A gastrolith is a stone swallowed by an animal, birds being the familiar example, to help grind food in its stomach. Mary F. C. Pratt's title sets up the joke before the poem begins. What follows is a mock etiquette guide to eating stones, delivered in a voice so poised that it never admits anything odd is going on. The poem is about class and taste. Its central idea is that the habit stays the same from the drawing room to the roadside, and only the presentation, and the price, change.
The deadpan is the main tool. The first stanza reads like a guide to correct behaviour, full of phrases such as "Traditionally," "has always been considered execrable taste," and "many discriminating people." Its details are absurdly precise. The rich "partook of diamonds" from bowls "subtly shaped / to show to advantage the clarity, the fire," and at embassy dinners a national flag is spelled out "in coloured gems" above the service plate. The vocabulary of fine dining (partook, service plate, butlers) is attached to something no one could digest. When "good cheap synthetics" arrive, the snobbery simply adjusts, and the fashion moves to obsidian or to "hand-knapped flints / from paleolithic sites in Middle Belgium or Southwest France." The most refined choice is the oldest and crudest human technology, stone tools, now sold as luxury. The tiny closing instruction, "A small monogram may be engraved on each," shows how far the fussiness goes.
The poem has no rhyme and no regular metre. Its long, prose-like lines imitate the unhurried voice of a manual, and the enjambment ("subtly shaped / to show to advantage") makes that voice sound smooth. The poem is built from lists, which suit a consumer's shopping mentality. The newly rich compare rivers, "the Amazon, the Volga, the Nile." They match stones to "decor," "dinnerware," and "the dining experience," a phrase borrowed from restaurant marketing. They garnish them with rose petals and then, in the driest line in the poem, "are careful to select compatible wines." The stones are treated as food while remaining stones.
The third stanza turns on the "Vegetarians, Progressives, and others of that ilk." The contemptuous "ilk" shows that the speaker is a snob, and the poem is partly mocking that snobbery. Yet these virtuous eaters are satirised too. Their "organic pebbles" come from "pure sources" and are scattered in "fountains of filtered rainwater." Ethical consumption is still a form of display. The stanza does contain one small difference: they swallow stones "whenever they feel the need." That phrase hints at appetite, which the rich ritual lacks.
The structure carries the argument. The stanzas shrink from fifteen lines to nine, then six, then four, so the poem itself gets poorer as it descends the social ladder. The last stanza drops the ornament:
"The poor grab whatever they can get:
broken cement, beach glass,
a handful of winter gravel
left over on the edges of the road."
"Grab" replaces "partook." The sentences are short, the nouns blunt, and the stones are no longer chosen, matched or served. They are "left over," the debris of other people's roads and building sites. Nothing is said about whether anyone is hungry, and the poem does not need to say it. The suggestion is that the rich swallow stones as a performance, while the poor swallow them because there is nothing else.
The poem is significant because it makes a familiar situation strange by taking the metaphor literally. Phrases like "a taste for luxury" or "consuming status" are everyday figures, but Pratt turns them into a dinner table where status is eaten, and the absurdity becomes visible. The comedy also has a hard edge. A diamond and a piece of gravel are equally indigestible, and the difference between them is in the handling and the audience. The poem lets us laugh at the monograms and the compatible wines, and then the final stanza removes the laughter and leaves only the gravel.