At the beginning of the year 1912, the nurses of the Tuberculosis Division of Baltimore had on their visiting lists about 2800 patients. Of these 2020 were positively diagnosed, and had been under supervision for over three months. Undiagnosed cases, and positive ones who had been under supervision less than three months were excluded. These 2020 cases were then classified according to their willingness or ability to follow instructions, the groups being: Fairly Careful, Careless, and Grossly Careless. We purposely omitted a “Careful” class, since adequate carefulness would imply a condition in which there was absolutely no danger, a condition hardly possible with this disease. In Fairly Careful we included all those patients who really tried to follow advice, doing so to the best of their ability. Careless included those who tried intermittently, or who were badly hampered by circumstances. Grossly Careless speaks for itself. The results of this analysis are here given: Patients visited over three months 194 Fairly Careful 98, or 50.5% Careless 75, or 38.65% Grossly Careless 21, or 10.82% Patients visited over six months 346 Fairly Careful 171, or 49.43% Careless 151, or 43.64% Grossly Careless 24, or 6.84% Patients visited over one year 623 Fairly Careful 300, or 48.15% Careless 267, or 42.85% Grossly Careless 56, or 8.98% Patients visited over two years 857 Fairly Careful 443, or 51.69% Careless 339, or 39.55% Grossly Careless 75, or 8.75% Total Number of Patients 2020 Fairly Careful 1012, or 50.09% Careless 832, or 41.13% Grossly Careless 176, or 8%