Organs which easily expand laterally by encroachment upon their neighbors, which is a common effect of local excitement, must be slow to make any impression upon the superjacent bone of the cranium. Cranioscopy, moreover, is incompetent to indicate the development of small regions or portions of a convolution; it gives but a rude survey of development. Being thus incapable of minuteness, accuracy and certainty, it cannot be considered a proper and sufficient basis for cerebral science. In the hands of Gall and Spurzheim, it had already very nearly attained its limits as regards the subdivision of organs, and the progress of their followers in discovery has been unimportant or fallacious. To what, then, can we resort, when the failures of Pathology and Vivisection are admitted, and we perceive the limited extent of the uncertain results of Craniology? Shall we not be compelled to resort to the same methods of investigation in the brain, which have been so successful in establishing the physiology of the nerves, viz.: direct experiment in exciting and arresting the action of the various masses of nervous fibre. Every sound physiologist must perceive that we are compelled to resort to experiment, or else to rest contented in ignorance of the true cerebral physiology. Muller, perceiving this, remarks, "The principle for the advancement of the physiology of the nerves then remains the same, viz.: experiment on the living nerves." We therefore experiment on the living brain in that class of persons who are susceptible of being thus influenced; hence arises the last and most perfect method of cultivating Anthropology, by means of HUMAN IMPRESSIBILITY.