ing them are their natural expression. A child said "Blessed are the shoe-makers," etc. When he had heard the word "peacemakers," no correct idea had been gained through the word and the expression linked itself with the nearest known idea. The following mistakes illustrate the same point. A child heard the verse: "A double-minded man is unstable in all his ways." He rendered it thus: "A double-minded man is in the stable all the time." A child said: "An average is what a hen lays on." He had heard some one say that "a hen lays on an average one hundred eggs in a season." I said to my boy of three: "That is a freight train." "Why is it afraid?" said he. Children on first seeing snow on the ground frequently call it sugar or salt. As it floats down they hail it as feathers or as butterflies. A child on seeing a pot of ferns called it a pot of green feathers. James says the sail of a boat is called a curtain by the child. His "child of two played for a week with the first orange that was given him, calling it a ball.' He called the first whole eggs he saw 'potatoes,' having been accustomed to see his 'eggs' broken into a glass, and his potatoes without the skin. A folding pocketcorkscrew he unhesitatingly called 'bad scissors."" Children unreflectingly often mistake new words for those that are similar. A "guardian" is thought to be a "gardener," a "salon" a "liquorshop." They make many curious errors in interpreting words having a variety of meanings. They think "dressed beef" has on some sort of clothing. A class of mine were told one day that we send ministers to England and other foreign lands. One child reported the next day that we sent preachers to England. The children in an upper grammar class of Berlin were asked what mountain (Berg) they had seen and all answered Pfeffenberg, the name of a beer-house near by. For all of them Berg meant a place of amusement. This, as Dr. Hall says, would cause an entire group of geographical ideas to miscarry. My children had heard us talk about picking out (selecting) goods from a catalogue. One boy of two years brought me a catalogue opened to a picture of a horse and asked me to "pick it out" expecting a real live horse to be taken out. A boy of two said: "I saw the trains unhitch." Another child asked a deaf person: "Are you blind in your ear?" A farmer's boy of ten inquired: "Will bees sting when they are not sitting?" (His experience with cross sitting hens had made him suspicious.)

12. How Do Children Differ from Adults in Sense

Perception?

[NORSWORTHY, Naomi and WHITLEY, Mary T., Psychology of Childhood, pp. 115-117. Copyright, 1923, by the Macmillan Co. Reprinted by permission.]

The chief differences between the sense perception of adults and of children grow out of these facts of development. In general, children lack in richness, in definiteness, and in detail of sense perceptions.

Another striking difference between the perceptions of children and adults is the difference in the amount of stimulus necessary to call up a percept.

...

. . . A third difference between children and adults in their perception lies in the power of "mind's set," or the passing mental content to determine the percept. Every one is influenced by the state of mind he is in as to what he will think in the next few minutes, and a previous mood is a strong factor in determining his point of view. We all tend to see or hear or feel what we expect; witness the tragic results that have come from simple fraternity initiations. But the child, because of the characteristics of his attention, is even more influenced by the passing mental state. Two important practical precepts grow out of this fact. In the first place, it is very necessary that with a child the aim of the work be kept very clearly in mind; he should know very definitely what he is to look for or to do if results worth while are to be obtained. In the second place, new material in any line should not be given until the child has had time to warm up, to adapt himself to the new line of work. To plunge a class immediately into new work in geography or reading when their thoughts have not yet had time to get out of the arithmetic system, leads to a waste of time and confusion. There is need of "preparation" of the child's mind by getting him into the other system before new material is presented.

13. The Use of Object Lessons

[DEWEY, John, School and Society, pp. 24-25. Chicago, University of Chicago Press, 1900.]

No number of object-lessons, got up as object-lessons for the sake of giving information, can afford even the shadow of a substitute for acquaintance with the plants and animals of the farm and garden, acquired through actual living among them and caring for them. No training of sense-organs in school,

introduced for the sake of training, can begin to compete with the alertness and fullness of sense-life that comes through daily intimacy and interest in familiar occupations. Verbal memory can be trained in committing tasks, a certain discipline of the reasoning powers can be acquired through lessons in science and mathematics; but, after all, this is somewhat remote and shadowy compared with the training of attention and of judgment that is acquired in having to do things with a real motive behind and a real outcome ahead.

14. Errors of Perception: Illusions

[TURNER, E. M., and BETTS, G. H., Laboratory Studies in Educational Psychology, p. 52. New York, D. Appleton & Co., 1924.]

Inadequate interpretation of objectively existing stimuli often results in an error of perception, that is, an illusion. When one mistakes the rustling of the wind for the approaching footstep of a friend, he is experiencing an illusion. An illusion is thus a false perception which is experienced under like conditions by practically all normal people, who, however, as a result of a more extended experience recognize the error of perception. The study of illusions and their causes aids one in understanding more thoroughly the process of perception.

