In the first place, tuberculosis is largely a disease of the poor—of those on or below the poverty line. We must further realize that there are two sorts of poor people—not only those financially handicapped and so unable to control their environment, but those who are mentally and morally poor, and lack intelligence, will power, and self-control. The poor, from whatever cause, form a class whose environment is difficult to alter. And we must further realize that these patients are surrounded in their homes by people of their own kind—their families and friends—who are also poor. It is this fact which makes the task so difficult, and makes the prevention and cure of a preventable and curable disease a matter of the utmost complexity. People of this sort, however, constitute almost the entire problem—otherwise the situation would be so simple that the word problem would not apply. This is why “cure” is not the solution of the matter. Too few people are cured, in comparison to the numbers annually infected, to make any impression on a disease of such wide prevalence. The sanatorium, valuable as it may be for certain cases, is of little use to those who relapse upon return to an environment they will not or cannot control. This is also why mere instruction in preventive measures, unaccompanied by effective isolation, is barren of results. Experience has taught us the unsatisfactory nature of so-called cures, and the futility of that prevention which allows the distributor of tuberculosis to remain at large in the community and heedless of his obligations. Hence we must look to segregation as the only reasonable course to pursue. If segregation can be obtained in the home, well and good. If not, then we must look to the institution to provide the proper care. This segregation, most of it voluntary, some of it enforced, is the only way to do preventive work on a scale large enough to count. To this end, we need dispensaries where the disease may be recognized and diagnosed, nurses to visit the patients in their homes, and hospitals for advanced cases, the function of the nurse being to teach patients and their families the necessity for segregating the former in hospitals.