The human aura is not always in a state of calm phosphorescence, however. On the contrary, it sometimes manifests great flames, like those of a fiery furnace, which shoot forth in great tongues, and dart forth suddenly in certain directions toward the objects attracting them. Under great emotional excitement the auric flames move around in swift circling whirlpools, or else swirl away from a centre. Again, it seems to throw forth tiny glistening sparks of astral vibrations, some of which travel for great distance. The clairvoyant vision is also able to discern what is called the "prana aura" of a person. By this term is indicated that peculiar emanation of vital force which surrounds the physical body of each and every person. In fact, many persons of but slight clairvoyant power, who cannot sense the auric colors, are able to perceive this prana-aura without trouble. It is sometimes called the "health aura," or "physical aura." It is colorless, or rather about the shade of clear glass, diamond, or water. It is streaked with very minute, bristle-like lines. In a state of good health, these fine lines are stiff like toothbrush bristles; while, in cases of poor health, these lines droop, curl and present a furlike appearance. It is sometimes filled with minute sparkling particles, like tiny electric sparks in rapid vibratory motion. To the clairvoyant vision the prana-aura appears like the vibrating heated air arising from a fire, or stove, or from the heated earth in summer. If the student will close his eyes partially, and will peer through narrowed eyelids, he will in all probability be able to perceive this prana-aura surrounding the body of some healthy, vigorous person--particularly if the person is sitting in a dim light. Looking closely, he will see the peculiar vibratory motion, like heated air, at a distance of about two inches from the body of the person. It requires a little practice in order to acquire the knack of perceiving these vibrations--a little experimenting in order to get just the right light on the person--but practice will bring success, and you will be repaid for your trouble. In the same way, the student may by practice acquire the faculty to perceiving his own prana-aura. The simplest way to obtain this last mentioned result is to place your fingers (spread out in fan-shape) against a black background, in a dim light. Then gaze at the fingers with narrowed eyelids, and half-closed eyes. After a little practice, you will see a fine thin line surrounding your fingers on all sides--a semi-luminous border of prana-aura. In most cases this border of aura is colorless, but sometimes a very pale yellowish hue is perceived. The stronger the vital force of the person, the stronger and brighter will this border of prana-aura appear. The aura surrounding the fingers will appear very much like the semi-luminous radiance surrounding a gas-flame, or the flame of a candle, which is familiar to nearly everyone.