15. Visual Defects

[TURNER, E. M., and BETTS, G. H., Laboratory Studies in Educational Psychology, pp. 24-26. New York, D. Appleton & Co., 1924.]

The teacher and the educational psychologist need to know how to determine the existence of sensory defects, particularly of the eyes and ears-the two most important avenues for obtaining information. The external stimulus has little effect if the sense organs do not respond. For the present, we are concerned with the visual defects.

In the normal eye parallel rays of light are focused directly upon the retina when the eye is at rest; that is, the refraction of the eye is normal and the retinal image is perfect. This condition is known as emmetropia.

The most common visual defects are due to some form of ametropia, that is, a defect in the shape of the eyeball, lens, or cornea which causes errors in refraction and hence a defect in the formation of the retinal image. The forms of ametropia are: myopia, hyperopia, and astigmatism. Myopia, or shortsightedness, is commonly produced by too long an eyeball, so

that the rays of light coming from an object beyond a certain distance are focused in front of the retina, hence when the rays finally impinge upon the retina a blurred image results. Myopia, in itself, usually causes no eye strain, but there is an effort of the muscles of the forehead and eyelids, thus causing strain and headaches. Unless discovered and checked by properly fitted concave lenses (which should be worn constantly) and also supplemented by cautious use of the eyes (that is, holding book and work at a proper distance from the eyes, etc.), myopia may increase in degree and with other complications result in blindness. Myopia may be found with other defects such as astigmatism.

Hyperopia, or far-sightedness, is commonly produced by too short an eyeball, so that the rays of light are intercepted too soon, thus being prevented from being brought to a normal focus; that is, the image would be formed at a point back of the retina if the rays of light were extended. The strain upon the muscles which attempt to accommodate the crystalline lenses in order to form as clear an image upon the retina as possible, is severe, especially for near objects. Hyperopia is frequently accompanied by one or more of the following symptoms; frontal or occipital headache; inflammation of the eyes, lids, or conjunctiva; and often a twitching pain within the eyeball. Students suffering from hyperopia may hold their work at some distance from the eyes, but in very severe cases, in order to increase the size of the image, they often hold the book near the eyes, thus giving the appearance of myopia. Properly fitted convex lenses (which should be worn constantly) tend to correct, but do not cure the errors of refraction causing this condition.

Astigmatism is due to the fact that the curvature of the cornea, or, less commonly, the lens, is not the same in all directions. The rays of light from some parts of the field of vision, due to the uneven radius of the curvature, may be focused either in front of the retina, as in myopic astigmatism, or intercepted too soon and therefore would, if they were extended, be focused at a point back of the retina, as in hyperopic astigmatism. Astigmatism may also be the result of a combination of these two conditions. Due to this condition one portion of the field of vision will be blurred while another will be clear and distinct. The surface of the cornea is normally spherical in form, but in astigmatism the cornea is curved more in one axis, or meridian, than in another. In correcting the errors of refraction due to this condition (it cannot be cured), a cylindrical lens of the proper curvature must be so placed before the eye that

it is at the proper axis to counteract the improper refraction. More than one-half of the headaches are considered to be caused by astigmatism. Astigmatism exists in a mild form in practically all people, and is often complicated with other visual defects. In fact, the various forms of ametropia commonly appear in combinations and also commonly are unlike in the two eyes of the same individual.

We have omitted from our discussion presbyopia, far-sightedness of old age, which, strictly speaking, is not a form of ametropia but is an anomaly of accommodation appearing in most people after the age of forty.

16. Color Blindness

[TURNER, E. M., and BETTS, G. H., Laboratory Studies in Educational Psychology, p. 34. New York, D. Appleton & Co., 1924.]

The occurrence of color blindness "in from 3 to 4 per cent of males and in only 0.3 of females," makes this condition not only one of theoretical interest but also of practical importance. The pupils who confuse red and green are at a disadvantage in such school work as domestic science, nature study, and other work in which color discrimination is involved. Various occupations such as railroading, medicine, chemistry, etc., ought to be closed to color-blind persons.

The most common confusion is the inability to discriminate between red and green. Violet blindness (also known as blueyellow blindness) almost never occurs, and in fact its existence is in much dispute. Total color blindness does exist, but it is rare and is probably due to a pathological defect. A number of theories have been proposed to explain color vision and color blindness, but no one theory so far advanced satisfactorily explains all the known facts, therefore these theories will not concern us here.

17. Auditory Acuity

[TURNER, E. M., and BETTS, G. H., Laboratory Studies in Educational Psychology, pp. 37-38. New York, D. Appleton & Co., 1924.]

The presence of even partial deafness in either one or both ears interferes with the pupil's progress in school work. Often subnormal hearing is the forerunner of such conditions as total deafness and mastoiditis. The teacher ought to be able to discover cases of partial deafness so that these pupils might be