Twain didn't just want mussels; he wanted steamed mussels, from San Francisco. He wanted terrapin from Philadelphia, stewed with sherry and cream (the recipe's main rival, from Baltimore, omitted the cream—Twain loved cream). He wanted partridge from Missouri, shad from the Connecticut River, and perch and canvasback ducks from Baltimore. The list went on. These were things that depended on the grasslands, woods, and waters of especially American places. And they were things that, in Twain's youth, could be found nowhere else.
In fact, Twain was so exact about wild foods because, during years of rambling travels, he'd tasted them all at their best—which meant eating them where they were from. He'd eaten prairie-chickens as a boy in Hannibal, Missouri, just across the river from the great tallgrass, and terrapin as a printer's assistant in Philadelphia. He'd eaten sheepshead and croaker fish as a steamboat pilot in New Orleans, and Lahontan cutthroat trout in Tahoe when he fled west, away from the draft agents of the Union and Confederate armies. In a very real sense, his menu was a memoir of fondly remembered travels, from the prairies to the mountains and from the New Orleans docks to the backstreets of San Francisco.
So Twain understood something about the rootedness of America's wild foods, and how they both relied on and helped shape the places they came from. When Twain was at Tahoe, for example (the first time was in the autumn of 1861), the lake's Lahontan cutthroat trout were simply colossal; the record specimen weighed in at over 31 pounds. It's hard to read about Twain eating such a fish, fried simply in bacon fat, and not think of Tom Sawyer's discovery in the eponymous novel that "open air sleeping, open air exercise, and a large ingredient of hunger" make freshwater fish incomparably delicious, especially when the fish has been swimming an hour before. And it's impossible not to reflect that Twain's description of Tahoe as the "masterpiece of the universe" must have owed something to his knowledge of the titans drifting in the depths.
After he left Tahoe for the last time, Twain never tasted its trout again. Other foods of the feast, though, he did encounter later in life. When he hunted prairie-chickens as a boy, some 12 million of the large grouse nested in the Illinois tallgrass; during mating season, their booming calls were a nearly physical presence. But by 1879, soon after Twain's return from Europe, a friend of Twain's could send a brace of prairie-chickens as a Christmas present to his Hartford home, shipping them over some of the many miles of new railroad that were steadily erasing the culinary boundaries between Hannibal and New York. A few decades after that, the birds were nearly gone, victims of the John Deere self-scouring steel plow that converted their habitat to cornfields (today a spare 300 remain in Illinois).

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It's no longer responsible or realistic to eat wild foods in the same amount and variety that Twain did, as modern stresses on oceanic fish amply prove. But, though Twain was most precise when speaking about wild foods, his favorite dishes were all fresh, local, and lovingly prepared; writing of them, he used words like earnest and generous, genuine and real. Whether wild or domestic, the dishes were based less on recipes than on the quality of the ingredients. At its heart, Twain's feast was about the connection between food and place, the way that the things that sustain us depend upon places we remember and love. That lesson remains as vital as ever.