We need not discuss here whether these writers in drawing their conclusion have done justice to all the premises I involved in the cases they treat of. We quote their arguments only to show how they appeal to the principle that _no actions but such as are done for an end, and show a choice of means, can be called indubitable expressions of Mind_. I shall then adopt this as the criterion by which to circumscribe the subject-matter of this work so far as action enters into it. Many nervous performances will therefore be unmentioned, as being purely physiological. Nor will the anatomy of the nervous system and organs of sense be described anew. The reader will find in H. N. Martin's 'Human Body,' in G. T. Ladd's 'Physiological Psychology,' and in all the other standard Anatomies and Physiologies, a mass of information which we must regard as preliminary and take for granted in the present work.[3] Of the functions of the cerebral hemispheres, however, since they directly subserve consciousness, it will be well to give some little account. FOOTNOTES: [1] _Cf._ Geo. T. Ladd: Elements of Physiological Psychology (1887), pt. iii, chap. iii, §§ 9, 12. [2] Zur Analysis der Wirklichkeit, p. 489. [3] Nothing is easier than to familiarize one's self with the mammalian brain. Get a sheep's head, a small saw, chisel, scalpel and forceps (all three can best be had from a surgical-instrument maker), and unravel its parts either by the aid of a human dissecting book, such as Holden's 'Manual of Anatomy,' or by the specific directions _ad hoc_ given in such books as Foster and Langley's 'Practical Physiology' (Macmillan) or Morrell's 'Comparative Anatomy and Dissection of Mammalia' (Longmans). CHAPTER II. THE FUNCTIONS OF THE BRAIN.