At the turn of the twentieth century nearly 40 percent of urban populations in America died from major infectious diseases, many of which, like tuberculosis and typhoid fever, were incubated in congested housing conditions and contaminated water and food supplies. This correlation between overcrowding and health is made vivid in James Ford's caption beneath Jessie Tarbox Beals's photograph of the dank interior of a Newark tenement: "Three successive families living in this room have suffered from tuberculosis." Activists enlisted the human cost and the widespread fear of such deadly scourges in their campaigns to advance municipal housing and sanitation regulations; and they appealed on moral grounds. The control of milk-borne diseases, which included tuberculosis, for example, became a particular focus for urban public health reformers in part because of the importance of milk in the diet of "innocent children." The milk blanks from the town of Brookline, Massachusetts, illustrate how government regulations were enforced through laboratory analysis and permitting to ensure purity. Reformers including Ford also assumed a righteous stance in their crusades against overcrowded housing conditions, listing as prime among its potential dangers "the moral contagion... where in congested districts the social vices are easily discovered by the inquisitive, and may become matters of current morbid discussion or of experience."