Page:Popular Science Monthly Volume 7.djvu/482

466 There are various remarkable phases of this inability to articulate. One man in the Paris asylum would say "Consisi;" and it might be expected that he could easily say "con-con" or "sisi," but it was only after several days' trying that Dr. Trousseau got him to say the former, and he never could say "sisi" alone. Another aphasic patient, a woman, could say very well, "Bonjour, monsieur;" but could never be got to say "Bonbon."

Aphasic patients are, as a rule, beneath the average of other men, as regards intelligence, and considerably beneath their former selves, when the comparison can be instituted. There is, however, a very rare form of aphasia in which the intellect is unaltered, memory is good, the patient writes easily, and expresses his thoughts correctly in writing as educated deaf-mutes do. The recovery of the art of writing (where it is recovered) is gradual.

The physiology of aphasia is a subject that has been a good deal controverted, but it now appears possible to explain most of the phenomena by the nature of lesions, and by the very constitution of the nervous system. The following representation of the facts (which we take, in the main, from an eminent French observer, M. Charles Richet) will convey some idea of what medical men hold on this subject.

The nervous system (let it first be understood) is formed of a central part, the brain and spinal cord, and of a peripheric part, the nerves. The nerves are simple conductors, while the central part perceives sensations and determines movement. Now, in this central part, the cerebro-spinal, inclosed by the cranium and vertebral column, as in a case, there are two distinct elements; an active element, and a conducting element. The white substance is the conducting: element; the gray substance the active. The gray substance forms a thin column, which is the central part of the spinal cord, and is continued into the brain where it enlarges. The whole of this column is surrounded by white substance; and in the higher types of vertebrates we find added the so-called "cerebral convolutions." Here the white substance of the brain is folded in various directions, and its entire surface is covered with a thin layer of gray substance. To this elementary exposition it need only be added that the gray substance in brain or cord seems to be formed, not by a single cord, but by a series of nuclei, or centres, placed end to end and connected together. These are sometimes called ganglions. It is in the outer gray substance that will, intelligence, instinct, seem to reside. If the upper part of the cerebral hemispheres be cut in a pigeon, the bird loses all activity: it is incapable of moving voluntarily. It is an automaton which flies when thrown into the air, which swallows when a grain is placed in its throat; but which is without consciousness. Its existence is purely vegetative.

If, instead of the superficial part of the brain, it be the gray axis,