If the blood is not a perfect building material it is because we have not put into the digestive mill the right materials; and if it is not properly circulated, it is because the circulation is impeded by positive constrictions, or, as is more frequently the case, because the composition of the blood is not perfectly suited to the demands of the vital activities. As a result, much of the material must be rejected as unusable, thus involving a great deal of extra work in disposing of it. If the excessive material is wholesome, though not at present usable, it may be packed away for future use as fat, this being the easiest, and perhaps the only possible way of disposing of it in the rush. The builders are not only overworked, but literally overwhelmed with excessive and unsuitable materials--and why?--that we may indulge perverted appetites. [Sidenote: Corpulency considered unhealthy] Even the excessive material packed away in the wholesome form of fat may, merely by its bulk, become an impediment to the circulation. It not only reduces the efficiency of the bodily mechanism, but also is so potent a factor in shortening life that a corpulent person is likely to be rejected by an insurance company, even though his present state of health may be good. [Sidenote: Defective circulation reduces efficiency] A condition often found illustrates most forcibly the manner in which defective circulation reduces the efficiency of the human power-plant, even as the scaly deposit impairs the efficiency of the steam boiler. "That tired feeling" of which so many complain, is so called because the person thus afflicted has a sense of painful exhaustion upon slight exertion--is tired all the time. If our diagnosis shows a state of chronic exhaustion, and we endeavor to increase the body-efficiency by increasing the food, we shall make the same mistake as the fireman who shovels more coal under a scaly boiler. [Sidenote: Exhaustion, the accumulation of body-poisons] Painful exhaustion in a perfectly healthy body results from violent, or too long-continued exercise of a muscle, and if there are no intervals of rest, excruciating pain results. The cells are broken down more rapidly than the resulting waste can be carried away by the circulation, hence the body-poisons and pain. The pain is a symptom, and where the condition of which it is the index is temporary, rest soon restores the normal condition of ease. [Sidenote: Rest is imperative]