The human body is merely a machine - a mechanism for converting latent energy into the active state. It takes the force latent or potential in food, water and air and transforms it into the energy which is manifested as work, heat and thought. When the amount of energy so transformed is great, the vitality is abundant and strong, and when it is small, the vitality is correspondingly lowered.

To illustrate this fact more clearly, I would explain that the human body generates vitality very much as a steam engine generates steam. By the proper attention to the engine, that is by providing for it the best of fuel, clean water and plenty of draught, we get the best service, the greatest amount of power. It is just so with the human machine - the body. By giving it the best food under the best conditions, supplying the quantity and quality of water needed and by removing the ashes (waste material), keeping it clean inside and out, we assist it to increase its product of energy or vitality. Human vitality can be increased to a high degree. As a practical asset the value of increased vitality is beyond all price. It gives the power for greater effectiveness, greater income, and greater success in any chosen endeavor.

As stated, the body manufactures the vitality from acting upon the food taken into it, but in this process of converting food into vitality, an outlay of energy is required. In other words, the process of digestion is work which consumes more or less of the vitality previously generated and stored up in the system. Here is where we must learn to use economy and not exhaust as much vitality during digestion as we gain from it. We must not tax the digestive organs unnecessarily. To guard against this we must use care in selecting such food as will yield a large percentage of energy at a small expenditure of vitality for its digestion. It is not the amount of vitality we generate but the amount we retain that makes us well and strong.

One of the most important factors in increasing the vitality is to select a diet that will require little digestive energy and will, at the same time, supply the largest amount of nutriment. To do this means that we must eat easily digestible, nutritious food.

We must consider the quality as well as the quantity of food we tax our digestive organs with. Food is converted into energy as the result of the action of certain fluids, - often termed gastric juices - which are poured by the digestive system into the food while it is passing through the alimentary tube. Now, these fluids are poured out in proportion, not to the amount of food present, but to the needs of the body. So, if more food is taken into the stomach than the needs of the body call for, it is not digested, but instead decomposes, forming a putrid acrid mass.

The digestion of food requires a quantity of the digestive fluids in relative proportion to the food, some food requiring more than others. Now supposing you fill your stomach to the limit of its capacity with food that requires, under normal conditions, from four to six hours to digest, and leave no room for the digestive fluids to enter, what is likely to be the result? There can be but one result. The food subjected to the heat of the stomach without the assistance of the digestive fluids, must quickly decay and form an offensive matter. This matter slowly works its way through the alimentary tube, and the tube, true to its function, absorbs not the pure, clean food that it needs, but the poison from this putrefying mass. The poisons thus absorbed into the blood derange the functions and cause symptoms ranging from foul breath, formation of gas in the intestines, cramps, slight headache, dizziness or palpitation to fatal apoplexy or heart failure.

You will now understand the danger that results from taking into the stomach food in excess of the needs of the body. The body is at once starved and poisoned. Starved because the food remains undigested; poisoned, because of the absorption of the products of its putrefaction. This condition is induced by the wrong food as well as by too much food.

It is easy to understand that the food we eat has a most important influence in the cultivation of enduring youth and vitality.

By the right choice of foods, by eating at the proper time in normal quantities, we can renew and preserve youth to a wonderful extent. Ignorance of the nutritive value of the food eaten is the cause of many people growing old and dying prematurely.

I have already explained several times in these lessons that bodily age is a delusion and that the body is constantly being renewed through molecular change. What is termed "Old Age" is in reality a hardening or ossifying of the tissues, arteries, etc., as a result of excessive deposits in the system of calcareous and other deleterious elements, resulting from undigested food and impure water, which settle in the tissues and around the joints. This substance is soluble and can be completely dissolved and carried out of the system. To do this one must select and eat food that is adapted for the purpose. Where these deposits have not already taken place, they can be forever prevented.