Moon-milk was very thick, like a kind of cream cheese. It formed in the crevices between one scale and the next, through the fermentation of various bodies and substances of terrestrial origin which had flown up from the prairies and forests and lakes, as the Moon sailed over them. It was composed chiefly of vegetal juices, tadpoles, lentils, bitumen, honey, starch crystals, sturgeon eggs, molds, pollens, gelatinous matter, worms, resins, pepper, mineral salts, combustion residue. You had only to dip the spoon under the scales that covered the Moon’s scabby terrain, and you brought it out filled with that precious muck. Not in the pure state, obviously; there was a lot of refuse. In the fermentation (which took place as the Moon passed over the expanses of hot air above the deserts) not all the bodies melted; some remained stuck in it: fingernails and cartilage, bolts, sea horses, nuts and peduncles, shards of crockery, fishhooks, at times even a comb. So this paste, after it was collected, had to be refined, filtered. But that wasn’t the difficulty: the hard part was transporting it down to the Earth.
— Italo Calvino, “The Distance of The Moon” (1965)