It has been our good fortune during the last three years to follow the course of many cases of the postencephalitic parkinsonian syndrome; the majority of the patients have been young people of the poorer class; the minority, older people in better circumstances. We have, however, found very little difference in the course of the disease in either.
In the parkinsonian syndrome occur the typical lesions of encephalitis, perivascular cell infiltration, hemorrhages, exudation, areas of degeneration, and destruction of nerve cells. These lesions occur in many and diverse parts of the central nervous system, but the basal ganglions bear the brunt of the attack. There is also an atrophy and reduction in the number of cells, together with a depigmentation, of a particular part of the brain; namely, the substantia nigra.
There have not been a large number of necropsies performed in cases of the parkinsonian syndrome. We were surprised