Thirty additional parasellar gross dissections and light microscopic examinations have been carried out, confirming a previous observation that the sympathetic nerve or nerves running with the carotid artery gives off a multitude of fine branches at irregular intervals on the way up, but the largest residual component joins the sixth cranial nerve and leaves to join the first division of the fifth cranial nerve. No similar fibers can be found by us to the sympathetic in the neck results in a Horner's syndrome and that section of the ophthalmic artery at its point of departure from the carotid does not result in any part of Horner's syndrome nor does secretion of the external, internal or common corotid in the neck, it is assumed that these fibers process the functions the absence of which result in Horner's syndrome.