By means of the nervous system, an intimate relation is maintained between mind and body, for nervous energy superintends the functions of both. The fibres of nervous matter are universally present in the organization, uniting the physical and spiritual elements of man's being. Even the minutest nerve-rootlets convey impressions to the dome of thought and influence the intellectual faculties. We recognize muscular force, the strength of the body, molecular force, molecules in motion, as heat, light, chemical force, electricity, and nervous force, a certain influence which reacts between the animal functions and the cerebrum, thus connecting the conditions of the body with those of the mind. We cannot speak of the effects of mind or body separately, but we must consider their action and reaction upon each other, for they are always associated. There are many difficulties in understanding this relationship, some of which may be obviated by a study of the development of nervous matter, and its functions in the lower orders of organization. Within the plant-cells is found a vital, vegetable substance termed bioplasm, or protoplasm; which furnishes the same nutritive power as the tissues of the polyp and jelly fish. Many families of animals have pulpy bodies, and slight instinctive motion and sensibility, and in proportion as the nervous system is developed, both of these powers are unfolded. Plants have a low degree of sensibility, limited motion, respiratory and circulatory organs. Animals possess quicker perceptions and sensibilities, the power of voluntary motion, and, likewise
A higher grade of organization requires a more complete arrangement of nervous substance. Stimulus applied to one organ is readily communicated to, and excites activity in another.
The nervous system of some insects consists of two long, white cords, which run longitudinally through the abdomen, and are dilated at intervals into knots, consisting of collections of nerve-cells, called ganglia. They are really nerve-centers, which receive and transmit impulses, originate and impart nervous influence according to the nature of their organic surroundings. The ganglia situated over the esophagus of insects correspond to the medulla oblongata in man, in which originate the spinal Man possesses not only a complete sympathetic system, the rudiments of which are found in worms and insects, and a complete spinal system, less perfectly displayed in fishes, birds, and quadrupeds, but, superadded to all these is a magnificent cerebrum, and, as we have seen, all parts of the body are connected by the nervous system. The subtle play of sensory and motor impulses, of sentient and spiritual forces, indicates a perfection of nervous endowments nowhere paralleled, and barely approached by inferior animals. This meager reference to brainless animals, whoso knots of ganglia throughout their bodies act automatically as little brains, shows that instinct arises simultaneously with the development of the functions over which it presides. Here begins rudimentary, unreasoning intelligence. It originates within the body as an inward, vital impulse, is manifested in an undeviating manner, and therefore displays no intention or discretion. While Dr. Carpenter likens the human organism "to a keyed instrument, from which any music it is capable of producing can be called forth at the will of the performer," he compares "a bee or any other insect to a barrel organ, which plays with the greatest exactness a certain number of tunes that are set upon it, but can do nothing else." Instinct cannot learn from experience, or improve by practice; but it seems to be the prophetic germ of a higher intelligence. It is nearly as difficult to draw the dividing line between instinct and a low grade of intelligence, as it is to distinguish The intimate relation of instinct to intelligence is admirably illustrated in the working honey-bee. With forethought it selects a habitation, constructs comb, collects honey, provides a cell for the ova, covers the chrysalis, for which it deposits special nourishment, and is disposed to defend its possessions. It is a social insect, lives in colonies, chastises trespassers, fights its enemies, and defends its home. It manifests a degree of intelligence, but its sagacity is instinctive. Reason, though not so acute as instinct, becomes, by education, discerning and keenly penetrative, and reveals the very secrets of profound thought. We recall the aptness of Prof. Agassiz's remark: "There is even a certain antagonism between instinct and intelligence, so that instinct loses its force and peculiar characteristics, whenever intelligence becomes developed." Animals having larger reasoning powers manifest less instinct, and some, as the leopard, exercise both in a limited degree. This double endowment with instinct and low reasoning intelligence, is indicated by his lying in ambush awaiting his prey, the hiding-place being selected near the haunt of other animals, where nature offers some allurement to gratify the appetite. Simple