V. Plant, Animal, Man

In waking life man lives in activities which bring him into connection with the outer world through his astral body and through his ego-organization; in sleep his physical and etheric organisms live on what has become the material residue of these two organizations. A substance absorbed by man, both in the sleeping and in the waking state, like oxygen in breathing, must therefore be differentiated as to its mode of action in the two conditions. According to these two conditions, the oxygen absorbed from without has the effect not of awakening, but of putting man to sleep. Increased uptake of oxygen leads to abnormal drowsiness. In waking life the astral body battles perpetually against the soporific influence of the absorption of oxygen. When the astral body suspends its work upon the physical, the oxygen unfolds its proper nature and sends the man to sleep.