Mrs. Richards had not devoted herself long to the study of her favorite science before she resolved to apply the knowledge thus gained to the problems of daily life. She saw, among other things, the necessity of a complete reform in domestic economy, and resolutely set to work to have her views adopted and put in practice. She was, in consequence, one of the first leaders of the crusade in behalf of pure food, and her lectures and books on this all-important subject contributed greatly toward the diffusion of exact knowledge respecting the dangers lurking in unwholesome food. She was likewise one of the first to apply the science of chemistry to an exhaustive study of the science of nutrition--to the study of food and the proper preparation of food materials. In this she was eminently successful, and was able to achieve for home economics what the illustrious Liebig had many years before accomplished for agricultural chemistry--put it on a firm and lasting basis. To her the kitchen was the center and source of political economy. The facts of science, indeed, were to Mrs. Richards more than mere uncorrelated facts. They are potential agencies of service, and their chief value consists in their enabling us to control our environment in such wise as to secure the maximum of physical well being. Hence her constant insistence on personal cleanliness, on the cleanliness of food, of the house we live in, and, above all, of the kitchen. Hence, also, her preaching, in season and out of season, on the necessity of pure air, pure water and abundance of vitalizing sunshine. We cannot, then, wonder that sanitary chemistry eventually became the life work of Mrs. Richards, and that, when the course of sanitary engineering was inaugurated in the Institute of Technology--the first course of its kind in the world--she became an important agent in its development and contributed immensely to its popularity and prestige. She held the position of instructor of sanitary chemistry in the institute for twenty-seven years. During this time she trained a large number of young men in her chosen specialty, and these, after graduating, engaged in similar work in various parts of the New and the Old World. The branch of sanitary chemistry to which Mrs. Richards devoted most attention was air, water and sewage analysis. In this she was a recognized expert, and her advice and services were sought in all parts of the country. During the last three years of her life she acted, according to her own testimony, as general sanitary adviser to no fewer than two score corporations and schools. In addition to this she was also during this brief period consulted on the subject of foods by nearly two hundred educational and other institutions.