Substances of the Perispirit
The gas that creates perispirit is a mediator between a very ethereal substance, which is extremely delicate, called the spirit, and a dense and rough material (called the body). We cannot see the perispirit in its ordinary and natural form with our current state of sight and senses because it cannot speak or show itself without the proper tool unless this mechanism is available under certain principles. This tool can either be a spiritual mediator, with the right talents, that the perispirit can speak through (called a medium), or tables and other equipment that spiritualists utilize. This notion is a general principle for all ethereal gases in the universe that cannot be visible until the proper instruments exist.