Dr. C. afterward goes on to prove that no single nerve, or organ, can perform two distinct functions, but that each is capable of one mode of action, and no more; that between a nerve, a muscle, and a gland, the only difference known to exist, is that of organization; and that if they are organized alike, and endowed with life, their properties will be similar, and they will act in the same way. So also between animals of the same race, we discover innumerable differences, which can be referred to nothing but differences in organization, and the same may be affirmed of vegetables. The conclusion to which Dr. C. arrives, and which he maintains with great ingenuity is, that independently of all other causes, differences in human temperament are to be attributed, in part, to corresponding differences in the organization of certain portions, or the whole of the body; and that, other things being equal, in consequence of this source of influence alone, one person differs from another in many of the qualities of both person and intellect. In other words, he is more highly gifted, sprightly, and vigorous, or the reverse; or he is more courageous or timid, generous or selfish, according to his organization. "But the second cause that was represented to be instrumental in diversifying the human temperaments is by far the most powerful. It will be remembered to have been, 'difference of size and vigor in certain ruling organs of the system.' The organs alluded to are those contained in the three great cavities of the body; the chylopoetic, situated in the abdomen, and including the stomach and intestines, with the liver, pancreas, mesentery, and lacteals; those of sanguification and circulation, situated in the thorax, and consisting of the lungs, heart, and bloodvessels; and the brain, with its appendages, the spinal cord and nerves. These three _groups_ (for the brain is _multiplex_ as well as the other two) are not only the ruling organs in the person of man; connected with the hard and soft parts that enclose them, they _constitute the person_. The upper and lower extremities are but appendages; important and necessary, it must be acknowledged; but still appendages. The individual can exist and be a human being without them. Nor have they any influence in imparting constitutional character to their possessors. Standing only in the capacity of subordinates to the controlling organs, they are not only nourished and put in motion by them; they labor mechanically for their uses, and serve as instruments to execute their purposes. They are composed of the extreme ends of the organized matter of the system, constitute only its outworks, and possess but little influence over its central parts. This representation rests on evidence that may be termed demonstrative. Many persons destitute of the upper or lower extremities, or both, have strong characters and well-marked temperaments. But the