The Abernethy biscuit was invented by doctor John Abernethy in the 18th century as a digestive improver and hence aid to health.
Abernethy believed that most diseases were due to disorders in digestion. The Abernethy biscuit is a type of digestive biscuit, a baked good originally designed to be eaten as a support to proper digestion. In creating his biscuit, Abernethy was following a trend of other medical practitioners like English William Oliver of Bath, Somerset (invented the Bath Oliver) and the American preacher Sylvester Graham who was a nutrition expert (the Graham cracker).
The Abernethy biscuit is an adaptation of the plain captain's biscuit or hardtack, with the added ingredients of sugar (for energy), and caraway seeds because of their reputation for having a carminative (prevents flatulence) effect making them beneficial in digestive disorders. The biscuit is a mix between an all butter biscuit and a shortcake, raising through use of ammonium bicarbonate. According to The Oxford Companion to Food, a baker at a shop where Abernethy regularly had lunch created the new biscuit when Abernethy suggested it, naming it after him.
Abernethy biscuits are still popular in Scotland. They are manufactured commercially by Simmers (Edinburgh), The Westray Bakehouse (Orkney Islands), Walls Bakeries (Shetland Islands), and by Stag Bakeries (Isle of Lewis).