Liquid nitrogen evaporates, and can cause violent oxidation of organic material. Ingestion of liquid nitrogen can cause severe internal damage, due to freezing of the tissues which come in contact with it and to the volume of gaseous nitrogen evolved as the liquid is warmed by body heat. In 1997, a physics student demonstrating the Leidenfrost effect by holding liquid nitrogen in his mouth accidentally swallowed the substance, resulting in near-fatal injuries. This was apparently the first case in medical literature of liquid nitrogen ingestion. In 2012, a young woman in England had her stomach removed after ingesting a cocktail made with
Vanilla ice cream the middle of the eighteenth century, French recipes for ice cream started to include egg yolks. When the use of vanilla in foods and drinks became independent of cacao, it became more prominent in French recipes. The French used vanilla to flavor French vanilla ice cream. Vanilla ice cream was introduced to the United States when Thomas Jefferson discovered the flavor in France and brought the recipe to the United States. During the 1780s, Thomas Jefferson wrote his own recipe for vanilla ice cream. The recipe is housed at the Library of Congress. To make ice cream in the United