I have alleged that the size of the three groups of ruling organs may be ascertained by that of the cases in which they are contained. Nor do I perceive on what ground any one, who is even moderately acquainted with the structure of the human body, can controvert the belief, or cherish the slightest doubt on the subject of it. In healthy persons (and my remarks relate only to such) the size of the brain is necessarily known by that of the head. As the viscus completely fills the cranium, the case cannot be otherwise. Although the bones of the head and the soft parts that cover them are thicker in some individuals than in others, the difference is so small as not materially to affect the result. The chest is filled by the lungs, heart, and large bloodvessels. Its measure, therefore, cannot fail to be the measure of them. Any deviation from exactness in this, that may be produced by varieties in the thickness of the skin, muscles, and other parts, is of no moment. Of the chylopoetic viscera the same is true. They also fill exactly the cavity prepared for them. The size of the abdomen, therefore, affords a knowledge of their size sufficiently accurate for all practical purposes. By a mere inspection of the person of man, then, the absolute measure of the groups of organs I am considering, as well as their magnitude in relation to each other, can be fairly ascertained. And it will appear on examination, as already stated, that the predominance in size and energy of any one or two of them, always imparts a corresponding diversity to the human character. Does the brain predominate? The individual to whom it belongs is more remarkable for the vigor of his intellect or feeling, or both, than for any other constitutional quality. These modes of mental manifestation constitute the natural functions of the brain; and when of an order unusually high, they give a peculiarity of character to the whole system. The person thus endowed feels more keenly, thinks more strongly, is more eager in pursuit of knowledge, and attains it with more facility. His relish for pleasure is also inordinately keen, and he pursues it at times with burning ardor. Such was the constitutional character of Mr. Fox, and also of our distinguished countryman the late Mr. Bayard. I need scarcely add, that this predominance of sensibility and mental action must necessarily modify the diseases the individual may sustain. But of this I shall speak hereafter. Do the lungs, heart, and bloodvessels predominate? A larger volume of highly arterialized blood is formed, and thrown more forcibly and in greater quantities throughout the system. From the abundance of that fluid, and the superior size of the vessels conveying it, those parts of the body nourished by the red blood will be comparatively most copiously supplied. But it is more especially the muscles that are thus nourished. They will be therefore large and powerful. Hence persons with broad and full chests have well-developed and