Hermes Trismegistus stated that the transformation of the disciple's soul goes in the proper way only under the constant heightened temperature kept in the retort which is sealed by the seal of Hermes. By fire under the retort, we mean an extreme situation which is regularly created for every disciple by the heightened atmosphere of the School, and which induces the inner tensions of the disciples, or inner temperature, as alchemists say. The extreme conditions are indispensable for the full transformation. ... The extreme situations, which cause inner temperature might have to do with heavy physical work as well as with complicated psychological situations. Then all the numerous 'selves' of the disciple clash with each other because of their contradictory wishes.
Source: The Techniques of Taoists, by Konstantin Serebrov
Contributed by: Graeme