PLATE 1 



EFP'ECTS OF ULTRA-VIOLKT LIGHT 

 I 



EXPLANATION OF FIGURES 



1 Tliis scalr shows ultra-violet light contraction. It was one of an inverted 

 pair. 



2 One of the scales exposctl to ultra-violet light with (hat in figure 1 but 

 turned face-up. 



3 An unexposed control scale in 0.1 M. NaCl. 



4 One of the inverted scales showing recovery from ultra-violet light con- 

 traction 10 minutes after a 10-minute exposure. 



5 A scale showing complete recovery from ultra-violet light contraction 20 

 minutes after a 10-minute exposure. 



6 An unexposed scale in 0.1 M. NaCl. 



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