reflex action is an instinctive expression, manifesting an intuitive perception, almost intelligent, as shown by the contraction of the stomach upon the food, simply because it impinges upon the inner coats, and thus excites them to action. A better illustration, because it displays sympathy, is when the skin, disabled by cold, cannot act, and its duties are largely performed by the kidneys. Though reflex action is easily traced in the lower organic processes, some writers have placed it on a level with rational deliberation. Undoubtedly, all animals having perception have also what perception implies—consciousness—and this indicates the possession, in some The psychical functions connect, not only with animal propensities, but also with the highest psychological faculties. Instinct is the representative of animal conditions, just as the highest spiritual faculties are indicative of qualities and principles. The consistent mean of conduct is an equilibrium between these ultimate tendencies of our being. The psychological functions render the animal nature subservient to the rule of purity and holiness, and deeply influence it by the essential elements of spiritual existence. The psychical organs sustain an intermediate relation, receiving the impressions of the bodily propensities, and, likewise, of the highest emotions. Obviously, these extreme influences, the one growing out of animal conditions, the other, the result of spiritual relations, pass into the psychical medium and are refracted by it, or made equivalent to one force. The body requires the qualifying influences of mind. The tendencies of the animal faculties are selfish and limiting, those of the emotive, general, universal. The propensities, like gravity, expend their force upon matter; the emotions pour forth torrents of feeling, and produce rhapsodies of sentiment. The propensities naturally restrict their expression to a specific object of sense; the emotions respond to immaterial being. The tendencies of the former are acquisitive, selfish, gratifying; of the latter, bestowing, expanding, diffusing. The one class is restricted to the orbits of time and matter, the other flows on through the limitless cycles of infinity and immortality. The former is satiated in animal gratification, the latter in spiritual beatification. The one culminates in animal enjoyment, the other expands to its ultimate conceptions in the perfections of Divine Love. In the present life, mind and body are intimately connected by nervous matter. In this dual constitution, the spiritual mental, and animal functions are made inseparable, and modify Every fact of mind has many aspects. A brain force, which results in thought, is simultaneously a physiological force, if it influences the bodily functions. Likewise, spiritual conceptions take their rise in the same blood that feeds the grosser tissues. This vital fluid is momentarily imparting and receiving elements from all the bodily organs, and these, in turn, must influence the process of thought, and, in a degree, determine its quality. The delicate outline, yea, even the substance of an idea, may depend upon the condition of the animal organs. Thought is subject to the laws of biology, and, therefore, is a symbol of health. Morbid conditions of the system hang out their signs in words and utterances. Words which express fear are as true symptoms of functional difficulty as is excessive palpitation. The organ representing fear sustains a special relation to the functions of the heart both in health and disease. Bright hopes characterize pulmonary complaints as certainly as cough. Exquisite susceptibility of mind indicates equally extreme sensibility of body, and those persons capable of fully expressing the highest emotions are especially susceptible to bodily sensations. Tears are physical emblems of grief, and fellow-feeling calls forth sympathetic tears. Excessive anxiety of mind produces general excitability of body, which soon results in chronic disease. Pleasurable emotions stimulate the processes of nutrition, and are restorative. This concomitance of mental and bodily states is very remarkable. Joy and Love, as well as jealousy and anger, flash in the eye and mould the features to their expression. Grief excites the lachrymal, and rage the salivary glands. Shame reddens the ears, drops the eyelids, and flushes the face; but profligacy destroys these expressions. The blush which suffuses the forehead of the bashful maiden betrays her love, and maternal love, stirred by the appeals of an idolized infant, excites the mammary gland The relationship of mental and physical functions may be illustrated by entirely removing the spleen of an animal, as that of a dog. An invariable result of its extirpation is an unusual increase of the appetite, for at times the animal will eat voraciously any kind of food. The dog will devour, with avidity, the warm entrails of recently killed animals, and thrive in consequence of such an appetite. Another symptom, which usually follows the removal of the