Bicarbonate bicarbonate – in conjunction with water, hydrogen ions, and carbon dioxide – forms this buffering system, which is maintained at the volatile equilibrium required to provide prompt resistance to pH changes in both the acidic and basic directions. This is especially important for protecting tissues of the central nervous system, where pH changes too far outside of the normal range in either direction could prove disastrous (see acidosis or alkalosis). Bicarbonate also serves much in the digestive system. It raises the internal pH of the stomach, after highly acidic digestive juices have finished in their digestion of food. Bicarbonate also
Digestive biscuit culture, the digestive is ranked the fourth most popular biscuit for "dunking" into tea, with the chocolate digestive coming in at number one. In 1839, digestives were first developed in the United Kingdom by two Scottish doctors to aid digestion. Digestives featured in advertisements for the Berkshire-based biscuit company Huntley & Palmers in 1876, with a recipe being given in Cassell's "New Universal Cookery Book" of 1894. In 1851 an issue of The Lancet London's advertising section offered "brown meal" digestive biscuits. At the time, it was asserted grain millers knew only of bran and endosperm. After 10% of the