Filtered Ultraviolet Radiation (Wood's Light) 275 



the edge of the glass. Around the edge ol the cloth is sewed a hem, in which 

 is placed an elastic drawstring. The cloth is then placed around the hood 

 of an ultraviolet lamp, and the drawstring is tightened until the fit is close 

 enough to exclude visible rays. The ends of the draw string ma) then be 

 sewed together, so that later the cloth may be quickly Stretched around 

 the hood of the lamp. In order to protect the glass filter from breakage, a 

 wooden frame may be glued to its edges. When lamps that produce con- 

 siderable heat are used, the cloth may not wear well because of its rubber 

 content. This objection does not arise when a better make of lamp is used. 

 The approximate cost of the attachment (with 6/2 in. filter) is $5.50. There 

 have been developed several units in which the filter is in the glass sur- 

 rounding the filament. Such portable lamps may be purchased from the 

 Westinghouse Electric and Manufacturing Company, Long Island City, 

 X. Y.. or from the Strobelite Company, New York City. We have found 

 both types to lie satisfactory for our work. 



4. USE OF THE RAYS 



In dermatologic practice the important fluorescent effects noted when 

 the filtered ultraviolet rays are used as a sole source of radiation may help 

 to detect pathologic conditions and to differentiate fungi in cultures. 



1. The value of the rays in cases of tinea capitis cannot be overstressed; 

 they aid not only in establishing a diagnosis but in following the progress 

 of the disease and in determining when cure has taken place. Furthermore, 

 in certain cases of infection with M. audouini when regrowth of hair is 

 considerable, the diagnosis of tinea capitis may not be suspected. In such 

 instances, when only scaling of the scalp may be noted, fluorescence of 

 the affected hairs is characteristic. If the disease is unrecognized, children 

 with this condition constitute a serious menace, as they are potential foci 

 for dissemination to other children. 



(a) In all types of infection due to Microsporum, except with M. fer- 

 rugineum, the affected hairs appear as luminous, short, yellowish-green 

 stubs. 



(b) In infections with Trichophyton endothrix the affected hairs are 

 dull and bluish. This observation is not in agreement with that of David- 

 son and Gregory, who stated that hairs infected with A. schoenleini fluo- 

 resce like those infected with Microsporum and that all the hairs infected 

 with Trichophyton do not fluoresce. It is true that hairs present in follicles 

 invaded by Trichophyton ectothrix do not fluoresce, but in our experience 

 in every case of infection with T. violaceum (endothrix) fluorescence of 

 the infected hairs was a useful observation. 



