hello, I've seen some texts where Mercury rules the nervous system - but also Mars. What would be the difference?
I believe in regards to Vedic astrology and Ayurveda, Mars rules fire and the Majja Dhatu, which is the bone marrow and nervous tissue. Reading from Graha Sutras, it is the electrical current seated within.
Where as Mercury rules earth and Tvak Dhatu, which is the skin, sheaths, or coverings. So from Graha Sutras, Mercury governs the cell membranes.