An idea of the number of dead cells constantly being thrown off from every part of the body may be gained by noticing the amount of dead skin cast off. The fine scales of “scarf” or “dead” skin, which we easily rub off in a friction bath, are composed of these dead cells which have been crowded out by the hosts of vital cells constantly forming beneath. The process is the same in every tissue and organ. The dead or worn-out matter within the body is burned by oxygen and put in condition to be carried by the blood to the organs of elimination, the kidneys, intestines, lungs, and skin. Much waste is eliminated in liquid form through the sweat glands. It is said that stokers throw off four pounds of water and waste a day through the skin. In the growing child the process of building and of eliminating is active and rapid. In the youth it is less rapid, in the adult still less, but unless the process is kept active, stagnation and death ensue. _Daily exercise is necessary to keep up the body activities; yet very few take the trouble to secure daily a complete, thorough circulation of blood, especially through the vital organs and the deeper tissues. Perfect circulation is the key-note of health._ Activity of any kind necessitates the expenditure of energy. The process is a chemical one and in all chemical processes heat is necessary to cause the decomposition of elements and their recomposition into different substances. Heat in its turn has two functions. It enables the chemical changes to be carried on which fit the food for the use of the various tissues, and it burns to an ash the worn-out products of the body’s activity, fitting them for elimination. It keeps the tissues flexible and the secretions fluid; coagulation takes place when the secretions become cold. As previously stated, food in the body, then, is needed for two purposes: (1) to build and maintain the cell until its work is done; (2) to furnish the heat necessary to decompose the food into its elements, and to produce the energy by which all the body processes are carried on. [Sidenote: Food Elements] That the food may be appropriated by the body it must be not only proper in kind and quantity, but the body must also be in condition to digest, absorb, and assimilate it and to eliminate the waste, otherwise the body needs are not met. It is the nourishment which _the body assimilates and appropriates to its needs_ which counts in food economy, _not necessarily the amount consumed_. Therefore if the food is to economically serve its purpose, the body must be in a condition to digest and assimilate it—_this condition depends largely on perfect circulation, correct position of organs, and correct breathing habits_.