You develop your faculties of self-mastery in proportion to the extent you succeed in developing your powers of concentration.
 
Watch the next person you see that has the reputation of being a strong character, a man of force. Watch and see what a perfect control he has over his body. Then watch just an ordinary person. Notice how he moves his eyes, arms, fingers; notice the useless expenditure of energy. These movements all break down the vital cells and lessen the person’s power in vital and nerve directions. It is just as important for you to conserve your nervous forces as it is the vital forces.
 
The mind is associated with muscle and nerve. When you steady your nerves and muscles, you steady your mind, but let your nerves get out of order and your mind will become erratic and you will not possess the power of direction, which, in other words, is concentration.
 
If the heart flutters, the circulation is not regular, and when the lung action is uneven, the mind becomes unsteady and not fit for concentration. This is why controlled breathing is very important as a foundation for physical health. The secret of controlling your emotions is in controlling your breathing. Your main physiological life function is your respiratory system.
 
You must not only concentrate your mind, but also the action of the eyes, ears and fingers. Each of these contains miniature minds that are controlled by the master engineer. You will develop much quicker if you thoroughly realize this.