408 PROTOPLASM 



therefore, cannot use unfiltered ultraviolet light if their results 

 are to be of significance. Results may be negative simply 

 because one wave length is having an effect in one direction and 

 another wave length is producing an effect in the opposite 

 direction. 



Studies of the effect of ultraviolet light on protoplasm are as 

 yet in their infancy, but something has already been accom- 

 plished. Lepeschkin, in continuing his work on the effect of 

 light on protoplasm wherein he found that visible light decreases 

 the stability of protoplasm and its resistance to temperature, 

 to mechanical injury, and to alcohol, observed that short expo- 

 sures of ultraviolet rays increase the stability of protoplasm, 

 while long or heavy exposures decrease it. 



X Rays. — Beyond the ultraviolet lie the shorter X rays. They 

 represent one of the most important forms of radiation in 

 therapy. They are used extensively in the treatment and 

 killing of organs and growths (cancer). By centering a beam of X 

 rays on an organ within the body and irradiating for a short time, 

 then rotating the body so that the organ to be treated or killed 

 always receives the rays while the surrounding tissue is subjected 

 to the rays but once, the organ becomes heavily radiated and may 

 be killed without intermediate cells suffering from the treatment. 



The therapeutic value of X rays, sunlight (ultraviolet), and 

 gamma rays lies in their ability to strip electrons from the atoms 

 upon which they fall — atoms such as those of sodium and 

 calcium, which, as a result of their electronic loss, gain new 

 combining powers. They are, therefore, able to enter into 

 new chemical combinations and form new compounds which 

 get into the blood stream and there act as curative agents. It 

 is an encouraging sign in the progress of science when so little 

 understood a process as the therapeutic value of radiation 

 can be interpreted in terms of so fundamental a physical theory 

 as that of atomic structure. 



X rays, more than ultraviolet, have their dangers from exces- 

 sive or misdirected use. 



The effect of X rays on protoplasm is in the early stages of 

 experimentation. Nadson and Rocklin find the first noticeable 

 effect to be an acceleration of streaming. Stimulation is followed 

 by depression. In yeast, there is an increase in the number of 

 fat droplets. Permeability changes also occur. The latter 



