The common cold has been the subject of intensive study for a number of years. In 1923 Frost and his co-workers in the United States Public Health Service commenced a study of the incidence of colds that extended over ten years, and numerous statistical studies emanated from the Public Health Service, prepared by Brundage, Britten and others. All these studies showed a fair degree of unanimity, allowance being made for the fact that the term "common cold" is descriptive rather than scientifically accurate. It is difficult, if not impossible, at times to determine when a cold is not a cold, and the term itself, in the popular usage, is mingled with other terms, such as grip, influenza, nasal infection, cough and sinus trouble so as to constitute a statistical headache for any one who strives to be accurate.
In recent years attention has been focused on sick absenteeism among industrial