tābhyo lohitam ābhṛtam
nadyas tataḥ samabhavann
Blood veins are compared to rivers; when the veins were manifested in the universal form, the rivers in the various planets were also manifested. The controlling deity of the rivers is also the controlling deity of the nervous system. In Āyurvedic treatment, those who are suffering from the disease of nervous instability are recommended to take a bath by dipping into a flowing river.