William Quan Judge,
The Ocean of Theosophy
“ The second method is by the use of the Astral body of the living medium. In this case the Astral form exudes from the side of the medium, gradually collects upon itself particles extracted from the air and the bodies of the sitters present until at last it becomes visible. Sometimes it will resemble the medium; at others it bears a different appearance. In almost every instance dimness of light is requisite because a high light would disturb the Astral substance in a violent manner and render the projection difficult. ”