spleen, is an unnatural ferocity of disposition. Without any apparent provocation, the animal will attack others of its own, or of a different species. In some instances, these outbursts of irritability and violence are only occasional, but the experiments show quite conclusively that the spleen moderates combativeness, restrains the appetite, and co-operates with the will and judgment in controlling them. We shall briefly consider the practical question whether the elements of mind can be ideally arranged and presented, so as to more completely reveal their relations to, and disclose their effects upon the bodily functions. Modern philosophers conceive that mind consists of a triad of essentials; Intellect, Emotion, and Volition. Physiologists assign to the cerebrum its functions, and neurological, as well as phrenological writers, have located them as represented in Fig. 68. True, there is no structural division between the parts of the cerebrum to indicate this diversity of function, nor is there any perceptible limit between the sensory and motor filaments of the game nerve. As no one has any reason for denying that separate portions of the brain may manifest distinct functions of the mind, we shall assume it as a conceded proposition. The regions of the cerebrum, thus ideally represented, occupy but little more than half of the arc of a circle, whereas it is evident that the base of the nervous mass is not idle, and is equally entitled to our consideration. In the posterior chamber
Nature answers to mind in physical correspondences. The planetary system is fashioned after a circle. Life itself springs from a spherule of forces. The perfection of an idea, or the completeness of a conception may be expressed by a circle. The elements of Science, Astronomy, Geology, and Natural History, are pictorially represented in this manner. How appropriately and logically can a fragment of natural history, this epitome of all nature and science—the mind—be illustrated by a simple circle! Every element must act and react, and be equal and opposite. Thus may the existence of the opposing energies and functions of each faculty be equally represented. The contrast aids us in understanding their ultimate tendencies, and enables us to correctly value and define their nature. Faculties of kindred qualities may be grouped together, and their antagonisms represented in the opposite arc of the circle. Let us employ a circle to represent mind. The conception of the abstract This is not an exceptional, but a common example of classifying Love, the highest and purest of the emotions, with Anger, an animal propensity. Is it not more practical and philosophical to group the emotional faculties together, and upon an opposite arc represent their antagonistic energies, the ultimate tendencies of which are criminal? Both groups are mutually modifying and restraining; the one relates instinctively to the bodily wants, the other to the requirements of mind, and each is essential to a consistent life. Accordingly, we deem it philosophical to consider words as symbols of mental faculties, and to classify together such spiritual unities as joy, hope, faith, and love, the tendencies of which are to quicken and transform the ultimates of carnal life into the rudiments of an immortal one, the beginning of heaven on earth. These restrain those opposites, which lead to crime and death. Love and Hate are as antagonistic as heat and cold, and the usefulness of both depends upon their proper temperament. Fig. 70 represents the antagonism of the Intellectual
REGIONAL DIVISIONS.
The anterior portion of the cerebrum is devoted to intellectual processes, which freely expend the vital energies. The Intellectual faculties are classified as represented in Fig. 71. The lower portion of the brain, bounded exteriorly by the superciliary ridge, corresponds to the Perceptive, the middle region to the Recollective, and the upper to the Reflective faculties. (See also Fig. 65, b.) If we divide the forehead by vertical lines, as shown in Fig. 71, the divisions thus formed represent respectively, the Active, Deliberative, and Contemplative departments of the intellect, all the processes of which are sustained by vital changes, the transformation of organized materials. No mental effort can be made without waste of
This kind of waste is best summed up in the words, VITAL EXPENDITURE. Upon the forehead, as represented in Fig. 72, we will therefore inscribe INTELLECT, ACTIVITY, and VITAL EXPENDITURE. Intellectual employment is usually accompanied by sedentary habits, neglect of healthful exercise, and a deprivation of pure air, to all of which ill health may be attributed. Were the intellectual expenditure arrested, and the forces turned into recuperative channels, many a person would become beautiful with the ruddy glow of health. Without health there is no use for thought; cultivation of the mind is just as natural and essential as the culture of the body, and the trained development of both is needed for mutual improvement. EMOTIVE FACULTIES.
