The serpent of light that sleeps at the base of the spine is said to rise through the body to the head like the semen retained in vajroli. Along the way, she reveals that within this fleshly body we take for granted resides a \"subtle body\" comprised of \"wheels\" (chakras) and passageways connecting them. As she rises along the vertical axis of the body, parallel to the backbone, these chakras open, one by one, like lotus flowers; and as each one opens, we are introduced to a new level of consciousness. Our subtle body amounts to an internal diamond ladder. Indeed, the name given tothe \"transubstantiated body,\" the body no longer comprised merely of flesh but made up of a \"ladder\" of chakras is the \"diamond body\" (vajra-deha). The Sanskrit word vajra is variously translated as \"thunderbolt,\" \"diamond,\" and \"adamantine.\" Hard and brilliant as a diamond, kundalini moves with the suddenness of a lightning bolt; and the body she reveals is of like substance. \"The Mahabharata mentions a race of beings whose bones are like diamond . . . They are said to have a steady gaze, to live without eating, and to emit a beautiful scent\"
This chapter will be limited to a discussion of kundalini as a transformative energy. We shall return to the topic of the subtle body in Chapter Eight. For now it will be sufficient to give only one indication that kundalini\'s rise through the several  chakras of the subtle body is by no means always a gratifying experience. Basing her account on texts from Kashmir, Lilian Silburn notes the following disturbing indications of kundalini\'s ascent.
If while freely moving up it stops for a few minutes at each wheel and causes it to vibrate, during the long period of preparation, and when a center is pierced for the first time, certain, often spectacular, disturbances do occur; under the terrific pressure of the ascending Kundalini and the extreme tension she generates, the body can react in unpredictable ways. Thus a violent tremor spreads from the heart; then the vault of the palate starts vibrating. And just as the yogin becomes omnipresent, he feels dizzy -- a stage indicating celestial sight (divyadrsti), which pierces through everything unobstructed. And again, under the influence of the pure mystic Science, the limbs oscillate at the joints, the heart throbs when the yogin shifts from the individual to the universal state.