Perhaps the most varied and individual collection in the Special Collections of the Washington University Libraries, the Philip Mills Arnold Semeiology Collection now numbers approximately 1600 volumes, extending in time from the Ars Oratoria of Jacopo Publicio (Augsburg, 1490) to Charles Kasiel Bliss's International Semantography (Sydney, 1948-49), and ranging in subject matter from cryptography to the sign language of the deaf. Dealing with the nature and characteristics of communication, the collection emphasizes material which appeared at early stages of the development of interest in topics relevant to semeiology; later materials are treated selectively.

Semeiology, often referred to as semiotics, has been defined by Charles Morris as "a theory of signs in all their forms and manifestations, whether in animals or men, whether normal or pathological, whether linguistic or nonlinguistic, whether personal or social." It seeks to bring attention to the non-verbal aspects of communication, and their relationships with written and verbal expression. Signs, of course, might include the punctuation of a printed page or the pauses of a speaker, the notations used by a stenographer or the alphabet of a writer.

Perhaps one of the most recognizable signs is that of writing itself. Viewed in the Arnold Collection primarily as a means for conveying information, the semeiologist's concern is the development of various types of writing as seen, for instance, in the work of Bernard de Montfaucon or the alphabet books of the Congregatio de Propaganda Fide. Writing may be transformed into a means, or series of signs, for conveying secret messages by way of cryptography. A particularly strong aspect of the Arnold Collection, material in cryptography ranges from the earliest work on the theory of cryptography by Johannes Trithemius to the more practical essays of Francisco Martí and other modern writers. As another form of writing, shorthand has common origins with cryptography, hence the inclusion of Pierre Carpentier's work on the decipherment of the Latin shorthand known as Tironian notes, as well as the more practical La Plume Volante of William Mason. Likewise, cryptographic methods have proved to be an aid in unravelling the signs of unknown languages, as seen in John Chadwick's The Decipherment of Linear B. Such efforts not only increase our knowledge of written forms, but also extend our understanding of the ways in which language functions and communicates ideas.

Language itself, viewed as the structured means of sharing related concepts, affects and is affected by the signs it employs. A strong aspect of the Arnold Collection, the language area includes items on semantics, linguistics, and universal grammar. Study of the common features of languages by such writers as Antoine Court de Gébelin and Bishop John Wilkins reveals the nature of the signs of language, such as words and grammatical relationships. The use of language signs, or symbols, as a means of communication, either written (pasigraphy) or spoken (pasilaly), which overcomes the barriers of diverse tongues is pointed to in the works of such writers as Benajah Jay Antrim and Cave Beck.

Not only does language affect the signs we use, but signs may also be employed to stimulate or arouse concepts or words we intend to instill in ourselves or communicate to others. Another major portion of the Arnold Collection is devoted to this aspect of semeiology. The development of mnemonics in the classical and mediaeval periods of western civilization is a notable instance of this. Ramón Lull, for example, demonstrates how signs may be used to enable the mind to recall and combine in various ways words and concepts previously learned. Cosmas Rossellius writes of the use of a visual alphabet for clewing in one's memory to select words. The works of Giovanni Pierio Valeriano Bolzani and Henry Estienne illustrate the way in which signs, or emblems, can be used to convey abstract concepts to others.

Finally, the use of signs in non-verbal communication may take the form of signaling of words or ideas. Such a sign may be telegraphic, as seen in Claude Chappe's telegraph, whose purpose was the sending of a message to a distant point by means of visible signals. It may be a sign language for use by the deaf, as developed by Charles Michel de L'Epée. The sign may be tactual, as in the William Moon method of reading for the blind by way of the hand moving over an embossed page.

Several factors further enhance the significance of the Philip Mills Arnold Semeiology Collection for Washington University. It is complemented by the Isador Mendle Memorial Collection on the History of Printing, also housed in Special Collections. It provides material for several linguistics programs in the university. Most important, it brings together for scholarly use books and manuscripts, especially older titles, frequently scattered in diverse libraries. Lee Thayer has said of this subject that "a phenomenon as ubiquitous as communication, a phenomenon which trascends so many traditional boundaries, is destined to languish. Welcome everywhere as an issue, but homeless, belonging to everyone but no one, an illegitimate handmaiden of so many disciplines, communication languishes in its own amorphousness." The Arnold Collection illustrates the significance of semeiological studies, until recently a largely untapped area. One of the increasing number of interdisciplinary studies, semeiology is now coming into its own right.