3879. CONCERNING AN IDEA NOT INTELLIGIBLE; ALSO CONCERNING THE BIRD, AND THE INHABITANTS OF MARS. When I spoke with him who was in the state of peace, concerning whom I now perceive that such have reference to the longitudinal sinus in the brain - for it lies between the two hemispheres of the brain, where it is also in a quiet state, caring nothing how the hemispheres of the brain may be in commotion, for it is wholly intermediate (between them) -