Page:Popular Science Monthly Volume 26.djvu/17

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of fits of anger, the liver is so deranged that the bile ceases to be produced, and pain is felt in that part of the body in which the liver is situated; and, when the emotion of pity is strongly experienced, a sensation of weakness, or, as it is sometimes called, a sinking feeling, is felt at the pit of the stomach.

It has been customary with modern writers—and I have until quite recently been of the like opinion—to regard these disturbances as being the effects of emotions that originated in the brain, and not as indicating that the organs in which they are felt have anything to do with the evolution of love or anger or fear or compassion, or any other passion or feeling. The idea has become so widely spread among educated persons that the brain is the only organ of the body that has any direct relation as a generator with the mind, that it seems like a tremendous blow at the system of existing facts to attempt to take from it any of its power. But it is only recently that physiologists and pathologists are beginning to make a thorough investigation into that great division of the nervous system consisting of the sympathetic nerves and their ganglia. If you will lock at this diagram, you will obtain some idea of the situation and connections of these nerves. As you see, they are situated on each side of the spine, and are in direct connection with the brain, and their ramifications extend to every one of the vital organs situated in the chest, the abdomen, and the pelvis. These nerves differ from the other nerves—those that convey impulses to and from the brain—in the remarkable fact that they have at various parts of their course little swellings or enlargements called ganglia, and which consist of gray matter. Now, gray nerve-tissue, wherever it exists, is a generator of nerve-force, or mind, and it is not unreasonable to suppose, therefore, that these masses of the tissue in question, that are placed around the heart, the liver, the spine, and other organs, and in vast number in their substance, have some influence in causing the production of those emotions that make themselves felt in the parts of the body with which former universal beliefs and our present forms of speech have associated them. We find, too, as an additional fact in support of this view, that in certain mental affections, characterized by great emotional disturbances, these ganglia are in various parts of the body the seats of disease.

Therefore, there is some reason for the opinion that not to the brain alone do we owe the evolution of mind, but that the sympathetic system of nerves is also concerned in its production.

But there is another part of the nervous system not generally regarded as a mind-producing organ, but which I am very sure is directly concerned in the evolution of the force which so pre-eminently by its presence distinguishes organic from inorganic bodies, and that is the spinal cord.

The spinal cord is contained in the vertebral column, or, as it is popularly called, the backbone. It extends from the brain to near the