The Mystery of Sex was written in German (Magie der Geschlechter). It has also been translated into French (Magie des Sexes), Spanish (La Magia del Sexo) and English.
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Let us not forget that our body will invariably be more complete the more developed and the more under conscious control is the sympathetic nervous system.
When the man and the woman make of sexual union a psychic union too, with the minimum possible movement, that is to say, with only those which are necessary to maintain and prolong the contact, only then will they have the opportunity to electrically charge the cerebro-spinal ganglia, which are linked to the pineal gland, sovereign of the body, and also to the solar plexus (plexus-coeliacus) with its numerous radiating plexi to the liver, intestines, kidneys and spleen.
The sexual organs can then devote themselves to the task from which they are frequently withdrawn; that is to serve the physical principle of assimilation and purification of matter, primarily through action on the plexus which is situated below the diaphragm (the ventral part of the sympathetic nervous system), which is essentially necessary as a base for the development of the most refined sensation.
Waldemar, Charles. 1960. The mystery of sex. New York: L. Stuart.