The reparative energy of nature has never been duly recognized, because the selfishness and pride of the doctors will not concede this as often as they ought. The doctor should be the most useful as a monitor to the sick, in guiding and controlling thought and conduct, in harmony with the curative energy of nature. From this point of view the pretensions of anyone effecting this or that cure are only a delusion, because the doctor effects nothing, he only assists, guides, and directs towards effecting a cure. What this curative force is has by no means been understood. Some believe it identical with life or vital action, which manifests itself only in organized substances, but even if we admit this identity, we are balked again, because we do not really know what life is, any more than we know what electricity is. Descartes resolved life into matter and motion; this, however, is rather the phenomena of life and gives us no idea of the real essence of the force that we call life. There is another theory, that all life whenever or wherever found is a spiritual force, ethereal and universal. For our purpose, the discussion of this question has no particular value, were it not for the fact that life, or vital activity, wherever we find it in organized substances, whether in the lowest living thing or in the highest type of physical development, is accompanied by or is endowed with the natural tendency to repair defects or injuries in that in which it is active. Regeneration, or the curative process of nature, is always the handmaid of vital activity. It is present at the earliest formation and division of a cell, which constitutes the unit of all organisms. Just as one brick is laid on the other with mortar or cement between them, so as to make a whole wall of a building, so are our bodies built up of minute cells, one added to the other, with cement between them, until the entire structure is completed. There is no tissue of the living body which was not at one time during its existence a cell. This curative force is beautifully illustrated in the lower animals, where parts of organs are replaced to a far greater extent than among warm-blooded animals.