64 Biography of a Yogisubstantially divergent from later understandings. Nevertheless, by suggesting
that the refraction of light particles occurred due to interference of an ethereal
medium, he established the basis for his successors to hypothesize that it was
exactly this medium through which the newly established transverse wave of light
must travel. This remained the reigning theory among physicists— even as several
sets of experiments conducted in the late nineteenth century proved it unten-
able by failing to discover any such substance— until the need for it was gradu-
ally eliminated by the advent and acceptance of quantum mechanics.^18 However,
even as ether continued to pervade the atmosphere of theoretical physics, it also
caught on in other circles. Indeed, Newton introduced a variety of functions for
his ether(s) that prefigure the various universal magnetic fluids that would later
be used to explain the phenomena of the pseudo- medical tradition of Mesmerism
and its more popular offspring, Spiritualism.^19
Magnetic Bodies and Mesmeric Trances
These connections are not at all coincidental, as Franz Anton Mesmer (1734–
1815) was decidedly a student of Newton’s work. Mesmer, borrowing heavily from
Newton’s more metaphysically inclined theories, set out to instrumentalize them
in the sphere of medicine. Mesmer’s dissertation, Dissertatio Physico- medica de
Planetarum Influxu (1766), built on— or possibly plagiarized from— the ideas of
Richard Mead, a prominent English physician, and adapted Newton’s hypoth-
eses to argue that bodies were universally subject to an all- pervading gravitation
emanating from the stars. He referred to this principle as “animal gravitation,” the
predecessor to his famous concept of animal magnetism.
In his subsequent medical practice, Mesmer experimented with using iron
magnets to treat illness, relying on the assumption that disease was caused by a
body’s having fallen out of harmony with a universal force, which was no longer
based solely on gravitation in relation to heavenly bodies but also emanating from
and pervading animal bodies. The initial stages of this therapy approached the
aforementioned theory from a very literal perspective, as patients swallowed a
solution containing traces of iron before having magnets placed on their bod-
ies to redirect and thereby recalibrate the flow of their vital magnetic energies.
Mesmer did not generally employ the language of ether in his work, but never-
theless spoke of a “fluid which is universally widespread and pervasive in a man-
ner which allows for no void, subtly permits no comparison, and is of a nature
which is susceptible to receive, propagate, and communicate all impressions of
movement.”^20 He analogized the operation of this force to the manipulation of
both magnetism and electricity, but insisted that the latter were only naturally