Beginning with the pioneers in the 19th century – Freud on cocaine, William James (Henry’s big brother) on nitrous oxide – Jay walks us through their pioneering trials on themselves. Theirs was a world of risk, the “forbidden game” in Baudelaire’s words.

Freud’s self-experiments became “impetuous and excessive”: imagine him as a Viennese Tony Montana pointing to his new couch and quipping: “Say hello to my little friend”.

This was a time when several (now banned) products were available over the counter. The 20th century was a much more controlling era that saw Prohibition, the War on Drugs, and a profusion of anti-drug legislation. Just say no, Zammo.

Clinical trials of potentially useful agents (cannabis as an analgesic/muscle relaxant, MDMA in palliative care) were prohibited by ethical committees.

Taking the right path became a tightrope act for physicians. Drugs were, in Jay’s words: “Both fetishised and demonised”.

But there’s a long and noble tradition of doctors trialling various medications and vaccines on themselves. Jay focuses his account on the history of drugs that influence the mind, specifically the modern Western consciousness. And there’s no end of Scots involved in such malarkey – here’s Robert Louis Stevenson guzzling burgundy infused with cocaine leaf.

A disproportionate number of Scots physicians were enthusiasts: James Young Simpson, professor of midwifery at the University of Edinburgh, is seen at the dining table, inhaling chloroform en famille, only for the team to end up “under the mahogany in a trice”.

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Sir William Ramsay (the genius who discovered the noble gases) inhales ether and nitrous oxide “at least fifty times”. Sounding like he might have been sampled by The Orb he concludes he now knew the truth of Bishop Berkeley’s theory of existence: “That nothing exists but thoughts.”

OTHER Scottish experiences sound downright spooky – in Kirkcaldy, a woman in labour given chloroform recovers after delivery only to tell her carers that she had seen the child and her own mother as spirits. It was only then the doctors told her the child was dead and that her mother died too, earlier that day.

Jay’s tone is often bathetic – we’re reminded regularly that the effects of drugs on the mind are generally ineffable. William James even wondered if “the Creator has intended this department of nature to be baffling, to prompt our curiosities and hopes and suspicions in equal measure”.

Then there’s Oliver Wendell Holmes, poet and doctor, whose own experiences on ether made him feel like an archangel. Filled with “a sense of infinite possibility” he realised “the one great truth” and somehow managed to write it down. Sober, he read his great reveal: “A strong smell of turpentine prevails throughout.”

Jay’s book has serious contemporary relevance given our current problems with nitrous oxide, those wee silver canisters lining the pavements.

Witness the recent case of an intoxicated killer driving over 130mph on the M62. Intellectual psychonauts are not the norm – for every daring Humphry Davy, there’s a hundred deluded Dee Dee’s grinding their jaws.

There are serious social costs – life expectancy is shorter in those with heavy drug consumption. Scotland has a drug problem; this we know.

But our fascination persists. Some smoke Sonoran Desert toad secretions. Others call 5-MeO-DMT the “God molecule”. Should we lay down all thoughts and surrender to the void?

Was Hegel right all along that nothing is fixed?

At this point in the review, I had to be subdued…