There are two chief ways in which historians deal with their subject-matter, though the moderns combine them. When oral tradition gives place to written records the lineal descendant of the bards and annalists collects his scanty authorities and compiles his story from them from beginning to end. The Anglo-Saxon Chronicle of Bede and Alfred, the Book of Howth, the works of Giraldus Cambrensis, the Chronicles of Froissart and the Memoirs of de Comines were composed in the only way that was then possible. But the muse of history entered on a deeper and more fruitful course when about ninety years ago the study of documents became an essential feature of historical work. It was then that the historian grew up, entered upon his finest inheritance and assumed his Greek title, Enquirer, Student of facts, Man of research. He is now nothing if not a man of science as well as of letters. With a wealth of documents within his reach so great that the 3239 Vatican cases full of them formed by no means the richest collection in the archives of Europe, he proceeds to read backwards correctly what many an earlier annalist read forwards falsely. “We are still at the beginning of the documentary age which is destined to make history independent of historians, to develop learning at the expense of writing, and to accomplish a revolution in other sciences as well.”[1] [1] Acton. _A Lecture on the Study of History_, p. 19. The Historian a Biologist. It is not too much to say that he who studies history, national, political, constitutional, ecclesiastical, military or economic is as much a biologist in the widest sense as the botanist and zoologist. Indeed these were till recently termed students of natural _history_, until the advance of knowledge gave us the various special groups of workers, conveniently called biologists. Though the study of human history by documents is an essential part of the historical method and the student may read _his_ subject backwards, this would not of itself warrant the technical biologist in doing so, even though he be a child of Nature and part of her--“Nature’s insurgent son.” But some reflection on the facts of certain provinces of science affords ample justification for the method. It is chiefly in questions of origin that it avails, while it fails in that form of research by experiment which is the glory of modern science. A few examples of the process of passing from the known to the unknown will illustrate the method. Darwin. Much of the _Origin of Species_ and all of the _Descent of Man_ was founded on this method; thus in the former the conceptions of struggle took their main rise from the work of Malthus on Human Population, and of variation from domesticated animals and plants, and this is true also of Wallace. A mere glance at the divisions of _The Descent of Man_ shows that it could never have been attempted in any other than the backward way. Geology.