326 



RECOVERY PROM FLUORITE RAYS 



mass reactions. I have plotted for comparison the curve for the 

 monomolecular reaction formula 



X = Xoe-^^ 



when K equals 0.0473, Xo equals the per cent of cytolysis when the 

 time interval is zero, and X the per cent of cytolysis after the inter- 

 vals of time, t. The calculated number of cytolized organisms is 

 given in Table I. It will be seen that the observed percentages fall 

 very close to the theoretical curve. 



When a number of organisms are exposed to fluorite rays they are 

 not all killed by the same length of exposure, but, owing to individual 

 idiosyncrasies and unknown variations in the experimental conditions, 



TABLE II. 



Relation between the Frequency of Cytolysis and Length of Exposure to 

 Fluorite Rays. 



some organisms are cytolized by a shorter exposure than others. 

 These differences in susceptibility to the influence of rays may affect 

 the shape of the recovery curve. The nature of the effect will depend 

 entirely upon the relative frequency of cytolysis for various exposure 

 times. 



The results of some experiments upon the relation between the 

 length of exposure and the frequency of cytolysis are given in Table 

 II and are represented graphically in Fig. 2. It was not possible in 

 these experiments to duphcate all of the conditions such as light in- 

 tensity, etc., of the recovery experiments; thus a 4 second exposure 

 did not cause any of the organisms to cytolize. The experimental 

 results are, however, significant in connection with the recovery ex- 



