There is, of course, a place, and an important place, for observation of the mere static qualities of objects. When, however, the primary interest is in _function_, in what the object does, there is a motive for more minute analytic study, for the observation of _structure_. Interest in noting an activity passes insensibly into noting how the activity is carried on; the interest in what is accomplished passes over into an interest in the organs of its accomplishing. But when the beginning is made with the morphological, the anatomical, the noting of peculiarities of form, size, color, and distribution of parts, the material is so cut off from significance as to be dead and dull. It is as natural for children to look intently for the _stomata_ of a plant after they have become interested in its function of breathing, as it is repulsive to attend minutely to them when they are considered as isolated peculiarities of structure. [Sidenote: Scientific observation] III. As the center of interest of observations becomes less personal, less a matter of means for effecting one's own ends, and less æsthetic, less a matter of contribution of parts to a total emotional effect, observation becomes more consciously intellectual in quality. Pupils learn to observe for the sake (_i_) of finding out what sort of perplexity confronts them; (_ii_) of inferring hypothetical explanations for the puzzling features that observation reveals; and (_iii_) of testing the ideas thus suggested. [Sidenote: should be extensive] [Sidenote: and intensive]