..»«.^*^. .. „. ^ TFAnC'pn%7 yi D. crat-^-i^ ^ ^x^|:l.«»-^^^^^^ ' Idea's Scries of PocI(et Tcxt=5ooll' the cere- bral cortex (S. Kam6n y Cajal). iniition for some distance from the cell-body. The length of an axon varies from a fraction of a millime- tre to nearly a hundred cen- timetres (some fibres of the pyramidal tract). The short axons divide into a great number of branches ; such cells have been termed den- dr axons, or Golgi cells of the second type (Fig. 2). The long axons at intervals give oif branches at right angles to their course, termed collaterals. This type of cell is called an in- axon, or Golgi cell of the first type. The axons and collaterals end by splitting into a brush-like arrange- ment, termed the end-brush, or end-tufts (Fig. 1). Ax- ons and their collaterals, excepting for a short dis- tance from their ending, are enveloped in a medullary sheath. Functions : The cell-body may either originate efferent nerve-impulses of various sorts (cortical cells) ; modi- fying impulses received from another neuron (gan- glion-cells of cord) ; or re- ceive and recognize afferent or sensory impressions. Efferent impulses are car- ried away from the cell-body by the axon, which may THE NEURON. 21 therefore end either by .surrounding with its end-brushes the dendrites of another cell, or in the " terminals " of the muscles (Fig. 3). Sensory impressions are collected either by an axon from the periphery (sensory end-organs) or from the axon of an- other neuron by the dendrites. These latter probably also collect nutrient materials from the blood for the cell-body. In addition to the neuron contiguous to the axon, each neuron is brought into relation with a number of other neurons by means of the collaterals. Neuron with short axon immediately breaking up into numerous fine filaments, n c, nerve-cell proper; x, axon ; d, dendrites. From the cerebellum (Andriezen). The life of the processes is dependent upon the cell-body ; if this is destroyed, -they degenerate and die ; or if part of a process is cut off from the cell-body by any reason, it dies.^ Neurons — their relations to each other : The cells are found in the gray matter of the brain, cord, and ganglia of the peripheral nerves. A group of them which together control some particular function of the body is known as a centre ; ' In such an event the entire neuron suffers, but not so rapidly nor to such an extent as the separated part. 22 INTRODUCTORY OR HISTOLOGY. for instance, that collection of cells situated in the lower part of the central convolutions which controls the movements of the tongue is the tongue-centre. Tracts. Projection-fibres : The axons form the various tracts, and are found principally in the peripheral nerves and white Fig. 3. Illustrating the varying relations of neurons to each other. NC, nerve-cell ; B, dendrites ; x, axon ; C, collaterals ; E, end-brush ; 31, muscle-fibre (after Ober- Bteiner). matter of the brain and cord. Those fibres which connect cortical centres directly with cells in the basal ganglia, the nuclei in the pons and medulla and in the gray matter of the cord, are termed jprojection-jibi'es (Fig. 4). These fibres form TRACTS. 23 the pathways by which motor impulses are carritid from the cortex to the spinal centres ; and by which sensory impressions are brought from certain ganglionic masses in the medulla Fig. 4. The projection-tracts joining the cortex with lower nerve-centres. Sagittal section, showing the arrangements of tracts in tlie internal capsule, a, tract from the frontal lobe to the pons, thence to the cerebellar hemisphere of the opposite side ; b, motor tracts from the central convolutions to the facial nucleus in the pons and to the spinal cord ; its decussation is indicated at K ; c, sensory tract from posterior columns of the cord, through the posterior part of the medulla, pons, crus, and capsule to the parietal lobe ; d, visual tract from the optic thala- mus (ot) to the occipital lobe ; e, auditory tract from the int. geniculate bodf (to which a tract passes, from the viii N nucleus, J) to the temporal lobe ; F, superior cerebellar peduncle ; g, middle cerebellar peduncle ; h, inferior cere- bellar peduncle ; cn, caudate nucleus ; cq, corpora quadrigemina ; vt, fourth ventricle. The numerals refer to the cranial nerves. and base of the brain to the cerebral cortex (see Motor and Sensory Tracts). These pathways, together with certain col- umns in the spinal cord and the peripheral nerves, form the motor and sensory tracts, which are therefore composed of two or more kinds of neurons. Association- tracts and -centers : All that part of the cortex (comprising about two-thirds) not connected with projection- fibres — i. e., that part in which are not included the sensory and motor regions and special sense-centres — contains, ac- cording to Flechsig, centres in which the various sensory 24 INTRODUCTORY OR HISTOLOGY. impressions are collected, arranged, and coordinated. These centres are termed by him association-centres, and are con- nected with the sensory and motor regions and special sense- centres by collections of fibres, termed association-tracts (Fig. 5). Fig. 5. The association-fibres, a, between adjacent convolutions ; B, between frontal and occipital areas; c, between frontal and temporal areas, cingulum; d, between frontal and temporal areas, fasciculus uncinatus ; e, between occipital and tem- poral areas, fasciculus longitudinalis inferior; cn, caudate nucleus; ot, optic thalamus. Fibres also connect the centres of one side with the corre- sponding ones in the other. These are termed commissural fibres. The location of the cerebral centres will be given under Cerebral Localization. The Motor Tract. The motor tract has its origin in the motor centres situ- ated about the fissure of Rolando. The axons of these cells (Fig. 6) converge as they pass down through the brain until they reacli the internal capsule, where they form a compact bundle occupying most of the posterior limb. They pass hence through the crus, pons, and medulla, and in the lower part of the latter most of them cross to the oppo- site side. Previous to this, however, in the lower part of THE MOTOR TRACT. 25 the pons and the upper part of the medulla, fibres liave heen given off, which decussate and pass to the nuclei of the inot cranial nerves (Fig. 6). Those fibres which cross iu * or the Fig. 6. Diagram of the direct or voluntary motor tract, showing the centre of the motor impulses from the cerebral cortex to the voluntary muscles, m, muscles ; n, cells of nuclei of motor cranial nerves in pons and medulla; a, motor cells in anterior horns of spinal cord ; dpi, direct pyramidal tract \ cpf, crossed pyram- idal tract: pc, peripheral cranial nerve; ps, peripheral spinal nerve (Van Gehuchtcn). lower part of the mednlla ])ass down in the posterior part of the lateral columns of the cord, as the crossed pyramidal tract^ and the " terminals" of these fibres surround the cells in the anterior horns. The axons from these cells and from 26 INTRODUCTORY OR HISTOLOGY. the cells of the motor cranial nerve-nuclei, mentioned above, form the motor divison of the peripheral nerves. The comparatively few fibres which have not crossed pass down in the middle portion of the anterior columns, forming the dh-eot pi-yamidal tract, or column of Tiirck, the fibres of which cross in the anterior commissure at diiferent levels and also connect with the motor cells in the anterior horns (Fig. 6). Function : This motor tract is concerned in all voluntary muscular movements. The cortical cells originate the im- FiG. 7. CereUellum Diagram of the indirect or involuntary motor tract. pulses and control or inhibit the functions of the spinal cells. The cord-cells receive and distribute the motor impulses to THE SENSORY TRACTS. 27 the muscles, maintain their nutrition, and with the sensory cells form reflex centres. There is another tract, known as the indirect motor tract, which, arising in the central convolutions, forms connections with the optic thalamus and the pons nuclei, and passes hence to the cerebellum, from which another series of fibres goes to the motor tract in the cord (Fig. 7). This tract plays a part in coordinating muscular move- ments and automatic acts, and possibly in maintaining muscle- tone. The Sensory Tracts. The sensory tracts are much more complicated and their course not so well-known as the motor. There are probably different pathways for the various forms of sensation — viz., tactile, pain, temperature, and muscle. The cells of the first neuron are situated in ganglia upon the posterior nerve- roots or sensory cranial nerves, as the case may be. Each of these cells gives off a long process, possibly a dendrite, which runs to the periphery as part of a peripheral nerve, and ends, according to the peculiar form of " sensation " that it conducts, in one of the various specialized end-organs in either the skin, muscles, or organs of special sense. From the cell the axon also arises, enters the spinal cord as part of a posterior root, and divides into a long ascending and a short descending branch. Some of the former pass up the cord in the posterior columns, in the nuclei of which they end. The cells of these nuclei are the beginning of another neuron, the axons of which forip the lemniscus or fillet, which also receives fibres from the sensory cranial nerve-nuclei (Fig. 8). Here they decussate and the fibres run to cells in the optic thalamus, axons from the cells of which, after pass- ing through the posterior part of the internal capsule, reach the cortex, where they are brought into relation with the motor neurons. Sensations of touch are probably conducted by this path. Other fibres leave the nuclei of the posterior columns, and by means of the inferior cerebellar peduncles of the same side reach the cerebellum. Hence, another series of fibres, by way of the superior peduncles, passes to the optic thalamus 28 INTRODUCTORY OR HISTOLOGY. and red nucleus, and hence by other neurons tlie tract reaches the cortex. Sensations from the muscles and joints probably travel by this route (Fig. 9). Fig. 8. The direct sensory tract, p s, peripheral spinal nerves ; pg, ganglion on posterior roots of spinal nerves ; g t, Gower's tract ; cgt, columns of GoU and Burdach ; en, nucleus cuneatus ; g n, nucleus gracilis; a, cells in posterior horn; pc, peripheral cranial nerve ; g, ganglion on cranial sensory nerve ; n, cells of cranial sensory nerves in medulla; /, fillet; o/, optic thalamus. Another series of fibres, after entering the cord, surrounds, with its terminals, cells in the posterior horns of the gray matter. From these cells axons arise which pass to the THE SENSORY TRACTS. 29 opposite side, where they form the antero-lateral, or Gower's, tract (Fig. 8). Part of the fibres of this column, probably by way of the fillet, reach the optic thalamus and corpora quadrigemina, from which points their course is doubtful ; Fig. 9. ellum Indirect sensory tracts. dc<, direct cerebellar tract. The numbers represent the different series of neurons. while others by way of the superior peduncles go to the cerebellum. Sensations of pain and temperature are probably conducted by this tract. Still other fibres join the cells of Clarke's column, the 30 INTRODUCTORY OR HISTOLOGY. axons of which form the direct cerebellar tract, which, without decussation, ends in the cerebellum through the in- ferior peduncle (Fig, 9). This tract also conducts sensations from the muscles, and probably also has some connection with the sympathetic system. Collaterals from the sensory fibres pass into the gray mat- ter, where they join the motor and sensory cells. By means of these and the short descending branches the different levels and various sensory tracts are brought into relation. The special sense-tracts will be described in connection with the diseases of their peripheral nerves. In addition to the cells and their processes just described, the nervous system is composed of connective tissue, neurog- lia, bloodvessels, and lymphatics, the whole being enveloped in the membranes which constitute the meninges. CHAPTER II. GENERAL PATHOLOGY. The functions of the nervous elements may be impaired by disease or abnormality of any of their structures. INFLAMMATION. In the nervous system, as elsewhere, inflammation is the reaction of the organism to an irritant. This irritant may be the product of microbic action or tissue-change, or of some chemical substance, as lead, alcohol, arsenic, etc. This in- flammation may be simple, without exudation or destruction of tissue ; or there may be exudation, and destruction of nerve-tissue, with the formation of connective tissue or pus ; furthermore the process may be chronic or acute. The following table (from Dana) shows the various forms and their causation : Classification of Inflammations. FOKM. Cause. Example. Simple exudative, with or Microbic or toxic. Meningitis ; without necrosis. Poliomyelitis. Purulent, with or without Microbic or necrobic. Meningitis and encepha- necrosis. litis ; Acute purulent myelitis. Productive or prolifera- Microbic or toxic. Chronic meningitis ; tive. Leprous neuritis. DEGENERATIONS AND SCLEROSES. By degeneration we mean a gradual death of the nerve-cells and their processes. This may be acute, chronic, primary, or secondary. Acute degeneration is due to the cutting otf of the blood- 31 32 GENERAL PATHOLOGY. supply, to traumatism, and the effects of inflammation. It produces the condition known as ueGrosis or softening. Chronic degeneration is caused by the continued action of various poisons, especially metallic and those of infectious diseases, and is accompanied by the formation of connective tissue and consequent sclerosis.' A primary degeneration is one due either to some inherent defect, as in the muscular dystrophies ; or to the direct action of some poison, as in locomotor ataxia. A secondary degeneration is due either to the cutting off of a nerve-fibre from its tropliic centre — i. e., the cell-body — as the degeneration of the pyramidal tract following a hemor- rhage into the internal capsule ; or to a deficiency in the blood-supply, as in old age due to obliterating arteritis. Grliosis. When we have an extensive proliferation of neu- roglia the process is termed gliosis, or gliomatosis. This proc- ess is found in syringomyelia. General considerations : It must be remembered that nerve- cells destroyed do not develop again. The nerve-fibres in the brain and cord, if destroyed, are not regenerated, but a periph- eral nerve-fibre may be destroyed, and if its trophic centre is intact it will grow again. Other forms of disease which may affect the nervous ele- ments are : malformations, incomplete or defective develop- ment ; hypersemia ; anaemia ; oedema ; diseases of the blood- vessels ; hemorrhage ; thrombosis or embolism ; atrophy ; softening ; syphilis and tuberculosis ; tumors ; parasites ; functional disorders ; disorders associated with glandular defects ; and disorders of nutrition, as myxoedema and acro- megaly. ^ In this process it is probable that there is also some increase of the neuroglia. CHAPTEE III. GENEKAL SYMPTOMATOLOGY AND METHODS OF EXAMINATION. The symptoms cuusecl when a nerve centre or tract is af- fected by any of the lesions mentioned in the preceding chapter depend upon whether the lesion is destructive or irri- tative. If destructive, the function of the involved part is diminished or destroyed ; if irritative, its function is increased. Symptoms produced by a combination of these two kinds of lesions may be present ; for instance, a cerebral tumor, while it causes destruction of the nerve-elements directly af- fected, will cause irritation of the neighboring jjarts. A lesion which may at first be irritative may finally be destructive. For instance, a meningitis may at first cause increased cere- bral action with convulsions, etc. ; but finally, as the disease progresses, these parts are destroyed and coma and paralysis result. Symptoms resembling those produced by an irritative lesion may also be produced if the higher or inhibitory centres in the brain are destroyed, thus allowing over-action of the lower or spinal centres to occur (see Contracture). Neurosis and psychosis : The general term for any derange- ment of the nervous system, exclusive of those of the higher or mental functions, is neuroms. This term is more commonly applied, however, to disorders of di functional nature, or those in which we can find no apparent organic cause. A disordered mental state is known as a 2}sychosis. The following prefixes are used to indicate derangements of function of the nervous system : viz., " hyper," meaning excess; "hypo," which means diminution; "a" or "an," which indicates entire loss; and "para" meaning perversion. For example, we speak of hypercesthesia, meaning increased 3— N. D. 33 34 GENERAL SYMPTOMATOLOGY. sensibility ; ancesthesla, or loss of sensibility ; and parcesthesia, for perverted sensibility. Symptoms caused by disorders of the higher or psychical centres : These are mostly found in mental diseases, as in- sanity, idiocy, and imbecility and will be discussed under that head. We may, however, find loss of will ; failure of mem- ory ; lack of control ; inability to concentrate the attention ; mental excitement ; or depression, in patients who are not insane (see Neurasthenia and Hysteria). Consciousness may be considered one of the higher func- tions of the brain. Impairment or loss of it is an important symptom of many nervous diseases both organic and func- tional. This loss may be due to disease of the brain-cortex or to the inhibitory action of lesions elsewhere in the brain. For instance, the loss of consciousness in cerebral hemorrhage is due probably to an irritative inhibitory action on the cortex. Stupor and coma : If the patient can be partially aroused by ordinary stimuli, we call the condition stupor. If he can- not be aroused, we term it coma. In stupor the reflexes are active ; in coma they are not, and the pupils are either contracted or dilated and immobile ; the pulse slow, sometimes irregular or frequent ; and the respira- tion slow and weaker than normal. The relaxation of the palate allows it to vibrate with the passing current of air, causing the so-called stertorous breathing. Frequently the respiration is of the Cheyne-Stokes type. In examining a case of stupor or coma the head should be carefully looked over for possible injury ; the existence of paralysis or spasm detected ; the presence or absence of re- flexes, superficial and deep, noted ; the breath examined for the odor of alcohol or opium ; and the urine, for evidences of nephritis or diabetes. Furthermore, it must be ascertained whether the patient is an epileptic who has just had a convul- sion ; or is a syphilitic or hysteric. The differential diagnosis of coma will be discussed under the head of Apoplexy. Symptoms Caused by Overaction of the Motor Tract. Convulsions : A convulsion, as defined by Herter, consists of " involuntary, paroxysmal, purposeless muscular contractions OVERACTION OF THE MOTOR TRACT. 35 of variable intensity and duration, and of extensive or limited distribution." Consciousness may be present, or lost. Convulsions are also termed spasms; but this term is usually applied to those of local or limited distribution ; as, for instance, the muscles supplied by one nerve, as the facial. Local spasms are often called " tics." Convulsions may be tonic — i. e., when the contraction is slow and continuous ; and clonic — i. e., when the contractions rapidly and alternately contract and relax. A lesion limited to the centres of a small group of muscles may cause a general convulsion by an overflow of energy. In such cases there are first spasm of the muscles governed by the affected centres, and then a gradual involvement of all the muscles (see Jacksonian Epilepsy). Contractures and contractions : A tonic spasm of long duration causes a contracture. This may be due either to irritation of the motor tract ; to a destructive lesion of the cortical motor neurons and consequent overaction of the spinal neurons, due to the deprivation of the inhibitory influence of the former ; or it may be of functional origin, as in hysteria. A contracture long continued often causes actual organic shortening of the muscle, and the condition is then termed a contraction. An unequal paralysis of antagonistic muscles will also cause a contracture, often seen in poliomyelitis. Contractures and contractions — examination : Contractures can be discovered by passively flexing and extending the limb, when an abnormal resistance will be noted, the limb often bending like a piece of lead pipe ; by supporting the proximal end of a limb and allowing the distal end to drop by its own weight ; and by noting the deformity which is produced by the unequal spasm of antagonistic muscles, one group of muscles overpowering their antagonists (Fig. 35). Functional contractures, unless of very long duration, can be differentiated from those of organic cause by noticing that they disappear while under the influence of sleep or an anaesthetic. Athetoid movements, or athetosis : Lesions in the motor tract sometimes give rise to a peculiar form of clonic spasm which causes slow, irregular vermicular movements of the fingers, toes, and rarely of the face, which are termed athetoid 36 GENERAL SYMPTOMATOLOGY. movements. The movements are independent of voluntary motion. They are a sequel of hemiplegia, particularly of the form that occurs in childhood. Often the paralysis has almost or entirely disappeared, and such cases may be mis- taken for chorea. A careful inquiry will usually elicit the history of a previous paralysis (Fig. 10). Fibrillary tremor : A fibrillary tremor, or contraction, is an involuntary contraction of small numbers of muscle-fibres. They are seen as fine wave-like contractions running along the muscle in whic^ they occur. Movement of the part is not caused by them They occur in muscles which are slowly atrophying from loss of neurotrophic influence. When they do not occur spontaneously they may be elicited by tapping the muscle witli the finger or some other mechanical irrita- tion. They are usually seen in chronic poliomyelitis, but may occur in neurasthenia. By tremor we mean a to-and-fro movement of a part due to a more or less rapid involuntary and rhythmical contraction of antagonistic muscles. It may affect the muscles of the limbs, or neck, face, and tongue. Tremor is probably due to either an interruption or exag- geration of the impulses as they pass from the cortex to the muscle. Adamkiewicz claims that tremor is due to disturbances in the equilibrium of the two innervating stimuli — i. e., a cur- rent passing down the posterior columns from the cerebellum which keeps the muscles in a state of tension ; and one pass- ing down the pryamidal tract which conveys voluntary im- pulses and regulates the degree of tension. The disturbance in the equilibrium is due to a weakening of the current passing down the pyramidal tract, from either organic or functional causes. Tremors are divided into those which only occur during voluntary movement (intention-tremors) ; those which are constant, but are increased by voluntary movement ; and those which cease for a time or diminish after voluntary movement. Tremor — examination : If a tremor is not apparent, it may be discovered by making the patient extend the arms and hands at full length, or perform some voluntary act. To be OVERACTION OF THE MOTOR TRACT. 37 Fig. 10. Examples of the position of the fingers in the movements of athetosis (Strumpell). 38 GENERAL SYMPTOMA TOLOQ Y. sure that a tremor is not an intention-tremor, it is a good plan to place the patient in a recumbent position. Tremor of the tongue is tested by causing it to be protruded ; that of the lips and face, by closing the eyes, showing the teeth, or whistling. Care must be taken not to mistake a tremor of the head due to the neck-muscles for shaking of the head due to tremor of the trunk. Tremor is always a symptom, although at times it is ex- ceedingly difficult to ascertain the cause. In studying such a case the different conditions which may produce tremor must be borne in mind. With the exception of the tremor of multiple sclerosis and paralysis agitans, all tremors in the early stages of the trouble are of the intention-type ; but as the disease progresses they may become constant. Tremors due to organic disease are usually slow ; those of functional or toxic origin are usually rapid. The following table gives the various causes of tremor and their character : Cause. Type of Tkemor. Rapidity. ■ Arsenic, Intention in early stages ; Eapid. Lead, later may become con- rr«^,-« Alcohol, stant ; may then be in- Toxic -1 Tot)acco, creased by exertion. Tea, Coffee. (■ Hysteria, Ibid. That of hysteria some- Neuroses -< Neurasthenia, times is slow ; others (_ Exophthalmic goitre. always rapid. Senility. Ibid. Rapid. Heredity. Ibid. Rapid. Any disease of brain, spinal cord, Ibid. May be slow or rapid, or peripheral nerves, except- or both combined. ing multiple sclerosis and paralysis agitans. Paralysis agitans (see p. 323). Often ceases for a few seconds after muscular exertion. Slow. Multiple sclerosis. Intention only. Slow. Choreic movements : These are sudden, jerking, incoordi- nate, non-rhythmical, and non-purposive movements of differ- ent groups of muscles. They usually cease during voluntary effort. Tics, or the spasms of a group of muscles acting habitually together, as of the face, have been sometimes termed choreic movements ; but they are more regular and coordinate than the true movements of chorea. DESTRUCTIVE LESIONS OF THE MOTOR TRACT. 39 Forced movements : These arc movements in which the patient is forced against his will to move in a certain direc- tion, to one side, forward or backward, or to rotate. Associated movements are seen when a movement of a non- paralyzed limb causes a movement in the paralyzed one ; or, more rarely, in cases of partial paralysis when movements of the paralyzed side cause movements of the sound limb. Symptoms due to Destructive Lesions of the Motor Tract. Paralysis : The result of a destructive lesion involving the motor tract is termed paralysis. If the function is not en- FlG. 11. CU represents a cell in the motor region of the brain-cortex ; PY is its axon, which forms part of the pyramidal tract ; SO represents a cell in the gray matter of the cord (anterior horns); PN, its axon, forming part of a peripheral nerve; M, muscle. A lesion destroying CU, or any part of the tract PY, causes a central palsy ; a lesion destroying SO, or any part of the tract PN, a peripheral palsy. tirely destroyed, it is sometimes called paresis. When one limb or a single group of muscles of a limb is affected it is 40 GENERA L SYMPTOM A TOL OGY. called monoplegia. When all or most of the nmscles of one side of the body are paralyzed it is termed hemiplegia. Paral- ysis of the lower limbs is known as paraplegia; and as diplegia when it affects corresponding extremities as two arms, two legs, or all four limbs. When one side of the face and the limbs of the opposite side are paralyzed we speak of an alternate or crossed paralysis. If contractures are present, the paralysis is said to be spastic. Paralysis — ^varieties : Paralyses are divided according to the portion of the motor tract affected, into central, in which some portion of the primary neuron is the seat of the lesion ; and peripheral, in which some portion of the peripheral neuron is diseased (Fig. 11). Table shoiving differences between central and peripheral paralyses : Nutrition of muscles. Tone of muscles. Electrical reaction (see Electricity). Reflexes. Disease of Peimaey Neueon OE Centeal. Good. Increased ; muscles usu- ally rigid and spastic. Same as normal muscle. Increased. Disease of Secondaey Neueon oe Peeipheeal. Poor; muscles atro- phied. Diminished ; muscles flaccid. Changed ; either quanti- tative decrease or re- action of degeneration present. Diminished or lost. Paralysis — methods of examination : In examining a case of suspected paralysis it is important to remember that some- times muscular weakness may be caused by exhaustion from some acute illness, and that the movements of a limb may be restricted, not from weakness due to the lesion of the nervous system, but from pain caused by making the movement. This is often seen in joint-inflammations. Impairment of motion may also be due to complete or partial anchyloses. In most cases the existence of paralysis is obvious. The inability to use the part, if an entire limb is paralyzed ; or the resultant deformity when a group of muscles only is involved (due to the unbalanced action of antagonistic mus- cles ; for example, the drooping of tlie eyelid in the paralysis of the motor oculi nerve), is at once apparent. DESTRUCTIVE LESIONS OF THE MOTOR TRACT. 41 However, wlien the weakness is slight, or there is a ques- tion of diagnosis from the conditions above mentioned, cer- tain tests are useful. From our knowledge of anatomy Ave know the uses of each muscle ; therefore, to detect weakness, we cause the patient to use the suspected muscles, comparing the movements with those of the opposite side. For instance, if the muscles of the face are being examined, we make the patient wrinkle the forehead, open and close the eyelids, smile, whistle, and draw the mouth from side to side. Paralysis of the soft palate can be detected by causing the patient to open the mouth and make the sound "ah." If both sides are paralyzed, the palate will be seen to move but slightly or not at all. If only one side is paralyzed, the palate will be drawn upward on the sound side only. . Weakness of the tongue is detected by noticing if it is pro- truded with difficulty or to one side ; and if, when protruded, it cannot be kept so long. Weakness of the muscles which move the eyeball may be roughly tested by covering one eye and causing the patient to follow the finger while it is moved in various directions, the head, of course, being kept fixed. Fig. 12. Hand dynamometer. The patient may also complain of seeing double, or diplopia. To test the movements of the iris, we notice if it contracts when a bright light is held before the eye and dilates when the light is removed, the other eye being kept covered. 42 GENERAL SYMPTOMATOLOGY. The arms are examined by causing the patient to contract the muscle while we apply counterforce ; by having him squeeze your hands with his ; or by using the dynamometer (Fig. 1 2) and comparing the records made. If a leg is weak, it is dragged as the patient walks. In slight cases an exces- sive wearing of the toe of the shoe is all that is noticed. If coma is present, we can often detect paralysis by notic- ing the less resistance with which the limb falls when allowed to drop, as compared with the other side. Atrophy, if marked, is at once apparent. Slight degrees are detected by noticing that the muscles are more flaccid than normal and by measuring. To measure, we select a fixed point, as the anterior iliac spine, from which, at equal distances on each side, we mark a number of points ; at these points we take the circumference of the limbs and compare the results. Valuable information is also obtained by using the electrical current (see Electricity). Symptoms due to Irritative Lesions of the Sensory- Tract. Hyperaesthesia : Irritation of the sensory tract may cause increased sensibility to pain (increased sensibility to other forms of sensation is not yet capable of being detected), a condition termed hypercesthesia. When it exists, slighter stimuli than normal should cause painful or disagreeable sen- sations. Irritation of any portion of the sensory tract may produce it. Pain : This is another expression of sensory tract irrita- tion. At times its character and situation may be of diag- nostic value. It may be limited to the distribution of a certain nerve, as in neuralgia and neuritis; it may be diffuse, as in cerebral meningitis or brain-tumor. Dull pains arc often present in diseases of the spinal cord and sometimes in neuritis. Care should be taken not to mistake them for rheumatism. Sharp, shooting pains are characteristic of neuralgia and often indicate irritation of the posterior nerve-roots, as in meningitis and locomotor ataxia. The so-called girdle-pain, a feeling as if a band were tied about the body, also indicates nerve-root irritation. The DESTRUCTIVE LESIONS OF THE SENSORY TRACT. 43 pain of neuritis may, in some cases, be described as burning ; such pain is known as '' cansalgia." Irritative lesions of the cortical centres may cause })ain to be referred to the limbs. Likewise, diseased parts of the body may cause pain to be referred to remote parts, if the nerv^e-supply is the same, as in the knee-pain of hip-joint disease ; or by the close prox- imity of the centres, as headache due to eye-strain, where irritation of the primary visual centres causes pain in the fifth nerve distribution. Where an irritation of one side of the body is felt at a corresponding point on the other, it is termed allochiria. If the diseased part is superficial, ten- derness is often also present, as in neuritis and meningo- myelitis dependent on disease of the vertebrae. Parsesthesia : Perverted or abnormal sensations, except- ing pain, such as tinglings, crawlings, burning, numbness, etc., are called parsesthesise. They may be due to organic nerve-disease of any portion of the sensory tract from the cortex to the periphery ; or they may have a subjective origin. When the touch of one point is felt as two or more it is termed polycesthesia. SYMPTOMS DUE TO DESTRUCTIVE LESIONS OF THE SENSORY TRACT. These symptoms differ according to which pathway is dis- eased — i. e., that for touch, pain, temperature, or muscle sense. They may be all damaged, or one or more may be and the others not. Sensory fibres often preserve their func- tions when damaged to an extent that would destroy the functions of the motor fibres, and they recover their function, when lost, sooner than do the motor fibres. Loss of sensa- tion may be due to either organic or functional disease. Anaesthesia : Strictly speaking, this word means loss of tactile sensibility, but is often loosely used to include loss of pain-sense. When the loss involves one-half of the body it is termed Jiemiancesthesia. The face may sometimes be spared. When complete, the entire lateral half of the body, including mucous membranes and special senses, is involved. If of organic origin, it means the existence of a lesion in the tract between the upper portion of the pons and the cortex of 44 GENERAL SYMPTOMATOLOGY. the opposite side. Crossed heiniansesthesia means anaesthesia of one side of the body and of the opposite side of the face. It is due to a lesion in the pons. Hemiansesthesia often occurs in hysteria. Irregular areas of ansesthesia scattered over the body and limbs also occur. They are usually met with in hysteria ; sometimes in locomotor ataxia. Analgesia means loss of sensibility to pain. As has been said, it may occur without loss of tactile sensibility, especially in diseases of the cord in which the pathways for touch and pain are widely separated. Loss of pain-sense in one lateral half of the body is called hemianalgesia. In some diseases (notably locomotor ataxia) we may have, instead of absolute loss, a delay in the transmission of a sensation, so that it is not felt for an appreciable interval after the reception of the stimulus. It should also be noted in testing both pain- and tactile sense whether the patient can correctly localize the point touched. Temperature-sense : When lost this is usually associated with loss of sensibility to pain, the two pathways being prob- ably closely related (see Sensory Tract). It occurs either as an inabihty to tell hot from cold ; or hot objects may give cold sensations, cold being appreciated, or vice vey^sa. Some- times great differences can be recognized while slighter ones cannot. In some affections of the nervous system (notably in syringomyelia, less commonly in diseases affecting the pos- terior nerve-roots as vertebral caries, cervical pachymeningi- tis, tabes, spinal tremor, myelitis, multiple sclerosis, and also in disease of the peripheral nerves and hysteria) there may be loss of pain- and temperature-sense with preservation of the sense of touch. When the cord is affected, as in syringo- myelia, this is probably due to the fact that fibres conducting pain- and temperature-sensations cross in the posterior com- missure to form Gower's tract, and consequently would be destroyed by a lesion destroying the central gray matter, while the fibres conducting tactile sensations pass up the pos- terior columns and escape. The explanation as to why this occurs in root-lesions is not so clear. It may be due to the fibres conducting tactile sensations being less vulnerable to pressure than those conducting pain- and temperature-sen- sations. SENSORY LOSS. 45 Muscle-sense : This includes a perception of passive and active movements ; of the position of the limbs ; and of press- ure and resistance. Stereognostic seiiHe is the name given to memories preserved in the central cortex (parietal lobe) of the characteristics of objects by which we are enabled to recognize them without seeing them. Thus when a blindfolded jierson recognizes a dollar placed in the hand he does so by his memory of the I)eculiar feel, weight, etc., of previous dollars. This sense depends, according to Sailer, upon "an intricate correlation of tactile, position, pressure, localization, and temperature perceptions and its interpretation by the higher psychic cen- tres." The most important element seems to be the muscle- sense, for it has been found impaired more or less in the re- ported cases, while other forms of sensibility may be pre- served. The stereognostic sense has been found impaired most frequently in hemiplegia.. Its impairment is termed astereognosis. Sensory Loss — Methods of Examination. Before applying the various tests used to detect sensory paralysis the patient should be blindfolded. Anaesthesia is tested for by touching the part with a light object, such as a piece of absorbent cotton. This may, begin- Bing at the face, be stroked down the body to the feet, telling the patient to advise you as soon as he does not feel it and then marking the spot. In this way the anaesthetic areas, if any, may be mapped out. This procedure should be repeated, changing the direction of the stroking to confirm the correct- ness of the observation. Analgesia is discovered by pricking the skin and mucuos membrane with a pin, going over the body systematically, as in the test for anaesthesia, and instructing the patient to inform you as soon as he feels it, or else to count each time he feels the prick. If he misses a count, we know that the patient does not feel it. It should also be noticed if the patient winces, or if there is delayed transmission, indicated by the announcing of the sensation being felt several seconds after the stimulus is used. 46 GENERAL SYMPTOMATOLOGY. Loss of temperature-sense is discovered by the alternate use of test-tubes filled with hot and cold water, or by painting ether over the skin. If loss of muscle-sense is suspected, we test the perception of passive moments by taking the joint firmly between the hands and moving it slightly, ascertaining if the patient knows what you do. Or move a finger of one hand gently, letting the patient perform the same movement with the finger of tlie opposite hand. Movement of the smaller joints should always be tested first. Perception of pressure and resistance may be tested by using rubber balls of the same size filled with different quantities of shot. These are placed on the hand or leg, and the patient is asked to determine which is the heavier. Knowledge of the position of parts is determined by placing a limb in a certain position and asking the patient to place the opposite one in the same position. The p)resence or ab- sence of the stereognostic sense is determined by placing familiar objects in the hand and requesting the patient to name them ; if he cannot, there is loss of the sense. Incoordination — Ataxia. Definition : For a muscular movement to be performed in a regular, smooth, and co5rdinate manner, it is necessary that the contraction of each muscle concerned in the move- ment, and also that of the antagonists of the muscles, be accurately proportioned in force and time. For example, when we use the flexor muscles of a limb, the extensors act as a balance; otherwise all movements would be quick and jerky. For the proper performance of this function, sensations travel from the muscles, articular surfaces, and tendons (muscle-sense), and to some extent from the skin (tactile sense) up through the posterior columns and direct cerebellar tract to the cerebellum, and thence to the sensori-motor region of the cortex. A lesion so situated as to prevent these sensa- tions reaching the cortex will produce incoordination. Hence lesions of the brain, cord, or peripheral nerves may produce this symptom, which is usnally known as ataxia. More JNCO ORDINA TION—A TA XI A . 47 properly the use of the term ataxia is only applied to that form of incoordination due to spinal cord disease. Ataxia, may also be present during apparent rest, and is then called static ataxia. To maintain any ])osture, coordi- nated muscular movements are necessary. When this func- tion is deranged swaying movements of the body, or irregular movements of the limbs, become manifest. Incoordination — cerebral : Cortical lesions, especially of the parietal lobes, may produce more or less disturbance of the muscle-sense and consequent ataxia. This is usually asso- ciated with hemiplegia and is known as post-hemiplegic ataxia. The incoordination which sometimes occurs in ^2^8- teria is also of cortical origin. Incoordination — cerebellar : Lesions of the cerebellum espe- cially of the middle lobe, cause a form of incoordination, commonly termed titubation. The gait resembles that of alcoholic intoxication ; the patient is unable to walk in a straight line, and there is often a tendency to fall always in the same direction, either right, left, or backward, as the case may be. The arms are not affected so commonly as the legs. Similar disturbances sometimes occur in disease of the pons or medulla in which the fillet is involved. Incoordination — spinal cord and peripheral nerves : In the great majority of cases this is due to disease, either of the posterior median columns, posterior nerve-roots, or both. The patient walks in such cases, if the symptom is marked, with his eyes fixed on the ground ; the legs wide apart ; lifts the feet higher than normal and throws them forward in a jerky manner. In some cases of multiple peripheral neuritis, if the paralysis is not marked, incoordination is present. Incoordination — examination : The existence of static ataxia is discovered by causing the patient to hold the limbs in some fixed position without support, when the movements described will be seen ; or to stand erect with the feet close together and the eyes closed. If the symptom is present, the patient will sway violently to and fro and may fall. This is known as the Romberg sign. Dynamic ataxia of the lower limbs is tested by making the patient walk forward and backward with the eyes first open and then closed ; turn suddenly while walking ; raise 48 GENERAL SYMPTOMATOLOGY. himself upon his toes with the eyes closed ; and stand on one leg. The upper limbs are studied by having the patient touch the end of his nose with his finger; pick up small objects; button his clothes ; and after separation of his arms by making him endeavor to bring the points of his fingers together. In- ability to perform these movements will indicate ataxia. Degrees of incoordination so slight as not to be noticeable in the gait are detected by examining for the Romberg symptom with the feet and legs of the patient bare ; in the effort to maintain his position contractions of the muscles of the legs Avill be caused, which can be detected by watching the ten- dons about the ankles. Examination of Special Senses. Sight : In diseases of the nervous system the sense of sight may be variously affected, the causes of which are either functional or organic. When there is a subnormal acuteness of vision due neither to refractive error nor visible organic lesion, we term the condition amblyopia. Amaurosis is a word sometimes used to express blindness. Hemianopsia denotes blindness of one-half the visual field. Homonymous hemianopsia indicates l)lindness of the outer half of one and the inner half of the other field of vision. When we wish to indicate which side of the retina is blind we nse the word hemiopia : thus, a right-sided hemianopsia would be a left-sided hemiopia. In all doubtful cases the eye should be examined by a skilled ophthalmologist, the presence of optic neuritis and atrophy, primary and secondary, being valuable symptoms of many organic diseases of the nervous system. The existence of hemianopsia — i. e., i)]indness of one-half the visual field — can be roughly determined by sitting the patient in front of you with one eye blindfolded, and tell him to look steadily at the end of your nose with the other. A white object is then brought from different points of the periphery toward your nose, and the patient is instructed to say when he sees it. If he does not, that part of the field is blind. The existence of refractive errors, a common cause of THE REFLEXES. 49 headache, may be surmised if the eyes water and letters run together after reading a while. The presence or absence of exophthalmos should also be noted. Hearing : This, to be accurately tested, also re(£uires the ser- vices of a specialist. Tiie existence of tinnitus should be in- quired for. The acuity of hearing can be determined by blind- folding the patient and covering one ear. A watch is then held some distance from the other ear and made to approach toward it, the patient signifying when he hears the tick. Watches, of course, differ in the loudness of tiu'ir tick; the normal distance being from two to four feet. In order to determine whether the deafness, if any, is due to disease of the nerve or of the middle ear, we use a large tuning-fork (note C), and note whether the sound is heard best when it is held at a distance from the ear or when placed on the top of the head. If aerial conduction is the better, the nerve is dis- eased ; if the sound by bone-conduc^tion is more distinct, the cause of the deafness exists in the middle ear. Smell: Care should be taken in testing smell not to use odors which are irritative, as ammonia. With one nostril closed ^ve test the other with musk, violets, or some perfume of like nature. The possibility of catarrhal trouble causing loss of smell must always be considered. Taste : In testing taste we use a bitter substance, as qui- nine ; a sweet one, as sugar ; and a sour one, as vinegar. The bitter should be used last. The patient keeps the tongue protruded, while one of the solutions is painted, with a camel's hair brush, on each side of the tongue, first posteriorly and then anteriorly. The patient can indicate if he tastes the solution by pointing to the name, which has previously been written on paper. Under no circumstances should the tongue be withdrawn into the mouth until the test is completed. To decide if there is complete loss of the sense, it should also be tested on the lips, the inner surfaces of the mouth, the palate, the pharynx, the epiglottis, and, when possible, the larynx. THE REFLEXES. To cause a reflex action there are necessary an afferent nerve, either an ordinary sensory or the special excito-reflex ^— N. n. 50 GENERAL SYMPTOMATOLOGY. nerve supplied to the viscera ; an efferent or inotor nerve ; and the cells (reflex centre) in the gray matter of the cord or medulla to which the alferent nerve runs and from which the efferent starts. This mechanism is controlled by the higher cortical (motor) cells, which exercise their influence through the pyramidal tract (Fig. 13). Fig. 13. -^ — ^^ Diagram showing reflex arc and inhibitory fibre, and some of the diseases which exaggerate or destroy the knee-jerk. Reflexes are o? four hinds : the skin, or superficial ; tendi- nous and muscular, or deep ; visceral, and idiopathic muscular. When any of the components of the reflex arc — viz., affer- ent nerve, cells in gray matter, efferent nerve — are damaged the refliexes under the control of that particular arc are lessened or absent. An irritative lesion of the pyramidal tract will sometimes, by increasing inhibition, cause a reflex to be diminished or absent. If the inhibitory influence of the brain is removed, as by a destructive lesion of the pyramidal tract, the reflexes are increased. The Skin-reflexes. These are produced by scratching, irritating, or tickling the skin, which, if the reflex is present, causes a contraction of the muscles near the irritated part. THE DEEP OR MUSCLE- AND TENDON-REFLEXES. 51 The most important are : The plantar reflex consists of a flexion of the toes upon the metatarsus and a quick, involuntary jeriving of the foot and leg when the sole of the foot is irritated. In making this test the leg should be in such a position as to insure muscular relaxation. M. J. Babinski has recently called attention to the fact, which has been confirmed by Collier and others, that when there are lesions of the pyramidal tract the toes are extended upon the metatarsus, instead of flexed. This does not hold good in infants. The cremasteric reflex is caused by irritating the skin on the inside of the thigh, when a drawing up of the testicle will be seen. The abdominal reflex consists of a contraction of the rectus muscle of the abdomen when the side of the abdomen is scratched. The lid-reflex consists of closure of the eye when the con- junctiva or retina is irritated. The pupillary skin-reflex consists of a dilatation of the pupil when the skin on the side of the neck is pinched. Those which are of not so constant occurrence are : The epigastric reflex, j)roduced by irritating the skin of the lower part and side of the thorax. This causes contrac- tion of the upper fibres of the rectus muscle. The erector spinae reflex consists of contraction of some of the fibres of the erector spin?e, caused by irritation of the skin along its outer edge. The scapular reflex consists of a contraction of the scapular muscles when the skin over them is irritated. The palmar reflex is produced by irritating ' the palms of the hand, when a jerking away of the arm and closing the hand will be seen. The Deep or Muscle- and Tendon-reflexes. Some of these are not found in healthy individuals, only being present when reflex activity is increased. The knee-jerk, or patellar tendon-reflex, is the most constant, but rarely it is not present in apparently healthy individuals. 52 . GENERAL SYMPTOMATOLOGY. It consists of a sucklen contraction of the quadriceps femoris and vastus intern us and externus mnscles, produced by strik- ing the patellar tendon while the leg hangs loosely at a right angle to the thigh ; for instance, the leg being crossed over the other. This may also be produced if the lower part of the muscle is struck. It may be increased, or at times brought into activity when absent — called reinforcement — if at the time the tendon is struck the patient performs some volun- tary muscular movement, such as tightly closing the hands or pulling on his clasped fingers. Reinforcement is not pos- sible if the absence of the reflex is due to organic disease. Ankle-clonus is caused by grasping the extended leg under the calf with one hand and suddenly making dorsal flexion of the foot with the other. When it is present there will be seen a series of rapid contractions of the calf-muscles causing to-and-fro movements of the foot. This reflex is never present in health. The tendo Achillis, or ankle-jerk, is elicited by striking the tendo Achillis, when the calf-muscles contract, causing a plantar flexion of the foot. It may be present when the knee-jerk is absent, or vice versa. The wrist-jerk is elicited by striking the flexor tendons at the wrist, made prominent by passive extension of the hand, the wrist of the patient being supported by the examiner. Flexion of the hand takes place. The elbow- or triceps-jerk consists in a contraction of the triceps muscle when its tendon is struck just above the elbow-joint, the forearm hanging loosely at a right angle to the supported arm. The biceps and supinator jerk is obtained by striking the lower end of the radius, the elbow being partly flexed at the time. Contraction of the biceps results. The jaw-jerk is produced by causing the patient to set with the mouth partly o])en with a ruler or something similar laid across the lower teeth. When this is struck the masseter muscles contract and the mouth closes. The wrist-, elbow-, and jaw-jerks are rarely found in health. If well marked, they always indicate disease. A muscle-jerk is obtained by striking the stretched muscle, when certain or all of the fibres contract. It may be present THE VISCERAL REFLEXES. 53 or increased in di.seasos in which the tendon-reflexes are absent; for instance, in chronic poliomye- litis. The Visceral Reflexes. The eye : Important reflexes are discovered by examining the eyes. The light-reB^ex is pro- duced by throwing a bright light into the eye, when the pupil con- tracts, to dilate again when the light is removed. The accommo- dation-reflex is brought out by causing the patient to look at a near and then at a far object; in the former case the pupil dilates ; and contracts in the latter. The other eye should be covered. When the light-reflex is lost and the accommodation- reflex remains we have what is known as the Argyll- Moberf son pujyil. The reflexes of the bladder, rec- tum, and sexual apparatus : Urina- tion and defecation are reflex acts, under the control of the higher centres. If the inhibitory influ- ence is removed, and voluntary control over the sphincters is lost, urine and fseces are expelled as soon as the bladder or rectum is full. This condition is seen to greater or less degree whenever the function of the pyramidal tracts is interfered with. If this condition persists, weakness of the detrusor muscles occurs after a time and the bladder is not com- FiG. 14. Diagram iUustrating the inner- vation of the bladder and the effect of lesions in various parts of the spinal cord upon the function of micturition. A lesion, ^1, which interrupts the voluntary path to the bladder- centre in the sacral cord, causes incontinence of urine. When a sufficient quantity of urine ac- cumulates in the "bladder there occur a reflex contraction of the detrusor and a relaxation of the sphincter. The sensory path from the cord to the brain being uninvolved, the patient is conscious of the process, but cannot exercise voluntary con- trol over it. With a lesion, B, which involves also the sensory path, the patient is unconscious of the filling and reflex empty- ing of the bladder. A lesion, C, which causes destruction of the sacral reflex centre of the bladder causes continuous dribbling of urine, and not its automatic expulsion at inter- vals (Herter). 54 GENERAL SYMPTOMATOLOGY. pletely emptied. If, in addition to the preceding conditions, the tone of the compressor urethrce nmscle is intact, there fol- lows retention of urine until the bladder-distention is suffi- cient to overcome this tone. Thus we have the incontinence of overflow. If any of the components of the reflex are involved, incon- tinence also takes place. If the motor- part is diseased, the sphincters are relaxed. In the case of the rectum this condition can be diiferenti- ated from the incontinence due to loss of inhibition by intro- ducing the finger into the rectum. In the former case the sphincter will be found relaxed ; in the latter, it grasps the finger firmly. When complete j)aralysis is not present there is difficulty in starting the stream of urine, or there may be obstinate constipation. Wlien the sensory pjcirt of the arc is damaged the patient is unaware that the bladder or rectum is full. Damage to the reflex arc governing the genital functions causes loss of the power of erection of the penis and loss of desire. Removal of the inhibitory influence may produce priapism. The reflex centres of these functions are in close proximity. The location in the cord of all of the various reflex centres and their localizing significance will be found under Localization in the Spinal Cord. Idiopathic Muscle -reflex. Paradoxical contraction consists of a tonic contraction of the anterior tibial muscles produced by suddenly flexing the foot on the leg, thus shortening the muscle. Its occurrence is always pathological. SYMPTOMS DUE TO TROPHIC, VASOMOTOR, AND SECRE- TORY DISTURBANCES. Trophic disturbances consist of hypertrophy or atrophy of muscles ; of cutaneous, osseous, and mucous tissues ; joint- afFections, known as arthropathies ; and various skin-eruptions as herpes, pigmentation, alopecia, and bedsores. Vaso-motor symptoms are pallor and coolness of the skin, SECRETORY DISTURBANCES. 55 due to spasm and congestion (arterial or venons); and nedema, due to relaxation of the bloodvessels. There may be an un- steadiness of action of the vaso-motors ; dilating and con- tracting in an irregular way, they cause various flushings and localized oedemas (angioneurotic oedema), a condition known as vaso-motor ataxia. Secretory disturbances consist of increase or diminution of glandular secretions, as excessive sweating, or hyperidrosis ; excessive dryness, or anidrosis. There may be peculiar odors or colors of the secretion. CHAPTER IV. GENERAL THERAPEUTIC MEASURES. ELECTRICITY. Physics. Potential : The laws which govern the electrical current are very similar to those which govern the flow of water. If we have two vessels of water one above the other and connected by a pipe, the fluid in the higher one will endeavor to get to the lower ; the water in so doing will exert force and conse- quently a ecvpacity to do work, which is called its potential. The fluid in the lower vessel would also endeavor to reach a lower level which is ultimately the level of the sea, and in so doing Avould exert force, but not so much as that exerted by the higher body of water. The sea-level would be zero potential. The difference in the force exerted by these two bodies of water would be their difference in potential. By means of certain agencies — viz., friction, chemical action, etc. — electricity is separated into positive and negative electric- ity, the positive being of higher potential than the negative ; these tend to Iiecome united, that of the higher potential tending to flow toward the lower, just as the fluid in the higher vessel tends to flow toward the lower ; and this ten- dency, when the conditions are favorable, causes an electrical current. The zero point of electrical potential is the earth. The volt : The force which starts the column of water flowing is that of gravity ; that which causes the electrical current to flow is termed the electro-motive force (E. 31. F.), and the xnit of measiirement of such force is the volt. The ohm : Certain substances are much more pervious to the passage of water than others ; so with the electrical cur- rent ; substances through which the current will flow with facility are known as conductors. In the order of their rela- 56 ELECTRICITY. 57 tive value they are the metals ; charcoal ; plumbago ; dilute acids; saline solutions; water; living animals, and flame. Those which do not permit its free passage are called insula- tors, or non-conductors. They are rubber ; silk ; glass ; wax ; sulphur ; resins ; shellac, and dry air. As the water flows through the pipe it meets with resistance ; so does the electri- cal current, as it flows through the conductor, and this resist- ance, similar to that which water would experience, will depend on tlie length, composition, and area of cross-section of the conductor — i. e., a current passing a sliort distance through a good conductor with a large area of cross-section will meet with less resistance than will a current subject to opposite conditions. The unit of resistance is the ohm. The ampere : The actual current-strength (C) depends on Ohm's law — viz., the current-strength is equal to the E. M. F. Q =zz — ^— ^ — ' |. Current-strength is measured in amperes ; and in medicine we use the one- thousandth part of an ampere, or a milliamphr. As water may be confined, so by means of insulators can electricity. It is then said to be static. The electric aparatus used in medicine is of three kinds — viz., static, gcdvanic, and faradic. The static machine, which generates electricity by friction, develops a very high electro- motive force, and consequently the electricity is of high potential. When the patient is insulated from the ground and connected with one of the conductors he becomes en- veloped in a layer of electricity which is confined by the dry air. When the other electrode is approached the current flies to the zero point, just as a large volume of water, which had been dammed, would do when the dam bursts. It does so with such force that it leaps through space, and by igniting the small particles from the conductors causes a sparh. The galvanic or constant current is commonly produced by chemical action upon two dissimilar substances. The current flows from the substance most acted upon (the positive ele- ment) to that least so (the negative element) ; and if they are connected by a conductor, from this back again to the posi- tive. Such a combination of substances is termed a cell (see 68 ELECTRICITY. Fig. 15). A combination of cells constitutes a battery. The point from which the current leaves the cell (the negative element) is called the positive pole ; and that where it enters, the positive element, or the negative pole. This constitutes a circuit. So long as the circuit is closed a constant E. M. F. Fig. 15. Zn Cu This represents a vessel filled with dilute H2SO4, into which plates of zinc and cop- Eer are immersed and connected by a piece of wire. The current starts at Zn, ows to Cu, and hence through the wire to Zn again. Cu is the positive pole, or anode ; Zn the negative pole, or cathode. is maintained and the current will flow ; when the circuit is open, the current ceases. The faradic current is produced by induction — i. e., if we make a coil out of the wire which connects the two elements of a cell, and surround this coil with another one having no connec- tion with it, and open and close the circuit in the first or pri- mary coil, an E. M. F. will be generated, which will cause a cur- rent to flow in the second or secondary coil. This current is but momentary, only occurring \^dlen the circuit is closed and opened. A current constantly flowing through the primary coil would not induce a current in the secondary coil. The induced current is an alternating or to-and-fro current. When the circuit is closed or made, the induced current in the sec- ondary coil flows in the opposite direction, while the current induced by l)reaking tJie circuit flows in the same direction as that of the inducing current. When a bar of soft iron in the centre of the primary coil is suddenly magnetized by closing the circuit and demagnetized by breaking it, currents are in- duced in the secondary coil. The current induced by mag- PHYSIOLOGY. 59 netization flows in the same direction as that produced by clos- ing the circuit; and that induced by demagnetization, as that produced when the circuit was broken. Under such cir(!um- stances there would be a double influence acting upon the secondary coil, with consequent increased strength of current. This principle is made use of in the construction of medical batteries for increasing current-strength. As any variation in the strength of the current in a circuit will induce a current in the conductor, a current is induced in the coils of the primary coil. This is termed the extra current. In batteries this is designated as the primary cur- rent. It obeys the same laws as to direction that the current induced in the secondary coil does. Accordingly when the circuit is closed, the induced current goes in the opposite direction and they tend to neutralize each other. This cur- rent may be consequently disregarded and the extra current considered as flowing in only one direction. The strength of the faradic current increases with the strength of the generating current, the number of windings in the coil, the approximation of the coils, and the sudden- ness of the change of current-strength. When the primary coil is surrounded by the secondary, the inducing current is weakened by its induction of a current in the secondary coil. Hence the extra current induced would be weakened. Hence the extra current grows stronger as the secondary coil is re- moved from the primary. This is utilized in the construc- tion of the Duhois-Reymond coil, the extra current being strongest when the secondary coil is slid away from the pri- mary. Physiology. The electrical current acts upon living tissues in various ways. It may cause electrolysis or chemical decomposition of the tissues at the electrodes, a property taken advantage of for the destruction of nsevi, small tumors, etc. It possesses the power of cataphoresis — i. e., of carrying solutions through the tissues in the direction of the current. By means of this property cocaine for local anaesthesia and other drugs may be introduced into the body at the seat of disease. 60 ELECTRICITY. It causes a modification of nerve-excitability known as electrotonus. At and in the vicinity of the anode the excita- bility is lessened, anelectrotonus ; while at and in the vicinity of the cathode the excitability is increased, catelectrofonus. Also when anelectrotonus is made to disappear suddenly by breaking the circuit at the anode, the cathodal increase occurs, and the nerve is thrown into a condition of ccdelectrotonus. The current also causes muscular contraction. These con- ditions can only be produced by a sudden increase or decrease of electrical excitement in the muscle or nerve supplying it. In other words, by a sudden increase or decrease of current- strength. When this is done gradually no contraction results. This being true, the most powerful excitement is caused by the voltaic alternative. It is produced by suddenly reversing the current direction, so that a nerve or muscle which had been in a condition of anelectrotonus is thrown into one of catelectrotonus, or from a state of — excitability to one of -\-, and ince versa. By simple closure and opening of the circuit the increase is only from to -f- excitability and to — ex- citability, which, of course, is not so great a variation. The galvanic current possesses all of these properties in more marked degree than does the static or far adic. In these latter the influence of the current is of such brief duration that they are practically only used to cause muscular con- tractions and to relieve pain. A degenerating muscle loses its power of response to static electricity first ; next, to faradic, and then to simple opening and closing of the galvanic circuit ; finally, to the voltaic alternative. Diagnosis and Prognosis. Electric irritability : In many diseases of the nervous sys- tem the muscles and nerves, when subjected to electrical stimulation, act differently than do normal muscles and nerves. Their electric irritahility may differ in two ways — either in quantity, meaning a diminution or increase of irritability ; or in quality, in which, along with the quantitative change, there is one in the character of the contraction. Quantitative changes : Simple increased irritability, or that DIAGNOSIS AND PROGNOSIS. 61 in which the muscle or nerve responds to a weaker current than normal, is met with most frequently in tetany. Decreased irritability, or that in which a stronger current than normal is required to produce contractions, occurs in mild cases of neuritis and sometimes in long-standing central paralyses. These conditions are generally the same for botli currents. ^ Quantitative changes — examination : To ascertain these facts : if the paralysis exists on one side only, the weakest current that will cause contraction of the normal muscle should first be learued ; then the difference in the strength of current necessary to produce the same result on the dis- eased muscles. If the affection is bilateral, the reactions may be similarly compared with the reactions of another normal person ; or we judge by experience as to what strength of current is usu- ally normally required. The qualitative changes consist of the reaction of degenera- tion (De R) and the viyotonic muscular reaction. The former is found in certain forms of paralysis, and when present always indicates that the causal lesion is situated in the periph- eral motor neuron — i. e., either in the motor cells of the medulla or cord, or the axons forming the motor nerves which come from them. The latter is a symptom of myotonia con- genita. Reactions of degeneration are complete or partial according to the degree of disturbance. The complete reaction consists of: (1) a rapid loss of the power of the muscle and its supplying nerve to react to the faradic current ; (2) a brief period of quantitative increase fol- lowed by a decrease when they are stimulated by the galvanic current; (3) the modal change — i. e., instead of tlie short, quick, jerky contraction caused by the stimulation of the healthy muscle or nerve by a galvanic current, the contrac- tion is slow, wavy, and sometimes tetanic ; and (4) the serial change, when the muscle alone is subjected togalvauic stimu- lation. The serial change dej)ends upon a difference in the way the muscle reacts to the different poles of the battery. Normally the weakest current that will cause a muscular contraction is 62 ELECTRICITY. when the circuit is dosed with the cathode on the muscle (cathodal closing contraction, CaClC). A little stronger cur- rent will cause an anodal closing contraction (AnClC); and so on. Representing anodal opening contraction by AnOC and cathodal opening contraction by CaOC, the normal formula will be CaClC > AnClC > AnOC > CaOC. The serial change in a complete De R consists of an increase of the AnClC and AnOC over the CaClC ; so that one for- mula would read AnClC = AnOC > CaClC > CaOC. Or this, AnClC > AnOC > CaClC > CaOC. The partial De R is more common than the complete. It may consist of nothing but the loss of faradic irritabil- ity and the modal change, the series being normal. Or this may be changed so that AnClC = CaClC. In partial reac- tions the nerve usually responds normally. In examining for the presence of De R we first use the faradic current as when testing for quantitative changes. Then use the galvanic electrode, placing a large indifferent electrode over the sternum, and the other, a small one, over the muscle. We then find the minimum strengths of current necessary to cause CaClC and AnClC. If a meter is at hand, this may be done by noting the number of milliamperes required ; or if not, by noting that the current which causes CaClC will not cause AnClC, or vice versa; or that they are equal. Another method consists in making the electrode positive and negative alternately, using the same strength of current and noting the difference, if any, in the intensity of the con- tractions. In all of these tests there should be a considerable interval (several seconds) between opening and closing the circuit. The myotonic reaction is due to a greatly increased irrita- bility : mild faradic and galvanic currents produce contractions that are tetanic in character, hollows and ridges in the muscle being often produced. In the case of the galvanic current AnClC becomes equal to or greater than CaClC. AVhen the galvanic current is allowed to flow without inter- ruption through a muscle, rhythmical contractions, ti'avelling from the negative to the positive pole occur. Electricity may sometimes help us in forming a prognosis. METHODS OF APPLICATION AND THERAPEUTICS. 63 As the complete De R is only present when extensive damage has been done, the prognosis should be more grave than when only the partial De R is present. It is best in those oases where no serial change occurs. Cases in which only a feeble AnClC can be elicited may be regarded as hopeless. Methods of Application and Therapeutics. Certain general rules should be borne in mind while using electricity. The muscles being treated or tested should be relaxed and in a comfortable position. To cause muscular contraction we should begin with a weak current, gradually increasing its strength until a slight contraction is produced. Violent contractions are harmful. Ten to twelve contractions of each muscle are sufficient. When using strong galvanic currents always increase and decrease their strength grad- ually ; otherwise a painful shock will be caused. To influ- ence a particular spot use a large indiiferent electrode, and a small one over the spot. To influence a considerable area two large electrodes may be used. To influence the skin the electrodes should be dry ; to reach the tissues under the skin, both electrodes should be moist with water or a saline solu- tion. The motor point is a certain spot in each mnscle that is more irritable to the action of the current (see Figs. 16 to 25). When there is great quantitative decrease contractions too faint to be seen may be often recognized by placing the finger lightly on the muscle. In the treatment of nervous diseases electricity is used as a tonic, either to the general system or to individual muscles and nerves ; to increase the sensibility of the skin ; as a seda- tive, for the relief of pain and spasm ; and for the introduc- tion of drugs into the diseased parts by utilizing the property of cataj^horesis. As a tonic, we may employ static, faradic, or galvanic electricity. > Static electricity used as a tonic : We place the patient upon an insulated stool, connect him with one of the poles of the machine, and by means of a metal ball-electrode attached to the other pole we draw sparks from various parts of the body, excepting the face, if used for a general etfect; or from the paralyzed or anaesthetic part, if the aifection is 64 ELECTRICITY. local. This may be done without removing the clothing. As a muscle-stimulant its employment is only of benefit in A diagram of the motor points of the face, showing the position of tlie electrodes during electrization of special muscles and nerves. The anode is supposed to be placed in the mastoid fossa, and the cathode in the part indicated upon the diagram (from von Ziemssen). 1, oceipitofrontalis (ant. belly) : 2, corrugator supercilii ; 3, occiplto-frontalis (post, belly) ; 4, orbicularis palpebrarum ; 5, re- trahens et attollens aurxim ; 6, pyraniidalis nasi ; 7, facial nerve ; 8, lev. lab. sup. et alse nasi ; 9, deep posterior auricular branch of facial nerve : 10, lev. lab. sup. propr. ; 11, stylo-hyoid ; 12, dilator naris ant. ; 13, digastric ; 14, dilator naris post. ; 15, buccal branches of facial nerve; 16, zygomat. niinor : 17, subcutaneous branch of inferior maxillary nerve ; 18, zygomat. major ; 19, splenius capitis ; 20, orbicularis oris ; 21, external branch of spinal accessory nerve ; 22, branch of levator menti and dep. ang. oris ; 23, sterno-mastoid ; 24, levator menti ; 25, sterno-mastoid ; 26, dep. lab. infer. ; 27, levator anguli scapulre : 28, dep. ang, oris; 29, phrenic nerve; 30, subcutaneous nerves of neck; 31, posterior thoracic nerve to rhomboid muscles ; 32, sterno-hyoid ; 33, circumflex nerve ; 34, omo- hyoid ; 35, posterior thoracic nerve to serratus magnus; 36, sterno-thyroid ; 37, branch of brachial plexus ; 38, branch for platysma ; 40, steruo-hyoid ; 42, omo-hyoid ; 44, 46, nerves to pectoral muscles. central paralyses. The psychic ejects of static electricity are marked ; hence it is of value in the treatment of hysterical METHODS OF APPLICATION AND THERAPEUTICS. 65 affections. The applications should last from fifteen to twenty minutes, made tri-weekly. The faradic current, as a musole-stimulant, is only of use in central paralyses, or in peripheral, when the muscle is hut slightly degenerated. Either the so-called primary or the secondary current may be used, the latter being somewhat the more powerful. Fig. 17. Trans, ab- dominis. Diagram of the motor points of the trunk (from von Ziemssen). A convenient method when using the slowly interrupted current is to place a good-sized electrode over the nerve sup- plying the muscle, say, over the brachial ])lexus if the arm is being treated, while the other electrode, which should be of smaller size, is placed over the motor ])oints (points in the muscles more irritable to the current: Figs. 16, 17, 18, 19, 20, 21, 22, 23, 24, 25) of tiie muscles l)eiug treated. Or, if 66 ELECTRICITY. the rapidly interrupted current only is convenient, the indif- ferent electrode being in the position above described, we stroke the paralyzed part with the other. This method does not necessitate a knowledge of the position of the motor Fig. 18. Diagram of the motor points of the arm, under side (from von Ziemssen). 1, Mus- culo-cutaneons nerve ; 2, musculo-cutaneous nerve ; 3, biceps ; 4, internal nerve of triceps ; 6, median nerve ; 8, brachialis anticus ; 10, ulnar nerve ; 12, branch of median nerve to the pronator teres. Motor parts of the arm, outer side (from von Ziemssen). 1, external head of tri- ceps ; 2, musculo-spiral nerve ; 3, brachialis anticus ; 4, supinator longus ; 5, ex- tensor carpi radialis longior ; 6, extensor carpi radialis brevier. points. An application every other day is usually often enough. When used to stimulate ancesthetic shin we employ the wire brush and the secondary current rapidly interrupted. The METHODS OF APPLICATION AND THERAPEUTICS. 67 Fig. 20. Motor points of forearm, inner surface (from von Ziemssen). 1, flexor carpi radialis ; 2, branch of the median nerve for tlie pronator teres ; 3, flexor pro- fundus digitorum; 4, palmaris longus ; 5, flexor sublimis digitorum : 6, flexor carpi ulnaris; 7, flexor longus pollieis : 8, flexor sublimis digitorum (middle and ring fingers); 9, median nerve; 10. ulnai- nerve; 11, abductor pollieis; 12, flexor sublimis digitorum (index and little fingers); i:''., uiiponens pollieis; 14, deep branch of ulnar nerve; 15, flexor brevis pollieis; ic, |.:iliiiaris brevis ; 17, adductor jiollicis ; 18, adductor minimi digit! : 19, lumbricalis (first); 20, flexor brevis minimi digiti : 22, (ipj)onens minimi digiti ; 24, liniil)ricales (second, third, and fourtli). 68 ELECTRICITY. brush is placed over the anaesthetic areas, the other being at some indifferent point. This should be done daily, at least. Fig. 21. Motor points of forearm, outer surface (from von Ziemssen). 1, extensor carpi ulnaris ; 2, supinator longus ; ?., extensor minimi digiti ; 4, extensor carpi radialis longioi- ; 5, extensor indicis; 6, extensor carpi radialis brevior; 7, extensor secundi internodii pollicis; 8, extensor communis digitorum ; 9, abductor minimi digiti : 10, extensor indicis ; 11, dorsal interosseus (fourth) ; 12, exten- sor indicis and extensor ossis metacarpi pollicis; 14, extensor ossis metacarpi pollicis; 16, extensor primi internodii pollicis; 18, flexor longus pollicis; 20, dorsal interossei. For gciifral ionic y>/fryjr).sr.s' we employ the method known as general faradization. The patient is placed in a recum- METHODS OF APPLICATION AND THERAPEUTICS 69 bent position and all the muscles of the hody caused to con- tract in turn by one of the methods aliove described. After Fig. 2-1 FKi. -I'i. Motor points of thigh, anterior surface. Posterior surface. (From von Ziemssen.) Fig. 22.— 1, tensor vaginae femoris (branch of superior gluteal nerve); 2, anterior crural nerve ; 3, tensor vagiiiBB femoris (branch of crural nerve) ; 4, obturator nerve ; 5, rectus femoris : 6, sartorius ; 7, vastus externus ; 8, adductor longus ; 9, vastus externus ; 10, branch of crural nerve to quadriceps extensor cruris ; 12, crureus ; 14, branch of crural nerve to vastus externus. Fig. 23.— 1, adductor magnus ; 2, inferior gluteal nerve for gluteus maximus ; 3, semi- tendinosus: 4, great sciatic nerve; 5, semi-membranosus : 6, long head of biceps ; 7, gastrocnemius (internal head) ; 8, short head of biceps; 10, posterior tibial nerve ; 12, peroneal nerve ; 14, gastrocnemius (external head) ; 16, soleus. this is done one pole may be placed at the nape of the neck, the other at the feet, and the current rapidly interrupted and made strong enough to produce a general tingling through 70 ELECTRICITY. Fig. 24. Fig. 25. Motor points of the leg, outer side. Inner side. (Prom von Ziemssen.) Fig. 24.— 1, peroneal nerve ; 2, peroneus longus ; 3, gastrocnemius (external head) ; 4, tibialis antieus ; 5, soleus ; 6, extensor longus poUicis ; 7, extensor communis digitorum longus ; 8, branch of peroneal nerve for extensor brevis digitorum ; 9, peroneal brevis; 10, dorsal interossei ; 11, soleus : 13, flexor longus poUicis; 15, extensor brevis digitorum ; 17, abductor minimi digiti. Fig. 25.— 1, gastrocnemius (internal head) ; 2, soleus ; 3, flexor communis digitorum longus ; 4, posterior tibial nerve : 5, abductor pollicis. the body for fifteen or twenty minutes. The treatment should be administered daily, except in women while men- struating. METHODS OF APPLICATION AND THERAPEUTICS. 71 The faradic current, especially wlicn rapidly interrupted, exercises considerable psychic influence. The galvanic current when used to influence the nvirilion of muscles much degenerated, as in severe acute poliomyelitis, is best used by placing the anode at some indifferent point (best over the supplying nerve), Avhile the cathode is rubbed over the muscles without breaking the circuit {labile)', or by allowing the cathode to remain stationary at the distal ex- tremity of the limb and the current allowed to flow from ten to fifteen minutes (stabile). If we wish to cause 'muscular contractions, the cathode is placed over the motor points and the circuit opened and closed alternately, at the cathode. Or the voltaic alternative reversion of the current may be used. Seances when the current is employed labile or stabile may be daily. When contractions are caused, tri-weekly is sufficient. In high grades of peripheral paralyses the galvanic current is the only one of value. As a general tonic it may be used as general galvanization, applied similarly to general faradization. Sedative influences are exercised by each of the three forms of current. We may secure the sedative influence of the static current by drawing sparks from the painful region, as described on p. 63. There are other methods, for which the reader is referred to works on electro-therapeutics. The faradic cfiirrent, most markedly that from the secondary current, rapidly inter- rupted, exercises a sedative influence. We employ it by placing an electrode over the painful area. The seance should last five to ten minutes and be repeated frequently. Local spasms may sometimes be relaxed by the same method. In using the galvanic current to relieve pain or spasm the anode is placed over the part to be influenced while the cathode is removed as far away as possible. The current is applied stabile or labile, being gradually increased and very gradually decreased in strength. The current should be as strong as can be borne, and used frequently. Cataphoresis is used in neurology principally in the treat- ment of neuralgia. If a solution of cocaine 10 per cent, is 72 MASSAGE. used to moisten the anode which is placed over the painful nerve, some of the cocaine will pen{>trate the skin and directly affect the painfid part. Special electrodes, the best of which is Peterson's, have been devised for the employment of cataphoresis. MASSAGE. Massage is the name given to a number of manipulations of the body, which possess marked value in the treatment of nervous diseases as Avell as of others. Effects : Massage properly applied stimulates the flow of the lymph- and venous currents ; increases temporarily the number of red blood-corpuscles ; accelerates the heart's action ; stimulates the motor nerve-endings and muscular contrac- tility ; and, according to the method used, exercises either a stimulant or a sedative action upon the sensory nerves. Indications : It is therefore of value in various forms of neurasthenia; hysteria; motor paralysis; ansesthesia ; head- ache ; neuralgia ; function -spasms ; insomnia ; and constipa- tion. It should not be employed where there is a diseased heart or bloodvessels. To administer massage properly requires special training. The movements consist of effiewrage, or gentle stroking ; mas- sage dfrietion, consisting of vigorous strokes with one hand and strong circidar and to-and-fro friction with the other ; p^h'issage, or kneading ; and tapotement, or striking with the hands or ends of the fingers. Passive movements are fre- quently combined with these. Efileurage and tapotement are most useful in treating painful conditions. Muscular Movements. Regular muscular movements, according to a fixed schedule, as first used by Weir Mitchell, but since elaborated by Frankel, are of value in the treatment of muscular inco- ordination. The exercises should be performed with care and precision twice daily. The following schedule, based upon that of Frankel and Hirschberg, is recommended by Dana : Exercises for the hands and arms : 1. Sit in front of a table ; MUSCULAR MOVEMENTS. 73 place the hand upon it, then (elevate each finger as far as pos- sible. Then, raising the hand slightly, extend and then flex each finger and thumb as far as possil)Ie. 1)0 this first with the right, then with the left. Repeat oikh'. 2. With the hand extended on the table, abduct the thumb and then each finger separately, as far as possible. Repeat three times. 3. Touch with the end of tlie thumb each finger-tip sepa- rately and exactly. Then touch the middle of each phalanx of each of the four fingers with the tip of the thumb. Re- peat three times. 4. Place the hand in the position of piano-playing and ele- vate the thumb and fingers in succession, bringing them down again, as in striking the keys of the piano. Do this twenty times with the right hand, and the same with the left. 5. Sit at a table with a large sheet of paper and pencil. Make four dots in the four corners of the paper and one in the centre. Draw lines from corner dots to centre dot with right hand ; same with the left. 6. Draw another set of lines parallel to the first, with the right hand ; same with the left, 7. Throw ten pennies upon the paper. Pick them up and place them in a single pile with the right hand ; then with the left. Repeat twice. 8. Spread the pennies about on the table. Touch each one slowly and exactly with the forefinger of the right hand ; then with the forefinger of the left. 9. Place an ordinary solitaire board on the table, with the marbles in the groove around the holes. Put the marbles in their places with the right hand ; same with the left hand. Patient may, with advantage, practise the game for the pur- pose of steadying his hands. 10. Take an ordinary fox-and-geese board with holes and pegs, and, beginning at one corner, place the pegs in the holes, one after the other, using first the right hand, and then the left. Exercises for the body and lower limbs : 1 . Sit in a chair. Rise slowly to the erect position without help from cane or arms of chair. Sit down slowly in the same way. Repeat once. 74 HYDROTHERAPEUTICS. 2. Stand with cane, feet together, advance the left foot and return it. Same with the right. Repeat three times. 3. Walk ten steps with cane, slowly. Walk backward five steps with cane, slowly. 4. Stand without cane, feet a little spread out, hands on hips. In this position flex the knees, and stoop slowly down as far as possible ; rise slowly ; repeat twice. 5. Stand erect, carry left foot behind, and bring it back to its place ; the same with the right. Repeat three times. 6. Walk twenty steps, as in exercise No. 3 ; then walk backward five steps. 7. Repeat No. 2 without cane. 8. Stand without cane, heels together, hands on hips. Stand in this way until you can count twenty. Increase the dura- tion each day by five, until you can stand in this way while one hundred is being counted. 9. Stand without cane, feet spread apart ; raise the arms up from the sides until they meet above the head. Repeat this three times. With the arms raised above the head, carry them forward and downward, bending with the body until the tips of the fingers come as near the floor as they can be safely carried, 10. Stand without cane, feet spread apart, hands on hips ; flex the trunk forward, then to the left, then backward, then to the right, making a circle with the head. Repeat three times. 11. Do No. 9 with heels together. 12. Do No. 10 with heels together. 13. Walk along a fixed line, such as a seam on the carpet, with cane, placing the feet carefully on the line each time. Walk a distance of at least fifteen feet. Repeat twice. 14. Do the same without cane. 15. Stand erect with cane; describe a circle on the floor with the toe of the right foot. Same with the left. Repeat twice. Between the fifth and sixth exercise the patient should rest for a few moments. HYDROTHERAPEUTICS. Water may be used either as a tonic or as a sedative. As a tonic we employ cold plunges ; shower-baths ; various HYDROTHERAPEUTICS. 75 forms of douches, as Charcot's and tlie Scottish cold sitz-bath ; salt baths, either sea or artificial, and short cold packs. These all have a stimulating and tonic effect. In giving them, es- ])ecially to weak people, it is best to begin with warm water and gradually lower the temperature. Showers and douches are the most stimulating. A reaction should always be obtained by vigorous rubbing afterward. For the cold plunge the patient jumps into a tub of water at a temperature of 60° to 70° F., and at once jumps out. He should then be rubbed vigorously. The shower- or rain-bath consists in allowing water to fall on the body from a height for one or two minutes, Avhile the feet are in warm water. Frictions of the body should be kept up during this process. A Charcot douche is given by directing a solid stream of water with force upon the back of the patient. By the Scottish douche we mean alternating a cold douche with a warm or a hot one. Cold packs are given by wringing a sheet out in cold water, wrapping it about the patient for a few moments ; when it is removed and the patient put to bed and rubbed. An artificial salt bath may be made by putting twenty-five pounds of salt in thirty gallons of water (2 per cent.). It may be warm or cold. To obtain sedative effects we may use the lukewarm bath, wet pack, hot sitz-baths, hot compresses, and drip sheet. The lukewarm bath is given at a temperature of 95° to 98° F. for ten to twenty minutes. To give a wet pack we spread a large, thick blanket upon the bed ; upon this is laid a sheet wrung out in water at a temperature of 40° to 60° F. The nude patient lies upon this and the sheet is wrapped smoothly about him, not in- cluding the head and feet. The sheet must be carried be- tween the legs and brought evenly in contact with the body. The blanket is then folded over him, with others added if desired. Hot-water bottles may be placed at the feet and cold compresses to the head. The patient lies in this for half an hour and is then rubbed ofF. The drip-sheet : Have a basin of water at 65° F. Put in the basin a sheet. The patient stands in comfortably hot 76 THE REST-TREATMJ^NT. water. Have ready a large soft towel and iced water. Wring out the towel in this and wrap it around the head and back of the neck. Standing in front of tlie patient, the sheet is seized by the two corners and thrown about the patient, who holds it at the neck. It is then smoothed out over the body. It is then dropped and the patient made to lie down on a blanket, which is wrapped about him. Dry thoroughly with coarse towels, wrap in a dry blanket for a time, then put to bed. The water should be gradually cooled day by day to 55° F. The bath, pack, and drip-sheet are valuable remedies for insomnia. A hot .sifz-bath consists of the patient's sitting in water at a temperature of 100° to 125° F. from twenty to thirty min- utes. Hot compresses are often used for the relief of local pains and congestions. THE REST-TREATMENT. This method of treatment, devised by S. Weir Mitchell, is of especial value in neurasthenia and hysteria. Its essential features are : isolation ; absolute rest ; diet ; massage ; electricity ; and the personal influence of a good nurse. Isolation from the patient's family and former surroundings is essential. The diet, if the digestion is bad, should be en- tirely of milk. Otherwise easily digested solid food may alternate with it. Mest must be absolute in severe cases ; even sitting up in bed should not be allowed. The duration of the treatment should be from four to eight weeks. The following schedule, as given by Dr. J. K. Mitchell, will illustrate the method : 7.00 A. M. : Cocoa ; cool sponge-bath, with rough rub and toilet for the day. 8.00 A. M. : Milk. Breakfast." Rest for one hour. 10.00 A. M. : 8 oz. peptonized milk. 11.00 A. M. : Massage. 12.00 M. : Milk or soup ; reading aloud by the nurse. THE REST-TREATMENT. ' 77 1.30 p. M. : Dinner ; rest one hour. 3.30 p. M. : 8 oz. peptonized milk. 4.00 p. M. : P^lcctricity (general faradization). 6.00 1'. M. : Supper, with milk. 8.00 p. M. : Reading aloud by nurse for one-half hour. 9.00 p. M. : Jjight rubbing by nurse with drip-sheet. 8 oz. malt-extract with meals; tonic after meals. . 82 SYMPTOMATIC DISORDERS. tutional neurosis, associated with violent paroxysms of pain, usually unilateral and confined to the course of the fifth nerve, and frequently accompanied with other sensory dis- orders and with nausea or vomiting, vaso-motor disturbances and mental depression. Synonyms : Hemicrania ; sick headache ; megrim. Etiology : Migraine is a disease of the first half of life, very few cases beginning after thirty. Heredity, either direct or indirect, is the most important predisposing factor. When direct, members of the family for several generations back have been afflicted. When indirect, they have been sufferers from other neuroses, especially neuralgia or epilepsy. Fre- quently other members of the same generation are sufferers either from migraine or one of the neuroses above mentioned. The gouty diathesis appears to have some influence : a father may be gouty and the son have migraine. In some cases, when the disease appears late, influences that depress or weaken the nervous system, as excessive brain- work, ansemia, and reflex irritations, seem to act as exciting causes. In those who are already sufferers, an attack may be precipitated by fatigue, excitement, digestive disorders, and eye-strain either by over-use or watching moving objects. Migraine — symptoms : In a typical attack the patient may or may not have for a day or so prodromes, as a feeling of heaviness in the head and somnolence. Usually the onset is sudden. A bright spot suddenly appears on one side of the visual field, which enlarges, becoming darker in the centre, and changing from round to angular and zig-zag shapes (for- tification spectra). In ten to thirty minutes these disappear, pallor of the face appears, and the pain begins usually in one temple, spreading until one side of the head is involved. The pain is increased by noise, light, or stooping, but feels better when a recumbent posture is maintained. In a few hours nausea is felt, which in a greater or less length of time culminates in the vomiting of first the stomach-contents, then mucus and bile ; the bile being due to retrostaltic action of the stomach. This is succeeded by sleep and relief from pain. The attack usually lasts about twenty-four hours, but in severe cases it may be longer. The pain, while usually unilateral, may be bilateral. In- MIGRAINE. 83 stead of the form of sensory disturbance above described, figures of men and animals and other forms of visual hallu- cination may be present. In other cases there is first noticed dimness of sight on one side, which increases until half of each field is blind (homonymous hemianopsia). Karely, in- stead of visual, disturbances of other special senses occur, as one-sided deafness ; tinnitus ; loss of taste or subjective sen- sations of taste. Tingling of the arm followed by anaesthe- sia, or vice versa, precedes the jjain in rare instances. Another rare symptom, occurring when the pain is left-sided, is a transient aphasia. This may be either a sensory, motor, or paraphasia. This symptom may be associated with transient right-sided tingling, numbness, or motor weakness of the arm ; more rarely of the leg. There may also be mental depression, restlessness, and either temporary loss or increase of memory. The vaso-motor symptoms are usually pallor of the face and coldness of the extremities ; more rarely there is flushing with sweating, sometimes unilateral ; or these conditions may alternate. In children fever is often present. The attack does not always follow the type above described. Very rarely it may consist of some of the various sensory disturbances described, M'ith very little or no pain ; or of that which is the most common of all forms — i. e., headache asso- ciated with vaso-motor disturbance, nausea, and vomiting. These attacks occur from two weeks to a month apart. Patients with migraine sometimes suffer from vertigo in the intervals. Pathology : Migraine possesses no morbid anatomy. It is probably due to periodical " discharges" from the sensory centres of the cortex, similar to the discharges which occur from the motor centres in epilepsy. The relationship between epilepsy and migraine is very close. In those instances in which diminished function (paresis, hemianopsia) occurs there is cortical inhil/ition preceding the discharge. Diagnosis : The distinctions between migraine, headache, and neuralgia have already been mentioned (p. 80). Those cases in which there are disturbances of special senses with- out headache closely resemble minor epilepsy with a visual or other special sense-aura. But epilepsy is of very brief 84 SYMPTOMATIC DISORDERS. duration — a few seconds — while the disturbance in migraine lasts twenty to thirty minutes. Epilepsy and migraine may coexist. Prognosis : As regards life the prognosis is good. As re- gards ultimate recovery it is not so good ; but there is a tendency for the attacks to diminish in the second half of life (the menopause in women). The prognosis is better when a history of heredity in this or other neurosis is not obtained. It is also more favorable when the disease is of recent development. In the majority of cases much can be done by appropriate measures to ameliorate the symptoms. Migraine — treatment : Frojjhylaxis is of importance. The children of families in which this or other neurosis exists should be carefully watched. All possible sources of reflex irritation (eye, nose, digestive organs) should be avoided or removed. Excessive mental and physical strain must be avoided, and an outdoor and regular life encouraged. Treatment may be divided into that of the attack and that of the disease. For the attack, rest in bed in a darkened room as soon as the premonitory symptoms appear, must be enjoined. If possible, the stomach should be washed out with hot water (105° F. or more). If this cannot be done, large quantities of hot water should be drunk. After this a saline cathartic, as a teaspoonful or two of Carlsbad salts, should be adminis- tered, the action of which may be hastened by a hot soap-and- water enema. Combined with these measures antipyrin, phenacetin, acetanilid, caffeine, the salicylates, and ergot, and the various local measures may all be tried, as recommended for headache. In addition, mild galvanic currents applied to the head and static sparks are sometimes of benefit. In treating the disease all possible sources of reflex irrita- tion must be removed ; the gastro-intestinal tract put in good condition ; and the diet must be simple, red meats aud fermen- tative articles being avoided. Of drugs, long-continued courses of cannabis indica to point of toleration are most successful. This may be combined with arsenic ; or, if there is a gouty diathesis, with ammonium salicylate or some of the salts of lithia. Either phospliate of sodium or Rochelle salt in water before breakfast is also of service. Combined with the use NEURALGIA. 85 of these drugs, should be tlie measures detailed under pro- phylaxis. NEURALGIA. Definition : Neuralgia is a functional disease of the sensory fibres of the nerve-trunks, and is characterized by pain (Sinkler). Forms : Neuralgias may be idiopathic — /. e., developed " spontaneously " ; or symptomatic — /. e., due to some known cause. According to their location, they are divided into : tri- geminal, or neuralgia of the fifth nerve ; sciatic ; intercostal ; cervico-occipital ; brachial ; lumbo-abdominal ; crural ; and visceral. Trigeminal, sciatic, and intercostal are by far the most frequent. Etiology : Neuralgia is a disease of adults, being rare in childhood and old age. Those possessing a neurotic consti- tution or a gouty or rheumatic diathesis are especially prone to it. It is more common in cold and damp climates, and in winter than in summer. The exciting causes of symptomatic neuralgia are exposure to cold ; toxsemias, as grippe ; uraemia ; gout ; rheumatism ; malaria ; diabetes ; lead and other metal- lic poisons ; anaemia ; debility from any cause ; reflex irrita- tions, as eye-strain, carious teeth, and gastro-intestinal de- rangements ; neurasthenia and hysteria. Neuralgia — symptoms : These consist of paroxysms of sharp, shooting, burning pain in the course of the affected nerve. In the intervals between the paroxysms there may be constant dull pain. The pain is increased or brought about by irritation, as by cold, heat, or pressure. There is frequently hyperesthesia in the region of the affected nerves ; but firm, long-continued pressure may give relief. In some cases tender points may be found which correspond to the exit of the nerve from a bone-canal or from the muscle or fascia (points of Valleix). Vaso-motor, secretory, and trophic disturbances may occur. Frequently the paroxysms may re- cur at the same time each day. Now and then we meet with a hysteric in Avhom a painful impression remains after the true paroxysm has passed away ; this is called " reminiscent " or " hallucinatory " neuralgia. Pathology : In many cases of so-called neuralgia there is 86 SYMPTOMATIC DISORDERS. really a low-grade neuritis. This is especially true in the trigeminal and sciatic forms. In those cases due to toxEemias the pain is probably due to the irritant action of the poison. That due to anaemia is often spoken of as " the cry of the nerve for more blood." In those cases in which no cause can be traced the trouble is thought to be due to some derange- ment of cells constituting the spinal or cerebral sensory neurons. Cases ^ occurring late in life have been found to be asso- ciated with arterio-sclerosis. In a number of Gasserian gan- glia and the nerve-divisions which were removed by Keen for tic douloureux, Spiller found there were in most instances marked evidences of degeneration of the nerve-fibres and ganglion-cells, and thickening of the vessel-walls, so that in some instances their lumen was obliterated (obliterating ar- teritis). Diagnosis : We have already spoken of the features which distinguish neuralgia from headache (p. 80). The diagnosis from neuritis would depend upon the facts that in newitis the pain is constant, not darting and shifting ; there is tenderness along the whole course of the nerve, made worse by firm pressure ; there is frequently anaesthesia, and motor paralysis occurs. The various forms of neuralgia will be discussed under diseases of the " cranial and spinal nerves," when treatment will also be discussed. PARESTHESIA. Definition : The general term " parsesthesia " has already been defined (p. 43). These sensations sometimes confine themselves to a certain locality or occur in the distribution of a certain nerve, and may be then considered as a disease. When the feet and hands separately or together are affected we call the disorder acroparcesthesia ; when it only occurs upon rising in the morning, we speak of wahing-numhness ; and when confined to the distribution of a particular nerve, as the ulnar or external cutaneous, meralgia paraesthetica is the term used. 1 Amer. Jour. Med. Sci., 1898, p. 503. PARESTHESIA. 87 Etiology : Par?estlicsia may occur in citlier sex, usually after middle life; but is more common in women, being especially frequent in women during the menopause and in those who do scrubbing, Avashing, and sewing. Those of either sex who are obliged to be upon their feet a great deal are prone to it. The gouty or rheumatic diathesis and alcoholism are causes. It has followed the infectious diseases. Parsesthesia — symptoms : These consist of feelings of numb- ness, tingling, or coldness, usually beginning in the hands, and as time goes by the arms, feet, and legs becoming in- volved. These symptoms are often felt just after aAvaking in the morning, and pass oif as the limbs are used (w-aking- mimbness) ; but if the disorder lasts long enough, the sensa- tions become constant. They may be so severe as to awaken the patient. The scalp and ears may rarely be affected. Cases have been described by Roth, Osier, and others in which a burning sensation was felt in an area about the size of the palm of the hand or the external surface of the thigh and just above the knee (parsesthetic meralgia). This form is aggravated by standing. There is usually no muscular weakness or anaesthesia, but a clumsy feeling may be present in the fingers, so that fine movements are performed with difficulty. In tvaking -numbness there is sometimes temporary weakness. General restlessness and nervousness are usually present. The urine may be excessive in amount and contain large amounts of urates or phosphates. Vaso-motor symptoms, character- ized by local congestions and sweating, are sometimes seen. Pathology : Parsesthesia is probably due either to a poison circulating in the blood, which irritates the sensory nerve- endings ; or to a disarrangement of the blood-supply to the nerves, either hypersemia or anaemia. In some cases there is most likely a low grade of neuritis. Paraesthesia — diagnosis : The condition must be distin- guished from neuritis ; organic disease of the brain and cord ; hysteria ; neurasthenia ; and Raynaud's disease. There is no tenderness of the nerve-trunks, muscular paralysis and atrophy, or anaesthesia, which we find in neuritis. Paraesthesia may be a symptom of organic disease of the brain, cord, and peripheral nerves ; of neurasthenia and hysteria ; but when 88 SYMPTOMATIC DISORDERS. present in any of tliese conditions, other symptoms character- istic of the disorder would be found, and the paresthesia would not be limited in distribution and constant in duration as in the forms we have described, but diffuse and temporary. Raynaud's disease is cliaracterized by extreme pallor of the affected parts, followed by congestion, symptoms which are not present in paresthesia. Prognosis : The disease is obstinate to treatment, and re- lapses are apt to occur ; it does, however, often get well. It never progresses to any serious disorder. Parsesthesia — treatment : Ergot in large doses, long con- tinued, as recommended by Sinkler, often does good. Fara- dization and massage of the affected limbs are of service. In those cases in which the gouty or rheumatic diathesis is sus- pected, salicylates, lithia, alkalies, and a proper diet should be advised. Tonics, as strychnine, arsenic, mineral acids, and iron, must be given after the symptoms subside ; and a change of air and rest, if practicable, be secured. In ob- stinate cases of meralgia paresthetica, stretching or resection of the external cutaneous nerve has been suggested by Spiller. VERTIGO. Definition : Vertigo, familiarly spoken of as giddiness or dizziness, is the consciousness of disturbed equilibrium due to a derangement of the nervous mechanism which governs the relations of the body to external objects. Pathology : For the securing of the balance or equilibrium of the body in its changing relations to external objects, ac- curately timed and ever-changing muscular contractions are necessary. The motor impulses necessary to cause these contractions are determined in the cortical centres by certain sensory impressions which are constantly being received for their guidance. These impressions are derived from the eye and its muscles ; the semicircular canals of the internal ear ; from the skin of these parts in contact with external objects ; and from the articular surfaces and muscles about them. Any cause which disturbs either the flow or reception of sensory impulses from these sources causes a derangement in time and force of the motor impulses. This is manifested by VERTIGO. 89 vertigo. The nausea, vomiting, and irregular pulse are due to reflex irritation of the vagus nerve. Etiology : The eauses of vertigo are : (1) Visual defects, as refractive errors and loss of muscle-balance. (2) Aural dis- turbances, as either disease of the labyrinth (Meniere's disease) or inflammatory conditions of the middle ear, causing irritation of the auditory nerve-endings in the labyrinth. (3) Toxa^nic conditions, as at the onset of infectious diseases ; alcohol, tobacco, lithsemia, dyspepsia, constipation. (4) Causes which produce derangements of the cerebral circulation, as arterio- sclerosis, hypersemia, anaemia, valvular disease of the heart, and fatty heart. (5) Neuropathic conditions, as neurasthenia, hysteria. (6) Organic disease of the brain, especially of the cerebellum and its peduncles. (7) Mechanical causes which produce disarrangement of the fluid in the semicircular canals, as swinging ; sea- voyages (sea-sickness); rotary movements, etc. In a few cases no cause can be detected ; these are known as " essential vertigo." General symptoms: An attack of vertigo comes on sud- denly, and as a rule is of momentary duration. Objects seem to whirl about the patient ; the floor or bed rises or sinks (objective vertigo) ; or the patient himself feels as if he were whirling rapidly about (subjective vertigo). There is apt to be mental confusion, but rarely loss of consciousness ; the patient totters and sometimes falls ; there may be nausea and vomiting, and irregular pulse often occurs in severe attacks. In attacks due to toxic substances, as alcohol, tobacco, and other narcotics, the vertigo is apt to last a considerable time. Sudden rising or other movements may increase the vertigo. Attacks may sometimes be produced when the head is held in certain positions. Auditory vertigo deserves special mention : Auditory vertigo : Inflammatory conditions of the middle ear or impacted cerumen in the canal may produce vertigo. They possibly do this by causing irritation of the auditory nerve-endings, and in some instances by the pressure of the stapes upon the labyrinthine fluid. These forms must not be confounded with Meniere's disease, which is due to primary disease of the in- ternal ear involving the end-organs of the eighth nerve in the labyrinth. The lesion in chronic cases may be caused by 90 SYMPTOMATIC DISORDERS. exposure to cold, gout, or syphilis ; or to atrophy of the audi- tory nerve. Some of the acute cases are due to hemorrhage. The affection is rare in early life. The patient suffers from deafness of nerve-origin ; tinnitus ; and paroxysms, oc- curring at regular intervals, of intense vertigo. The erect posture is impossible, and the recumbent position even does not relieve it. The paroxysm is usually terminated by nausea or vomiting, and sometimes syncope. The paroxysms may occur daily, or weeks may intervene. The acute or apoplectiform attacks begin suddenly with tinnitus and paroxysms of vertigo as just described. In the intervals there is apt to be impairment of equilibrium, so that the patient walks with difficulty. The prognosis is uncertain. A small proportion of cases may recover with total loss of hearing on the affected side. In the majority of instances the disease, with intervals of improvement, continues through life. Vertigo — diagnosis : The presence of the symptom usually may be recognized without difficulty. In some instances the possibility of the attack being due to epilepsy in the form of petit mal must be considered. In this, however, loss of con- sciousness can always be discovered ; the attack is of shorter duration ; and giddiness, nausea, and vomiting are not pres- ent as in vertigo. The cause must always be determined if possible. This is done by a careful physical examination of the heart, eyes, ears, bloodvessels, etc., of the patient and inquiry into the associated symptoms. The possibility of epilepsy must be borne in mind. The prognosis depends upon the cause. If that can be corrected, it is good. In that due to organic brain disease or Meniere's disease, it is, of course, not favorable. Treatment : The treatment of vertigo consists of (1) that of the attack ; (2) that of the cause. The attack is best treated by rest in the recumbent position, and the administration of aromatic spirits of ammonia and the bromides. In 3fSniere's disease quinine in ascending doses until cin- chonism results, when the drug is stopped for a time (Char- cot). Or the use in moderate doses of the salicylates may be tried. Sinkler recommends the long-continued use of ergot INSOMNIA. 