What results follow the natural and the excessive exercise of the EMOTIVE FACULTIES? AS distinct organs of the body have diverse functions, so, in like manner, different parts of the brain perform the separate operations of the mind. It is easier to discriminate between the products of these dissimilar endowments than to determine the location of the faculties. The intellect deals with concrete subjects, and the emotions with abstractions; the intellect is exercised with material things, the emotions dwell upon attributes; the intellect considers the forces of matter, the emotions, the powers of The quality of the emotional faculties is represented by Benevolence, Sympathy, Joy, Hope, Confidence, Gratitude, Love, and Devotion, all of which are the very antitheses of the attributes of animal feeling, described as Melancholy, Fear, Anger, Hate, Malevolence, and Despair. To the emotions we refer the highest qualities of character, while their opposites represent the animal or baser impulses. True, the emotions modify the propensities, as sympathy softens grief. They may subdue and refine the animal feelings, and thus veil them with a delicacy characteristic of their own purity; but the unrestrained influences of grief find vent in loud lamentations, and the bitter disappointments of the selfish faculties are passionate and violent. The Emotive Faculties—the organs of spiritual perceptions—are impersonal, outflowing, bestowing. The function represented by Benevolence, is willing, giving. Devotion expresses dedication, consecration; Gratitude manifests a warm and friendly feeling toward a benefactor.
Love flames toward its object, is out-pouring, blessing; indeed, all the emotions are gushing, effusive, impetuous, and profusely flowing; grand, torrent-like, overwhelming; employing ideal, immaterial, spiritual expressions, developing principles and perfections while aspiring to happiness and immortality. Though beginning with humanity, they embody the Divine. They expand to their ultimate conceptions in the sublime attributes: the perfections of the God of Love; associating We may consider their counteracting influences, for, without doubt, by checking the selfish tendencies and restraining the animal propensities, they assist in controlling the sensual passions, and thus balance the mind and body. Such an equilibrium we call happiness. If the emotions be acute and vehement, they will absorb all other impressions and revel in their culminating and delightful experiences. They exhaust all the bodily energies, and a functional suspension, termed ecstasy, follows. It is a swooning, or fainting, a temporary loss of sensation and volition, accompanied by involuntary movements of the arms, smiting of the hands, sighing, and short ejaculatory expressions of rapture. This condition, occasioned by excessive emotion, as in praying, singing, exhortations, and sympathetic appeals, is contagious, often spreading with mysterious rapidity. Its culmination, ecstasy, is popularly termed "the power." When gradually induced, it is called trance, and each state is regarded by many as supernatural, caused by the immediate influence of the Holy Spirit. The explanation is this: when the emotive faculties are suddenly and powerfully excited, they quickly expend the organic forces, so that the individual swoons from sheer exhaustion. Undue expenditure of this class of brain functions not only consumes the bodily powers, but exhausts and prevents other mental operations. The sudden collapse of all voluntary functions resembles the fainting produced by blood-letting. We may sum up this rapid expenditure of energy in one expressive word, EXHAUSTION, which results in Ecstasy, or trance, and which, if carried a degree further, terminates in death. Beginning with the natural exercise of the emotions, we may state the order of sequences thus:
VOLITIVE FACULTIES.What are the physiological and morbid results attending the ordinary and the immoderate exercise of the VOLITIVE FACULTIES? The generic term will, comprehends those faculties, the action of which is termed volition. The faculties of the will are Determination, Firmness, Decision, Ambition, Authority, and Vigilance, all of which indicate strength and continuity of purpose. Bordering upon the emotions are Patience and Perseverance, while adjoining the animal faculties are Power, Coarseness, and Love of Display. The former exhibit moral, the latter animal heroism. A sense of power urges forward, whether it be higher or lower, just as the sense of greatness makes a man great by inspiring him with confidence to put forth exertion. Nature is truthful in her aspirations. We know that courage, assurance, and conscious power are necessary for the fulfillment of purpose, because intention precedes action. Will-power is an indication of HEALTH, and the constant exercise of these mental faculties exerts a steady, regular, and strengthening influence over the bodily functions. We translate mental energies into physiological industry. These faculties impart tone to the