Thoughts and Circumstances of Life, Health and Thoughts, The Synapse

Consciousness determines its own health in intelligent and rational form, by means of the might of its thoughts. But it furthermore also extensively determines the health of the body or its decline.

Might of Thoughts page 150
The body which - as a gentle and plastic instrument - immediately reacts to the kind of thoughts which the human being tends and nurtures. This is the reason why the human being should not allow habitual thinking to take upper hand to much.

Plastic, in this case, means easily shaped or molded. The body is said to react without any intervening time or space to the toughts which are tended and nurtured. Nurture means to encourage the growth or development of ... When something is habitual it is done constantly as a habit. Remember that habits tend to occur unconsciously. The Habitual behavior often goes unnoticed in persons exhibiting it. This is a more or less fixed way of thinking.