.anxiety states, three schizophrenics, and one organic (manic-depressive with disseminated sclerosis). At the beginning of this study the pressor effect of the drug was studied as well as its central effects, and careful observations of the blood pressure and the mental state were made throughout the day. The blood pressure was taken each morning at 9 o'clock, in the lying and stand ing positions, the third reading being taken in each case. The drug was then given, the variations in dosage being concealed from the patient by using tablets of a neutral substance (calcium lactate) as well, so that the same number of tablets was given each time. The normal variations of the blood pressure in the individual were also determined. These observations presented nothing new, and will not be discussed further. After a time, there fore, we ceased to study the blood pressure alterations and devoted our interest entirely to the psychological changes, and it is these which form the main topic of this paper. After Davidoff and Reifenstein's (1937) excellent paper and a recent leading article on benzedrine in the British Medical Journal (1937) it is unnecessary to review the literature at length. The two main effects of this sym pathomimetic drug?the pressor and the central action? are now familiar. Its use in narcolepsy (Prinzmetal and Bloomberg, 1935 ; Ulrich, Trapp, and Vidgoff, 1936), post encephalitic Parkinsonism (Solomon, Mitchell, and Prinz metal, 1937), intestinal spasm and hence its employment in gastro-intestinal radiology (Myerson and Ritvo, 1936), as a vasoconstrictor in rhinology (Scarano and others, 1934), and its effect on the gastric juices (Myerson, Rinkel, and Dameshek, 1936), now require no further mention. A more recent non-psychiatric use is in orthostatic hypo tension (Korns and Randall, 1937), in which favourable results have been observed ; it seems, however, inferior to ephedrine in the treatment of this condition. Although containing a benzene ring no effect on the blood con stituents has been observed either at the time or months later (Sch?be, Raskin, and Campbell, 1937), although before this Myerson, Loman, and Dameshek (1936) had reported dramatic changes, including a polycythaemia in some cases, as well as a striking leucocytosis. It would appear that still further work on this problem is required in view of these observations. So far as its use in psychiatry is concerned there is fairly general agreement as to its effects ; the change of mood in the direction of elation, removal of inhibition, fatigue, and so forth call for no further mention, but before discussing the psycho logical effects in greater detail the present results will be considered. # The Present Investigation