Bourne, exactly half Sargent’s age, was born in suburban New Jersey and had rarely left New York. He was a tough journalist, an adamantly left-wing intellectual, and a denizen of the city’s downtown bohemia. He was also, to many eyes, a freak: a five-foot-tall hunchback with a misshapen face. He was the kind of person Sargent did not paint. Sargent was the kind of artist Bourne disdained.

Image A photograph of the writer Randolph Bourne.

Yet in their different ways they shared a revulsion toward a war that had gripped the nation like a fever. Bourne’s view was history based. What the American government advertised as a principled war “to make the world safe for democracy,” he saw as a replay of the age-old marriage of ruling-class rapaciousness and militarism. When he put his ideas forward, friends backed away; journals censored him. He continued to work, in isolation.

Sargent’s war aversion was sudden and visceral. He originally envisioned painting a homage to gallantry. But in France, he visited a field hospital crowded with soldiers who had been exposed to mustard gas, a poison that burned the body inside and out. Horrified, he had his theme.

His mural-size “Gassed” ennobles its subject, but only somewhat. Its line of stricken soldiers has the poise of Greek frieze, but also the twitch of a dance of death. In the distance, beyond a field littered with bodies, a soccer game is underway.

“Gassed” was voted best painting of the year by the British Royal Academy of Arts in London. Bourne’s great essay, “The State,” was found unfinished in his wastebasket after he died of influenza, at 32, in New York. Both works have had only semi-visible afterlives. “Gassed” is often left out of standard accounts of Sargent’s career as being too uncharacteristic. Bourne’s writing is still known only to small circles of readers, and recently in ideological contexts that might have dismayed him.