The IV Drip (Intravenous Saline)

Introduction — a Leith doctor saves a dying woman with salt water

In the spring of 1832, in a cholera hospital in Leith, the busy port of Edinburgh, a young Scottish doctor did something no one in human history had ever done before. Dr Thomas Aitchison Latta carefully inserted a tube into the arm vein of an elderly woman who was, by every visible sign, dying. She was cold, pulseless, sunken-eyed, her face fixed in what Latta called 'the manifest impress of death's signet'. Then, ounce after ounce, he injected six pints of warm salt-and-soda water into her bloodstream — and watched her come back to life.

This was the world's first intravenous saline infusion in a human being. It is the moment from which every IV drip running in every hospital on Earth today is descended. Yet the man who performed it has almost no portrait, no grave monument, and is unknown to most of the public he helped to save. This is the story of Thomas Latta of Leith — the forgotten Scottish doctor who invented the IV drip.

The context — the cholera pandemic of 1831–1832

Asiatic cholera reached Britain for the first time at the port of Sunderland in October 1831, part of the second great cholera pandemic that had begun in Bengal and swept across Asia and Europe. From Sunderland it spread north into Scotland, reaching the Edinburgh and Leith area by early 1832. As a teeming North Sea port, Leith was uniquely exposed.

Cholera is terrifying because of how fast it kills. It causes torrential watery diarrhoea and vomiting; victims can lose litres of fluid in hours, and they die not of the infection directly but of catastrophic dehydration and the loss of the body's salts. Sufferers turned cold, shrivelled and bluish — hence the period names 'blue cholera' and 'blue stage'. Case-fatality in 1832 commonly ran around half of those seriously affected, and in some local outbreaks it was higher still.

Crucially, medicine in 1832 had no idea what caused it. Germ theory lay decades in the future — Pasteur's foundational work came in the 1850s and 60s, and the cholera bacterium Vibrio cholerae was not isolated by Robert Koch until 1883. The standard treatments of the day — bleeding, opium, calomel (mercury chloride) and brandy — did nothing for the underlying fluid loss, and bleeding actively made it worse. But one vital clue had been noticed: the blood of cholera victims was abnormally thick and dark, as though it had lost its watery part.

The key insight — O'Shaughnessy proposed it; Latta did it

The man who first chased that clue was William Brooke O'Shaughnessy (1809–1889), a brilliant young Irish-born physician and chemist, Limerick-born and Edinburgh-trained (MD 1829/1830). Responding to the Sunderland outbreak, O'Shaughnessy chemically analysed the blood of cholera victims and showed that they had lost large quantities of water and saline salts. He published his findings in The Lancet — including 'Proposal of a New Method of Treating the Blue Epidemic Cholera by the Injection of Highly-Oxygenised Salts into the Venous System' (The Lancet, 10 December 1831). The logic was that the way to save these patients was to restore the blood to its natural state by injecting water and its normal salts directly into the veins.

But here is the essential distinction: O'Shaughnessy proposed it; he did not do it. He performed some animal experiments and made the theoretical and chemical case, but he never treated a cholera patient with intravenous fluid. He soon left for India, where he had an astonishing second career: he became the pioneer of the electric telegraph in India, building an experimental line near Calcutta in 1839 and the vast trans-India network, for which he was knighted in 1856. The telegraph connection is real and remarkable — but the IV drip was not his work.

It was Thomas Latta who read O'Shaughnessy's published work and had the courage and skill to put it into a living human being. He was the first person in history to do so.

The first intravenous saline infusion — the 1832 experiment

Latta first tried the cautious route of giving salt solution by mouth and by enema into the bowel. For the worst patients this produced 'no permanent benefit'. So, as he wrote, 'I at length resolved to throw the fluid immediately into the circulation. In this, having no precedent to direct me, I proceeded with much caution.'

His first subject was an aged woman in the terminal 'collapse' stage of cholera. In Latta's own unforgettable words: 'She had apparently reached the last moments of her earthly existence… so entirely was she reduced, that I feared I should be unable to get my apparatus ready ere she expired. Having inserted a tube into the basilic vein, cautiously — anxiously, I watched the effects; ounce after ounce was injected, but no visible change was produced. Still persevering, I thought she began to breathe less laboriously; soon the sharpened features, and sunken eye, and fallen jaw, pale and cold, bearing the manifest impress of death's signet, began to glow with returning animation; the pulse, which had long ceased, returned to the wrist… and in the short space of half an hour, when six pints had been injected, she expressed in a firm voice that she was free from all uneasiness, actually became jocular, and fancied all she needed was a little sleep.'

The apparatus was improvised from what was available: a Read's patent brass syringe — normally used for enemas or pumping poisons from the stomach — connected by flexible 'shammy leather' tubing to a cannula inserted into the basilic vein in the arm. The salt solution was strained through chamois leather and given warm. The composition Latta and his colleagues recorded was about two drachms of muriate of soda (common salt) and two scruples of carbonate of soda dissolved in about 60 ounces (six pints) of water — strikingly close to, though not identical with, a modern saline drip.

