Lecture X

If we ascend from digestion to breathing, we notice that man produces carbon out of himself, and that this is to be found everywhere within him. This is sought out by oxygen, becomes changed into carbonic acid, and is then exhaled. Carbonic acid is the combination of carbon and oxygen. The oxygen, which is drawn in through breathing, masters the carbon, absorbs the carbon into itself; carbonic acid, the product of oxygen and carbon, is then exhaled. But before exhalation occurs, the carbon becomes the benefactor, so to speak, of human nature. This carbon—in that it combines with the oxygen, in that it combines to a certain extent what the blood-circulation brings about with what the breathing produces—this carbon becomes the benefactor of the human organization, for, before it leaves the human organization, it disperses through it an out-streaming of ether. Physical science merely states that carbon is exhaled with carbonic acid. This, however, is only one side of the whole process. Man exhales the carbonic acid; but in the process of this exhalation something of the carbon taken up by the oxygen is left behind in his whole organism, namely ether. This ether penetrates into man's etheric body, and it is this ether, continually being produced by the carbon, which makes the human organization capable of opening itself to spiritual influences, of absorbing astral-etheric forces from the cosmos. This ether, which is left behind by the carbon, attracts the cosmic impulses, and they in their turn work formatively upon man, so preparing his nervous system, for instance, that it can become the bearer of thoughts. This ether must continually permeate our senses, our eyes, for example, so that they may see, so that they may receive the outer light-ether. Thus we are indebted to carbon for the supply of ether within us which enables us to come into contact with the outer world.