Carbon dioxide is a transparent, odorless and colorless gas. It is a very important constituent in the atmosphere and a very slight variation either in its increase or decrease will vitally interfere with both animal and vegetable life. Green plants in the sunlight absorb great quantities of carbon dioxide and give off oxygen. The body obtains its carbon from the food that is taken in while the oxygen is obtained from the air that is breathed. It is maintained that one acre of ordinary tree land will withdraw as much as four and one-half tons of carbon dioxide from the air in one season. Carbon dioxide is also absorbed by water; hence the oceans and other large bodies of water perform a very important function in this respect. In certain localities, such as industrial centers, a very large amount of carbon dioxide is given off into the air; but this is quickly taken up and thoroughly mixed with the atmosphere by the constant motion which is maintained by the varying temperature, air pressure and other involved factors. It is not allowed to accumulate in any one place in larger amounts than normal. In this way the proportion is kept the same at all times. Hygienists maintain that the regulation of breathing is largely dependent on the concentration of carbon dioxide in the air cells of the lungs. This, however, is not true since the process of respiration is not a question of chemical action nor the influence of any chemical element in the lungs or in any part of the respiratory system. The breathing, like all other functions of the body, is under the direct control of Innate Intelligence within the body. Innate Intelligence, recognizing the need for more oxygen in the tissue cells, will bring about an intellectual adaptation by increasing the respiration. This does not take place, however, until the need has exceeded the already adaptative possibility when the reserve amount of oxygen contained in the residual air in the lungs has been exhausted. In inspiration the air is taken into the lungs and the oxygen is taken up by the hemoglobin of the blood as before stated; then the oxygen is given off to the tissue cells. The hemoglobin absorbs the carbon dioxide from the tissues and it is then carried back to the lungs where the process is reversed. That is, the carbon dioxide is given off and the oxygen is absorbed by the hemoglobin.