91 and cannabis indica. The continuous use of the bromides and the hypodermatic injection once daily (Hirt) of ten drops of a 2 per cent, solution of pilocarpine have been of service. Vertigo due to either arterio-sclerosis or senility is bene- fited by nitroglycerin and potassium iodide. The treatment of the other forms consists of the removal of the cause, when possible. INSOMNIA. Definition : Insomnia is the term used to designate a condi- tion characterized by habitual incomplete sleep, or by periods of entire absence of normal sleep. Etiology : The physiology of sleep is not well nnderstood. It has been found that during sleep there is ansemia of the brain accompanied by dilatation of the bloodvessels of the limbs ; but as anaemia from disease does not canse an excessive desire for sleep, it is evident that this is not the cause. Wil- cox advances the view of Rabl-Ruckhard that sleep is due to a retraction of the dendritic processes of the neuron, which, of course, would prevent for the time being communication between the different parts of the nervous system and inter- change of nerve-impulses. Symptomatology : Insomnia may be a symptom of any of the organic and functional diseases of the nervous system. It is especially common in the neurasthenic and overworked. It is also a symptom of disordered action of other organs — viz., in toxic states of the blood from infectious disease ; kidney diseases ; lithsemia ; or drugs, as tea, coffee, alcohol ; and in diseases of the heart and bloodvessels. Its prolonged presence causes mental depression and irri- tability. Insomnia — treatment : Treatment should, of course, be directed to the cause of the symptom when it can be ascer- tained. In treating insomnia drugs should be avoided when possible. Often one of the following measures, used before retiring, will answer : muscular exercise ; massage ; a cup of hot milk or bouillon ; or a hot bath (104° F.), continued until the cuta- neous surface is reddened. A season of camp-life may bring relief when all else fails. 92 SYMPTOMATIC DISORDERS'. When drugs are required, one of the best is trional, gr. XV— XXX in hot milk, an hour or two before bedtime. Chloral, gr. XV— XX, or by the method of Ringer, gr. v every half- hour until four or five doses are taken, is of much service. Sulphonal, paraldehyde, and chloralose are also of use. When accompanied by excitement or agitation hydrobromate of hyoscine, gr. yq-q, repeated every four hours as required, is most useful. Opium should never be prescribed for in- somnia unless caused by pain. To avoid the formation of drug-habits, whatever drug is used, it is well, if possible, to prevent the patient from either knowing what it is or being able to renew the prescription. CHAPTER VI. DISEASES OF THE PERIPHERAL NERVES. COMPRESSION- OR PRESSURE-PALSY. Definition : Pressure-pulsy is a paralysis of certain muscles clue to long-continued pressure upon tiie nerve supplying them. Symptoms : When a nerve-trunk is subjected to slight pressure, if long continued, numbness, tingling, and a feeling of heaviness, and at times transient inability to move the limb are experienced. These sensations are familiar to all, and are commonly described by saying that the part is "asleep." When the pressure is more pronounced or of longer duration the symptoms do not pass away, and a paralysis of the muscles supplied by the compressed nerve results. The musculo-spiral, from the frequent habit of sleeping with the head resting upon the arm, is especially liable to receive pressure, and is the nerve most commonly affected. A history of previous indulgence in alcohol is fre- quent in these cases. Other nerve-trunks that are more or less commonly affected are the ulnar, sciatic, and anterior tibial. The patient complains of a feeling of numbness and inability to use the muscles. There is no tenderness over the nerve-trunk, and usually no anaesthesia. Atrophy takes place, but it is not excessive as a rule. The electrical reac- tions are either normal or in aggravated cases there is a quantitative decrease to galvanism and faradism. Pathology : The compression, in producing these symptoms, acts by separating the molecular elements of the white sub- stance, and setting up a secondary degeneration of the same character as results from the division of a nerve (Gowers). The diagnosis of pressn re-palsy is based u])()n the discovery that pressure, as from crutches, sleeping with the head upon 93 94 DISEASES OF THE PERIPHERAL NERVES. the arm, etc., has been exerted upon the nerve. The absence of pain and tenderness distinguishes the condition from neu- ritis. When the musculo-spiral nerve is the seat of the trouble neuritis due to lead might be thought of; but the absence of other symptoms of lead-poisoning and the usual unilateral paralysis distinguish it from that. Pressure-palsy — treatment : Measures to promote the nutri- tion of the muscles, as electricity, massage, and strychnine, either hypodermatically or by the mouthy are indicated. NEURITIS, OR INFLAMMATION OF NERVES. Neuritis may be confined to a single nerve-trunk and be local ; or a number of nerves may be affected, when it is termed multiple. It may be interstitial or parenchymatous. It may be either acute or chnmic. The acute form often has a tendency to subside into the chronic. Morbid anatomy : Inflammation of a nerve may be inter- stltialy in which the connective tissue is the primary seat of the process ; or parenchymatous, wlien the nerve-fibres are dis- eased without involvement of the connective tissue. In acute interstitial neuritis the changes occur in the peri- neurium and endoneurium. The nerve is soft, swollen, and reddish in color. Microscopically we find the bloodvessels distended ; infiltration of round cells between the nerve-bun- dles ; and the perineurium and connective-tissue trabeculse are increased in size. In very advanced forms partially de- generated fibres, with flitty myelin-sheaths, and swollen axis- cylinders, are found ; ultimately the nerve-fibres may be de- stroyed. The changes in the nerve-fibres are secondary to those in the connective tissue. Chronic interstitial neuritis may follow the acute form or occur independently. The nerve is hard, the connective tissue increased ; the bloodvessel-walls are thickened, their lumen sometimes obliterated ; and more or less round-cell in- filtration is found in the connective tissue. The nerve-fibres are degenerated, and many of them have disappeared. Fre- quently there is proliferation of the cells in the neurilemma. Ascending degeneration in the ]>osterior columns of the cord and changes in the o;ano'lion-cells are often found. LOCALIZED NEURITIS. 95 In parenchymatous neuritis we lind the nerve-trunks slightly firmer and grayer than nornial. The usual evidences of inflammation are absent ; the myelin is segmented and divided into drops and granules ; and the axis-cylinders are granular, subdivided, and finally disLip])ear. The nuclei on the sheath of Schwann proliferate, and finally the nerve be- comes a fibrous cord. Changes are frequently found in the anterior ganglion-cells in the cord (reaction at a distance). Localized Neuritis. Etiology : Localized neuritis arises from : (1) Exposure to cold. (2) Traumatism, as wounds ; blows upon the nerve ; the tearing: and stretchino- v.diich follow a dislocation or fract- ure ; and electrical shock. (3) The extension of inflamma- tion from neighboring parts, as neuritis of the facial nerve due to inflammation of the middle ear ; septic wounds of the extremities, etc. Localized neuritis is usually interstitial. Localized neuritis — symptoms: Slight constitutional dis- turbances may be present. A most prominent symptom is pain in the course of the nerve and parts to Avhich it is dis- tributed. This is of a burning, boring character, worse at nights and increased by movements of the atfected part. The nerve is tender when pressed upon. Occasionally redness of the skin over it and ojdema are present. The function of the muscles supplied by the affected nerve is impaired, and they become flaccid and finally atrophy. Changes in their response to the electrical currents, varying from a quantita- tive decrease in mild cases to a typical DeR, are found. At the onset muscular twitchings are sometimes noticed. Vari- ous parsesthetic sensations are experienced. Hypersesthesia may be present, and after a time sensation may be lessened, or total anaesthesia in small areas is found. The skin be- comes atrophied and glossy, or more rarely thickened, and the nails are ridged and brittle. Increased perspiration has been observed. These symptoms vary in severity according to the acuteness of the process. Constitutional s}'mptoms are absent in subacute and chronic cases, the pain and tenderness usually are not so severe, and 96 DISEASES OF THE PERIPHERAL NERVES. ill tlie latter, when it does not follow an acute attack, the development of the symptoms is gradual. In these, contract- ures due to overaction of sound muscles may develop. When the inflammation is confined to the connective tissue and there is not much exudation, the function of the nerve- fibres is not much impaired. In these cases pain and ten- derness may be the only symptoms noticeable, but careful examination will also show some flaccidity and weakness of the muscles. The inflammation, especially Avhen due to traumatism, at times may extend up the nerve-trunk and involve other nerve-trunks in communication with it. At times the spinal cord may be reached and meningitis or myelitis, or both^ be produced. This is known as ascending 'neuritis. The duration of a neuritis may vary from a few" weeks in mild cases to months and even years. Traumatic neuritis is .especially liable to become " ascending." Localized neuritis — diagnosis : From the ordinary rheu- matic attack localized neuritis is differentiated by the local- ization of the pain and tenderness to the course of a nerve, and the impairment of function of the muscles supplied by this nerve. In this connection it must be remembered that in very acute attacks the pain may be diffuse and the muscles tender ; but investigation of the nerve-trunks and the quickly resulting muscular disability and atro^^hy will settle the question. Chronic neuritis, especially those mild cases in which the motor symptoms are not marked, may be mistaken for neu- ralgia ; but in neuritis pain and tenderness of the nerve are constant ; in neuralgia the pain is darting and paroxysmal, and tenderness, when present at all, is so only during par- oxysms and is confined to spots of definite localization (tender points of Valleix). In neuritis there is usually some degree of weakness and flaccidity of the muscles ; in neuralgia there is none. The pains due to some cord-diseases may simulate neuritis ; but there are not local tenderness of the nerve and limitation in distribution to a single nerve. Prognosis: This is always doubtful. Apparently mild cases are often intractable to treatment. The gravest forms are LOCALIZED NEURITIS. 97 those due to secondary infection from a local suppurative in- flammation. As the symptoms are more intense, especially the evidences of neural degeneration as seen by muscular atrophy and well-marked DeR, the prognosis becomes worse. In neuropathic subjects the pain is apt to remain even after all other symptoms have vanished. Ascending neuritis is always most obstinate. Localized neuritis — treatment : In acute neuritis rest of the part where the inflamed nerve is situated is of first impor- tance. For the relief of pain antipyrin, phenacetin, and like drugs can be administered and the part wrapped in hot lead- water and laudanum or other hot applications. Care must be taken not to blister the skin with these, as troublesome sores may remain. If the patient is gouty or rheumatic, salicy- lates in full doses should be administered. In the author's experience one of the most efficient means for the relief of pain is the passage of a constant galvanic current down the course of the nerve for ten or fifteen minutes daily. In some cases this may aggravate the pain, when it should be discon- tinued. After the more acute symptoms have subsided, vigorous counterirritation by means of fly-blisters or the cautery should be substituted for the lead- water and laudanum. In this stage the use of the extreme dry heat (250°-300° F.), applied by an apparatus devised for that purpose, is useful. When the acute stage is past or has subsided into the chronic, in conjunction with counterirritation, measures to promote the nutrition of the muscles — viz., massage, elec- tricity, and strychnine, preferably hypodermically — must be employed. In ascending neuritis vigorous counterirritation should be maintained above the area of inflammation ; and the question of resection of the nerve or even amputation above the seat of inflammation may sometimes have to be considered. Neuritis of some special nerves may demand some modifi- cation or addition to this treatment, which will be described when we describe the diseases of these nerves. 7— N. D. 98 DISEASES OF THE PERIPHERAL NERVES. Multiple Neuritis. Etiology : Multiple neuritis is probably always due to the influence of a poison circulating in the blood ; although in some cases we may be unable to determine its nature. These causes are expressed in the following table, modified from that of Ross : I. Idiopathic form (due to an unknown poison) : a, acute; b, subacute ; c, chronic form ; d, recurrent. II. Poisons introduced from without: a. diffusible stimu- lants — alcohol ; carbon monoxide ; carbon bisulphide ; dinitro- benzine ; aniline, b. Infectious diseases: diphtheria; influ- enza ; typhoid fever ; scarlatina ; measles ; pertussis, etc. ; septicsemia ; syphilis ; tuberculosis ; pneumonia ; malaria ; beri-beri ; leprosy, c. Metallic poisons : lead, arsenic ; mer- cury ; phosphorus ; silver, d. Ptomains} III. Poisons produced ivithin the body : Gout ; rheumatism ; pregnancy and the puerperal state ; chorea ; diabetes. IV. The dyscrasic form : Chlorosis ; marasmus ; cancer and other forms of cachexia ; vascular degenerations. Multiple neuritis may occur at any age. Morbid anatomy : The inflammation in these cases is almost invariably of the parenchymatous variety. Multiple neuritis — symptoms : All of the causes above men- tioned do not produce similar symptoms. From some, sen- sory nerve-fibres especially suffer ; from some, the motor ; while from others both motor and sensory fibres are alike affected. Again, certain poisons seem to have a predilection for certain nerve-trunks ; for instance, that of lead for the musculo-spirals. For these reasons we have certain types due to certain causes, these types being sufficiently constant to enable us in many cases to be almost positive of the cause from the symptoms produced. Some of the causes mentioned are but rarely the cause of neuritis, both because the individual is infrequently brought under the influence of many of them, and because the nerves seem to be more susceptible to the toxic influence of some ^ Spiller (Phila. Polyclinic, vol. vii. p. 455) has recently reported a case of multiple neuritis due to the ingestion of putrefying pork. MULTIPLE NEURITIS. 99 than of others. Only the more common forms will be here described. Idiopathic multiple neuritis : This may occur at all ages from infancy to old age, the majority of the cases occurring during middle life. In some cases it appears to follow chill- ing of the body after being overheated or exposure to cold. In most of them no cause can be ascertained. The attack usually begins with a chill followed by rise of temperature, pain in the back and limbs, headache, and general malaise. Parsesthetic sensations are felt in the hands and feet ; the skin may be hypersesthetic and the muscles and nerves are tender. Loss of power soon becomes manifest. It usually begins in the flexors of the feet and extends upward ; more rarely the arms may be first involved. The paralysis extends until in severe cases the muscles of the trunk and those of respi- ration are involved. Atrophy of the muscles occurs early ; the deep reflexes are lost ; those of the skin may be present or not. In the early stages there is merely a more or less quantitative decrease in the response of the muscles to the faradic current. As the disease progresses partial reactions of degeneration may be found. There may or may not be areas of anaesthesia present. Recurrent multiple neuritis: In 1891 Dr. Mary Sherwood reported two cases in which, without apparent cause, the patients had had several attacks of neuritis. Since then a few others have been reported, the last being by H. M. Thomas, whose case was then in the fifth attack of multij^le neuritis. The symptoms of these cases are the ordinary ones. It has been noted that rarely patients who have had lead- neuritis, have recurrences without renewed exposure. No evidences of lead, however, were present in most of the cases reported as recurrent neuritis, and the cause of these attacks remains doubtful. Alcoholic multiple neuritis : Alcohol is a frequent cause of neuritis. It is more apt to occur in persons who drink steadily than those who indulge in periodical sprees. Women appear to be especially lialde. 