The distinction between right and left has a certain inherent and more or less mysterious difficulty. To convince one's self of this it is only necessary to try a little experiment on the first fifty persons one chances to meet. The experiment is as follows. Say: "I am going to ask you a question and I want you to answer it as quickly as you can." Then ask: "Which is your right hand?" About forty persons out of fifty will answer correctly without a second's hesitation, several will require two or three seconds to respond, while a few, possibly four or five per cent, will grow confused and perhaps be unable to respond for five or ten seconds. Some very intelligent adults cannot possibly tell which is the right or left hand without first searching for a scar or some other distinguishing mark which is known to be on a particular hand. Others resort to incipient movements of writing, and since, of course, every one knows which hand he writes with, the writing movements automatically initiated give the desired clue. One bright little girl of 8 years responded by trying to wink first one eye and then the other. Asked why she did this, she said she knew she could wink her left eye, but not her right! One who is resourceful enough to adopt such an ingenious method is surely not less intelligent than the one who is able to respond by a direct instead of an intermediate association. It seems that normal people never encounter a corresponding difficulty in distinguishing up and down. The writer has questioned several hundred without finding a single instance, whereas a great many have to employ some intermediate association in order to distinguish right and left. It is the "p's and q's" that children must be told to mind; not the "p's and b's." The former is a horizontal, the latter a vertical distinction. Considering the difficulty which normal adults sometimes have in distinguishing right and left, is it fair to use this test as a measure of intelligence? We may answer in the affirmative. It is fair because normal adults, notwithstanding momentary uncertainty, are invariably able to make the distinction, if not by direct association, then by an intermediate one. We overlook the momentary confusion and regard only the correctness of the response. Subjects who are below middle-grade imbecile, however long they have lived, seldom pass the test. This test found a place in year VI of Binet's 1908 scale, but was shifted to year VII in the 1911 revision. The Stanford statistics, and all other available data, with the exception of Bobertag's, justify its retention in year VI. It is possible that the children of different nations do not have equal opportunity and stimulus for learning the distinction between right and left, but the data show that as far as American and English children are concerned we have a right to expect this knowledge in children of 6 years. VI, 2. FINDING OMISSIONS IN PICTURES