Each of the four primary elements as taught by the early philosophers has its analogue in the quaternary terrestrial constitution of man. The rocks and earth correspond to the bones and flesh; the water to the various fluids; the air to the gases; and the fire to the bodily heat. Since the bones are the framework that sustains the corporeal structure, they may be regarded as a fitting emblem of the spirit—that divine foundation which supports the composite fabric of mind, soul, and body.