One dreads to imagine the desperation, the famine, that must have driven some ancient experimenter to quench their thirst with spilled blood that had been allowed to fester for days. Yet we should be fortunate that they did, for the brewing of soma stands alongside beer, writing and agriculture as one of the pillars on which early human civilization stood.

Like beer, soma was a product of fermentation. Unlike beer, which begins with wheat or barley, soma began with a mash of blood and pulped flesh as its chief ingredients, ultimately producing a sour but potable liquid. To ancient societies, it was a vital store of protein in lean times. It was venerated highly for its intoxicating euphoria, its reputed benefits to health and fertility, and, most of all, its remarkable ability to alter the appearance of those who consumed it.

When introduced into a blend of human or animal tissue, the humble yeast, Saccharomyces mutagenes, sets to work on the dying flesh, breaking down cell walls and disassembling the genome into a free-floating suspension of plasmids and proteins. When this mixture is consumed (often with a generous flavoring of spices to conceal the taste), the foreign genetic material slips inside the drinker's cells, rapidly rebuilding the body to fit the new blueprint of the 'donor material'. By adjusting the original wort, brewers learned to control the final result. The blood of a virgin maiden was thought potent enough to make a woman out of a man, while the remains of a sacred bull could be boiled down into a draught to grant beastly strength, even horns or hooves, to a warrior.

None of the science behind soma production was known to ancient brewers, of course; it was preserved instead in religious rituals and symbolic formulae. Its use in pagan rites led medieval religious authorities to suppress all knowledge of its creation, until by the 20th century it survived only as fable. Only with the archeological unearthing of sealed bottles of soma, has it experienced a revival, quite literally, with the strain of S. mutagenes successfully isolated and cultivated in a laboratory.

Research is ongoing. Translations of tablets recovered from the ruins of Ur have offered new insights, suggesting that soma may have been used in the domestication of animals through horizontal gene transfer - or, perhaps, more unsettlingly, in the animalisation of humans into the domesticated livestock breeds that we farm and eat today.