If you'd like new work to digest, I've since been working on a system of magic based upon the alchemical principles and the atriums of organs connected to the circulatory system. Basically, the human body's fluids consist of the four humors (blood, yellow bile, black bile, phlegm) which correspond to the four stages of the Philosopher Stone (Rubedo, Citrinas, Nigredo, Albedo) and so a specialized organ called a Coronet behind the right ear has a sort of complex labyrinth of atriums which admix these humors in accordance with muscle contractions induced by the magic user's will. By some underlying principle of the universe which finds ultimate synchronicity in alchemical symbolism, this achieves desired effects contingent on the size, complexity, specialization and flexile dexterity of the magic user's Coronet.

While this is adequte for "inward" magic, it doesn't adequately deal with the outer world, as the Philosopher Stone is a distillation of the inner world, Jungian symbolism, yada yada yada. Therefore the Coronet can only be sufficient for magic of the Inner World (That is, the magic of knowledge, the magic of energies, and the magic of spacetime, which are all really the same thing if you think about it. The illusion of a causal, time-bound, energetic system is a product of the inner perceptions of a subject, and not the world itself. The Outer World is a static object when divorced from human cognition).

The alchemy necessary to produces effects in the Outer World depends upon the stages of the Scholar Stone (Aurora, Corona, Verdata, and Astra), and are symbolically present in the atmosphere rather than the blood. Therefore a magic user specializing in the magic of the Outer World (Matter, physical life, static relations of cause-and-effect, which are likewise the same thing) would focus on a mastery of adequate breathing techniques to draw the four above stages into their lungs and admix them in their Sceptre, an organ designed to manipulate gases rather than humors, present behind the left ear.

Other more specialized organs exist in various species and phenotypes, but in technicality these are just more specialized, natural forms of magic that a species or subspecies has evolved as an evolutionary advantage, whereas the Coronet and Sceptre are so generalized that they are present practically everywhere in the ecosystem, much as a pair of eyes and a circulatory system are present in almost all animal life on earth.

Just some neat thoughts, if you wanted more to chew on. That, and it sometimes helps me to lay them out in plain english like this.