218 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1942 



illation of cases of severe wound infection which was frequently fatal. 

 In operating rooms where ultraviolet light is properly installed, the 

 greatest amount of air in such rooms comes under the continuous 

 direct action of the rays. Sterilized instruments and other equip- 

 ment, dressings, bandages, and other materials can be kept sterile 

 by continuous ultraviolet irradiation of the air in contact with such 

 materials. This method is used in hospitals, in the private offices of 

 physicians and dentists, by barbers and beauticians, and others. 



In nurseries, in cubicles, in children's wards, better air sanitation 

 and reduced risk of cross infections have resulted from the use of 

 ultraviolet light. In many instances, the ultraviolet rays have been 

 properly placed across the entrance to each cubicle or small room. 

 Such a barrier or curtain of ultraviolet light has aided in preventing 

 the spread of air-borne bacteria. Properly engineered installations 

 will mean normal and comfortable air currents free of disease-pro- 

 ducing bacteria, which will pass through doorways or corridors or 

 from ward to ward, and will eliminate the danger of cross infection 

 or of transporting infectious organisms from one patient to another. 



Not so many years ago, fumigation was a commonly practiced 

 procedure. Rooms and other quarters which had been occupied by 

 patients with contagious diseases were treated with formaldehyde 

 and other suitable gases, but this method as a sanitary aid was dis- 

 continued because of its inefficacy. Other techniques for the dis- 

 infection of such environments have been used, but all of them are 

 costly or time consuming, or there are other reasons for seeking a 

 more satisfactory procedure. Ultraviolet irradiation is being used in 

 various contagious-disease hospitals as a valuable aid in the prepara- 

 tion of hospital rooms, not only to reduce the length of time of prep- 

 aration and thereby increase the length of time of occupancy, but 

 also to prepare rooms with an atmosphere low in the content of bac- 

 teria and certainly lower than was previously possible. 



Hospitals are experimenting with ultraviolet irradiation in 

 quarters other than mentioned above, as in kitchens, on conveyors 

 holding food trays, in corridors, waiting rooms, clinic rooms, dis- 

 pensaries, examining rooms, incubator rooms, nurseries, isolation 

 wards, etc. The experience of the management in the foregoing 

 will make available in the near future more data concerning this 

 valuable sanitary safeguard. There are some physicians and dentists 

 who are using ultraviolet irradiation in the waiting rooms of their 

 private offices. Solaria, children's homes, and other institutions also 

 are utilizing this new tool. 



Air-conditioning systems. — Modern air-conditioning systems pro- 

 vide air which is at the proper humidity and desired temperature, is 

 practically free of dust and dirt, and is low in its bacterial content. 

 In these systems there usually is a recirculation of the air in the 



