Two of the most potent predisposing causes of consumption are want and overwork. This is why tuberculosis is so largely a disease of the poor. Want means not only bad nutrition of the body but bad housing. When the body does not get enough nutrition it becomes good soil for the tubercle bacillus. Bad nutrition may be due to insufficient food or insufficient fresh air. The poor are apt to lack both food and fresh air, partly because they cannot afford to buy them and partly on account of ignorance. Much of the food which poor people buy contains little nutrition and they, moreover, do not know how to prepare it so as to make it digestible. Poor people should learn to buy milk and eggs rather than pastry and sweets. They can really get more nutrition for their money in milk and eggs than they can get in any other food. Fresh air is at the command of everyone and there can scarcely be any excuse for anyone not having enough of it. In a sense, however, we are compelled to buy fresh air indoors because we need houses into which fresh air can be admitted. Houses are not built in a way which makes it easy to get fresh air into them, but with better understanding of these matters all houses will be built so that the inhabitants of them can sleep in the open air. However humble the dwelling the inhabitant of it should insist upon having the sleeping room so ventilated that he is practically in the open air. As to overwork this is not always within the control of the individual. Working people, however, should realize that excessive fatigue greatly predisposes to consumption, and when they have to work hard should take rest on every possible occasion. When people have tuberculosis they should reduce their work to within the limits of fatigue, as otherwise they are bound to go under. Of all predisposing causes to the disease, overwork is probably the most potent.