Читать книгу Fear - A. Mosso - Страница 20

Table of Contents

During my medical career I had more than once an opportunity of seeing the human spinal cord injured or severed. The most interesting case was that of a peasant, who, in falling from a tree, had severed the spinal cord in the dorsal region a little below the shoulder-blades, with a pruning hook. He moved his arms, spoke, but did not feel the lower part of his body any longer, nor the pain which a wound he had on the shin-bone would otherwise have caused him, although the leg moved whenever we touched the sore in order to treat it.

Marshall Hall proved that all generative acts are dependent on the lower part of the spinal cord, and Brachet tells of a soldier who became the father of two children although the lower half of his body was paralysed and quite without feeling. The only thing we do not find in an animal with the spinal cord severed are those irregular movements of the part separated from the brain, corresponding by their spontaneity to those we call voluntary.

Frogs and other animals of which one has cut the spinal cord are in general motionless and paralysed in the parts separated from the brain; we must touch them in order to make them move. If one pinches or slightly presses the hind-paw of a dog with the spinal cord severed in the dorsal region, he moves it or draws it away, but does it unconsciously, as we do if we are touched while asleep. If the stimulus is strong, he moves the other leg and his tail; if stronger still, he moves his whole body and trembles.

Even when the brain is wanting, slight stimuli produce a wagging of the tail; strong stimuli the drawing of the tail between the legs. This proves that certain characteristic phenomena of fear are produced without any participation of the will or consciousness.

The liveliness and restlessness so characteristic of youth arise from the greater excitability of the nervous system, which one always notices in young animals. The age, race, and bodily condition render very dissimilar the reflex movements by which animals deprived of their brain respond, even when they are excited in the same manner. The differences observable in character correspond to anatomical and functional differences of the nerve-centres.

As it is impossible to find two men having all parts of their brain or spinal cord exactly alike, we infer that these differences in the structure of the nerve apparatus materially influence other functional differences which seem to depend on causes of a higher order known under the generic name of will. What many call free-will is only a fatal necessity, an indissoluble chain of causes and effects, of physical and mechanical actions, of automatic and unconscious reactions in the living machine.