It is for this reason that man depends for his sustenance on all these substances. There is mineral substance which is good for his health, there is the vegetable kingdom on which he depends for his food, and there is the animal kingdom which also serves for his sustenance. Because his body is made of these elements it is also sustained by these elements; man is made of these four substances, the flesh, the blood, the skin, and the bone representing the four different clays.