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function, the sensitiveness to painful and thermic stimuli is blunted, and optic atrophy may make its appearance.

3. Paralytic Stage. The interval between this and the preceding stage is also variable. The ataxia gradually increases, and can even be noticed as the patient moves about in bed, the gait becomes more and more pareticataxic, and finally walking becomes impossible. As a rule, there is never a true paralysis.

The disturbances of sensation and of the bladder function increase.

The lancinating pains are constantly present and periodically culminate in the so-called tabetic crises, consisting in intensely painful attacks of colic, vomiting, cough, and dyspnea (abdominal, gastric, laryngeal crises, etc.).

cases.

Effusions into the joints, arthropathies (trophic ?), and ulcerations (mal perforant) are common. Not infrequently paralysis of the eye muscles and of the trifacial nerve and hemicrania-like conditions occur early in the disease. The diagnosis of tabes presents no difficulty in ordinary It may, however, be obscured by an atypical mode of onset and by the absence of important symptoms, such as the pupillary reflex, and the abolition of the patellar reflex. Alcoholic and diabetic neuritis and hereditary ataxia must be excluded. The differential diagnosis from these conditions will be discussed under their respective heads.

Treatment. The value of antisyphilitic treatment is doubtful. Baths, rest, massage, gymnastic exercises to correct the muscular incoordination, attention to diet, electricity, suspension; nitrate of silver, potassium iodid, secale cornutum, antinervin, narcotics.

14. Hereditary Ataxia (Friedreich's Disease).This is a combined system disease. The degeneration in the posterior columns of the spinal cord is accompanied by a similar process in the direct cerebellar tract and pyramidal tract. The cerebellum is probably also involved. The disease often appears in families.

It begins in early life, with a gradually increasing disturbance of the coordination in the movements and attitude of the extremities, trunk, and head; ataxia of the legs and arms-Romberg's phenomenon. The incoordination manifests itself in the trunk, both on motion and during rest, as when the patient is seated. The gait is vacillating, resembling the cerebellar gait, and the paresis is usually more prominent. In addition there are nystagmus, slight disturbances of speech, and some disturbance of sensibility and of the bladder function.

Diagnosis. The knee-jerk is abolished, but the pupillary reflex is normal—a differential point in the diagnosis from tabes. The neuralgic pains of tabes are also absent. The disease slowly progresses to a complete paralysis; contractures in the fingers are common. It lasts many years. Recovery has never been reported.

Treatment.-Symptomatic.

Other forms of combined system diseases similar to hereditary ataxia also occur, presenting in the main the symptoms of a spastic spinal paralysis with some disturbance of sensation and bladder function, combined with ataxia. This class includes a hereditary form of spastic spinal paralysis affecting the pyramidal tract, posterior columns, and lateral cerebellar tract, besides other varieties concerning which but little is known.

IV. DISEASES OF THE PERIPHERAL NERVES.

A. DISEASES OF SINGLE NERVES.

A great variety of causes may produce lesions of the peripheral nerves: Traumatism, tumors of all kinds (tumors in the soft parts, small exostoses in the bony canals, neuromata), cicatricial processes, chemic changes produced by the formation of toxic substances during the course of, or subsequent to, acute infectious diseases in which individual nerves may be injured-toxic neuritis. A spontaneous (inflammatory ?) affection of single nerves

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rheumatic neuritis-is also quite common, especially facial

neuritis.

In severe neuritic processes the nerve-fiber is completely destroyed and replaced by sclerotic connective tissue. In milder grades of the degenerative processes the nerves may be completely regenerated (parenchymatous neuritis), the nerve tissue differing in this respect from the tissues of the spinal cord. We distinguish various forms according to their severity.

1. The Diseases of the Motor Nerves.-Any of the above-mentioned lesions affecting a purely motor or mixed nerve may give rise to paralytic and irritative symptoms (localized muscular spasms) in the domain of the affected nerve. We distinguish three forms of paralysis: A severe, a moderately severe, and a mild form, depending on the duration, which in turn depends on the severity of the neuritic process.

For the details in the diagnosis the student is referred to the paragraph on Electric Diagnosis, Part IV, page

108.

