All pathology arises from departures from bionomic ideals. Whatever is actually prejudicial to the general health becomes a factor in the production of all pathology, from a cold to cancer. The deficiencies and excesses of which the whole human race is unconsciously guilty may be properly regarded as the basic or remote cause of pathology.

Food deficiencies are most talked of, but since we have considered these elsewhere, we will do little more than mention them here.

Indolence, or lack of exercise--work--weakens both body and mind. Exercise is as necessary as proper bathing, eating and clothing, to physical vigor, strength and development.

Lack of sunshine weakens the whole organism. We rob our bodies of the sun's benefit by living indoors and by clothing them to exclude the sun. Dark clothing excludes the beneficial rays of the sun from the body and thus weakens, not only the skin, but the body as a whole. Sunlight is an absolutely essential factor-element in normal nutrition, as much so for the animal as for the plant. Man is, by nature, a nude animal and the nearer he approaches this ideal the more healthful will he become. Clothing should be light and porous in texture and made of light colors or of white.