Poole — On the Distribution of Activity in Radium Therapy. 471 



Three curves are shown for card and leather, whose absorption per unit 

 mass is almost identical. In curve A the activity of the bare tube is taken 

 as 100, and each unit on the horizontal axis represents 1 gram per sq. cm. 



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Fig. 2. 



[i.e. 1 cm. of animal tissue approximately]. The initial absorption of /3 rays 

 is better shown on curve B, in which the horizontal scale is 10 times as open, 

 i.e. for this particular curve each unit represents 01 gram per sq. em. [1 mm 



