The overtasked teacher finds a child slow, and places it with more backward children, which increases its slowness. A more exact test of the child's mind may show that it is indeed slow, but that the slowness is more than counterbalanced by intensity and range. Methods must be applied which will shorten the time of thought, and will not interfere with its force and extent. We can determine what size and composition of class, what length of lesson, session, and term are most favorable. We can learn whether it is better for the student to do a thing, to see it, to hear it, or to read about it. We can never build a road to learning which need not be traveled by the student, but we can build a royal road in the sense that it is the shortest and best of roads. Above all, our tests and measurements will demonstrate the value of learning itself, and tell us whether under given circumstances it is secured by the development or sacrifice of more essential qualities, such as health of body, serenity of mind, common sense, honesty, and kindliness.
In laboratories of psychology not only children but every one can be tested, and small defects or changes in the senses and faculties can be discovered. Psychology may thus become an ally of medicine. Degenerations which escape common observation, and even the practiced eye of the physician, can be detected and measured by scientific methods. The overstrained clergyman or man of business can be told when a holiday is necessary, how long it must last, whether rest or amusement be required. As an example of the co-operation of psychology and medicine, surgery of the brain can be given. The part of the brain which is diseased is determined by psychophysical methods, the skull is opened, the diseased part of the brain is removed, and the patient may be cured. Psychological methods are useful not only in the diagnosis but also in the cure of many diseases. We know much better than formerly how the insane, the vicious, and the criminal should be treated. We know, for example, that social work is far better than solitary confinement. Even diseases not directly dependent on the nervous system may be cured by psychophysical methods—for example, suggesting to the patient in the hypnotic state that he will be cured.
Those in good health may also profit from an examination in a laboratory of psychology. Valuable traits can be determined as well as defects, and the profession and mode of life most suitable to the person can be indicated. As has been suggested by Mr. Galton, such tests would be peculiarly useful in civil-service examinations. They would determine the real qualities and fitness of the candidate in addition to (or in place of) the superficial knowledge temporarily acquired by "cram." While we have but little power to alter the individual character, we could exert
