following table shows the relation of the body-viscera to these headpoints and also to the body-areas :

TABLE SHOWING ASSOCIATED PAINFUL AREAS ON THE HEAD RELATED TO VISCERAL DISEASE IN THE BODY.

In like manner disease within the head and neck has its referred pain, associated tender area, and maximal point. They may be thus tabulated :

Brain disease presents pain of two varieties: First. When the meninges are involved there is a local pain and tenderness on pressure and percussion. Second. In conditions of intracranial pressure and disease of the brain proper there is superficial tenderness and the pain is widely distributed. In the second class of cases pain is usual in the brow, vertex, occiput, back of the neck and shoulder, and similarly distributed tenderness is common.

The descriptions of some pains by patients are classical and almost diagnostic. The lightning pains of tabes, the gnawing pains of rheumatism, the burning pains of neuritis, the girdle pains of spinal disease, the lead-cap pressure pain of neurasthenia, the pain under the breast and in the groin in hysteria, the daily recurring brow pain of malaria, and the nocturnal pains of syphilis have a significance quite their own. The circumstances under which pains occur often throw light upon their nature. Sciatica and lumbago are provoked by motion and allayed by rest. The head pains of eye-strain bear a distinct relation to ocular employment. Neurasthenic pains always increase under fatigue or depressing that is, exhausting-emotions. A pain that is practically circumscribed has a tendency to spread to associated organs and to neighboring areas after long duration, general depression, or the onset of any marked physical illness. It thus becomes generalized.

CHAPTER VII.

THE SPECIAL SENSES.

Sight. The eye presents many interesting and valuable symptoms in a wide variety of nervous affections. Its systematic examination should be a part of the case-taking in every instance.

The lids on the two sides may show a difference in the palpebral opening due to paralysis or spasm. Exact symmetry is the rare exception in health, but any marked acquired inequality, unless due to scars or local conditions, such as conjunctivitis, irritation, swelling, new growths, etc., implies some variation of muscular control or nerve-supply. A falling of the upper lid, or ptosis, is a common early symptom of tabes and syphilitic brain disease, while in a facial palsy an inability to close the lids is a marked sign. From the same cause the lower lid may be everted. An acquired prominence of the eyeball may greatly enlarge the palpebral opening. In exophthalmic goiter the lids frequently fail to follow the upward and downward excursion of the ocular globe. This is not entirely due to the protrusion of the eye, as it has been noted in the absence of this condition, and in some instances is congenital. In hysteria a condition often confounded with ptosis, but really an orbicular spasm, is sometimes encountered. Blepharospasm as a limited facial tic is a very common affection. Many states of brain and optic-nerve disturbance are marked by the closed lids of photophobia, which should not be confounded with that arising from inflammatory conditions of the lids, cornea, or iris.

Attention has already been directed to the reactions and reflexes of

the pupils. Irregularities in their outline or inequalities in size are to be carefully noted, but pupillary deformities from antecedent inflammatory processes or injuries followed by synechia must not be mistaken for perverted innervation. Paralysis of the pupillary muscles is iridoplegia; paralysis of the ciliary muscles-cycloplegia—is marked by the loss of the function of visual accommodation. They are usually found together, and then constitute ophthalmoplegia interna. Paralysis of the external muscles of the eye-namely, the recti, obliqui, patheticus, and the elevator of the lid—is denominated ophthalmoplegia externa.

The external muscles receiving their innervation from three sources, the third, fourth, and sixth cranial nerves, are very frequently involved singly or in groups. This gives rise to various deviations of the visual axes of the eyes or loss of power in directing them conjointly in some given direction, with resulting indistinctness of vision or complete double vision, diplopia. Rarely a monocular diplopia is encountered as a pure hysterical symptom, but it may be the result of defective curvatures in the ocular media, as in corneal deformities. The special examination to determine the muscle or muscles at fault in these squint conditions will be taken up under the consideration of the diseases of the cranial nerves distributed to the ocular apparatus. Great and unwarranted stress has been put by some enthusiasts upon a condition of a lack of balance among the extrinsic muscles of the eye, named heterophoria. Of much greater importance are errors of refraction and accommodation in myopia, hyperopia, and astigmatism. They are attended by conscious or unconscious efforts at clear vision, constituting a condition of eye-strain that may constitute an active source of nerve waste. Extreme and constant deviations from the normal control of the extrinsic eye muscles can, no doubt, act in the same way, but slight variations in conditions of ill-health are commonly the result and not the cause of such states. As the general state fluctuates, they correspondingly vary

for better or worse.

Vision can be readily tested by the types of Jaeger, and when seriously defective, by having the patient count fingers held in a good light against a dark background. Astigmatic error is roughly and quickly shown by the use of the numerous familiar charts for the purpose. For further details reference should be had to systematic works on the eye.

The ophthalmoscope is one of the most important instruments in the diagnostic outfit of the neurologist. An ability to readily examine the ocular fundus at the bedside or elsewhere is one of his most needful accomplishments. Familiarity with the normal ophthalmoscopic picture, supplemented by experience in recognizing vascular disturbances, choked dise, and atrophy of the optic nerve, will often render positive a host of otherwise obscure indications.

The visual field is the area over which objects are visible while the eye is fixed. In health its limits are tolerably uniform, being modified above and within by the brow and nose. In this field colors of objects are recognized by the normal eye at various distances and in a certain order from the fixed point upon which the gaze is directed. From without inward come white, blue, yellow, orange, red, green, and violet.

The form of the test-object is perceived before its color is apparent, as is shown by the chart (Fig. 24).

Fig. 24.-Normal visual fields for form and the various colors (after Souques). Form field unshaded. The blue field is inclosed thus ➖➖➖➖, the red field thus ++++, the green field thus +-+.

The visual field is peculiarly modified by various diseases. In pronounced hysteria we have usually a concentric uniform reduction of the field. The color-fields may be reduced almost to the fixing-point or entirely obliterated. Even more characteristic is a rearrangement of them so that the red field overlaps or completely surrounds the blue. The relation of red and blue is therefore to be remembered. In neurasthenia the fields are frequently much reduced, and fatigue conditions promptly increase their contraction. In well-marked cases the efforts put forth by the patient in responding to the tests may serve to greatly increase the reduction of the fields within a few moments. In tobacco and alcohol poisoning and other toxic conditions the fields are sometimes greatly contracted and present blind areas, or scotomata. Destructive diseases occurring back of the globe may cut off a portion of the field, producing hemiopia, scotomata, central blindness, concentric blindness, or blindness in a quadrant of the field, as the fibers or centers related to the given area are involved.

To test the field of vision a perimeter is of service, and, for accurate examinations and records, indispensable. Roughly it can be done by placing the patient opposite a fixed point on a bare black or dark wall, at the distance of eight inches. With one eye covered he is ordered to maintain his gaze unswervingly on the fixed point. A small white object preferably about a centimeter in diameter, is brought into the field from the periphery along various lines radiating from the fixed point and the spot marked at which it is first perceived by the patient. By joining a series of such points the outline of the field is constructed and the various color limitations are similarly defined by noting the distances at

which the color of the test-object is clearly recognized. Large blind spots may in this way sometimes be detected, the test-object being carried across the field to the fixing-point. The normal blind spot corresponding to the optic papilla must not be mistaken for a symptom of disease. More roughly still the field can be rapidly tested by facing the patient at a distance of about two feet. He is then directed to look you steadily in the eye opposite the one to be tested; that is, if the patient's left eye is under examination, he looks at the examiner's right. A small object is brought into the field of view in a plane midway between the patient and physician, and the distance at which it is recognized is noted. At the same time the examiner's own perception furnishes a check and measure to the test.

The subjects of Daltonism, or color-blindness, are congenitally defective in color perceptions. Some have complete achromatopsia, everything to them being probably of a neutral tint; others do not distinguish some elementary colors, as red from green; and others, again, fail to detect marked shades of the same color. This defect would modify tests of color-fields accordingly.

Hearing. The sense of hearing is most often modified by local conditions in the meatus and middle ear. Our usual problem is to determine whether the nerve-apparatus is impaired. To this end we note at what distance on either side the patient can hear a watch, remembering that in advanced years such high-pitched sounds are not heard so readily as lower tones, like those of the voice. If the watch is not heard through the air, the ear should be closed by pressing in the tragus with the finger and the watch brought into contact with the root of the zygoma, the mastoid process, the parietal bone, or the teeth. If it is now heard, the difficulty is presumably in the conduction apparatus, and not in the nerve. This can be confirmed by using a tuning-fork in Rinne's test. Set it in vibration and place the handle against the mastoid or zygoma, the meatus being closed. When no longer heard, unstop the ear and hold the still vibrating fork close to it. mal ear will detect tones through the air that do not reach it by boneconduction, but if there be obstruction in the external or middle ear, the bone-path will be the more acute. The formula is B. C. > A. C. or

The nor

B. C. A. C. If there is no recognition of high or low tones by boneconduction, the nerve-apparatus is undoubtedly diseased, or if with hearing greatly reduced A. C. > B. C. is still found, the probability is that the nerve is diseased.

Auditory hyperesthesia is occasionally encountered in acute cerebral meningeal conditions and in hysteria. Severe headaches, meningitis, and many cerebral affections are marked by dysacousia,-sounds producing discomfort, which may or may not be attended by real auditory hyperesthesia. In the relaxation of the tensor tympani muscle attending facial palsy low notes are heard with unusual distinctness, while those of high pitch may not be so clearly perceived as in health.

Subjective sounds, varying from an insignificant tinnitus to pronounced and formulated auditory hallucinations or loud explosions in the head, are referred to with great frequency by nervous invalids. Their starting