This report concerns 100 patients treated by prefrontal leucotomy. The technique employed has followed that of Freeman and Watts.

In the case of the 47 manic-depressive patients treated the prognosis without operation was considered very poor. The majority (34/44) had failed to respond to electric convulsive therapy, which was contra-indicated in the remainder by reason of physical health. Seven out of these 47 cases had been in hospital under two years, but there was a history of many years' poor social adaptation or recurrent mental illness. The average duration of illness in the recovered cases of this manic-depressive group was 31 months. That of the failures 45 months.