Odic force (also called Od [õd], Odyle, Önd, Odes, Odylic, Odyllic, or Odems) is the name given in the mid-19th century to a hypothetical vital energy or life force by Baron Carl von Reichenbach. Von Reichenbach coined the name from that of the Germanic god Odin in 1845.
As von Reichenbach was investigating the manner in which the human nervous system could be affected by various substances, he conceived the existence of a new force allied to electricity, magnetism, and heat, a force which he thought was radiated by most substances, and to the influence of which different people are variously sensitive. He named this vitalist concept Odic force. Proponents say that Odic force permeates all plants, animals, and humans.
Believers in Odic force said that it was visible in total darkness as colored auras surrounding living things, crystals, and magnets, but that viewing it required hours first spent in total darkness, and only very sensitive people had the ability to see it. They also said that it resembles the Asian concepts prana and qi. However, they regarded the Odic force as not associated with breath (like India's prana and the qi of Chinese martial arts) but rather mainly with biological electromagnetic fields.
Von Reichenbach did not tie Odic force into other vitalist theories. Baron von Reichenbach expounded the concept of Odic force in detail in a book-length article, Researches on Magnetism, Electricity, Heat and Light in their Relations to Vital Forces, which appeared in a special issue of a respected scientific journal, Annalen der Chemie und Physik. He said that (1) the Odic force had a positive and negative flux, and a light and dark side; (2) individuals could forcefully "emanate" it, particularly from the hands, mouth, and forehead; and (3) the Odic force had many possible applications.
The Odic force was conjectured to explain the phenomenon of hypnotism. In Britain, impetus was given to this view of the subject following the translation of Reichenbach's Researches by William Gregory, professor of chemistry at the University of Edinburgh.