system, sustain the processes of nutrition, circulation, assimilation, secretion and excretion, and their distinguishing characteristics are vigor, tension, and elasticity. They temper each element of character, as well as every vital act. They infuse the organism with a resisting power which renders it proof against the influence of miasma and malaria, and overcomes that passivity and impressionability so favorable to disease. Firmness expresses a physiological cohesiveness which strongly binds together the fibers of the tissues, and renders the organization compact and powerful. He, who can skillfully employ these energies, is already master of half of the diseases incident to mankind, and wields an indispensable adjunct to medicine, in the practice of the healing art. It is the key to success, for it unlocks difficulties and opens wide the door which leads to favorable results. Surplus energy sustains the circulation, increases capillary action, as if the excess of nerve-power were discharged from VOLITIVE FACULTIES.The natural effect of FIRMNESS is physiological stability. The exercise of the volitive faculties displays both mental and bodily ENERGY.
ANIMAL FACULTIES.
Under this generic term we will group those cerebral powers which are common to the inferior animals, and closely allied to bodily conditions and necessities. As denoting a group of animal faculties they relate not only to the organic functions and self-preservation, but combat the action of the intellect, The animal faculties are skeptical, stubborn, and dogmatic, readily combining with those of the violent class, the ultimate tendencies of which are criminal. They are likewise conceited, assuming, and clannish. Any person distinguished by them, will cling to old associations, perpetuate the status of existing parties, be a stickler for creed, ceremonies, and stale opinions, and adhere to ancient orthodoxy in medicine and religion. The animal faculties, since they are staid and regular, are naturally
BASILAR FACULTIES.The ultimate tendencies of the faculties, represented by the posterior base of the cerebrum, are violent and criminal. Being contiguous to the junction of the cerebrum and spinal system, they are subject to the influence of animal experiences. A large development of these faculties is indicated by an unusual breadth and depth of the back part of the base of the brain, and a full, thick neck, both of which denote good alimentary and digestive powers. Active nutrition, plethora of the circulation, vigorous secretion, a well developed muscular system, a large heart and lungs, are accessory conditions. We do not associate corpulence or surplus of vitality with a long, slender neck. The character of cerebral manifestations is represented by the baser faculties of mind, such as Combativeness, Destructiveness, Desperation, Turbulence, Hatred, and Revenge. If unrestrained, these culminate in violent and criminal acts; if regulated, they are employed in personal defense. When unduly excited, they lead to dissipation, obscenity, swearing, rowdyism, and licentiousness; when perverted, they are the source of recklessness, quarrels, frauds, falsehoods, robberies, and homicides. They are unlike instinct, inasmuch as they are not self-limiting. The intimate relation which they sustain to the stomach and nutritive functions is strikingly displayed in the habit of alcoholic intoxication. Spirituous drinks deprave the appetite, derange and destroy the stomach, poison the blood, and pervert all the functions of mind and body; and their injurious influence upon the nerves and basilar faculties is equally remarkable. They excite combativeness, selfishness, irritability, and exaggerate the influence of the animal organs. Intemperance results in disputes, fights, brawls, The pangs of hunger cause soldiers to act more like ravenous beasts, than rational beings. It is animal instinct which impels the soldier to seek first for the gratification of his appetite. Some persons, instigated by carnivorous desires, yearn for raw meat, and will not be satisfied unless their food is flavored with the flesh of animals. Their bodies increase and thrive, even to repletion. Contrast these individuals with pale, lean, anÆmic people, who crave innutritious articles of diet, and eat soft stones, slate, chalk, blue clay, and soft coal. Such perversions of the appetite are manifested only when there is either a diminution in the volume of blood, deficient alimentation, defective assimilation, or a general depravity of the nutritive functions. Morbid conditions generate vitiating tendencies and destroy the natural appetite. While alcoholic stimulants affect the medulla oblongata principally, opium acts chiefly on the cerebrum, and excites reverie, dreamy ideality, optical delusions, and the creative powers of the imagination; some of these hallucinations are said to be grotesquely beautiful and enjoyable. The effects of this agent differ from those of alcoholic intoxication by not deadening the moral sensibilities, or arousing the animal propensities. Opium smokers are dreamy and abstracted, not quarrelsome or violent. Those who use ardent spirits lose their moral delicacy, their intellect becomes dull, the reason cloudy, and the judgment is overruled by appetite. It is conceded that the trophic center is principally in the medulla oblongata; the cerebellum and lower cerebral ganglia, however, favorably influence the nutritive functions, and, when these organs are large and active, a plethoric condition is the natural consequence. Redundancy of blood in the body indicates preponderance of the basilar organs. These faculties The Animal Faculties correspond to the lower instinctive manifestations.
