Finally, if such affection is sleep, and this is a state of powerlessness arising from excess of waking, and excess of waking is in its origin sometimes morbid, sometimes not, so that the powerlessness or dissolution of activity will be so or not; it is necessary that every Reading epei (Susemihl) for eti. creature which wakes must also be capable of sleeping, since it is impossible that it should always be actualizing its powers.