The most frequent forms of paralysis are: Facial paralysis usually rheumatic-in middle-ear disease, due to a compression neuritis of the nerve in its course through the bony canal. Paralysis of the radial nerve, usually due to compression and occurring especially in narcosis, in paralysis of the fifth and sixth roots of the brachial plexus, by compression between the clavicle and the first rib during sleep, and in lead-poisoning; oculomotor paralysis -postdiphtheric; recurrens paralysis, due to compression by aneurysms or tumors; paralysis of the spinal accessory; paralysis of the brachial plexus during labor; paralysis of the median and thenar nerves from injuries.

For a detailed account of the symptoms of these and other possible paralyses consult Part IV, 3, page 97.

Of the localized muscular spasms produced by disease of individual peripheral nerves the more frequent are the following:

Spasm of the facial nerve, clonic convulsions of the entire musculature of one side of the face (tic convulsif). A partial form is represented by blepharospasm, or tonic and clonic convulsions of the eyelids.

Spasm of the muscles of mastication, or trismus, a tonic spasm usually central in origin.

Spasm of the spinal accessory,-spastic torticollis,— a severe tonic and clonic convulsion, frequently involving, in addition to the trapezius and sternocleidomastoid, the other nuchal muscles innervated by the cervical plexus (splenius, etc.). The latter group may also be attacked separately.

Clonic spasm of the diaphragm, singultus, spasm of the calf muscles (crampus sensu strictiori), and others.

The cause of these cramps is not by any means always a lesion of the peripheral motor nerves. In many cases they are reflex in character, as, for instance, in violent neuralgia, etc.

It is often very difficult to distinguish convulsions of central (psychogenic) origin from those due to peripheral irritation. The two causes may be at work at the same time and together produce the convulsions (predisposition due to central disease and peripheral exciting cause). The spasms that are to be interpreted in this way include fits of yawning, laughing, weeping, and shouting (see Hysteria), the saltatory reflex spasm (muscular contractions when the patient attempts to walk), multiple paramyoclonus (see Hysteria), also the so-called occupation neuroses which occasionally attack neurasthenic individuals and consist in disturbances of the coordination of certain muscles required for definite movements performed in the course of the patient's ordinary occupation, especially in manual work (reading, sewing, violin- and piano-playing, etc.).

Writer's cramp-mogigraphia-consists in uncontrollable spasms in the muscles of the hand and fingers, accompanied by tremors an kness and, occasionally,

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painful sensations. Continuous writing becomes utterly impossible (spastic paralytic tremor-like neuralgic form). The disability is increased by psychic emotion and fear, greatly as in stammering.

Treatment. The patient must stop writing at stated intervals and use a thick penholder (Nussbaum's holder). Cold sponging, massage, gymnastic exercises, electric treatment, bending of the arms, writing machine.

Note.-Occupation palsies similar to the occupation spasms and also associated with muscular atrophy are sometimes observed. Blacksmiths are attacked in this way in the small muscles of the hand; drummers in the extensor and flexor longus of the thumb; dairymen suffer a paralysis of the ulnar nerve, etc. Other forms of paralysis and spasms, as a rule, require no treatment in mild cases, although electricity and massage may be employed.

In the severe forms treatment is usually of very little value. Removal of the cause, gymnastic exercises, massage, baths, cutaneous irritation, actual cautery for spasms. (For psychic treatment see under Hysteria and Neurasthenia.)

same

2. Diseases of the Sensory Nerves.-The sa causes acting on sensory nerves produce either anesthesia in the area of distribution, representing the paralytic symptom, or violent radiating pains, representing the irritative symptom. The latter are more important than the former. These neuralgic pains, which occur in paroxysms, are not infrequently accompanied by paresthesia and by some disturbance of the sensibility in the affected portion of the skin. They develop most frequently after severe infectious diseases (malaria, influenza), or in other toxic diseases, such as diabetes, syphilis, gout, nephritis; in arteriosclerosis (sciatic nerve); as a result of mechanical injury (tumors, scars, neuromata). Acute spontaneous forms (neuritis?) may be accompanied by cutaneous affections, such as herpes zoster, urticaria, and erythema.

For the diagnosis of neuralgia it is necessary that the pain should correspond exactly to the area of distribution