The importance of the study of picture-writing depends partly upon the result of its examination as a phase in the evolution of human culture. As the invention of alphabetic writing is admitted to be the great step marking the change from barbarism to civilization, the history of its earlier development must be valuable. It is inferred from internal evidence, though not specifically reported in history, that picture-writing preceded and generated the graphic systems of Egypt, Assyria, and China, but in America, especially in North America, its use is still current. It can be studied here without any requirement of inference or hypothesis, in actual existence as applied to records and communications. Furthermore, the commencement of its evolution into signs of sound is apparent in the Aztec and the Maya characters, in which transition stage it was arrested by foreign conquest. The earliest lessons of the genesis and growth of culture in this important branch of investigation may, therefore, be best learned from the western hemisphere. In this connection it should be noticed that picture-writing is found in sustained vigor on the same continent where sign language has prevailed and has continued in active operation to an extent historically unknown in other parts of the world. These modes of expression, i. e., transient and permanent thought-writing, are so correlated in their origin and development that neither can be studied to the best advantage without including the other. Unacquainted with these facts, but influenced by an assumption that America must have been populated from the eastern hemisphere, some enterprising persons have found or manufactured American inscriptions composed of characters which may be tortured into identity with some of the Eurasian alphabets or syllabaries, but which sometimes suggest letters of indigenous invention. This topic is discussed in its place.
For the purposes of the present work there is no need to decide whether sign-language, which is closely connected with picture-writing, preceded articulate speech. It is sufficient to admit the high antiquity of thought-writing in both its forms, and yet it is proper to notice a strong current of recent opinions as indicated by Prof. Sayce (_a_) in his address to the anthropologic section of the British Association for the Advancement of Science, as follows: