Whilst the disease cannot be inherited a predisposition to it may be inherited. Some families undoubtedly are more prone to tuberculosis than others. This is not only true of families but of races. The negro race and the Indian race are very much more susceptible to consumption than the white races. Some white races are more susceptible than others. Moreover, in some people the disease runs a much more violent course than in others and is much more likely to prove fatal. Some races get the disease readily but have it in an exceedingly mild form so that it rarely proves fatal. Predisposition is usually divided into three kinds, individual, family and racial. The individual predisposition is often brought about by improper living and by excess in eating and drinking. Family predisposition may be due to inherited tendencies or to environment under which the family lives. Racial predisposition appears to hinge largely upon the length of time to which the race has been exposed to the disease and the resistance which the race has built up against the disease. "We do not know yet exactly what constitutes predisposition and why it exists but there is probably the same fundamental law underlying it which governs the usefulness of soil for certain crops. We all know that some crops do better on some soils than others and that if we continue to plant the same crops on the same soil, year in and year out, it is only a question of time until the soil will no longer produce the crop. Future observations and study will no doubt give us more light upon this subject.