The Martian principle is evident in its rulership of the blood (production of red and white blood cells), the action of muscles, acute conditions and the adrenal glands.  Red blood cells produced by the bone marrow stimulate the absorption of iron which itself is the fuel for the production of new red blood cells. White blood cells are produced to control the destruction of pathogens and hence the efficiency and aggressiveness of the immune system.  Mars breaks down just as Venus builds up. 

There is much symbolism around Mars that concerns the desire nature that emanates from the Soul (Pluto), energy production, sex drive, aggression and motivation.  Many spiritual diets advocate a vegetarian diet as the consumption of red meat stimulates the desire nature, the Fire/Agni aspect of our energy system which can burn too ‘hot’ for those attempting to transcend the carnal desires of the animal soul. 

Mars has rulership of Aries which concerns the instinctive and animal impulse and hence has much to do with the adrenal glands and the fight or flight response.  Mars is also responsible for the production of inflammation in the body, a natural healing response to congestion caused by toxic (Neptune/Pluto) residues and other influences.

Ingrid Naiman states that:  “the Tibetan suggested that Mars and Neptune can never be simultaneously active since both utilize the solar plexus chakra and therefore create an either/or type of situation. If one has devoted oneself to service, self-sacrifice, and perhaps even martyrdom, it goes without saying that Mars has had little opportunity for expression.”

In esoteric circles Mars and Neptune are associated with the 6th Ray of Devotion and Idealism and hence their dual action through the solar plexus chakra.

The combination of Mars and Neptune in aspect can certainly lead to a weakening of the whole system as Neptune undermines the direction and focus of the otherwise directed Martian energy.  Any outer planet aspect to the inner planets and the luminaries will tend to swamp that planet with the transformational energy of the outer planet for better or for worse as archetypal forces act upon, and through, the lesser vehicles.  The conscious alignment of the principles of the lower planet with the higher allows for a harmonious interaction between the two and a resolution between otherwise disparate energies.  It is not an easy accomplishment but the elevation of the lower to the higher is the ultimate goal of evolution.

Depending on your source of information, I have heard Zinc being ruled by Neptune (Marcia Starck), Uranus (Robert Jansky) or Jupiter (Eileen Nauman) but none provide convincing proof for their designations.  I’m inclined to assign rulership to Mars simply because of the antagonistic relationship between Copper (Venus) and Zinc.