SINCE Sakel (I) introduced treatment by insulin a vast literature has emerged from all countries. This was admirably reviewed by Wilson and Rees-Thomas (2) in 1938, so that consideration is given here to publicalions since that date. Even so, it has not been possible to incorporate all the publications, but a sufficient number has been drawn upon to present the essential position as it is to-day. Whatever may be the final judgment on the efficacy of insulin therapy, there is no doubt that its introduction has been an enormous stimulus to therapeutic endeavours. Its main interest has been to the psychiatrist, but the problems presented have attracted the atten tion and interest of workers in other branches of medicine. Ebaugh (3) has summarized this interest thus : “The physiologist has become interested in the mechanism which produces the coma; the biochemist is interested in studying the various chemical changes which take place during therapy; the neuro pathologist is concerned with the pathologic changes that occur during and after the therapy; the internist is concerned with the problem of ‘punishment’ that the body is furced to absorb during the actual treatment; the psychologist is absorbed in following the psychological changes which take place under the influence of the treatment; the orthopaedist desires to know the type of fractures occurring during insulin, electrical and metrazol therapy; the neurologist studies the influence of these therapies upon the organic nervous system; and the psychiatrist attempts to explain the manner in which the psychosis is altered.”