In many cases reactions must be attributed to individual intolerance for the drug. Undoubtedly, when a number of patients receive arsphenamin of the same lot by the same method of administration and only one or two show reactions, it is safe to assume that they are due to an idiosyncrasy.
There are also numerous cases in which the technic of the intravenous administration is responsible for serious reactions. Schamberg, Kolmer and Raiziss1 were the first to suggest that the cause of reactions can be attributed to impurities in the drug. "We are firmly convinced that the complex symptoms characterized by flushing, edema, etc., are due to the drug administered and not to extraneous causes." This is the graphic formula of arsphenamin:
The analyses for arsenic, nitrogen and other elements in most of the samples correspond to the above