The study of two cases of hyperthyroid psychoses demonstrates that the organically determined anxiety appears in the psyche as symptoms or manifestations involving the destructive instinct. In these cases it is impossible to say whether anxiety or aggression is the primary state; both appear together. An increase in heterosexual libido in both cases bound the aggression and anxiety, so that libido appeared as an antagonist of the aggression. Concerning the principles involved in hyperthyroid psychoses, it seems to be a new point that the anxiety and aggression produced by a thyrotoxicosis are elaborated by the psychic apparatus to increase the severity of the superego and give rise to a clinical picture of depression. The mental processes follow the same course as those which we have learned

from the psychoanalysis of comparable neurotic states. Thus our knowledge of the organic processes at work here throws light upon the analytic material.