Show colds colda headed off air has been used very successfully as a preventive of colls collo and lung troubles by the students ol of lite die chemistry division of the s ity of MIsso missouri url A small ol of chlorine Is mixed with the air and this Is sont sent into file lie room through special ventilators rs hv by this means the air Is purified as it enters alie ahe room und and the use of air outlets makes it possible for the nir air to be changed ns as often na as it Is thought necessary A decided tin pro provement has been noticed so BO far as the prevalence of colds Is concerned among the students |