MIRACLES OF SCIENCE 



there are radiations of a more familiar type that have 

 recently been shown to influence living tissues in a 

 way no less interesting. 



It has long been known that the rays of sunlight 

 furnish, the all-essential stimuli that make possible 

 the work of the vegetable cell in performing the mir- 

 acles of transforming inorganic into living matter. 

 It now appears that the same light also contains rays 

 that are directly inimical to the life of lower vege- 

 table organisms. The fact was first demonstrated in 

 connection with the treatment of the superficial ma- 

 lignant growth known as lupus, which is due to the 

 presence of the tubercle bacillus, growing in a local- 

 ized colony, and not tending to spread inordinately, 

 but proving so tenacious of its hold upon the territory 

 already invaded that it was formerly regarded as al- 

 most ineradicable even with the use of the knife. 



About the year 1895, a Danish physician, Dr. N. 

 R. Finsen, developed a treatment for lupus which con- 

 sists in exposing the diseased tissue to a concentrated 

 beam of light rich in ultra violet rays ; that is to say, 

 in the ethereal vibrations lying just beyond the violet 

 end of the spectrum, and thus composed of light 

 waves that are shorter than the shortest visible ones. 



Dr. Finsen demonstrated that these short waves of 

 light destroy bacteria. He was able with their aid 

 to kill the tubercle bacilli in the diseased tissues and 

 thus to cure a very large proportion of cases of lupus. 

 Ultra violet light thus used came to be known as 

 the "Finsen ray." 



The germicidal effect of ultra-violet light has since 

 been everywhere recognized. The treatment of tu- 



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