The sharpest controversy is now focused on three problems in tuberculosis:
Is a negative or a positive tuberculin reaction more desirable?
Are the lesions developing in recently exposed young adults of "primary" or "reinfection" type?
From what point should one date the clinical incipience of tuberculosis?
With regard to these three questions, it is in the first place to be emphasized that they have arisen only recently and are the result of the epidemiologic conditions which have developed in our midst within the last generation.
Previously in most communities it was true for the vast majority of persons that they become positive tuberculin reactors by the time they reached adolescence; that, while primary infections occurred in childhood, progressive pulmonary tuberculosis developed mostly only in early adult age; that a latent interval of a decade usually elapsed between the time of the infections and the evidence of progressive