RADIATION AND THE STUDY OF MUTATION IN ANIMALS 1237 



ucts. On such a basis it must follow that the ultimate effects, except 

 where secondary reactions bear other than a linear relation to the primary 

 products, must be directly proportional to the quantity of radiation; 

 moreover the simplest expectation would be that, with high-frequency 

 radiation, variations in wave-length should make no difference, except- 



Table 19. — A Comparison of Several Groups of Data on the Relation between 

 X-RAY Dosage and Percentage of Lethal Mutations in the A' -chromosome 



OF Drosophila melanogaster 



