and Evanston. Both the ice cream cone and banana split became popular in the early 20th century. The first mention of the cone being used as an edible receptacle for the ice cream is in Mrs. A.B. Marshall's Book of Cookery of 1888. Her recipe for "Cornet with Cream" said that "the cornets were made with almonds and baked in the oven, not pressed between irons". The ice cream cone was popularized in the US at the 1904 World's Fair in St. Louis, Missouri. The history of ice cream in the 20th century is one of great change and increases in availability and popularity. In the United States in the early 20th century, the ice cream soda was a popular treat at the soda shop, the soda fountain, and the ice cream parlor. During the American Prohibition, the soda fountain to some extent replaced the outlawed alcohol establishments such as bars and saloons. Ice cream became popular throughout the world in the second half of the 20th century after cheap refrigeration became common. There was an explosion of ice cream stores and of flavours and types. Vendors often competed on the basis of variety: Howard Johnson's restaurants advertised "a world of 28 flavors", and Baskin-Robbins made its 31 flavors ("one for every day of the month") the cornerstone of its marketing strategy (the company now boasts that it has developed over 1000 varieties). One important development in the 20th century was the introduction of soft ice cream, which has more air mixed in, thereby reducing costs. The soft ice cream machine fills a cone or dish from a spigot. In the United States, chains such as Dairy Queen, Carvel, and Tastee-Freez helped popularize soft-serve ice cream. Baskin-Robbins would later incorporate it into their menu. Technological innovations such as these have introduced various food additives into ice cream, most notably the stabilizing agent gluten, to which some people have an intolerance. Recent awareness of this issue has prompted a number of manufacturers to start producing gluten-free ice cream. The 1980s saw thicker ice creams being sold as "premium" and "super-premium" varieties under brands such as Ben & Jerry's, Chocolate Shoppe Ice Cream Company and Häagen-Dazs. Composition Ice cream is a colloidal emulsion made with water, ice, milk fat, milk protein, sugar and air. Water and fat have the highest proportions by weight creating an emulsion that has dispersed phase as fat