Serum therapy in the form in which it finds application in the treatment of diphtheria patients is an antitoxic or detoxicating curative method. It is based on the view, held by Löffler in Germany and by Roux in France, that the parasites causing diphtheria, the Löffler diphtheria bacilli, do not themselves cause diphtheria, but that they produce poisons which cause the disease to develop. With...