The spirit soul is born in many different species of life within the material world. Some species are born from eggs, others from embryos, others from the seeds of plants and trees, and others from perspiration. But in all species of life the prāṇa, or vital air, remains unchanging and follows the spirit soul from one body to another. Similarly, the spirit soul is eternally the same despite its material condition of life. We have practical experience of this. When we are absorbed in deep sleep without dreaming, the material senses become inactive, and even the mind and false ego are merged into a dormant condition. But although the senses, mind and false ego are inactive, one remembers upon waking that he, the soul, was peacefully sleeping.