EFFECTS OF RADIANT ENERGY ON THE EYE. 



645 



Determination of the Limit of Abiotic Action with Respect 

 TO Wave Length. 



The critical wave length at which abiotic action on tissue cells 

 ceases has not hitherto been accurately determined. For bacteria 

 it has been found to be about wave length 295 mm- In this connection 

 the observations of Henri ^^^ and his wife are important. These 

 observers determined the coefficient of absorption of egg albumin for 

 various wave lengths and found that the results corresponded closely 



q: 



2o0 



Wave length 



SOOfJifl 



Figure 3. Variation of abiotic power with wave length. (Plotted from 

 Henri's results). 



with the time value'of^bactericidal action for the wave lengths tested. 

 The curve of absorption plotted from their results (Fig. 3) shows 

 that the abiotic action of light with reference to wave length may be 

 expected to diminish rapidly and terminate at about 310 mm- The 

 experiments of Widmark, Hess, and Martin, in which the lens epi- 



