of his own into it; he is struck by phrases or words in the document which correspond to his own ideas, or agree with his own _a priori_ notion of the facts; unconsciously he detaches these phrases or words, and forms out of them an imaginary text which he puts in the place of the real text of the author.[132] II. Here, as always in history, method consists in repressing the first impulse. It is necessary to be penetrated by the principle, sufficiently obvious but often forgotten, that a document only contains the ideas of the man who wrote it, and to make it a rule to begin by understanding the text by itself, _before_ asking what can be extracted from it for the purposes of history. We thus arrive at this general rule of method: the study of every document should begin with an analysis of its contents, made with the sole aim of determining the real meaning of the author. This analysis is a preliminary operation, distinct and independent. Experience here, as in the tasks of critical scholarship,[133] has decided in favour of the system of slips. Each slip will contain the analysis of a document, of a separate part of a document, or of an episode in a narrative; the analysis ought to indicate not only the general sense of the text, but also, as far as possible, the object and views of the author. It will be well to reproduce verbally any expressions which may seem characteristic of the author's thought. Sometimes it will be enough to have analysed the text mentally: it is not always necessary to put down in black and white the whole contents of a document; in such cases we simply enter the points of which we intend to make use. But against the ever-present danger of substituting one's personal impressions for the text there is only one real safeguard; it should be made an invariable rule never on any account to make an extract from a document, or a partial analysis of it, without having _first_ made a comprehensive analysis[134] of it mentally, if not on paper. To analyse a document is to discern and isolate all the ideas expressed by the author. Analysis thus reduces to _interpretative criticism_. Interpretation passes through two stages: the first is concerned with the literal, the second with the real meaning. III. The determination of the literal meaning of a document is a linguistic operation; accordingly, Philology (in the narrow sense) has been reckoned among the auxiliary sciences of history. To understand a text it is first necessary to know the language. But a _general_ knowledge of the language is not enough. In order to interpret Gregory of Tours, it is not enough to know Latin in a general way; it is necessary to add a special study of the particular kind of Latin written by Gregory of Tours.