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Psychology Applied to

Medicine

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CHAPTER I

SUMMARY

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Books recommended: James, "Psychology," Henry Holt; Donaldson, "Growth of Brain," Scribners; Sandford, Experimental Psychology," Heath; Waldstein, "The Subconscious Self," Scribners; Bramwell, "Hypnotism," Lippincott; Sidis, Psychology of Suggestion," Appleton; Sidis, "Multiple Personalities," Appleton. — Modern psychology is becoming an important branch of medicine, because it is recognized that "no mental modification ever occurs which is not accompanied or followed by bodily change."-Cerebration is accompanied by a temporary association and grouping of nerve cells, but thought is not a physical matter. - Development of nervous system a part of organic evolution.—Psychic missing links. Instincts, common to man and beast. - Man alone possesses reason. "No action but such as shows a choice of means can be called indubitable expression of mind.”— Recepts and concepts. - Man has three sets of impulses : (1) Congenital reflexes, (2) acquired reflexes, (3) reason.

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PROFESSOR LADD has defined psychology as science which describes and explains the phenomena of consciousness."

While abstruse logic and cosmic philosophy are

still legitimate departments of the subject, the new psychology is not strictly metaphysics, it is a physiological psychology, in fact a mental physiology. The very word experimental, as applied to the subject, suggests appliances and individual research quite beyond the scope of logic.

It is a recognition of the law laid down by Professor James, that "no mental modification ever occurs which is not accompanied or followed by a bodily change," which renders it imperative that a physician should be well grounded in the fundamental truths of psychology.

The comprehensiveness of the subject is overwhelming. The present essay is an attempt to present only a few well-recognized facts which bear directly on the subjects of physiology and hygiene.

It may be well at the outset to have a clear idea of our limitations. The old controversy between the spiritualist and the materialist is perhaps not yet ended, but there has been a decided reaction from the ultramaterialism of fifty years ago. The attempt to identify thought and molecular motion has few defenders to-day. It used formerly to be said by this class of thinkers: "The brain secretes thought as the liver secretes bile." This is a distressing confusion of two distinct realms in nature, -the psychical and the physical.

Recent developments in neurology have thrown much light on the phenomena of brain activity. Cerebration is now thought to be accompanied by a

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temporary association of nerve cells; but were we able to trace the nervous impulse, thru all its intricacies, to the brain centers, did we know the exact molecular changes which cause the efferent impulse, the nature of a thought would be as much a mystery as ever. Indeed it is doubtful if the question is ever solved by the finite mind. Tyndall said: "There is no fusion possible between the two classes of facts. The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable."

It is not claimed that the unknown is necessarily the unknowable, but it is a line of investigation which cannot be taken up in any superficial way. This confession of ignorance is in fact a great step toward a higher knowledge. It is a refined agnosticism. The fact seems to be that the brain is the organ of the mind, just as the body is the organ of the brain.

SENSATION

Simple protoplasm possesses irritability, contractility, and elasticity - that is, it has sensation equal to its needs. Professor Sutherland has said: "A nervous system is an arrangement by means of which an organism becomes conscious of its environment (food, friends, and foes) and adapts itself thereto." 1 This is a very comprehensive definition suited to any form of life except unicellular organisms, and even here, altho there is no aggregation of nerve

'Anatomical Lectures, B. U. Med. School.

elements into a system, yet monocellular forms react to touch, pressure, etc.

When the ameba envelops and ingests the food particle that touches its periphery, it evidences a "consciousness of environment and adjustment thereto." It is evident that the word consciousness is here used in a general sense. Some psychologists have restricted the term to define a human attribute only, and others have asserted that consciousness without a central nervous system is impossible. From a biological standpoint all life is conscious.

REASON AND INSTINCT

By studying the evolutionary scale of life as it exists to-day, it is seen that the nervous system, like its accompanying organism, progresses from the simple to the relatively complex, till in man it reaches a development capable of what we call

reason.

Undoubtedly psychology has drawn too sharp a line between reason and instinct. The reaction from this was the contention that the lower animals reason, the difference being one of degree, not of kind. The earlier idea that reasoning was an attribute of man only was natural in preëvolutionary times, and was based on the belief in the immediate creation of perfected organisms, the so-called special creation, because special creations had distinct endowments. The evolutionist maintains that since the establishment of the general law, "from the

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