physiologic and psychologic function. Individual experience is based upon native endowments and upon opportunities of environment. A bright child will observe and experience more than a dull child, and favorable or unfavorable home conditions-life in centres of civilization, or in the country; travel, companionship, and many other elements-will determine in a large measure the length of the radius of the circle which is covered by individual experience. Again, the effect of school training will depend upon the length and regularity of attendance, upon the personal influences of teachers and schoolmates, and upon the kind and character of the school the child has attended.

Some of these data will be obtained from the Child History information, and in a measure from the physical information. But much can be gained from a careful valuation of the response of the child to the tests themselves. In the final summary, a succinct statement of these facts should be given.

A. Visual Tests. It is of the utmost importance, in testing a child, first to make absolutely sure that he is in full possession of his sense-perceptions, that his senseorgans function rightly. Deficiencies or irregularities in this field deprive the individual of the opportunity to gather accurate impressions of the outside world, and to learn from these experiences as they are mediated through the senses. As a matter of fact, our knowledge and our mental operations are bound up with senseimpressions, and are dependent upon them. "Nihil est in intellectu quid non fuerit in sensu."

That school progress is closely interrelated with clear sense-perception needs hardly to be discussed. Be the instruction oral or from text-books, it can reach the

mind only through the sense-channel. Even the value of any mental tests, be they what they may, becomes doubtful unless the examiner first convinces himself that the child can see the things he is being tested with; can hear distinctly and with understanding what the examiner says, and has sufficiently accurate percepts otherwise of the subjects comprised in the examination. If such preliminary tests are not made, the examiner lays himself open to grave errors in diagnosis.

The blind child, also the child whose vision is merely impaired, cannot possibly receive the benefit of visual object-teaching, of pictures, or of the printed page. In the present time, visual impressions comprise the vast majority of all mental stimuli, and they are far more varied than any other sense-impressions.

The visualization of problems, quite apart from the perception of objects and their qualities, is a mental element of no mean importance. Judgment will depend in a large measure upon the power of visualization. (Cf. p. 126.) It enables the individual to grasp a situation, to get the perspective of things, to choose his path. Take, for instance, a test in this series, under P, 5, "Problem in Judgment." The problem the author uses is the follow ing: Imagine a short line of boys, or soldiers, marching in single file. Two are marching in front of one; two are marching behind one, and one is in the middle. How many boys (or soldiers)? Unless the child visualizes the situation accurately, he will fail to find the right answer: Three.

It will be seen that a majority of all tests require accuracy of vision as a "conditio sine qua non." The threading of needles, the imitation and concentration tests, the discrimination tests, the form-board tests, etc.,

all presuppose the child's ability to see normally, as a condition to perform something which may give the examiner information about other faculties.

In the educational clinic, sense tests can be made only in the rough, so to speak.

It is not the function of an educational clinic to transgress into the field of exact physiological and medical measurement and diagnosis. But it can and must ascertain the general faculty of sense-perception and discrimination, and detect danger-signals. The educational clinic will instantly refer the child to the medical specialist, who will examine the child with reference to the suspected defects, and only after his diagnosis is made and re

corded should the educational examination proceed. Distance Tests. In the distance tests the physiologic function alone is the object of the examination.

adapted to the power of the child to identify objects. Before the child knows his letters he may be supposed to identify objects. For this period of development the late Doctor Wendell Reber, of Philadelphia, has constructed a "Kindergarten Test Card" (published

by the McIntyre, Magee and Brown Co.) of which he says:

The chief points in the construction of any object test-card are that (1) it shall consist of objects readily recognized by little children; (2) the objects should conform as nearly as possible to the accepted scientific standard by subtending the correct angle for a distance of 6 metres. I doubt whether an absolutely scientific object test-card, in the sense just mentioned, will ever be constructed. In the very nature of things they will have to be approximations. . . . The first three objects (the dog, the horse, and the cat) are of value because they are almost immediately recognized by even very young children. . . . The remainder of the objects figured lend themselves more completely to the correct angular construction. The circle or ring is of value in estimating spherical errors. The flag and window are of value in indicating some variety of rectangular astigmatism, while objects like the star, the scissors, and the gate are of value in the indications they give as to some form of oblique astigmatism. Such objects as the hat, the hammer, the hand, and the cup are far from being scientifically satisfactory, but some objects must be introduced for variation and these have been found to serve fairly well.

Where a difficulty is found in the identification of these objects (this difficulty may be a mental one), it is well to employ still simpler methods of determining the physiologic function. The E-fork test was invented by the late Professor Herrmann Cohn, of Breslau, the pioneer in testing the eyes of school children. It presents the capital letter E in various positions, which can be indicated by the child with the use of a large pasteboard form of the letter, resembling a fork with three prongs.

A few years ago the McCallie Vision Tests (published by Edwin Fitzgeorge, Trenton, N. J.) have been brought into the market. The illiterate set of these cards are an inexpensive substitute for the Cohn test, representing a

boy, a girl, and a bear, playing hoop-ball; the ball is seen in different hoops and the child can state in which he sees it.

Children who know their letters can be tested with the ordinary Snellen test-cards, which are known to

FIG. 14.

McCallie's illiterate vision test.

every one; or with the "literate set" of the McCallie cards. In all cases great care must be taken to have proper illumination and to be sure of the distance from which the characters are recognized. Guard against guessing on the part of the child. Each eye must be tested separately, the vision of the other eye being ob