These naturally give rise to the following diseases: Inflammation, Rheumatism, Gout, Convulsions, etc., which, in these conditions, pursue a violent course. REGION OF FEEBLENESS.Although the middle lobe of the cerebrum, at the base of the brain, does not denote decided force of character, or energy of constitution, yet it has a certain sphere of normal action which is essential to the harmony of mind and body. If this region is largely developed, the constitution is languid, inefficient, sensitive, and abnormally disposed. But if it be deficient, the volitive energies preponderate, and there is a lack of those susceptibilities of constitution, which prevent excessive waste. The cerebral faculties are Fear, Anxiety, Sensibility, Servility, Relaxation, and Melancholy, and their excessive predominance indicates a weak, vacillating, irresolute character, and the existence of those bodily conditions which produce general excitability and chronic derangement. A full development of this portion of the brain indicates that the person is naturally dependent, inferior, and subservient to stronger characters. Such a one is fearful, fretful, complaining, irritable, dejected, morose,
The organ of alimentiveness, located directly in front of the ear, indicates the functional conditions of the stomach, which, when aroused by excessive hunger, exerts a debasing influence upon this and all of the adjacent organs, and is demoralizing to both body and mind. In obedience to the instinct of hunger, children will slyly plunder gardens and orchards, displaying profligate, if not reckless tendencies in the gratification of the appetite. In this regional division we include the medulla, the posterior and middle portions of which give rise to the pneumogastric nerve. This nerve receives branches from the spinal accessory, facial, hypoglossal, and the anterior trunks of the first and second cervical, and its filaments are distributed to the We have already alluded to the perverting tendencies of alcoholic stimulants. Their peculiar influence upon the cerebellum causes the subject to reel and stagger, as though a portion of that organ were removed; the group of energetic faculties is stupefied, and mental as well as corporeal lethargy is the result. The reaction, which inevitably follows, is almost unbearable, and relief is sought by repeating and increasing the poisonous draughts, the primary influence of which is stimulating, the ulterior, depressing. Alcoholic stimulants unduly excite the nervous centers, the heart, and the arteries, and, consequently, the blood is carried to the surface of the body, where it counteracts the influence of cold and exposure, the frequent attendants upon drunkenness. The use of alcoholic beverages perverts the appetite, interrupts habits of industry and destroys all force of character. Pecuniary, physical, and mental ruin, therefore, are sure to follow as the consequences of habitual, alcoholic intoxication. That ordinary alimentation, which includes the process of digestion, the subsequent vital changes involved in the conversion of food into blood, and its final transformation into tissue, causes mental languor and dullness, as well as bodily exhaustion, is attested by universal experience. A torpid condition of the liver, one of the most inveterate of chronic derangements, is
This classification shows their tendencies to chronic disease, functional derangement, insanity, and suicide. GENERAL CONSIDERATIONS.Before the structure of the brain was understood, Buffon spoke of it as a "mucous substance of no great importance." Its functional significance was so slightly appreciated that some people hardly suspected they had any brains, until an accident revealed their existence. Latterly, however, it is generally understood that the perfection of an animal depends upon the number and the development of the organs controlled by the nervous system, the sovereign power of which is symbolized by a grand cerebrum, the throne of Reason. That animal which is so low in the scale of organization as to resemble a vegetable, belongs to an ascending series ending in man. The lowest species have no conscious perception, and their movements do not necessarily indicate sensation or volition. Instinct culminates in the Articulates, especially in Insects; while created intelligence reaches its acme in man, the highest representative of the Vertebrates.
