desire to form such habits, by a rational exercise of the attentive activity, and by permitting no exceptions while the habit is being formed. (y) The consciousness that one is not the slave of old habits, but can put forth effort in the successful formation of new habits, is of great value to the learner. (z) In training the habit of attention, the following should receive special emphasis: 1. The selection of only those things which are 3. The selection of only those representative ideas 4. The establishing of permanent relations by keeping the mind moving along related points. 5. The habit of continuous effort, established by holding the mind rigidly to a definite line of investigation for a definite period of time. 6. The grasping of large wholes in one act of attention. 7. The acquisition of valuable knowledge. 8. The practical application of the knowledge gained. CHAPTER VI The Psycho-physical Organism What effect does the reception of bad news exert upon the appetite? What effect does fear exert upon the power to do physical work? What effect does an aching tooth exert upon the power to do mental work? Give similar examples of the effect of the Physical on the Psychical and vice versa. Explain the educational importance of having "a sound mind in a sound body." The question of the relation of mind and matter has occupied the attention of Philosophers for centuries. It is a problem of Metaphysics rather than of Educational Psychology, and we shall not attempt to investigate it. We shall take for granted the reality of both mind and body and shall confine our attention to them as united in the Psycho-physical Organism of our life experience. As we have already seen, our experience is always that of a self-active, undivided personality moving forward in the attainment of its life purposes. In our analysis of conscious process we shall find it convenient at times in this and succeeding chapters to consider elements as separate which are never found thus isolated in consciousness, e.g., on p. 63, we speak of e, as representing a Sensation. It is important to bear in mind that such abstraction and differentiation is made solely for purposes of investigation, and that a sensation never appears by itself thus differentiated, but is only one aspect of a complex process involving all other mental activities. I. THE NERVOUS SYSTEM: A person rings a bell where you can hear it and at the same time holds up a red card where you can see it. Describe the changes in your consciousness which result from these acts. Describe the bodily organism by means of which you heard the sound of the bell, and that by means of which you saw the red color. Point out differences between the ear and the eye and show that each is adapted to the special work which it performs. Describe the Nervous System. Procure specimens of eye, ear, brain and spinal cord, and dissect them. By such dissection and with the assistance of textbooks obtain a working knowledge of the genesis, structure and function of the nervous system. The Special Senses. Name five senses. Muscular Sense.-Lift a weight and cause the muscles of the arm when lifting to twist or roll upon one another. Note the peculiar sensation. Similarly roll the eyeball and note the feeling. Such sensations are called Kinæsthetic and are said to belong to the muscular sense. When the optic nerve is mechanically stimulated (e.g., when a heavy blow is received on the head), what sort of sensation results? When the same nerve is electrically stimulated, what is the result? Can stimuli of any kind, applied to the optic nerve, result in any other sensations than those of light and color? Can a stimulus acting upon any other nerve produce sensations such as come to you from a different sense? Why may "touch" be considered to be "the foundation sense"? Point out differences between a sensation of hunger and a sensation of sight. Senses such as sight, hearing, etc., the nerve endings of which are exposed to external stimulus, are called special senses. Senses such as hunger, which aid in administering to the needs of the body, are called general senses. Point out distinctions between these two classes of sensations. Sensations from the special senses are always occasioned by stimuli, and the stimulus normally acts on the end organ in some form of motion. "Vibrations of a lower rate than about 24 per second affect us only through the sense of touch. Above this rate, and up to 40,000 per second, we have sensations of sound. The pitch of the tone is measured by the number of vibrations per second, 40 giving the lowest bass notes, and 40,000 the shrillest sound which can be heard. Doubling the number of vibrations of any tone produces another tone an octave higher. The pitch of the human voice is ordinarily between 87 and 768 vibrations per second, or within a range of a little more than three octaves, while the human ear can take in eleven octaves (40 to 40,000 vibrations). The intensity or loudness of a sound depends on the amplitude of vibration of the sounding body, a violin string bowed gently gives a faint sound, and bowed strongly, gives a note of the same pitch, but louder. "Colors are produced by ether waves, which succeed one another at the rate of 392 millions of millions times per second, increasing through orange, yellow, green, blue to violet, whose rate is nearly 800 millions of millions per second. To lower or higher rates of vibration than these the eye is not sensitive, though the lower produce electrical and thermal changes, and the higher have chemical effects. The color scale of vision thus corresponds to the scale of pitch in sound. In sight, as in sound, the intensity of the sensation depends on the amplitude of the wave, large waves giving rise to a bright light and small waves to dim light." Consider the following: In the body there are white thread-like substances called sensory nerves, whose function is to carry messages to the brain, and other similar substances, called motor nerves, which carry messages from the brain to the muscles. Different sensory nerves respond to different kinds of external stimuli (light waves, sound waves, etc.), and each nerve is furnished with an end organ (at the surface of the body) constructed in such a way as to receive the particular form of stimulus to be transmitted by that nerve. It has been found, also, that certain fairly well-defined localities of nerve action in the brain are the organs of definite sensations and movements. For example, Broca's convolution in the frontal region of the left hemisphere is the speech centre. An injury to that portion of the brain causes motor aphasia, that is, the loss of the power of speech without loss of voice or paralysis of tongue or lips. In general, on the sensory side the occipital lobes are the centres for sight, the temporal lobe is the seat of hearing and probably of smell, while taste and touch are, as yet, not very satisfactorily located. On the motor side the convolutions in front of the fissure of Rolando are the centres for bodily movement. From the genetic functional standpoint, we find that we have a development of the nervous system in increasing complexity from lower to higher forms of animal life, and that at every stage the nervous system has definite and important work to perform. The lowest forms possess a very simple nerve structure, with no definite organized centre of control. The nervous system, consisting of brain and spinal cord, appears in its most elementary form in the lowest vertebrates, and in more complex form in each higher class of vertebrate until it reaches its highest specialization in man. The growth of the brain is most rapid during the first years of life. The maximum weight of brain is reached by males |