Thoughts Cause Physiological Disorders.
Every change in thought makes a vibration in your mental body and this when transmitted to the physical body causes activity in the nervous matter of your brain. This activity in the nervous cells causes many electrical and chemical changes in them. It is thought-activity which causes these changes.
Intense passion, hatred, long-standing bitter jealousy, corroding anxiety, fits of hot temper actually destroy the cells of the body and induce diseases of the heart, liver, kidneys, spleen and stomach.
It is a point worthy to note with care that every cell in the body suffers or grows, receives a life impulse or a death impulse, from every thought that enters the mind, for you tend to grow into the image of that which you think about most.
When the mind is turned to a particular thought and dwells on it, a definite vibration of matter is set up and often, more of this vibration is caused, the more does it tend to repeat itself to become a habit, to become automatic. The body follows the mind and imitates its changes. If you concentrate your thought the eyes become fixed.
~ Sri Swami Sivananda, Thought Power