100 DISEASES OF THE PERIPHERAL NERVES. The first symptoms are sensory disturbances, pain in the extremities, with pins-and-needles sensations, and a feeling of numbness. There is marked hypersesthesia of the calf- muscles. Muscular weakness soon appears, the extensors of the feet being usually first aifected, those of the hands soon following. Double foot-drop and wrist-drop are then pro- duced. The former is a most characteristic symptom of the Fig. 26. •in. Multiple neuritis. Double wrist-drop and double foot-drop (Lloyd). disorder (see Fig. 26). Eventually the other muscles of the limbs become paralyzed. The motor cranial nerves may be- come affected, and rarely the optic. The sphincters are not involved. Marked muscular atrophy soon ensues, and changed electrical reactions, from quantitative decrease to reactions of degeneration of varying degrees, are present. The knee-jerk is lost early ; the skin-reflexes are usually active. Severe pain is always present ; the nerve-trunks and muscles are exceedingly tender, the latter more so than in any other form of neuritis, and the skin is hypersesthetic. Trophic symptoms are rare, but glossy skin and roughening of the nails may occur. Excessive sweating is sometimes seen. In severe cases there are elevation of temperature, the pulse is rapid and weak, and the capillary circulation bad. Mental symptoms, evidenced by delirium, hallucinations, de- lusions of grandeur, confusion and loss of memory, are pres- ent, In most cases the mental symptoms do not resemble DIPHTHERITIC NEURITIS. 101 delirium tremens, but it should be remembered that it may coexist. When the patient becomes able to walk the gait is charac- teristic ; owing to the foot-drop the knees must be lifted high in order to clear obstacles — the so-called " steppage " gait. Incoordination may then be also a feature, and the disease is then sometimes known as pseudotabes. . Multiple neuritis from lead : This form is peculiar in that the musculo-spiral nerves are usually the first to be affected, causing paralysis of the extensors of the wrist and fingers (see p. 154). For some unknown reason the spinator longus and the extensor ossis metacarpi pollicis, also supplied by this nerve, escape. One arm, usually the right, may be affected first ; but the other soon follows, and the patient in a short time has a double wrist-drop, atrophy of the affected muscles rapidly occurs, and the reaction of degeneration in various degrees is present. The supinator longus, not being diseased, stands out prominently. There is usually neither pain nor tenderness. Rarely slight tenderness of the nerve- trunks and spots of anaesthesia may be found. The disease may remain limited to the musculo-spirals, or may spread to other nerves, causing paralysis of other muscles of the arm, especially the biceps and deltoid. The leg may be affected. The deep reflexes are absent. There is another type, not so common as the above, in which atrophy is first noticed in the adductor muscles of the thumb and intrinsic muscles of the hand (lumbricals and in- terossei), and the symptoms resemble in their progress those of progressive muscular atrophy (p. 222). In these cases there is involvement of the ganglion-cells in the anterior horns of the cord. Arsenical neuritis : It is important to remember that arsenic given in medicinal doses has caused neuritis. The symptoms consist of paralysis of the extensors of the arms and legs ; muscular atrophy ; pains of a shooting, darting character ; tenderness over the nerve-trunks, and frequently anaesthesia. Eruptions and pigmentation of the skin are often present. Diphtheritic neuritis : The paralysis usually makes its ap- 102 DISEASES OF THE PERIPHERAL NERVES. pearance during convalescence, but may occur in the midst of the attack. It begins in the muscles of the palate, evi- denced by a nasal voice and difficulty in deglutition and re- gurgitation of liquids through the nose. Inspection shows the palate to hang lower than usual, and that it is not elevated when the patient utters the sound " ah." In mild cases the paralysis may remain confined to this part. More usually it extends to muscles of the eyes, especially the ciliary, evidenced by impaired vision and loss of the power of accommodation. The arms and legs may then become affected. In 125 cases analyzed by GoodalP paralysis of the palate was noticed first in 83 ; of the ciliary muscles in 20 ; of the palate and ciliary muscles in 6 ; in 4, of the palate and lower extremities ; in 3, of the lower extremities ; in 2, of the muscles of the pharnyx ; and of the muscles of respira- tion in 2. In the remaining 6 cases the parts first affected were scattered, one case each, over various other parts of the body. When the limbs are affected the muscles soon become flaccid and atrophy, and the reaction of degeneration in various degrees is found. The knee-jerk is absent — in fact, it may be absent before other signs of paralysis are mani- fest. Sensory disturbances are most frequently absent. If present, they consist of numbness, tinglings, and ansesthesia. The heart's action is often rapid and irregular, due to in- volvement of the pneumogastrics. In rare instances there are incontinence of urine, and in adults loss of sexual power. Beri-beri, endemic neuritis, or kak-ke, is probably due to a spe- cific micro-organism. Diet appears to have considerable in- fluence in its production. Yorderman, a Dutch physician, has stated that those who eat white rice, that which has been de- prived of the pericarp, are much more liable to suffer than those who eat the red, from which it has not been removed. It is infectious and contagious, and is met with in epidemics in Japan, China, Philippine Islands, Ceylon, parts of India, and other tropical localities. It also occurs among sailors on ships carrying cargoes of sugar. Intestinal parasites have been 1 " Diphtheritic Paralysis," E. W. Goodall, M. D. Lond. ; Brain, p. 282, 1895. MULTIPLE NEURITIS. 103 found to be very prevalent in those suffering from beri-beri. It can be propagated by water. The symptoms are the usual ones of multiple neuritis — viz., pain ; tenderness ; muscular weakness and atrophy ; anaesthesia in varying degrees, associated with oedema ; a tendency to effusion into serous cavities ; cardiac disturbance ; and general malaise. In some cases the oedema and serous effusion are absent, and these cases are attended with exten- sive paralysis, even of the facial muscles, and excessive pain. In others the pain, tenderness, and atrophy are absent, the symptoms consisting of oedema, weakness, and loss of knee- jerk (moist variety). The pneumogastric, phrenic, and cardiac plexuses of nerves are apt to be affected, when death ensues. Degeneration of the peripheral nerves is found in the ordinary cases, while in the moist cases the phrenic, sympathetic, and vaso-motor nerves only are involved. Other forms of multiple neuritis : The remaining forms re- semble in their general features those just described. Multiple neuritis — diagnosis : There should not be any diffi- culty in making a diagnosis of multiple neuritis. The dis- eases most likely to be confounded with it are acute polio- myelitis, acute ascending myelitis, and locomotor ataxia. The differences between it and poliomyelitis are well shown in the following modification of the summary by Starr : Acute poliomyelitis. Sudden onset, with fever and development of paralysis in all the limbs, followed in from three to five days by subsidence of par- alysis, which remains in a few muscles of one limb ; or, if two are affected, the paralysis is rarely symmetrical. If the onset is sub- acute, four weeks are the duration of onset. The muscles are not tender. Sensory symptoms are rare, and when present soon sub- side. Multiple neuritis. Fatigue for some weeks ; then sudden onset and progress for two weeks with or without fever. Legs usually first affected, then arms, then body. The paralysis has no tendency to subside for some time (months). The limbs are affected symmetrically. Usually there are tenderness of the nerve-truuks and affected muscles, and pain, with areas of anaesthesia. 104 DISEASES OF THE PERIPHERAL NERVES. In acute myelitis the loss of sensation is complete, and be- gins at a well-marked line which extends around the body at the level of the cord-lesion and involves all parts below it. A girdle-pain is usually present. There is incontinence of urine and faeces, and bedsores develop. There is no tender- ness of the nerve-trunks. In loGomotoi' ataxia there are no muscular or nerve tender- ness, muscular weakness, nor atrophy, and the Argyll-Robert- son pupil can usually be found. Idiopathic multiple neuritis may be mistaken for Landry^s paralysis ; in this, however, there are but slight, if any, sen- sory symptoms, and no changes in the electrical reactions. The fact that the neuritis is due to alcohol can be deter- mined by the history of steady indulgence, although in women this may often be denied ; by the intense pain and muscular tenderness, especially of the calves ; by the peculiar distri- bution of the paralysis (extensors of both arms and legs) ; and by the frequent accompanying mental symptoms. That lead is the cause can be recognized by finding the blue line upon the gums, often a history of preceding lead-colic, and exposure to the poison ; the absence of pain and tender- ness ; and the paralysis first appearing in and often confined to the muscle supplied by the muscnlo-spirals, excepting the supinator longus and extensor ossis metacarpi pollicis. In musculo-spiral paralysis from other causes these muscles do not escape, and the trouble will be most likely unilateral. Diphtheritic neuritis is peculiar in the frequent absence of sensory symptoms, the muscles of the throat and eye being first attacked. When the muscles of the extremities are primarily paralyzed an attack of poliomyelitis might be sus- pected ; but the previous history of recent diphtheria, the symmetry and frequently progressive character of the par- alysis, and slighter changes in the electrical reactions which distinguish the neuritis, are not characteristic of poliomyelitis (see p. 207). It must be remembered also that there are other forms of palsy associated with diphtheria. As in other acute infectious diseases, sudden hemiplegia due to either thrombo- sis, embolism, or hemorrhage may occur. This form resembles cerebral hemiplegia from other causes (see Cerebral Palsies of Children). Diphtheritic paralysis may be accompanied MULTIPLE NEURITIS. 105 by a rapid and complete palsy of one or more of the cranial nerves, which is apt to be permanent, and is probably due to an acute inflammation of their nuclei. In cases of multiple neuritis which do not conform to the types above described, careful investigation must be made for the existence of any of the rarer causes mentioned. Multiple neuritis — prognosis : In patients previously healthy and in whom the heart or respiratory muscles do not become paralyzed, recovery is the rule. Before this is complete, months will usually elapse. Some muscles may never en- tirely recover, and then contractures are apt to result. Sen- sory symptoms always disappear first. Idiopathic, alcoholic, and diphtheritic neuritis are especially liable to a fatal issue, owing to the liability to involvement of the nerves supplying the heart and respiratory muscles. Multiple neuritis — treatment : When possible the cause should be removed. In alcoholics this must be done with caution, large doses of strychnine and other heart-tonics being substituted. Absolute rest in bed is essential, excepting in those cases due to lead, in which the arms are alone affected. For the relief of pain similar measures to those recommended for local neuritis may be employed. Owing to the depressing effects of the drugs recommended for this purpose, salicylates and others, they must be used cautiously, and strychnine or caffeine are advantageously combined with them. Morphine should only be used as a last resort. After the acute symp- toms have subsided, measures to increase the nutrition of the muscles are indicated, as massage ; causing muscular contrac- tions by electricity ; and tonics, such as strychnine in large doses, especially indicated in the alcoholic form. Cod-liver oil, iron, and small doses of bichloride of mercury or iodide of potassium may also be useful in this stage. The food dur- ing the acute stage should be easily digested and nutritious. Care should be taken to prevent contractions of the muscles. This may be done by passive movements and mechanical ap- pliances. Thus : foot-drop may be overcome by pads exert- ing pressure against the ball of the foot. If there is much hypersesthesia, measures to support the bed-clothing must 1)6 employed. CHAPTER YII. DISEASES OF CEANIAL NERVES. OLFACTORY NERVES AND TRACT. The functions of these nerves may be disturbed by dis- ease anywhere in their course, from their distribution in the nasal mucous membrane to their centres in the cerebral cor- tex (imcinate gyrus). This disturbance may be manifested in subjective sensations of smell, or parosmia ; increased sensi- tiveness, or hyperosmia ; and loss of the sense of smell, or anosmia. Parosmia : Hallucinations of smell are found in the insane, in whom the sensation is usually unpleasant ; in epileptics, in whom sometimes the aura may be represented by an unpleas- ant odor ; and in cases of tumor situated in the region of the cerebral centres for smell. Rarely, after head-injuries the sense is perverted, odors of different character appearing alike or the odor may be changed. Hyperosmia : This usually occurs in nervous, hysterical individuals. Anosmia : This may be produced by : (1) Affections of the " terminals " of the nerves in the nasal mucous membrane, with diseases of which it is commonly associated. This is the most frequent cause. (2) Lesions of the bulbs or tracts, which may be due to falls or blows ; caries of the cranial bones ; meningitis or tumor. The sense of smell may be lost in locomotor ataxia, probably due to atrophy of the nerves. (3) Lesions of the olfactory centres. In some cases the loss may be congenital, owing to the centres not being de- veloped. Tests for the sense of smell have been described on p. 49. OPTIC NERVE AND TRACT. The visual pathway : This commences in the rods and cones of each retina, the deepest layer of which gives origin to the 106 P'iG. 27. 1^4 t^t^™! r^^^PYe^g. The visual tract. The result of a lesion anywhere between the chiasm and the cu- neus is to produce homonymous hemianopsia. H, lesion at chiasm causing bilateral temporal hemianopsia ; N, lesion at chiasm causing unilateral nasal hemianopsia; T, lesion at chiasm causing unilateral temporal hemianopsia; SN, substantial niga of crus; L, lemniscus in crus ; RN, red nucleus; 111, third nerves. lor 108 DISEASES OF CRANIAL NERVES. optic nerves. These pass to the chiasm, where partial decussa- tion occurs, and each optic tract as it leaves the chiasm con- tains fibres " originating " in the retina of each eye. Each nerve therefore contains three fasciculi : (1) a bundle of direct fibres which comes from the external or temporal third of each retina and passes into the optic tract of the same side ; (2) a bundle of fibres which comes from the internal or nasal two-thirds of the retina, and at the chiasm passes into the optic tract of the opposite side ; (3) a bundle of fibres which proceeds from the macular region and, decussating, passes partly to the optic tract of the same side and partly to that of the opposite side (Fig. 27). After leaving the chiasm each tract passes backward, winding around the cerebral crus, and most of the fibres end in the anterior quadrigeminal body, the geniculate bodies, and the posterior part of the optic thalamus, or pulvinar. These constitute the primary optic centres, and are concerned in the movements of the eye and reflex movements of the iris and ciliary body. From these centres fibres arise which pass through the posterior part of the internal capsule, and, as the radiations of Gra- tiolet, pass to the region about the calcarine fissure in the occipital lobe. The angular gyrus is also connected with this region. In the calcarine region (primary cortical centre) of each side are represented the temporal third of the retina of the same side and the nasal two-thirds of the opposite side. Each angular gyrus (higher or secondary cortical centre) is, according to Ferrier,^ in relation with the macula of the opposite side. It has its highest development upon the left side. Functional Disturbances of Vision. Toxic amaurosis may occur in uraemia and in poisoning by lead, alcohol, and rarely quinine. Hysterical amaurosis : Complete loss of sight in one or both eyes may occur in hysteria. Amblyopia, however, is the more frequent condition (see Hysteria). Tobacco-amblyopia is caused by the excessive use of tobacco. The loss of sight is gradual and equal in both eyes. The ^ Wilfred Harris contends that the cortical centre for the macular region is in the cuneus. Brain, p. 360, 1897. OPTIC NEURITIS. 109 centre of the field of vision is particularly affected. Central scotoma (blind spots) are found for red and green. Changes in the fundus are frequently absent. A chronic neuritis of the orbital part of the optic nerve (retrobulbar neuritis) may develop. If the use of tobacco is persisted in, atrophy may occur. Retinal hypersesthesia is sometimes seen in hysterical indi- viduals. Optic Neuritis. Neuritis of the optic nerve occurs in two forms : first, in which there are distinct lesions at the intra-ocular end of the nerve (intra-ocular optic neuritis) ; and, second, those cases which are unassociated with such lesions (orbital optic neur- itis or retrobulbar neuritis). The^rs^ is the only form which concerns the neurologist. It is also known as papillitis. When there is great engorge- ment of the end of the nerve, so that it projects into the interior of the eye, the condition is spoken of as choked disc. Etiology : The mechanism of the development of papillitis is not well understood. The most probable explanation is that it is an inflammatory condition due to irritation of the nerve by infection of the subarachnoid by products from an intracranial lesion ; or by the action of toxic substances cir- culating in the blood. The most common intracranial cause is tumor of the brain. " Choked