And when we come to the mental part of our being, that mechanism is still more delicate than our body. There is a tone also, and every being has a different tone according to his particular evolution, and everyone feels in good health when his own tone is vibrating; but if that tone does not come to its proper pitch, then a person feels lack of comfort, and any illness can arise from it. Every expression of passion, joy, anger, fear, which breaks the continuity of this tone interferes with one's health.