In considering the findings it is to be kept in mind that the point of interest is not the effects of the drugs on the series of cases, butthe study of the varying correlations in the four fields of enquiry as shown by the individual cases. A correlation was considered to exist whenever one of the other readings seemed to move concurrently and significantly with the behavior chart irrespective of the direction of the trend.On this basis it was found that the tests at the level of mentation gave the best correlations with the behavior chart, the mental tests being rather the more sensitive but requiring the behavior chart for their proper evaluation.The indirect tests gave less close correlation with the behavior chart. Their results were hard to evaluate as they were influenced both by the drug and by the improvement or deterioration in the patient's condition.The patient's own statement was the least reliable. Moreover, improvement was reported later than by the behavior chart, and in a qualitative manner, i. e., improvement in sleep was usually first reported, improvement in mood came very late and was rarely reported. This is an important point when one considers the extent to which our records rest upon the patient's statement both in checking up the course in hospital and in the anamnesis. The correlations between the reaction time and the test for perseveration were not sufficiently great to allow one to consider them as testing the same thing.On the basis of these findings I would suggest that with the aid of such a synthesis of methods and hierarchy of tests we are in a position to make more exact investigations into disorders than is at present possible by the various methods used alone.