PREOCCUPATION OF MIND
This is true, not only for ordinary sensations, but even for such as would ordinarily be presumed to be so insistent in their call that they could not be neglected. The concentration of mind necessary for this is not common to all mankind; it is possessed only by a few individuals whose intellect represents the larger portion of their personality. Certain of the great investigating scientific geniuses have had the faculty of so concentrating their attention upon the questions with which their intellects were engaged, that even the call of appetite did not make itself felt. Newton was one of these. Over and over again, he was known to neglect to take his meals, even though they were brought to him, and, occasionally, he would entirely forget whether he had taken a meal or not. But Newton is not an extreme exception. Most of the great mathematicians have had experiences of this kind and, indeed, mathematics seems to be that special branch of intellectual work which most readily brings about a preoccupation of mind sufficient to completely shut out the outer world for the time being. Archimedes, the great ancient mathematician, lost his life because of preoccupation with mathematical problems that kept him from telling the Roman soldiers, who had strict orders to spare him, who he was.
Complete absorption of mind to the exclusion of all external sensations is not, however, confined to the mathematicians. Mommsen, the historian, was famous for his fits of mental abstraction. Once he patted a school-boy on the head and asked whose boy he was, to be told rather startlingly, "Yours." Lombroso, the criminal psychologist, was subject to abstraction in almost as great a degree. Men have become so preoccupied in study as not to appreciate the significance of warnings, indicating that a serious accident was about to happen, such as a fire or the fall of some object that they should have avoided, or some other danger to themselves. The tendency to such abstraction is responsible for many accidents on busy city streets. When so preoccupied, painters walk off scaffolds, and such preoccupation of mind is extremely dangerous, not only for the man himself, but for those who are working with him.
Everyone knows that a slight headache frequently disappears in pleasant company. There is sometimes the suspicion, though it is quite unjustified, that because a person has a headache which can be cured by engaging in a favorite occupation, the headache is more imaginary than real. The common experience with toothache shows the falsity of this opinion. There is no imagination in regard to toothache, yet it, too, except in very severe cases, will be so modified as to be quite negligible if the victim has some mental occupation that is very absorbing. Pains of other kinds that are just as real, may be modified in the same way. I have known a boy to suffer enough from the presence of an unsuspected kidney stone to give up play and come into the house, yet he could be made entirely to forget his discomfort by a game of checkers. On account of the ease with which the pain was thus dispelled, the suspicion was harbored that his ache was more imaginary than real. The ache continued and at the end of about a year there was an acute exacerbation which justified an operation, and the stone was removed.
In all these instances there is evidently a question of the unmaking, or at least imperfect making, of connections between the peripheral and central neurons, because of the existence of connections between different portions of the brain itself which take up the attention. This attention to mental things may become exaggerated, and must be guarded against, but it represents a valuable psychotherapeutic remedy. Whenever the peripheral connections are unmade, external sensation is unfelt. Even though the peripheral neuron may be suffering to some extent, this is true. It is this law of attention that must be taken advantage of for psychotherapeutics. People who are liable to be too much concerned with their sensations, must be taught to occupy themselves with interests that will absorb the attention. Central neurons can, except under very serious circumstances, be made to connect with one another so intimately as to bring about the neglect of many bothersome external sensations.
FIG. 20.—COMPLEXITY OF CELL OF THE CENTRAL NERVOUS SYSTEM. A Golgi cell after Andriezen. (Barker.)
On the other hand, when the connections with the periphery are well made, external sensations flow in on us to the exclusion of thought and then even simple sensations may be exaggerated so as to become painful. Anything that attracts our attention so much that we cannot think quietly about it, is likely to be a disturbance rather than a pleasure. Music is distinctly pleasant, yet very loud music becomes painful. The reason is that the peripheral neuron is so much disturbed that these excessive vibrations are communicated to other neurons connected with it and they are unable to occupy themselves with anything except this over-strenuous sensation. A very bright light has something of the same effect, and the same thing is true for all the other senses. A pleasant odor, if over strong, becomes disgusting. A very sweet taste is cloying. This over excitation of neurons may come from without, or may come from within. If the central neuron is so much occupied with itself, and the sensation that is flowing into it, that it is prevented from making such connections as would communicate and distribute the sensations properly, then the sensory phenomenon becomes painful, though it may not be exaggerated in the peripheral neuron.
VITAL ENERGY BEHIND BRAIN CELLS
In all of these phenomena there is something more than brain cells at work. Brain cells are guided, co-ordinated, controlled, and even overseen, in their labors. The same conclusion becomes inevitable with regard to the action of the cells of the body generally. A generation or two ago it was the custom to attempt to explain all the processes in the body by chemical and physical principles. Respiration, for instance, and absorption of gases into the blood in the lungs and the expiration of gases that have been generated within the body during vital processes, were supposed to be entirely explicable on the principle of the diffusion of gases. The absorption of various substances into the body proper from the intestinal tract, and the excretion of various substances from within the body into the excretory organs, as well as the process of secretion, were supposed to be nothing more than varying phenomena of osmosis and exosmosis. There has since been a general recognition of the fact that these principles do not explain many of the incidents within the body in its relations to its surroundings, and that vital processes are something much more than merely manifestations of physics and chemistry.
The lungs are not mere laboratories in which refinements of the laws of the diffusion of gases may be studied, for under varying pressures from without that would vitiate the ordinary laws of diffusion, inspiration and expiration continues. Fishes live at depths where the pressure is so great that expiration would seem to be impossible, yet they succeed in eliminating harmful gaseous material. Prof. Haldane of Cambridge has called attention to many of these processes. Animal stomachs are not test-tubes. Animal excretion, and above all, secretion, is carried on sometimes in accordance with but, almost more often, in defiance of chemical and physical principles. The individual, even in the lower animals, counts for much more than the chemical constituents of the tissues and the physical principles involved.
Besides, all the parts of the organism are co-ordinated, and there are wonderful checks and counterchecks which show that animals are much more than colonies of cells fortuitously growing together and habituated to such common life by many generations of heredity and environment and training. In a word, the old vitalistic principle has become popular once more and even great physiologists have insisted that there is a principle of life which guides and controls and co-ordinates the different portions of the body. Especially does this seem to be true of the brain. We have here an intensely complex machine, composed literally of billions of parts which work together, and in doing so accomplish wonderful results. Of the existence of this machine, much more of the great intricacy of its parts and mechanism, we are quite unconscious. We learn to use it in very early years with an assurance and a perfection that is amazing, considering how complex it is. The less we think about it and its workings, the better does it work and the less disturbance of function is there in its accomplishment.
Fig. 21.—SECTION THROUGH THE CORTEX OF THE GYRUS OCCIPITALIS SUPERIOR. (Hammarberg. Barker.)
If a vitalistic principle were needed to enable us to understand the workings of the ordinary body cells, how much more is it required for the workings of brain cells. There is something behind that guides and rules the brain, and through which it accomplishes