monomania--which is generally harmless and quiet--a radically false but fixed idea is often associated, and is not inconsistent with an extraordinary shrewdness on all other points. Nevertheless, this fixed erroneous idea, being made the center of all other thoughts and of the whole consciousness, produces that confusion and that disorganization of the mind which characterizes this form of a disordered intellect. But in true madness, or frenzy, the seat of the disease is in the soul, which, having broken loose from all the ties and restraints of reason and rational habit, appears to have fallen a prey to some hostile, wild, and raging force of nature. In idiotcy, lastly, especially where it is inborn and conjoined with the perfection of the external organs of sense, we must assume the existence of some faulty organization, some defect in the brain, or whatever else is the unknown but higher organ both of thought and life. The source of the last is altogether physical and corporeal, whereas moral causes often co-operate in the highest degree to the production of the former two. The deaf and dumb, if left wholly to themselves, would, in all probability, belong always to the third class, since, with the loss of speech they are simultaneously deprived of a leading condition of rationality. And, accordingly, the first object with those who undertake the difficult task of training these unfortunate beings is to furnish them with another language, by means of signs, instead of the ordinary audible speech of which the accident of birth has deprived them. This instance, therefore, is only a further confirmation of what I have already advanced, that the intellectual character is, in every respect, most intimately dependent on the faculty of speech. A more minute examination of these matters belongs to physical science. Nevertheless, our passing remark on the triple character of this psychological evil, or misfortune, will not, I hope, be found inappropriate here, as affording, even in this narrow and special sphere of a disordered intellect, a further illustration of the general principle of our theory of the human consciousness.