A watch or clock is the nearest approach which has been made by man to the creation of a living being. A watch, for instance, contains the principle of its action in itself, and is not moved from without; in that it resembles a living creature. We can easily conceive of a watch which might be made to go seventy years, without being wound up. It might need to be oiled occasionally, but not as often as an animal needs to be fed. A watch is also like a living creature in having a unity as a whole not belonging to the separate parts, and to which all parts conspire,--namely, that of marking the progress of time. Why, then, say that a man has a soul, and that a watch has not? The difference is this. The higher principle of unity in the watch, that is, its power of marking time, is wholly an effect, and never a cause. It is purely and only the result of the arrangement of wheels and springs; in other words, of material conditions. But in man, the principle of unity is also a cause. Life reacts upon body. The laws of matter are modified by the power of life, chemical action is suspended, living muscles are able to endure without laceration the application of forces which would destroy the dead fibre. So the thought, the love, the will of a living creature react on the physical frame. A sight, a sound, a few spoken words, a message seen in a letter, cause an immense revulsion in the physical condition. Something is suddenly told us, and we faint away, or even die, from the effect of the message. Here mind acts upon matter, showing that in man mind is not merely a result, but also a cause. Hence men have generally believed in the existence of a soul in man. They have not been taught it by metaphysicians, it is one of the spontaneous inductions of common sense from universal experience. But this argument applies equally to prove a soul in animals. The same reaction of soul on body is constantly apparent. Every time that you whistle to your dog, and he comes bounding toward you, his mind has acted on his body. His will has obeyed his thought, his muscles have obeyed his will. The cause of his motion was mental, not physical. This is too evident to require any further illustration. Therefore, regarding the soul as a principle of life, connected with the body but not its result, or, in other words, as an immaterial principle of activity, there is the same reason for believing in the soul of animals that there is for believing in the soul of man. But when we ask as to the nature of the animal soul, and how far it is analogous to that of man, we meet with certain difficulties. Let us see then how many of the human qualities of the soul are to be found in animals, and so discover if there is any remainder not possessed by them, peculiar to ourselves.