You may look in Browne Faber's book, if you like, and you will find that to the present day men of science are unable to account for the presence, or to specify the functions of a certain group of nerve-cells in the brain. That group is, as it were, land to let, a mere waste place for fanciful theories. I am not in the position of Browne Faber and the specialists, I am perfectly instructed as to the possible functions of those nerve-centers in the scheme of things. With a touch I can bring them into play, with a touch, I say, I can set free the current, with a touch I can complete the communication between this world of sense and--we shall be able to finish the sentence later on. Yes, the knife is necessary; but think what that knife will effect. It will level utterly the solid wall of sense, and probably, for the first time since man was made, a spirit will gaze on a spirit-world. Clarke, Mary will see the god Pan!"