LABORATORY AND TEACHING DEVICES MADE FROM PLASTER OF PARIS

A method has been described whereby models of septic tanks for teaching public health and oncometers for physiological demonstration and research may be constructed by employing a wire frame and covering it with plaster of Paris These models should prove especially useful to teachers in rural and suburban communities and to extension workers whose task it is to keep a vast number of our population informed as to the best measures of protecting their health These models may be rendered impervious to air and water by means of paraffin, varnish or brushing lacquer.