The experiment of consistence of Bayer 205 in blood and cerebrospinal fluid

1. By means of the Wormall test, estimations were made on the concentration of Bayer 205 found in the plasma of African sleeping-sickness patients who had been treated with this compound. Huge variations were found between one individual and another.

2. In persons who had received a single intravenous dose of 1 gramme, the average concentration was about 3 mg. per 100 ml. after two days, and about 0•6 mg. after nine days.

3. In persons who received courses of four doses, the concentrations reached depended more upon the individual peculiarities of the patient than upon the spacing of the doses. One day after the fourth dose, the concentration in the blood ranged from 4 to 15 mg. per 100 ml. After courses of five or six doses, Bayer 205 could be demonstrated in the blood of some patients up to eight or nine months later; in other patients it had disappeared within five months.

4. Estimations were made on the cerebrospinal fluid. Although Bayer 205 was present in the plasma of these patients in considerable concentrations, it did not penetrate into the fluid in sufficient amounts to be detected by the chemical test.

5. Since individuals vary so greatly in their tendency to retain Bayer 205 in their blood, it is strongly recommended that the treatment of European cases of sleeping-sickness be controlled by chemical estimations.