IT TOOK TWENTY YEARS , but from being one of the Mississippi valley’s most pestilent places, Memphis became one of the cleanest. There was a temporary setback in the autumn of 1879, when the work was only starting. A new epidemic of yellow fever hit. This time there were 2,000 cases and 583 deaths—and this time was the last. Though yellow fever raged again in the valley in 1888, 1897, and 1989, Memphis remained untouched. Its mortality rate from all causes dropped from 46.6 per thousand in 1872 to 21.5 per thousand as early as 1889. A medical journal marveled that the change in the city in a decade seemed “more like the tales of romance than the mere realization of a scientific and economic truth”—the truth being that sanitation paid off.

All the same, the change was too late for glory. The epidemic struck at Memphis when it was one of many cities scrambling to became a mercantile and industrial capital. While Atlanta, Birmingham, Dallas, and other rival towns were growing in numbers from 1870 to 1880, Memphis dropped from 40,000 to 33,000, and climbed to over 100,000 only by 1900. No one can prove that other towns would not have outgrown it in any case, thanks to advantages of location, and there are some who even hold that the “ruination” of Memphis by the yellow jack is a myth of local historians. But if a front-runner in a race trips and falls, then recovers and finishes far back in the pack, only stubbornness would maintain that the tumble had no effect at all.

Memphis emerged as a sanitary, modern city, but a measure of sophistication and cosmopolitanism had disappeared.

And Memphis was almost certainly set back in another way too. A paved, sanitary, outwardly modern city did replace the disheveled, overgrown, old river landing. But urban modernity is more than public works. Sophistication and cosmopolitanism figure in the equation, too, and these Memphis did not regain. Back-country blacks and whites replaced the vanished Catholic Irishmen as well as the Germans with their choral societies, beer gardens, and gymnastic clubs. By 1900 the foreign-born population of Memphis stood at under 10 percent.

The elite of the renewed city was a Southern rural elite. The city’s major historian, Gerald Capers, defined its cultural view: “From every man was demanded allegiance to four conventional ideals: to an unadulterated Protestant fundamentalism; to a fantastic entity called the Old South; to the principle of white supremacy; and, rather paradoxically, to the Constitution of the United States.”

Twentieth-century in externals, Confederate at heart, Memphis became renowned for Beale Street and Boss Crump (whose father died in the epidemic). Writing in 1938, Capers found the reborn city nothing like Christopher Wren’s London, built on the ashes of the Great Fire of 1666. “Hopelessly provincial,” Memphis lacked “that unnameable quality which conspicuously differentiates Boston, Charleston, and New Orleans from Pittsburgh and Kansas City.”

Things may have changed in Memphis (and Pittsburgh and Kansas City) in forty-six years, but nothing has transformed the city so rapidly and dramatically as three months of yellow fever did in 1878. And it will not happen again. Once Walter Reed and others had found that the mosquito was the essential element in sustaining an outbreak of yellow fever, the disease proved conquerable with screens for windows and doors and, later, with vaccines and eradication of the mosquito from the Western Hemisphere. Yellow fever disappeared from American cities after 1905. And one by one, other epidemic diseases fell before the advance of research.

So although we who live in cities today have our share of plagues—crime, pollution, economic decay, abandonment—we need no longer fear mass death by viral infection.