Intramuscular bismuth therapy against syphilis ranges between the extreme of very slow absorption from the oil suspensions of compounds that dissolve very slowly in water, such as the subsalicylate, and the other extreme of the relatively rapid absorption from watery solutions. With the watery solutions an effective concentration of bismuth in the blood and tissues is reached in a short time, perhaps after a single injection. As the excretion of these solutions is also more rapid, their action is relatively brief and they must be administered more frequently. The oil suspensions have the advantage that they may be given at longer intervals. They tend to become cumulative when injected once a week. The effective concentration in the blood is therefore approached more slowly, probably only after from two to four weeks. These extremes are bridged by a variety of bismuth preparations, such as oil suspensions of more soluble compounds and the oil-soluble compounds. It occurred to us that it might be advantageous to approach the problem in a different way, namely by an interlocking sequence of watery solutions and salicylate suspensions, adjusted to build up an effective concentration rapidly by use of the watery solution and a continuous concentration meanwhile by use of the salicylate suspension, the injections of the watery