In the case of both physical growth by eating and mental growth by instruction there is no possible escape from the law of alternating periods of objective and subjective activity. When the child has digested and assimilated a meal there is but one possible thing that can follow--return to his source of supply for another meal. When the student has digested and assimilated the lesson given to him the only possibility of further mental growth lies in his return to the class-room for more material. And so it is with the human soul in its work of evolving its latent powers and possibilities. There is no other road forward but the cyclic one that brings it back to the physical life incarnation after incarnation, but always at a higher point than it previously touched. The very hunger of the child that insures its return to the table for more food is analogous to the desire of the soul for sentient expression that brings it to rebirth. These alternating periods with the element of constant return are found everywhere in the economy of nature. All her evolutionary expressions are cyclic. But the cyclic movement is not in closed circles. It represents a spiral. The "evolutionary ladder" that the soul climbs is a winding stairway. In its upward progress it makes many rounds but it is always mounting and never returns to the same point. In each cycle, that is made up of the journey from the heaven world through the astral plane, into the physical and then back through the astral plane into the heaven world, it touches each of them at a higher point, or in a higher state of development, than it had previously attained. Each rebirth finds it abler here to gather a larger harvest of experience and each return to the mental plane, or heaven world, finds it abler to digest and assimilate its experiences, and to comprehend more of the realities of the life of its home plane. This round, or cycle, through the physical, astral and mental regions, is a continuous progressive journey of the soul which began away back at the dawn of mind in man and will continue until he is the perfected mental and moral being. At each incarnation here he gathers experience in proportion to his alertness and to the opportunities his previous lives have made for him. He learns to help others, to be sympathetic, to be tolerant. Such activities will give him pleasure in the astral life and joy and wisdom in the mental region, or heaven world. But he also does some evil things. He makes enemies, he generates hatred and he injures others. This will give him distress in the astral life and no results for soul growth or general progress in the heaven world. If he does an equal amount of good and harm his progress will be slow. If he does much good and little evil his progress will be rapid and his existence happy. If he is a man of great energy, and no very great moral development, and selfishly does much wrong, he will suffer much in the astral life.