Harris (1951) adequately summarizes the work done on nitrile compounds and their therapeutic use in psychiatric disorder. This work is highly controversial and the results contradictory. He adds a series of thirty cases of his own treated with dinitrile succinate (“Suxil” or “Psychil”), and concludes that no clear evidence of its therapeutic value was obtained. Twenty of his cases were treated by six or less injections of 0.1 gm. for the first, and 0.2 gm. for subsequent injections. He says: “Later, following representations by the manufacturers, this was extended to twelve.” He also comments on the suggestibility of some of his patients and the high spontaneous remission rate which make assessment of the efficacy of therapy peculiarly difficult. As far as can be seen from his paper, the assessments were made entirely impressionistically. Our preliminary trials, confirmed by our further experience with this drug, indicated (in complete harmony with Harris's opinion) that the drug is “safe, easy to administer, and quite free from toxic effects in the doses recommended.” We felt, therefore, that a further experimental trial was indicated.