But before I proceed to explain it, I desire to announce my own theory respecting disease--a theory essentially radical in its character, and of which I am the originator, and that is:

This may sound strange, for the majority of people imagine that there is a different and specific cause for every ailment, and physicians generally do not combat the opinion. But as a matter of fact, there is only one disease, although its manifestations are various, and there is only one cause for it, and that is the retention of waste matters in the system. These substances may be in the gaseous, liquid or solid form, but they are foreign bodies, inimical to the welfare of the organism, and their presence must result in derangement of bodily function.

The Royal Road to Health — Part 19

The great need of the present day is adequate instruction in physiology and hygiene, that humanity may not only know how to secure the restoration of health, when lost, but by attention to physiological and sanitary laws may retain good health indefinitely. The body is the theatre of constant change. The processes of tearing down and building up proceed without intermission during life. If construction exceeds destruction, the result is health; but just as surely as destruction exceeds repair, disease is the result. But during every moment of life waste is being formed by the destruction of tissue, and this effete material must be promptly removed if the individual would enjoy health. Nature has provided adequate means for the removal of these substances which are valueless to the economy, the retention of which obstructs and irritates the complex mechanism of the system, the principal avenues for its expulsion being the lungs, the skin and the intestinal canal. The latter is infinitely more important than the others, since by it the waste products of digestion are expelled. If it fails to promptly fulfil its office, every vital function is interfered with; and in addition the fluid portion of the semi-liquid waste is re-absorbed directly into the circulation, redepositing in the very fountain of life, matter which the system has thrown off as worthless. Should the system be exposed to a chill, while in this condition, a congestion of the surface excretory vessels takes place; and practically the whole work of elimination is thrown upon the already hard-worked kidneys, frequently resulting in uræmic poisoning and death.

The Royal Road to Health — Part 19