In discussing this theme before a scientific assembly it is needless for me to say that I make no claim to be the bearer of a new revelation, or the creator of a revolutionary therapeutic. My function is much more modest; it is to raise some questions that may lead to profitable argument, questions which have excited great attention in psychological circles in France, Germany and America, and yet which have scarcely stirred a ripple of interest amongst ourselves. Men of international reputation assure us that they have applied with singular success these psychical methods in the treatment of certain forms of mental disturbance, and our excellent English textbooks in psychiatry either ignore the whole subject or put the reader off with a few superficial remarks that afford no practical insight into the matter. Such men as Freud, Jung and Prince may publish their refined and delicate analyses and we continue to repeat our well-worn formulas, never dreaming for a moment that these men may have something to teach us. Their theories may be right or wrong, but their therapeutic successes are not open to question. Surely here, in Ireland, amid a population peculiarly amenable to psychic influence, it is for us of especial moment to learn how such influence may be exercised and by what methods it can be brought to bear upon disordered personalities. My purpose, then, is to make clear what these methods are, to indicate their strength and their weakness, and to show their bearing on mental hygiene.