Index · The Agents · Nitrous Oxide

03.1Nitrous Oxide

Nitrous oxide is the clearest single case of the gap between knowing what a substance does and using it. It was prepared in 1772, its surgical possibility was printed in 1800, and it was still not established practice a lifetime later.

Preparation and description

The gas was prepared in 1772 during a period of intense work isolating what were then called different airs. At that stage it was one entry in a growing catalogue of gases, of interest because it was new rather than because it did anything useful. The serious investigation came at the end of the century, when a young chemist at a research institution devoted to the medical use of gases breathed it repeatedly, recorded the effects on himself in detail, and published a long account of the work in 1800.

That book is the founding document of the subject even though it produced no immediate practical result. It contains careful descriptions of the sensations produced, of the apparatus used to make and store the gas, and of the effects on other people who breathed it. It also contains a single sentence observing that, since the gas appeared capable of destroying physical pain, it might be used to advantage during surgical operations. The observation was printed, in a book that was widely read, forty-six years before anyone acted on it.

The exhibition years

What the gas became instead was entertainment. Through the first decades of the nineteenth century it was demonstrated at public shows and private gatherings, where volunteers breathed it and behaved amusingly, and it acquired the name laughing gas from exactly that context. Ether was used the same way at similar events.

This is the real reason for the delay. A substance whose public identity is a fairground amusement is not a candidate for serious professional use, and the association was strong enough to keep it out of the operating room for a generation. It also explains how the connection was finally made: it was made by people who attended the exhibitions and noticed something the audience was laughing at. Participants who injured themselves while intoxicated showed no sign of feeling it, and at least one observer in 1844 drew the obvious conclusion.

1844 and 1845

That observer arranged the following day to have one of his own teeth extracted while breathing the gas, and reported that he had felt nothing. Encouraged, he arranged a public demonstration in Boston a few weeks later. It failed. The patient cried out, the audience concluded the method was worthless, and the demonstrator's reputation did not recover.

The failure was almost certainly a matter of quantity and timing rather than of principle. Nitrous oxide is a weak agent: given alone and in air it will not reliably produce surgical insensibility, and the margin for error in a public setting with improvised apparatus is very small. The episode is a useful corrective to the idea that demonstrations settle questions. The same substance, in the same city, in front of the same kind of audience, produced a rejection in January 1845 and would have produced acceptance with a slightly different technique.

The long return

Ether arrived twenty-one months later and the gas was forgotten for most of two decades. Its eventual return came through dentistry rather than surgery, where the procedures are short and a weak, rapidly reversible agent is well suited to the task, and through the recognition that it need not be used alone. Given with oxygen, and later alongside other agents, its weakness became a virtue: it contributes to the effect without contributing much depth of its own.

The historical lesson is about how a technique becomes established. The chemistry was settled in 1772. The physiological observation was published in 1800. The clinical observation was made in 1844. None of that was sufficient, and what finally mattered was a reliable method of delivery and an understanding of the substance's limits. Discovery, in this record, is almost never the difficult part.