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28 ACUTE POLIOMYELITIS

round-cell infiltration have also been found in the posterior horn and in Clarke's column (Parrot, Joffroy, Dejerine, Huet, v. Kahlden and Praetorius).

The sequelae of the initial destruction in the anterior horn are most evident: they consist of degeneration and atrophy of the intraspinal tracts, of the anterior roots of the motor nerves, and of the muscles.

Jagic, Bing and Mott have demonstrated by the Marchi method secondary degeneration in the antero-lateral and cerebellar tracts and in the posterior columns. The same changes can be seen in the anterior roots. The degeneration is followed by atrophy, which is usually well marked in the region of the antero-lateral tracts (Cornil).

The muscles, also, atrophy. Occasional hypertrophied fibers occur between the atrophied (Dejerine, Lovegren). Sometimes the muscle fat is increased.

Bing and Jagic were able to demonstrate in the pons, during the transition stage, morbid changes of slight extent. Eisenlohr observed in a doubtful case of several years' duration, a patch of sclerosis with degeneration of the ganglion cells in the facial nucleus.

Similar changes have been noticed in the brain: Lamy found, in addition to the usual changes in the spinal cord, four small sclerotic foci in the cortex of the left hemisphere, one in the parietal, the others in the frontal lobe. In Rossi's case, the remains of the encephalitic process were much more diffuse; part of the frontal lobe, the inner surface of the paracentral lobule on both sides, and the greater part of the corpus callosum were implicated.

In the cases reported by Sander, Rumpf, Colella and Probst, a flaccid paralysis of the extremities was associated with atrophy of the central convolutions. This cerebral atrophy was explained as secondary to the destruction of the peripheral neurons.