I have, on another occasion, shown that the organs in which sensations are realized, and volition energizes, are the segments of the cranio-spinal cord in which the sentient and voluntary nerves are rooted. I think I see now that the seat of the attention is the “medulla oblongata.” For—alas for the imperfect conceptions into which the imperfection of language as an instrument of thought forces us!—what is the faculty of attention, which we have been considering almost as a separate element of mind, but the individual “ich” energizing, now keenly noticing impressions and thoughts, now allowing them to pass, while it looks on with lazy indifference; now, at length, worn out and exhausted, and incapable of further work? But this inspecting and contrasting operation, where should it more naturally find its bureau than at a point situated between the organs of the understanding and those of the will?—that is to say, somewhere at the junction of the spinal marrow and the brain. Well, Magendie ascertained that just at that region there is a small portion of nervous matter, pressure upon which causes immediately heavy sleep or stupor, while its destruction—_for instance, the laceration of the little organ with the point of a needle_—instantaneously and irrevocably extinguishes life.[4] This precious link in our system is, reasonably enough, stowed away in the securest part of our frame—that is to say, within the head, upon the strong central bone of the base of the skull. How came the fancy of Shakspeare by the happy figure which seems to adumbrate Magendie’s discovery of to-day, in poetry written three hundred years ago? [Footnote 4: The reader who wishes to pursue this subject farther, will find it expounded, in connexion with a large body of collateral facts, in my work entitled _The Nervous System and its Functions_. Parker, West Strand: 1842.] “Within the hollow crown, That rounds the mortal temples of a king, Keeps Death his court; and there the antic sits Mocking his state, and grinning at his pomp; Allowing him a breath, a little hour, To monarchize, be feared, and kill with looks; Infusing him with self and vain conceits, As if the flesh that walls about our life Were brass impregnable. Till, humoured thus, He comes at last, and, with a little pin, Bores through his castle wall—and farewell king!”