Tuberculous infections are extremely common, much commoner even than their high mortality reveals. After long and critical discussion with a number of persistent denials, it is now generally conceded by authorities in the disease that the old maxim "after all, all of us are a little tuberculous" is substantially correct. Very few human beings entirely escape infection from the tubercle bacillus at some time in life. The great majority of us never become aware of the presence of the disease and succeed in conquering it, though the traces of it may be found subsequently in our bodies. Careful autopsies reveal, however, that very few even of those who did not die directly from tuberculosis fail to show tuberculous lesions, usually healed and well shut off from the healthy tissues, in their bodies. One in eight of those who become infected have not the resistive vitality to throw off the disease or the courage to face it and take such precautions as will prevent its advance. All those, however, who give themselves any reasonable chance for the development of resistance survive the disease though they remain always liable to attack from it subsequently if they should run down in health and strength. {169} Heredity, which used to be supposed to play so important a rôle in the affection, is now known to have almost nothing to do with the spread of the disease. Family tendencies are probably represented by nothing more than a proneness to underweight which makes one more liable to infection, and this is due as a rule to family habits in the matter of undernourishment from ill-advised consumption of food. Probably a certain lack of courage to face the disease boldly and do what is necessary to develop bodily resistance against it may also be an hereditary family trait, but environment means ever so much more than heredity. There is a well known expression current among those who have had most experience in the treatment of patients suffering from tuberculosis that "tuberculosis takes only the quitters", that is to say that only those succumb to consumption who have not the strength of will to face the issue bravely and without discouragement to push through with the measures necessary for the treatment of their disease. In a word it is only those who lack the firmness of purpose to persist in the mode of life outlined for them who eventually die from their affection of the {170} lungs. No specific remedy has been found that gives any promise of being helpful, much less of affording assured recovery, though a great many have been tried and not a few are still in hopeful use. Recent experience has only served to emphasize the fact that the one thing absolutely indispensable for any successful treatment of tuberculosis of the lungs is that the patient should regain weight and strength and with them resistive vitality so as to be able to overcome the disease and get better.