I have a nice opportunity to do some Science on the Streets tours in Glasgow this week. It’s a bit like a ghost walk but the guide talks about the scientific history of the area. The subject I’ve chosen and researched is the Glasgow tobacco trade, the scientific background to nicotine, its addictive effect and its future opportunities as a useful drug. The text below is a slightly edited version on the ‘street presentation’ – so it’ll read a bit informal!
Glasgow Tobacco: Science on the Streets
With the Act of Union in 1707, which made Scotland and England one country, the Scottish merchants had access to the overseas English colonies. Glasgow was superbly placed to capitalise on trade with the American colonies: the wind blows from the American eastern seaboard straight to Glasgow! For a ship to get to English and French ports it needed to sail across the Atlantic to Scotland and then south, costing shipping companies a week or two (and time is money).
What made Glasgow rich was tobacco and a small group of merchants became known as the Tobacco Lords. The streets of Glasgow still bear their names: Andrew Buchanan (Street), Archibald Ingram (Street), Alexander Oswald (Street), Andrew Cochrane (Street) and John Glassford (Street), Alexander Speirs (Wharf). The facade of William Cunningham’s 18th century mansion was ‘recycled’ into the impressive front face of the Gallery of Modern Art.
The Glasgow Tobacco Lords developed a global business empire: rather than buying from middle men or acting as selling agents, they traded directly with the growers, shipped the tobacco on their own ships and sold it without using brokers. They invested in the American farmers by a system of lending and credit: it sounds almost ‘Fair Trade’, but its wasn’t! As debtors, the tobacco farmers were forced to sell exclusively to the Glasgow merchants and often at low prices. By the 1760’s one tobacco farmer was in debt to the modern equivalent of £150K. But on this side of the Atlantic the Tobacco Lords were doing very nicely, John Glassford’s trading empire traded nearly £40 million pounds (modern equivalent) worth of business a year in the mid-1700’s. We’ll come back to both these men at the end.
Tobacco is made from the dried leaves of plants from the Nicotinia genus, which is a member of the Solanaceae family (these include the potato, tomato, capsicum – chillies – and deadly nightshade). The tobacco plants produce the chemical nicotine as an in-built herbicide to stop insect attack and the leaves can contain quite a lot (between 0.5 to 5% of the leaf weight is nicotine). A molecular model of the chemical nicotine is on the right.
Pure nicotine is a liquid. It absorbs through the skin, or any other membrane in the body really quickly and is highly toxic (about 30 x the toxicity of cocaine).
At lower concentrations nicotine can act on the brain as both a simulant and a relaxant depending on the dose. When nicotine is inhaled it passes into blood stream in the lungs, through the blood-brain barrier (a sort of special chemical bulletproof vest for the brain) and acts to release neurotransmitters and hormones like acetyl choline, histamine and adrenaline. As a stimulant it increases mental concentration, suppresses the appetite, increases metabolism and enhances the brain’s ‘reward systems’. At higher doses nicotine can slow the nerve impulses leading to a pain killing and sedative effect.
Nicotine is not believed to be carcinogenic (cancer-causing), but smoking is. Recent figures suggest that 86% of lung cancers and 19% of cancers overall are caused by smoking. While it wasn’t until the 1950’s that the association between smoking and lung cancer was accepted scientifically, German doctors were publishing health concerns before WWII. Tobacco smoke contains many different chemicals which are associated with cancer, including tars, arsenic, benzene and cadmium. Rather than dominating Glasgow economy, tobacco now dominates Glasgow’s health: 30% of adult Glaswegians smoke (compared to 24% in Scotland and 21% as a UK national average) and the Greater Glasgow and Clyde Health board estimate that 1/3 of all deaths in the area are attributable to smoking.
Nicotine is also being studied as a pharmaceutical drug for certain conditions. The same effects on the brain highlighted above are believed to treat ADHD, Alzheimers, Parkinsons and depression. It also acts an anti-inflammatory for treatment of colitis, allergic asthma, and atopic disorders. However, all these studies seem to be in small, early clinical trials and nicotine is not a licensed pharmaceutical anywhere in the world, except as a smoking cessation therapy.
If the future of nicotine is beginning to brighten – it’s moving from being a drug that causes cancer and death to being one that treats some of the conditions modern medicine is finding particularly problematic – that wasn’t the case for some of the Glasgow Tobacco Lords.
The debt of the tobacco farmers was a significant driver of the colonies’ independence movement, culminating in the American War of Independence (starting in 1775). None of these massive debts were paid during, or in the years immediately after, the war and the Glasgow tobacco trade dried up. Some of the Tobacco Lords sold up before the crash, others moved onto the cotton trade, but John Glassford had debts of the modern equivalent of nearly £7million when he died in Shawfield Mansion in 1783. That same year was a very good one for the debt ridden tobacco farmer: as General George Washington he lead the Americans to independence and as a results became the first president of the US 6 years later in 1789.
I have used various references for this blog as listed below.
Neil’s Oliver’s BBC series The History of Scotland (and the associated book) deals with some aspects of the Glasgow Tobacco trade and are both currently available. Tom Devine’s book Tobacco Lords was the most comprehensive study of the tobacco trade I came across (although it’s now out of print). Devine and Oliver appear to disagree over the motivation behind the system of extending American growers credit, although both concur over how it was perceived in the colonies.
A lot of this information also comes from various wikipedia sources, in particular: Tobacco/Nicotine/Solanaceae/Nicotinia/Tobacco Lords/John Glassford/George Washington/History of Smoking
The location of Shawfield Mansion is outlined in www.glasgowstory.com – Shawfield Mansion. (Note this link was updated on 7th April 2014.)
The information on the future of nicotine as a drug therapy come from google searches of nicotine clinical trials and licensed medication.