Man, in the faculties of mind, possesses more than a complement for instinct; some of the lower animals, however, seem to share his rational nature, and to a certain degree become responsible to him. Finally, the manifestations of mind bear a relation to the development of cerebral substance, and to the bodily organization which supplies the brain with blood. Fig. 76 shows the relative amount of brain matter in the lower animals, compared with
The sympathetic ganglia of the chest correspond in number with the terminations of the ribs, over which they are situated. Each ganglion receives two filaments from the intercostal nerve, situated above it, thus forming a double connection. The thoracic ganglia supply with motor fibres that portion of the aorta which is above the diaphragm, the esophagus, and the lungs. In the abdomen the sympathetic centers are situated upon the coeliac artery, and are termed, collectively, the semilunar The sympathetic ganglia of the pelvis consist of five pairs, which are situated upon the surface of the sacrum. At the extremity of the spinal column this system terminates in a single knot, designated as the ganglion impar. Owing to the position of the sympathetic ganglia, deeply imbedded in the tissues of the chest and abdomen, it is exceedingly difficult to subject them to any satisfactory experiments. A few isolated facts form the basis of all our knowledge concerning their functions. They give off both motor and sensory filaments. The contraction of the iris is one of the most familiar examples of the action of the sympathetic system. In the reflex actions of the nerves of special sense, the sensation is transmitted through the cerebro-spinal system, and the motor impulse is sent to the deep-seated muscles by the sympathetic system. Physiologists enumerate three kinds of reflex actions, which are either purely sympathetic, or partially influenced by the cerebro-spinal system. Dr. Dalton describes them as follows: First.—"Reflex actions taking place from the internal organs, through the sympathetic and cerebro-spinal systems, to the voluntary muscles and sensitive surfaces.—The convulsions of young children are often owing to the irritation of undigested food in the intestinal canal. Attacks of indigestion are also known to produce temporary amaurosis [blindness], double vision, strabismus, and even hemiplegia. Nausea, and a diminished or capricious appetite, are often prominent symptoms of early pregnancy, induced by the peculiar condition of the uterine mucous membrane." Second.—"Reflex actions taking place from the sensitive surfaces, through the cerebro-spinal and sympathetic systems Third.—"Reflex actions taking place through the sympathetic system from one part of the body to another.—The contact of food with the mucous membrane of the small intestine excites a peristaltic movement in the muscular coat. The mutual action of the digestive, urinary, and internal generative organs upon each other takes place entirely through the medium of the sympathetic ganglia and their nerves. The variation of the capillary circulation in different abdominal viscera, corresponding with the state of activity or repose of their associated organs, are to be referred to a similar nervous influence. These phenomena are not accompanied by any consciousness on the part of the individual, nor by any apparent intervention of the cerebro-spinal system." |