THE DEGREE OF INFECTION IN RELATION TO THE PARASITICIDAL ACTIVITY OF CHEMOTHERAPEUTIC COMPOUNDS

¹ From the Research Institute of Cutaneous Medicine of Philadelphia, Pennsylvania

1. Arsphenamin and neoarsphenamin were more effective when given to rabbits three to four weeks after intratesticular inoculation with Spirochaeta pallida and when orchitis had developed, than when given immediately after inoculation.

2. Arsphenamin, neoarsphenamin, atoxyl, treparsol and other trypanocidal agents were more effective when given to rats eighteen to twenty-four hours after intraperitoneal inoculation with Tr. equiperdum than when given immediately or within twelve hours after inoculation.

3. In other words these spirocheticidal and trypanocidal agents were more effective in the presence of early light infections than when given for abortive treatment immediately after inoculation.

4. When administered after the infections had been given a longer start with a numerically heavier infection, the minimal curative doses were also larger.

5. It would appear that the same principle applies to experimental streptococcus infections, that is, that smaller amounts of chemical agents are effective when given after the infection has become established than required if administered immediately after inoculation.