2. Human Duality

The systems of organs, or systems of instruments, of the human organism to be considered first in this connection, must be the apparatus of nutrition and all that lies between this apparatus and that wonderful structure the heart, which we readily experience as a sort of central point of the whole human organism... And here even a superficial glance shows us at once that these systems of instruments, especially the apparatus of nutrition as we may call it in everyday speech, are intended to take in the substances of our external, earthly world and prepare them for further digestive work in the physical organism of man. We know that this apparatus of digestion begins by extending downward from the mouth, in the form of a tube, to the organ which everyone knows as the stomach. And a superficial observation teaches us that, from those articles of food which are conveyed through this canal into the stomach, the portions which are to a certain extent unassimilated are simply excreted, whereas other portions are carried over by the remaining digestive organs into the organism of the human body.