REMARKS. It is interesting to follow the child's acquisitions of language distinctions relating to spacial orientation. Other distinctions of this type are those between up and down, above and below, near and far, before and behind, etc. As Bobertag has pointed out, the child first masters such distinctions as up and down, above and below, before and behind, etc., and arrives at a knowledge of right and left rather tardily. How may we explain the late distinction of right and left as compared with up and down? At least four theories may be advanced: (1) Something depends on the frequency with which children have occasion to make the respective distinctions. (2) It may be explained on the supposition that kinæsthetic sensations are more prominently involved in distinctions of up and down than in distinctions of right and left. It is certainly true that, in distinguishing the two sides of a thing, less bodily movement is ordinarily required than in distinctions of its upper and lower aspects. The former demands only a shift of the eyes, the latter often requires an upward or downward movement of the head. (3) It may be due to the fact that the appearance of an object is more affected by differences in vertical orientation than by those of horizontal orientation. We see an object now from one side, now from the other, and the two aspects easily blend, while the two aspects corresponding to above and below are not viewed in such rapid succession and so remain much more distinct from one another in the child's mind. Or, (4), the difference may be mainly a matter of language. The child undoubtedly hears the words _up_ and _down_ much oftener than _right_ and _left_, and thus learns their meaning earlier. Horizontal distinctions are commonly made in such terms as _this side_ and _that side_, or merely by pointing, while in the case of vertical distinctions the words _up_ and _down_ are used constantly. This last explanation is a very plausible one, but it is very probable that other factors are also involved.