1. Cholesterol, administered intraperitoneally, in these experiments definitely prolonged the lives of tuberculous guinea pigs when the infection was of an acute type produced by inoculation with a small dose of very virulent human type organisms.
2. Intraperitoneally administered cholesterol did not definitely prolong the lives of tuberculous guinea pigs when the infection was of the chronic type produced by the injection of a small dose of human type tubercle bacilli of relatively low virulence, or when the infection was more acute owing to the injection of a large dose of organisms of low virulence. It had no beneficial effect on an acute type of infection produced by the bovine type organism.
3. Cholesteryl chloride, cholesteryl toluide, cholesteryl anilide, sodium cholesterol sulfate, and quinine cholesterylate did not significantly prolong the lives of tuberculous guinea pigs.
4. Sodium cholesterylate, in optimal dosage, definitely prolonged the lives of tuberculous guinea pigs.
5. There was a significant shortening in the duration of life of tuberculous guinea pigs subjected to the trauma of intraperitoneal injection and repeated handling as compared with tuberculous guinea pigs that were not handled or traumatized by intraperitoneal injections.