=13. Reconnaissance and investigation.= In striving to indicate the true value and worth of ecological study, it becomes necessary to draw a definite line between what we may term _reconnaissance_ and _investigation_. By the former is understood the preliminary survey of a region, extending over one or two years. The objects of such a survey are to obtain a comprehensive general knowledge of the topography and vegetation of the region, and of its relation to the other regions about it. The chief purpose, however, is to gain a good working acquaintance with the flora: a reconnaissance to be of value must do this at all events. Certain general facts will inevitably appear during this process, but they will invariably need the confirmation of future study. It would be an advantage to real ecology if reconnaissance were to confine itself entirely to the matter of making a careful floristic survey. Investigation begins when the inquiry is directed to the habitat, or to the development and structure of the formation which it bears, i. e., when it takes up the manifold problems of the οἶκος. Such a study must be based upon floristic, but the latter becomes a part of investigation only in so far as it leads to it. Standing by itself, it is not ecological research: it is the preparation for it. This distinction deserves careful thought. The numerous recruits to ecology have turned their attention to what lay nearest to hand, with little question as to its value, or to where it might lead. The result has been to make reconnaissance far outweigh investigation in amount, and to give it a value which properly belongs to the latter. Furthermore, this mistaken conception has in many cases, without doubt, prevented its leading to valuable research work.