Merda d’artista is an edition of 90 signed and numbered works that Manzoni said he made from his own excrement. Each is a 30-gram can of shit, measuring 4.8 x 6.5 cm, “freshly preserved, produced and tinned”, as stated on the label. This information appears in Italian, French, German and English, against a background pattern produced by repeating the artist’s name in block letters. Because Manzoni sold each can by weight at gold’s daily market price, the shit literally became worth its weight in gold. In retrospect, this has proved to be a bargain. At $35.20 (£18.07) per ounce – the price at which the London Gold Pool (an international consortium of central banks) wanted to fix the precious metal – a tin originally would have cost about $37. That was 1961. Thirty years later, Sotheby’s auctioned one for $67,000. Then, the price of gold had climbed to $374 per ounce. If Manzoni’s initial pricing scheme still held, it should have cost only $395.77. In other words, in 1991 Merda d’artista had outperformed gold in price by more than 70 times.