The problem of estimating objectively the value of any new form of treatment is constantly presenting itself in all branches of medical work. In the case of shock therapy applied in the treatment of mental disease, the task is especially difficult. Standards of initial severity and degrees of improvement in mental diseases are subject to very wide interpretations. Disagreement on questions of diagnosis is common even among psychiatrists who employ the same terminologies. Thus, it is not surprising to find that widely divergent claims have been made about the value of shock treatment in mental diseases. In most of the large surveys, patients have been classified as (i) Recovered, (ii) Much improved, (iii) Improved, or (iv) Unimproved after shock treatment, but little unanimity about the results has emerged. In Table I, the figures given by Malzberg (1938) and Pollock (1939) for New York State and those for Ohio, given by Bateman and Michael (1940), are compared with figures obtained in a survey of the Ontario Mental Hospitals in 1941.