“According to Sherrington the nervous system responds in action as a whole, and to but one stimulus at a time.... Under the influence of fear or (fear of) injury the integration of the common path is most nearly absolute.... Hence fear and injury (or fear of injury) drain the cup of energy to the dregs....
“We can understand why it is a patient consumed by fear suffers so many bodily impairments, (so many functional disturbances) and diseases even. We can understand the grave digestive and metabolic disturbances under strain of fear.... We can understand the variations in the gastric analyses in a timid patient alarmed over his condition and afraid of the hospital. The patient is integrated by fear, and since fear takes precedence over all other impulses, no organ can function normally (under the influence of fear)” ... Dr. Crile arrives at the conclusion that “Fear dominates the various organs and parts of the body....”
Dr. Crile lays special stress on the pathological character of the fear instinct: “That the brain is definitely influenced, damaged even, by fear has been proved by the following experiments: Rabbits were frightened by a dog, but were neither injured nor chased. After various periods of time the animals were killed and their brain cells compared with the brain cells of normal animals, wide-spread changes were seen (in the brain cells of the animals affected by fear). The principal clinical phenomena expressed by the rabbits were rapid heart, accelerated respiration, prostration, tremors, and a rise in temperature. The dog showed similar phenomena, excepting that, instead of such muscular relaxation as was shown by the rabbit, it exhibited aggressive muscular action.”
Animals in which the fear instinct can be aroused to a high degree become paralyzed and perish. The animal mechanism is by no means perfect. A stab in the heart, a rip in the abdomen, a cut of the carotids, a prick in the medulla, a scratch of a needle infected with anthrax, or tetanus bacilli, a drop of hydrocyanic acid, an arrow tipped with curare, extinguish every spark of life. Organic material may be delicate and complex, but for that reason it is highly imperfect and vulnerable.
Living matter is the feeblest material in nature, and is as fragile as a delicate crystal vase. Protoplasm, or living matter, may be wonderful material, but it can be crushed with a pebble. The most beautiful colors may be displayed by a thin, delicate bubble, but it bursts at the least touch. Living matter is like a bubble, like foam on the ocean. Perhaps no better material is available for the functions of life.
Meanwhile it remains true that the flimsiness of living material makes it easily subject to decay and destruction. It is a profound error, having its root in prejudice, that nature always helps, and that the processes going on in the organism are always of benefit to the individual. Nature is as ready to destroy life as to protect it.
Preservation or destruction of a particular individual depends on the fact as to whether or no normal or pathological processes predominate in the total economy of the organism. This holds true of the fear instinct. The fear instinct is a delicate mechanism, and when its action is slightly intensified, the animal is on the way to destruction. For the cosmic forces are careless of the creatures which keep on pouring forth in generous profusion from the lap of nature.
Living matter, or protoplasm can only exist under special, restricted conditions,—the least variation means death. The more complicated, and more organized protoplasm is, the more restricted are the conditions of its existence. A rise of a couple of degrees of temperature or a fall means disease and death. The same holds true of the rise and fall of quantity and quality of bodily secretion of glands and of other organs. Protoplasm can only exist in an optimum environment. Any change spells disease and death.
The fear instinct, being at the heart of highly organized life activities, is delicately responsive to any changes and variations from the optimum, requisite for the proper functioning of the organism. Any deviation from the optimum environment, external or internal, produces corresponding changes in the fear instinct with consequent pathological changes in the organism.