When the words phthisis and consumption were employed by Hippocrates, they designated exactly what the physician saw when he made the diagnosis. Later, when it was known that the disease usually exists for a long time before the body visibly wastes away, the word tuberculosis was coined. This word is all inclusive and in the light of recent observations may be applied to the disease from the time the neutrophils first phagocytose tubercle bacilli until the death of the host results. Until recently physicians were unwilling to make a diagnosis of tuberculosis until clinical manifestations were present, such as symptoms and abnormal physical signs, with roentgen findings, or until the laboratory methods revealed tubercle bacilli in the sputum or pleural effusion or elsewhere. Although diagnoses based on these criteria were made far earlier in the course than those in the time of Hippocrates and for many centuries thereafter, they usually