The caduceus of Hermes or Mercury

The central axis, Shushumna, is the channel for the Quintessence— the concealed Glory, all-pervading Akasha. But do not hold too rigidly to the idea that the Shushumna is confined to the subtle equivalent of the spinal column. Sometimes in meditation, the Shushumna can appear as fine as a hair and, at other times, so wide that the entire body becomes one stream of force, a fire of highest inspiration, annihilating all limits, and growing until it fills the whole universe. 

The Chinese say A picture is worth a thousand words. The following is from Arthur Avalon s book, The Serpent Power, in which he records an experience that a European friend of his had. 

Commence with the preliminary exercises (fountain breath cycle), ascend the Tree of the Assiah, and perform the Qabalistic Cross and the Parting of the Veil mudra. Project the table from your Tiphareth center and take your seat in your siege. 

Go through the left-hand doorway, beneath the sun-cup symbol. This spiral stairway ascends in a deosil (clockwise) direction. You can feel a warm, dry breeze blowing up this stairway—blowing up behind you, not unpleasantly. It plays with your hair and the folds of your robe as you ascend. While climbing the stairs, you can see other doors and landings, but these do not concern you in the present practice. 

3 Arthur Avalon, The Serpent Power (New York Dover, 1974), pp. 20-21. 

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