Fatty degeneration is not an invariable consequence of the muscular paralysis. Even when it occurs, it is often not universal, and proceeds much faster in some bundles of fibres than in others.
The bones as well as the muscles become wasted. Their development and growth are retarded, and their density diminished.
Symptoms.—The attack is sudden, and the paralysis reaches its height at once, both hi distribution and degree. In many cases the child exhibits no symptoms of illness. He goes to bed to all appearance perfectly well. In the morning one or more of his limbs is found to hang loosely and to be motionless, otherwise he shows no sign of ill health. In quite young babies, who cannot walk, the loss of power may remain unnoticed for several days. In a second class of cases the symptoms are a little more marked. A child who has been put to bed in his usual health is seized in the night with fever. He cries and is very restless. In the morning more or less extensive paralysis is discovered. In a third class of cases the child is feverish and poorly for several days before the paralysis occurs, some times he is delirious,_ or he may have an attack of convulsions followed by stupor. In all cases, probably even in those where the symptoms are the least accentuated, there is some preliminary fever, but this may last only a few hours, and is often unnoticed by the attendants.
The paralysis is complete. It may be widely distributed, or may be limited to one muscle or a group of muscles. It may affect all four limbs; it may attack only the lower extremities ; it may assume the hemiplegic form and fix upon the arm and leg of one side ; or, again, it may settle upon one limb only—in such a case the right foot is said to be the part most frequently selected. In this form of paralysis the face' and parts sup plied by cerebral nerves are never affected, the intelligence, after the first onset, is never impaired, and control over the rectum and bladder, at any rate after the first few days, is never lost. Sensibility in the paralysed parts remains in every way normal ; there is no pain anywhere ; no rash upon the skin ; no tendency to the formation of sores or sloughs upon parts exposed to pressure ; no rigidity of the joints. The affected limb is
perfectly flaccid and painless, but also perfectly motionless. In some rare cases the onset of the disease has been said to be attended by pains in the back and limbs, and by hypermsthesia of the skin ; but these phenomena are not directly the consequence of the spinal lesion, and form no neces sary part of the group of symptoms which are held to ,,be characteristic of infantile paralysis.
The flaccidity of the paralysed muscles is accompanied by a loss of re flex phenomena and a diminution or complete disappearance of the nor mal contractility. This takes place early in certain muscles, so that in the course of a few days they may be found to respond faintly or not at all to faradic stimulation. While, however, the muscles have ceased to re act to the strong faradic current, they will still respond to slow interrup tions of the constant current. When contractions are obtained by this means in a muscle which has lost all faradic contractility the phenome non is called "reaction of degeneration." It implies that the muscle for the time is physiologically cut off from the influence of the spinal cord. Besides this, early signs are noticed that the nutrition of the limb is no longer efficiently maintained. The part is cold and often looks purple ; the pulse is smaller ; the fat becomes absorbed; the muscles waste ; the ligaments of the joints are relaxed and there is even a slackening of growth in the bone. These trophic changes are usually marked, and generally continue after apparent restoration of power in the affected limb.
The paralysis is at first complete and much more extensive than it afterwards becomes. After some weeks, or perhaps months, a partial re covery takes place in the muscles whose faradic contractility had not been entirely destroyed. Sometimes this restitution of motor power is perfect, and, except for the impaired nutrition in the affected limb, the child may seem to be well. More usually, however, certain muscles, or groups of muscles, still continue disabled ; and when the paralysis has thus limited itself, the parts which remain crippled are in most cases permanently use less.