The wide distribution of symbolic forms and the remoteness of their resemblance to the objects they symbolize led us to a consideration of the question of their history. We examined particularly the theory that all artistic reproduction is by origin naturalistic and that geometrization grows up only when the artist tries to introduce ideas that are not inherent in the object itself. We saw that this theory cannot be maintained, because realistic representation and geometrization spring from distinctive sources. In plastic art the contrast between the two tendencies does not appear as clearly as in graphic art. In the former it is found more in surface treatment than in general outline. In graphic art the matter is complicated by the difficulties involved in representing a three-dimensional object on a two-dimensional surface, a problem which the artist has to solve. This may be done in one of two ways. Either a perspective representation of the object as it appears at a given moment may be attempted, or the artist may decide that the essential point is to show all its characteristic parts, no matter whether they are visible in a single view or not. The former method lays stress upon the accidental features, it is impressionistic; the latter stresses those elements that are felt to constitute the fundamental qualities of the object, it is expressionistic. The two methods which we called the symbolic and the perspective are absolutely distinct and the one cannot be developed from the other. We have also seen that the consistent application of the perspective method is reached only when we introduce also the principle of indistinctness of those points that are removed from the center of the field of vision and that of dependence of color upon environment. Both of these have been tried in our day, without having found general acceptance. The symbolic method is always more or less wavering in the application of its principle. Sometimes perspective correctness of outline is attempted with a considerable degree of freedom in regard to the detailed treatment of those symbols that are considered important. Of this character are the Egyptian paintings with their vacillation between front and side views. In other cases the realism of outline is entirely sacrificed and the form may be reduced to a mere assembly of symbols.