In spite of extensive and intensive studies which have been made of the Wassermann reaction since its introduction in 1906\p=m-\orperhaps, because of them\p=m-\thetest might almost be said, at the present time, to be undergoing its "trial by ordeal." It is to be regretted that much of the criticism of the reaction as concerned with its specificity and reliability has come from clinicians not always, perhaps, fully qualified to express a dogmatic opinion, and in this connection it must be noted that the mere possession of expert and skilled knowledge of genito-urinary diagnosis and treatment does not always predicate an equally expert and skilled familiarity with the finer details of complement-fixation technic, particularly with regard to the numerous important factors which may be responsible for variations in reports and results. It seems obvious that it is the duty of the clinician to acquaint himself with the details of complement-fixation technic to such a degree as will enable him to interpret properly the reports received. Errors there have been, it is true, and for many the true respon¬