The choice of the preparation of arsphenamine to be used in syphilis, and the most judicious dosage to employ, have had much consideration since the introduction of the remedy by Ehrlich. Schamberg1 advocates the use of neoarsphenamine as against arsphenamine. Despite the fact that, dose for dose, arsphenamine is more therapeutically active than neoarsphenamine, the latter is definitely preferred throughout the world and is being employed in Europe and in America about ten times as frequently as the former. This is particularly true in Germany, where scarcely any specialist of prominence prefers arsphenamine; in the United States, arsphenamine is still preferred by a small group of prominent dermatologists.
As a result of the simplicity of clinical preparation of neoarsphenamine for use, the more concentrated character of the solution and its milder nature, a good neoarsphenamine is less apt in general to give rise to complications. The chief disadvantage of