The body, however, is not the Life; it is merely the material agency that enables the Life to manifest in a material universe for a certain, though not necessarily a given, period of time. It is the Life, or the Soul, or the Personality that uses, and that in using shapes and moulds, the body and that also determines its strength or its weakness. When this is separated from the body, the body at once becomes a cold, inert mass, commencing immediately to decompose into the constituent material elements that composed it--literally going back to the earth and the elements whence it came.
It is through the instrumentality or the agency of thought that the Life, the Self, uses, and manifests through, the body. Again, while it is true that the food that is taken and assimilated nourishes, sustains and builds the body, it is also true that the condition and the operation of the mind through the avenue of thought determines into what shape or form the body is so builded. So in this sense it is true that mind builds body; it is the agency, the force that determines the shaping of the material elements.
Here is a wall being built. Bricks are the material used in its construction. We do not say that the bricks are building the wall; we say that the mason is building it, as is the case. He is using the material that is supplied him, in this case bricks, giving form and structure in a definite, methodical manner. Again, back of the mason is his mind, acting through the channel of his thought, that is directing his hands and all his movements. Without this guiding, directing _force_ no wall could take shape, even if millions of bricks were delivered upon the scene.
So it is with the body. We take the food, the water, we breathe the air; but this is all and always acted upon by a higher force. Thus it is that mind builds body, the same as in every department of our being it is the great builder. Our thoughts shape and determine our features, our walk, the posture of our bodies, our voices; they determine the effectiveness of our mental and our physical activities, as well as all our relations with and influence or effects upon others.
You say: "I admit the operation of and even in certain cases the power of thought, also that at times it has an influence upon our general feelings, but I do not admit that it can have any direct influence upon the body." Here is one who has allowed herself to be long given to grief, abnormally so--notice her lowered physical condition, her lack of vitality. The New York papers within the past twelve months recorded the case of a young lady in New Jersey who, from _constant_ grieving over the death of her mother, died, fell dead, within a week.