The very first step of rendering albumen suitable for use by photographers was breaking eggs. The albumen was then strained and frothed, using various devices of ingenious design. For example, M. Aleo's 1860 article On the Preparation of Positive Paper from the The Photographic News advises thus: "break the eggs into a graduated measure, carefully avoiding the mixture of yolk with the whites, and when the desired quantity of albumen is obtained separate the germs and pour the whites into a glazed earthen vessel." The 20th century articles found in this section of the Library also provide good narrative descriptions of albumen preparation (Reilly, 1978 and 1980) as well as dealing with issues of protein chemistry including characteristics of the various proteins found in albumen and the conditions by which they are denatured ( Messier, 1991; Vitale & Messier, 1994).