Insanity: Its Causes and Prevention

by Henry Putnam Stearns

3. The condition of the nervous system in chorea presents another illustration. Between the ages of ten and fifteen years, in some children, there may occur such changes in the condition of the nervous element, from the altered character of the blood, as to render it more or less unstable in some portion. One arm or one leg, or a hand, or some of the muscles of the face or neck, cannot be kept long at rest by any effort which can be exerted by the individual, and this may be so slight as scarcely to attract attention, or it may be so great as to cause extreme suffering for a long time, and ultimately destroy life.

Now the primary condition in the above cases is one of instability of nerve function. Such a change has occurred in the elemental tissue of the nerve, as to injure its power of activity so far as it is under the control of the will. The nerve has been stimulated to over-activity, or its energy impaired by other causes arising within the system itself.

These illustrations have related to those portions of the nervous system which are more immediately connected with motion, and which, consequently, are located in the muscular system. If, now, we pass from these portions of the nervous system up to its grand centre, or that part of it whose function is connected with mental operations, we shall find similar effects resulting from like causes.

If a person experiences a sudden mental shock, occasioned, it may be, by sad intelligence of some kind, or if he passes suddenly through some great personal peril, or if he has made unusual mental effort in some abstruse study, or in the conduct of business, which has been long protracted, he becomes conscious of what is called mental fatigue. The brain refuses to respond to any calls which may be made upon it for further action, or partially refuses; it becomes confused and bewildered, and unsteady in its action; it is difficult to force it to further application, or to connected lines of thought, and if, by a strong effort of the will, this is done during a short time, it is inclined soon to wander from the subject, and there exists a more or less distinctly recognized sensation of pain as well as inability to regulate its action.

In this case, also, as in the others, there may result any degree of effect, from a sensation of fatigue up to mental spasm, and the amount will depend on the condition of the brain during the time the effect continues, and its intensity. The two conditions of instability and pain may be less marked in the case of the brain than in the nerves of motion, but there can be little doubt there has resulted something of a similar character in both.

Precisely in what this change which has taken place consists, may not be easily determined. There may have occurred actual lesion of nerve element, or only impairment or exhaustion of functional power without lesion; probably the latter condition only, in the primary stages of the operation. Certain portions of the brain have been over-stimulated in action, and consequently their power of normal activity and stability is impaired, as was seen in the cases of nerves distributed to the muscles of the arm and other portions of the body.

II. Again, if the arm or hand of a vigorous person, which has long been trained to make either large efforts, or the more delicate movements, or again, to make but little effort in any direction, be placed in splints, or be suspended in a sling so that there is little or no activity for a few weeks, more or less, there results a failure of nerve-function; and there may be any degree of impairment, from that of slight degree, such as may be evinced by spasm, to that of paralysis.

The same is true in reference to any portion of the nervous system which can be placed in a state of inactivity.

A few sentences of recapitulation in our process of reasoning will now be in order.

1. We have seen that imperfection and instability of nerve-function may be inherited; that weakness, or impairment, exists with many persons from the time of birth, which affects more or less the functions of the various portions of the nervous system; and that this is seen not only in the mechanical operations of the hand and arm, in the execution of all the more delicate movements of which it may be susceptible, but also in the mental operations. By no possible amount of training can the nerves of the arm in certain persons be educated to do the finer portions of mechanism, any more than can their brains be educated to continuous or concentrated thought on the solution of problems in the higher mathematics; that the broadest diversity as to strength and steadiness of nerve-function exists from the period of childhood to old age: while the nerves and brains of some bear long-continued and large effort without disturbance or failure of function, these portions of the system in others soon manifest the effects of such treatment, and ere long break down; and there may exist any degree of difference, from the manifestations of genius, to those of imbecility.