An honest reckoning — mixed results and the truth about the first patient

It is important to be honest about what happened next. That celebrated first patient recovered dramatically and then relapsed and died a few hours later, after Latta — exhausted — had left her in the care of the hospital surgeon. Many popular retellings omit this. Latta himself was, however, convinced of the principle, and subsequent patients did recover fully.

The wider results were genuinely mixed. The Leith and Edinburgh intravenous series carried a very high mortality, because Latta and his colleagues were deliberately treating only those patients on the very edge of death — patients other physicians had given up on. Reports from the time vary: Lewins reported 'three of six patients treated by Latta' recovered; he separately told the Central Board that '12 out of 15' intravenously treated patients had died across the wider Leith and Edinburgh effort; and a Drummond Street hospital tally (MacKintosh, 1836) gave 156 patients injected with 25 recovered — about 16% — reflecting that deliberate selection of the near-dead, not Latta's personal cases. Even so, lives were saved that would certainly have been lost.

Why the breakthrough was forgotten for half a century

Latta did not live to see his idea triumph. He died of tuberculosis on 19 October 1833, aged about 37, in Leith, the year after his breakthrough. With his death and the end of the epidemic, the technique fell out of use almost completely for around fifty years.

The reasons were as much scientific as practical. There was no germ theory, so contamination was inevitable and infections were common. There was no understanding of electrolytes or osmotic balance, so solutions varied wildly and were sometimes dangerous. There were no sterile needles, no glass IV bottles, no rubber tubing as we know it. And the medical establishment of the day, with its faith in bleeding, opium and calomel, was reluctant to accept that the answer to a terrifying disease might be six pints of warm salt water.

It was only in the 1880s, as germ theory took hold and the chemistry of blood was finally understood, that intravenous therapy began to be 'rediscovered' and refined. The IV drip we know today — sterile saline, glass and plastic bottles, controlled drip rates — is the heir of that long second chapter. But the principle, and the first proof that it worked in a human being, was Latta's.

Latta's place in medical history

Latta has almost no memorial. There is no portrait, no grave monument; even his birth year is an estimate, because his Presbyterian dissenting congregation did not enter births in the established Church registers. A modest street, Latta Place, was named in his honour in Edinburgh in 2014 — almost two centuries late.

Yet his contribution is monumental. Every one of the countless IV drips running in hospitals around the world today is a direct descendant of what Thomas Latta did, with a brass enema syringe and a tube of salt water, in Leith in 1832. The United States alone now gets through over 200 million litres of saline a year. The principle he proved — that you can save a dying patient by restoring fluid and salts directly to the blood — underpins resuscitation, surgery, intensive care, chemotherapy, dialysis and the everyday treatment of dehydration.

It is one of the great Scottish contributions to medicine, alongside Joseph Lister's antiseptic surgery, James Young Simpson's chloroform anaesthesia and the Glasgow Coma Scale. And it deserves to be remembered as such.

Frequently Asked Questions

Who invented the IV drip? The first intravenous infusion in a human being was performed by the Scottish physician Dr Thomas Aitchison Latta in Leith, the port of Edinburgh, in the spring of 1832. The underlying idea — to inject water and salts into the veins to treat cholera — had been proposed by the Irish chemist-physician William Brooke O'Shaughnessy in The Lancet in late 1831, but it was Latta who first put it into a living patient and reported the results.

Was Thomas Latta Scottish? Yes. Latta was born around 1796 at Jessfield House, near the fishing village of Newhaven on the Forth shore of Edinburgh. He was trained at the University of Edinburgh, graduated MD in 1819, and worked as a physician in Leith from 1822 until his death in 1833.

What was the first intravenous treatment? It was the injection of warm saline — about two drachms of muriate of soda (common salt) and two scruples of carbonate of soda dissolved in roughly six pints of water — into the basilic vein in the arm of a dying cholera patient in Leith, in the spring of 1832, using a Read's patent brass syringe and flexible 'shammy leather' tubing.

Why was intravenous saline revolutionary? Because for the first time it directly addressed the actual cause of death in cholera — catastrophic loss of fluid and salts from the blood — rather than relying on the bleeding, opium and calomel that defined orthodox 1832 medicine. It proved that the human circulation could be safely supplemented from outside the body, opening the door to every modern form of fluid resuscitation, blood transfusion and intravenous drug therapy.

How did Latta help cholera patients? By dissolving common salt and carbonate of soda in warm water and injecting six pints of the solution directly into the vein of a collapsing patient, Latta replaced the fluid and salts the disease had stripped from the blood. His first patient revived from apparent death within half an hour — 'became jocular', as he put it — and although she later relapsed, subsequent patients did recover fully, proving the principle worked.

Why is Thomas Latta important today? Because every IV drip in every hospital on Earth is a descendant of what Latta did in Leith in 1832. Intravenous therapy is now one of the most common medical interventions in the world — used in surgery, intensive care, chemotherapy, dialysis, resuscitation and the everyday treatment of dehydration — and it began with a Scottish doctor, a brass syringe and a bowl of warm salt water.