But, since the soul must be regarded as an active principle, to call a new one into existence out of nothing is necessarily to add to the force previously in the world. And, if this has been done in the case of every individual who has been born, and is to be repeated for every individual hereafter, the totality of force must be continually increasing. Moreover, to many devout persons there is something very revolting in the suggestion that the Almighty is a servitor to the caprices and lusts of man, and that, at a certain term after its origin, it is necessary for him to create for the embryo a soul. Considering man as composed of two portions, a soul and a body, the obvious relations of the latter may cast much light on the mysterious, the obscure relations of the former. Now, the substance of which the body consists is obtained from the general mass of matter around us, and after death to that general mass it is restored. Has Nature, then, displayed before our eyes in the origin, mutations, and destiny of the material part, the body, a revelation that may guide us to a knowledge of the origin and destiny of the companion, the spiritual part, the soul? Let us listen for a moment to one of the most powerful of Mohammedan writers: "God has created the spirit of man out of a drop of his own light; its destiny is to return to him. Do not deceive yourself with the vain imagination that it will die when the body dies. The form you had on your entrance into this world, and your present form, are not the same; hence there is no necessity of your perishing, on account of the perishing of your body. Your spirit came into this world a stranger, it is only sojourning, in a temporary home. From the trials and tempests of this troublesome life, our refuge is in God. In reunion with him we shall find eternal rest--a rest without sorrow, a joy without pain, a strength without infirmity, a knowledge without doubt, a tranquil and yet an ecstatic vision of the source of life and light and glory, the source from which we came." So says the Saracen philosopher, Al-Gazzali (A.D. 1010). In a stone the material particles are in a state of stable equilibrium; it may, therefore, endure forever. An animal is in reality only a form through which a stream of matter is incessantly flowing. It receives its supplies, and dismisses its wastes. In this it resembles a cataract, a river, a flame. The particles that compose it at one instant have departed from it the next. It depends for its continuance on exterior supplies. It has a definite duration in time, and an inevitable moment comes in which it must die.