Abstract
The guinea pig infected with virulent tubercle bacilli develops much more anti-sheep amboceptor than do controls when given like amounts of sheep red blood corpuscles. The curve of antibody production in the guinea pig when treated with sheep red blood corpuscles shows a departure from curves previously determined in other animals. These facts were ascertained as part of an effort to learn mbre of the functional nature of the inheritable factors controlling natural resistance to disease. The nature of some of the problems involved is outlined, and the limited bearing of the experiments on these is discussed.